Been doing axles for 50 years, I never claim to know it all and crazy how you can still learn something you didn't know or at my age forgot. Lol.. Great job on the video.
@@maxnovakovics2568 any more these days, it seems like Teraflex has got it figured out and would have whatever you need. Plus, a lot more knowledge than me. good luck 👍
I knew absolutely nothing about gear ratios before this video. I feel like I need to swap out my rear-end now thanks to this guy! Amazingly detailed information.
Wow! I have discalculia, so I tend to shy away from math, but this lesson has me COMPLETELY understanding it and the formula is memorized, which is odd for me. I just bought a Dakota 4x4 that the guy put a rear end out of the Dakota suburban, which is very high, and you can't go in 4 wheel on pavement or hard surfaces, as it fights itself. Gotta find a stock gearset.
If you are wanting to learn about gear ratios then THIS is your video to watch.. It is pretty simple when the person explaining it to you really knows what the heck he is talking about.. Most excellent video dude..
Thanks for posting this tutorial. I have a 1989 F-350 7.3 L diesel backed by the three speed C-6 transmission. It had 3.55:1 gears and 215/85r16 tires from the factory. The previous owner said he put in 4.10:1 with 225/70r19.5. The new tires and gears both are taller and the engine screams at 3,000 RPM at only 65 MPH. I was going to go back to factory 3.55:1 but after doing the math you explained, I should go to a 3.73:1. Thanks! I hope it gets my RPM's down to around 2,000 RPM's at 65 MPH....or 2200 at 75 MPH. For those that care, I'll post the result of my change.
I didn't plan to watch this entire video.... But after listening in for about a minute... I was suddenly captivated. Your explanation was very thorough and elementary in lecture... So easy to understand! Fantastic video! Thank you for all the knowledge!!
As a scientist I have to tell you your videos are great. Very detailed and well explained. Your thoroughness makes these vids extremely helpful. Sometimes a person thinks they need to know one thing but what they really need to know is something different that they haven't considered or were unaware of and your videos can point those things out. Hope you keep making them this well.
@John Edwards I would think that is self explanatory since everyone knows how thorough and detailed scientists are in their work and explanations just like he was here. It is a fair comparison and a good compliment to his efforts. To suggest that is arrogant says more about you and how you feel about your own experience or education. If he was giving legal advice/explanations on something and a person said as a lawyer myself I have to tell you that you did a great job you'd be an idiot to bash that person. It's the same thing. Compliments from peers in an area are always appreciated by those that receive them.
Krushim yep arrogant as fuck...if you're so thorough why have you edited your comment and still made a typo? you are not more important than anyone else.
You're an excellent explainer. I'm a college graduate but have very little mechanical knowledge, and I believe I understand about 90 percent of what you explained in this video. Thank you very much!
This was very helpful. Thanks. I do want to ask if you can do a video class on differential rebuild/setup. Start to finish. Measuring for all the shims, back lash, preload, what tools, etc. Since you are a great teacher and most of us can’t go to a school for this training it would be a GREAT service to your viewers. I know it would be long and hard but I believe in you, you can do it. Nobody else has, I’ve looked. Again THANKS.
Yes, that would be amazing. I can't afford much but I'd pay to learn by watching the video. Edit: he has a Patreon page for donations. We gotta help this guy out for all his useful information
another rule of thumb I was told years ago...and it too is a 'guideline' to compare to. I would still use your calculation too. But, it goes like this: for each inch in diameter you increase, it's like subtracting .1 from your rear end ratio. So for tetnas, when you jumped 4" in diameter, you needed to come up with an extra .4 for your 3.07s...so 3.47s, rounding up to 3.55s
honestly had no idea how to match gear rations to tire size or even knew that it mattered what gear ratios you match with tire size before this. was just gonna slap some new tires on my truck. super helpful now i know to change gear ratio for best performance & best mileage.
Very good video. I’m not a 4 wheeler, but this applies to street tires too. To keep things clear in my mind I’ve always equated gear ratios as revolutions rather than numbers of teeth unless I’m looking at actual gears to determine the ratio. So a drive shaft would turn 4.11 revolutions for every single tire rotation in a 4.11 rear end for example. I especially liked your formula for determining the gear set needed for a tire change.
I'm impressed with your easy to understand explanation! I am so confident now to finish replacing with my soon his XJ Cherokee front differential, and be able to mach it to the rear diff. modified by new 35" tires..... Thanks a bunch!
My plan for my DD 2018 Jeep JK Willy’s 3.73 manual, putting Eaton Truetrac front and back, and 4.56 or 4.88 gears, running 33” tires. Thanks to you I’ll do the math now!! Advice from you is welcome!
Ran the formula; 33X3.73/32=3.84 . So I don’t really need to re-Gear, unless I want larger than 33” tires, and I don’t on my daily driver. Do you agree with that, of should I not be under-geared at all?
Dude this video is hands down the best explanation of axle gear ratios I've seen after looking casually for the last couple weeks. Im going to keep watching your videos and hope you have other topics like this.
Yo dude I know this video has been up for a while, but I just bought a JK well like six months ago and I’m upgrading to 37 inch tires and this video is a lifesaver. Good stuff brother! Stay safe, wish the best happiness and health for everyone
This is the best explanation I have found thus far. Love having the formu;a for gearing. Looking to put 37' on my Rubicon with 4.10. Now I know how to adjust, and to understand what my local shop is recommending. Agin, thanks!
OMG dude you just saved me a lot of money in possible damage. I stumbled on this video by accident, and Im glad I did. I already purchased a 3.25 lift and 35's for my 14JKU. I had no idea about the gears...Thanks again!
Thank you excellent video! Are the 3.8 wranglers and outlier when it comes to this formula? According to the formula 35*4.1/32.1=4.47 Most of the charts I have seen recommend 5.13's.
Thank you so much for this video, I just got a 1985 Toyota pickup with 33" tires and the guy I bought it from change the gears and wrote it on the door pillar, I had no clue what it was, but now I know, you explain it in such an easy way to understand, thank you so much.
I've been waiting for you guys to do this video for a long time and I was NOT disappointed! Thank you this video was very well done and very helpful. Keep up the good work guys!
Good info. I have an 06 TJ with the 4.0L, Dana 30/35s, a 6 speed manual, with a 2.5 in. body lift on 33 inch MTs. Sixth gear is useless on the highway. I’ve started venturing out of state more often and need it to keep up with friends on the hwy.
Brilliant ! Really well done mate . Your knowledge and presentation skill is to be commended ! Thanks so much for all your effort putting these vids together , they are a great resource and I for one value them greatly ! Cheers from Australia
I wish I had seen this video before regearing too low for my daily driver. Everything is subjective, and according to many commenters on the internet and a few local gear shops, "5.13 is the perfect ratio to run when you have a 35" tire on a JKU with the Pentastar." They must rarely run their rigs on the highway, because my 3000 RPMS at 60mph on flat highway disagrees. Using this equation, I should be running a 44" tire to best match up with the 5.13s. Conversely, the closest ratio using 35s is 4.10, based on the fact that my stock setup was 32s with 3.73s. A very expensive lesson that could've been avoided had I seen this earlier. Great video!!!!
SouthernFried87 A bunch of threads on the various Jeep forums. Yeah the 3.73s were definitely liveable. I just test drove a Rubicon with 4.10s and 35s to see if I should go that route. It didn't feel much different than the 3.73s. I'm pretty sure 4.56 is the right gear for me now.
Tyler Bleepinjeep Damn helpful! I'm new to this off-road technicalities I plan to get a Jeep Wrangler 3dr or 5dr sport since rubicon is so much and I'm not an extreme off-roader. I plan to put a 35" tire with a 3inch lift I'll be using this jeep as a daily commuter/occasionall off-roading. Do I need to upgrade my gears? I would value your insights on this. Thank you
New to the Jeep community and don’t know much about cars but the way you explain this makes so easy to understand things. I bought a 2017 Jeep Wrangler Sport Unlimited with 35/12.5 tires lift 2.5 My gas mileage is horrible I get 12 mpg in the freeway and 9 in the city. I knew something must’ve been wrong with it so I started to do some research and found out that I need to regear. I’ve watched so many videos and yours is one of the most informative. Keep them coming.
Big tires come at a cost the weight costs fuel to turn them. Like the OP said you will be giving one for the other (low end crawling/acceleration or high speed fuel efficiency) your 9mpg city driving wont change much if any with a gear swap. If your daily driving a jeep with 35/12.5's your either rich or stupid. Pardon my dry straight forwardness...What did the jeep come with for stock size tires 225/75/16 (29.5in tire)? What rpms are you at when going 35 and 60mph.. how often do you off-road? Assuming your running MT tires due to size you gave also E rated more than likely. That's a 60-70 pound tire in place of a stock 30-40lb C-D rated tire. Fuel mileage costs of heavy rotating mass is way different than that of added payload mass. Tire size increases rolling resistance thusly reducing fuel mileage again. Lowering gear ratio (higher numerically) to give you proper acceleration decreasing fuel mileage yet again. Do you see where I am going with this? If you are daily driving going with a E-rated LT 265/75/16 AT would be 15lb lighter per tire with less height (not needing a gear swap) around 31.5x10.5 this only drops your ride height 1.75 inches . 10.5 section width reduce rolling resistance/friction increasing fuel mileage and still give 2.5 or so more section width over stock. This would also fit the stock wheels which are likely long gone just like your hopes of ever getting 15mpg. Prolly got wheel spacers in that mix to while running 70lb tires on a JEEP (0.O)… and by all means lets be thorough and add your likely running the wrong pressure for your vehicles carrying capacity like all the others with E rated tires on a jeep.. Hur hur "I run at the door jamb rated pressures or max rated of tire (on road) cause I never seen a tire pressure to load chart". Guessing you got aftermarket 18's to fit those 35's on... You also have to be aware that an E-rated tire carries less payload at the same pressure as your stock C-D rated passenger tires did (so if your running the door jambs stated pressure the E rated tires pressure is to low). You would then look at the door jamb (owners manual) for your weight requirements per tire should be around 2000lbs a tire then cross reference that weight to the corresponding rim size/tire size/load range on a chart like this one tirepressure.com/35x12-50r18-tire-pressure.... I see all this too many times over day in day out.... My suggestion if you want the 35's and regear the rig park it and offroad it or weekend it buy yourself another car. If you want to daily drive it take all that crap off go back to stock wheels on the tires I suggested the LT 265/75/16 AT tires like I said it will only be 1.75 inches lower ride height and way more fuel efficient getting you close to 16mpg HW and 12city. Good luck hope you took well the my prodding and learned something from it. Remember the OP isn't daily driving on a brighter note if your running 3000rpm on the highway like him your doing some serious carbon and catalytic cleaning in that process lol.
good explanation however I learned something new last week about gear ratio's....I always thought that the tooth count on the R&P had to be the same regardless of the size of the R&P for example I have 4.56 gears front and rear, my front axle tooth count is 32/7 and my rear axle tooth count is 41/9 and the ratio is still 4.56, when I explained this to the guys in the gear shop he says as long as the ratio is the same it doesn't matter what the tooth count is. Here is the example he gave me which makes since...95+5=100, 90+10=100 , 80+20=100
EXCELLENT Video and tons of great information delivered in a very understandable fashion. May I make one slight observation? When you were discussing the ratio differences at the end you make the comment they were close enough in the THOUSANDS. Correction: The fist digit to the right of the decimal point is TENTHS. the second digit is HUNDRETHS and the third digit is the THOUSANDES on an Inch. I realize you must know that and it is easy to say what comes off your tongue. I know you know that difference with how informed you presented yourself in the rest of your video. I'm NOT SLAMMIMG YOU HERE. Anyone can make that slip of the tongue. Other than that tad bit you presented an awesome video and showed important information NO OTHER VIDEO I've come across of this type has. Your video has more content than some classes I've had to take for my job. My hat's most definitely off to you Sir...Great Job!
Awesome video! I loved the formula you showed, as I have been wondering what gear ratio to go to in the future. Right now I am running 31" tires with 3.73 gears, and in the future I want to upgrade to 33"- 35" and have been wondering what gear to go with. With this formula, that question is now answered :)
+TxGamer13 I used 4:88 gears and 33" tires. Most guys will say that's too low. But I love it!! I bought my Jeep to run good at slow speeds in the dirt, and I was willing to sacrifice some high speed performance. You can go 65 on the highway at about 2600 rpm, but you don't want to go much faster. However, the low range is creepy crawly. It Is Awesome. I have a TJ with the 4.0 and the AX15 transmission.
(stock gear/stock tire)x(new tire)= new gear. choose the closest gear set numerically to the "new gear" number. So if you get something like 3.95 then you should use 4.1 because 4.1 is numerically closer than say a 3.73. If you get a "new gear" number that is smack dab in the middle like 4.33 (right between 4.1 and 4.56) then you can choose to either get more low end torque going with 4.56 or better fuel economy with a 4.1.
If you go to a machinist and ask him to cut one thousanths off, he will cut .001". If you tell him to cut ten thousandths he will cut .010". If you ask him to cut a hundred thousandths or one hundred thousanths he will cut .100". If you ask for a tenth he will cut .0001. I think that is why Mike asked the question.
@@lockcracker I work in an engine remanufacturing company and train machining parts and assembling engines. You are correct and so many people get that confused
BleepinJeep, thank you so much for this video! I'll just be honest and say I am a total noob to 4x4 trucks. I was planning on just putting a 6 inch lift and 35 inch tires on my truck and calling it good. You just saved me alot of headache down the road!
Very helpful I was considering going from 33' to 35" on my dodge ram, now I know what gear ratio to go to. Thank you for making this easy to understand,
Just want you to know I'll probably never ever have to use what you just did but now I know how my rear end and front end work I leave it all up to the professionals like you thanks for the video very cool
This is brilliant man. Thanks for this! My son has his eye on a used Wrangler with huge tires and I wanted to make sure it was set up properly. You just armed me for my research!
Here is one other thing to keep in mind that I didn’t hear you discuss. Wh A 3.07 gear will turn the tire more revolutions then a 4.88 gear. However a larger tire will travel more road distance per revolution than a smaller tire. Thus you could have 3.07 gears with a smaller size, and 4.88 gears with a larger tire travel the same road distance per revolution of the drive shaft feeding the differential. Using the same tire size… 3.07 gears will have a higher top speed then 4.88 gears for the same engine rpm’s. Other then the fact it takes more energy to turn a larger heavier tire then a small one. The 4.88 gears with larger tires will generally help gas mileage some when placed with lower gear ratios. But it isn’t a linear graph due to the fact that larger tires are generally heavier.
In talking bout tires you omited the the radias if the specified OEM wheel all those factors were designed to. The talker wheel is traveling the same distance( speed) at a lower Rpm if the engine and gear set . All factors of the equation.Dandahermit
Currently running 37” tires on stock 3.73 gears on my 2016 Wrangler JK. Debating between 4.56 and 4.88 for gears for my Dana 30. But I may go down to 35” tires next time I get them. Do you think going with 4.56 gears is the smarter choice? (Especially if I go down to 35s)
Carrier is the case (often referred to as a ‘dif case’)… it carries the differential which holds the ring gear, Hope this helps. FoMoCo Sterling Axle Plt engineering Love the content!! Awesome resource! Thank you for posting!
That was GREAT ! I hate to admit it but I've never had a clue about gear ratios ! Thank You ! All I knew is that when I was a kid most of us guys had cars with either 3.73 's or 4.10''s . . . late 60's early 70's . Nice to finally understand ! Wish I had some of those cars back too ! LOL.
My dad once showed me how to determine gear ratio by turning the tire and counting rotations of the driveshaft but I don’t remember it exactly, but it was a spot on way to determine without opening the diff.
Your video was very helpful. I learned something today, which is a good thing. Between my son’s calculations and your’s, i know i need 4.56 gears in my 97 TJ.
I have an 05 TJ, and it had 3.73 from the factory. I’m running 33s, and changed my gears to 4.56. GPS reads 2 MPH slower than my speedometer. A Dana 44 will accommodate a 3.73. I put a E-locker to run the 4.56.
Very helpful thank you for your time .... I have a 1968 gladiator jeep truck with a 12 valve Cummins with a NV 4500 with 37” tires ... I’m thinking 4:10 would be the best but I’m not sure
Awesome Video. I'm just getting into and preparing to start off-roading (again after years away from it) and will be 'building my own' Jeep. This has been extremely helpful. And delivered in a wonderful way = smart, down-to-earth, not at all condescending (and there is zero sarcasm here which is Abby Normal for me). Thank you. Really just an EXCELLENT video demonstration.
From doing research on forums, a lot of people were saying 4:56 for 35's then another fellow that really seemed to know what he was talking about to me, he said you don't want it exactly way it was from Factory because of the added weight of the tires, And that 488 would only bring it up a couple hundred more RPM, so... I installed 488, I ordered some dip switches and solder to my speed sensor spent days finding out the binary code, it shifts right, well it did until I blew the gutless Tbi i350 up in my 93 Chevy, it now has a 6.0 LS in a 4 L 80 e Terminator X Max, but I digress, for a daily driver, I should have gotten 456 . I could just put 37's and that would be killer, except for its IFS, I know I know boo! You can't climb Boulders with those, just passed along a little hopefully helpful information that's all. If you really want a boo I'm considering putting a 9.5 IFS I saved out of the donor truck and Putin a locker in it 🤯because I can't afford to SAS, especially when the truck spends 75% of its time on pavement and my only ride/ but if I could afford to spend as much on front suspension as the whole rest of the truck I would be all over it about it and jumping off the top of it 🤞come on LOTTERY
Thank you, that was interesting. I learned how to calculate the tire size, Carrier brake and gear fudging. All good stuff I can teach to my students. I have one question and one comment. I have never seen carrier brake specification when purchasing a new case. How can I find that information? When you spoke about gear fudging you said the gear ratios need to be withing 2 - 3 thousandths. That is: .002 - .003 and I believe you meant to say between 2 - 3 hundredths written .02 - .03 such as 3.73:1 and 3.70:1 gears are withing 3 hundredths of each other.
I'm going to be putting 215 85R16 tires on my XJ and this makes me feel good about having already decided on going with 4.10 gears. According to this the ideal ratio is 3.96 but I plan on doing some hauling and towing so I think the 4.10s will do nicely.
HOOLY CRAP, this is one awesome gearing video! I've got a 2016 Willys Wheeler, and it came with 3.73 gears. I upgraded the suspension to 3.5" and tires to 35"; it does feel pretty sluggish coming off the line, but is fine after getting up to speed...but the mileage is crap at about 12-13mpg! I'm now kicking around different options to help with horsepower/torque, and was pretty much a noob when it came to gearing. Thanks for the schooling!
Thank you so much for the video. God bless you! Your knowledge will help many others, like myself, got ripped off previously due to my lack of knowing how.
thank you!! your the only one i’ve seen who mentions the two different carrier sizes in the dana’s . i bout a 5.13 foolishly and am now finding out i have a 3.21 gear set stock.
Yup just swapped to 30inch tires for winter and noticed on the highway it’s hard for my Jeep to find a gear between 65 and 70 during the summer I have 32 inch tires so now gotta watch more for my ratio need
I have been a mechanic for almost 30 years and you just taught me something new! Thanks a million
Probably wouldn't brag about that, just say'n.
@@andrewpropes3646 probably wouldn't be talking with a dumb name like that just sayin...
thats a compliment,,, to 'both of ya',,, think bout it a min :)
@@andrewpropes3646 Sorry Andrew, you must be a young man because only a young man would make such a rediculous statement!
@@jaysantos514 this true, you are correct
Only took me 87 videos and three weeks to find this genius on UA-cam!
Not me wanting to know this for years 😭.
Save the video if you ever need it again.
this is the kind of video UA-cam should feature.
Been doing axles for 50 years, I never claim to know it all and crazy how you can still learn something you didn't know or at my age forgot. Lol.. Great job on the video.
What axles would you recommend to one ton swap a rwd auto MJ?
@@maxnovakovics2568 any more these days, it seems like Teraflex has got it figured out and would have whatever you need. Plus, a lot more knowledge than me. good luck 👍
I knew absolutely nothing about gear ratios before this video. I feel like I need to swap out my rear-end now thanks to this guy! Amazingly detailed information.
Wow! I have discalculia, so I tend to shy away from math, but this lesson has me COMPLETELY understanding it and the formula is memorized, which is odd for me. I just bought a Dakota 4x4 that the guy put a rear end out of the Dakota suburban, which is very high, and you can't go in 4 wheel on pavement or hard surfaces, as it fights itself. Gotta find a stock gearset.
left for almost 6 yrs and this man is still taking me to college... thanks man... appreciate ur time and teaching.. ty..
This is an example of someone teaching you who knows the subject well. Thanks for clear and to the point explanation.
I’ve had Jeeps for 14 years and you taught me more about gears in 20 minutes.
If you are wanting to learn about gear ratios then THIS is your video to watch.. It is pretty simple when the person explaining it to you really knows what the heck he is talking about..
Most excellent video dude..
This was the best explanation and mathematical breakdown I have ever come across.
Wow, I’m a ford technician and I learned a lot. Very intelligent. Thank you for the gear ratio lesson!
Weird to see you here brother😂👌🏻
maybe you can pass you power train ASE exam now
What?
No wonder Fords are left on roads dead🤭
Haha, this really puts a lot of things into perspective when it comes to ford
Thanks for posting this tutorial. I have a 1989 F-350 7.3 L diesel backed by the three speed C-6 transmission. It had 3.55:1 gears and 215/85r16 tires from the factory. The previous owner said he put in 4.10:1 with 225/70r19.5.
The new tires and gears both are taller and the engine screams at 3,000 RPM at only 65 MPH. I was going to go back to factory 3.55:1 but after doing the math you explained, I should go to a 3.73:1.
Thanks! I hope it gets my RPM's down to around 2,000 RPM's at 65 MPH....or 2200 at 75 MPH.
For those that care, I'll post the result of my change.
Appreciate this video even 8yrs later!!!
I didn't plan to watch this entire video.... But after listening in for about a minute... I was suddenly captivated.
Your explanation was very thorough and elementary in lecture... So easy to understand!
Fantastic video!
Thank you for all the knowledge!!
As a scientist I have to tell you your videos are great. Very detailed and well explained. Your thoroughness makes these vids extremely helpful. Sometimes a person thinks they need to know one thing but what they really need to know is something different that they haven't considered or were unaware of and your videos can point those things out. Hope you keep making them this well.
Thanks!
Krushim why "as a scientist"? makes you sound slightly arrogant
@John Edwards I would think that is self explanatory since everyone knows how thorough and detailed scientists are in their work and explanations just like he was here. It is a fair comparison and a good compliment to his efforts. To suggest that is arrogant says more about you and how you feel about your own experience or education. If he was giving legal advice/explanations on something and a person said as a lawyer myself I have to tell you that you did a great job you'd be an idiot to bash that person. It's the same thing. Compliments from peers in an area are always appreciated by those that receive them.
Krushim yep arrogant as fuck...if you're so thorough why have you edited your comment and still made a typo? you are not more important than anyone else.
Clayton Magnet I second that
You're an excellent explainer. I'm a college graduate but have very little mechanical knowledge, and I believe I understand about 90 percent of what you explained in this video. Thank you very much!
This was very helpful. Thanks. I do want to ask if you can do a video class on differential rebuild/setup. Start to finish. Measuring for all the shims, back lash, preload, what tools, etc. Since you are a great teacher and most of us can’t go to a school for this training it would be a GREAT service to your viewers. I know it would be long and hard but I believe in you, you can do it. Nobody else has, I’ve looked. Again THANKS.
Yes, that would be amazing. I can't afford much but I'd pay to learn by watching the video.
Edit: he has a Patreon page for donations. We gotta help this guy out for all his useful information
I couldn’t find any videos on YT that could explain gear ratios! You’re the only guy that could explain it! Thank you!
Easily one of the most informative videos I've ever seen. Thank you.
Seriously just been schooled
Thank you, thank you thank you!!!! Now I understand. Top notch video, maybe the best motor-head video I have ever seen.
another rule of thumb I was told years ago...and it too is a 'guideline' to compare to. I would still use your calculation too. But, it goes like this: for each inch in diameter you increase, it's like subtracting .1 from your rear end ratio. So for tetnas, when you jumped 4" in diameter, you needed to come up with an extra .4 for your 3.07s...so 3.47s, rounding up to 3.55s
honestly had no idea how to match gear rations to tire size or even knew that it mattered what gear ratios you match with tire size before this. was just gonna slap some new tires on my truck. super helpful now i know to change gear ratio for best performance & best mileage.
Excellent! Can get college credits for having taken this short course?
lol
I agree very well done
Thanks!
Very good video. I’m not a 4 wheeler, but this applies to street tires too. To keep things clear in my mind I’ve always equated gear ratios as revolutions rather than numbers of teeth unless I’m looking at actual gears to determine the ratio. So a drive shaft would turn 4.11 revolutions for every single tire rotation in a 4.11 rear end for example. I especially liked your formula for determining the gear set needed for a tire change.
An excellent video for someone like me, who’s never been trained or exposed to auto mechanics…Very educational, thanks!
I'm impressed with your easy to understand explanation! I am so confident now to finish replacing with my soon his XJ Cherokee front differential, and be able to mach it to the rear diff. modified by new 35" tires..... Thanks a bunch!
My plan for my DD 2018 Jeep JK Willy’s 3.73 manual, putting Eaton Truetrac front and back, and 4.56 or 4.88 gears, running 33” tires. Thanks to you I’ll do the math now!! Advice from you is welcome!
Ran the formula; 33X3.73/32=3.84 . So I don’t really need to re-Gear, unless I want larger than 33” tires, and I don’t on my daily driver. Do you agree with that, of should I not be under-geared at all?
33's on a JK will be fine. unless you're moving up more than 2 inches or so from stock, its not gonna make that big a difference.
i may have actually paid attention in math class if my teacher used examples like this
EXACTLY
Kevin Yourk yeah. Right. But I guess back then when ya in school you would equally hate to learn anything mechanical.
I agree 💯 percent
So what about 31/18.5/15/with a 430/gears with a 35 fool spool 1350/ c10/ 2/ wheel drive with a/ 400/an a 496 roller tlk back bud
@@tramelponder6600 Simple, put it in "P" and walk.
Dude this video is hands down the best explanation of axle gear ratios I've seen after looking casually for the last couple weeks. Im going to keep watching your videos and hope you have other topics like this.
This was a really clear explanation of gear ratios and extremely helpful for understanding what they do. Thank you!
Yo dude I know this video has been up for a while, but I just bought a JK well like six months ago and I’m upgrading to 37 inch tires and this video is a lifesaver. Good stuff brother!
Stay safe, wish the best happiness and health for everyone
Great job on the video! Usually I end up more confused at the end than when I started. Very informative.
This is the best explanation I have found thus far. Love having the formu;a for gearing. Looking to put 37' on my Rubicon with 4.10. Now I know how to adjust, and to understand what my local shop is recommending. Agin, thanks!
OMG dude you just saved me a lot of money in possible damage. I stumbled on this video by accident, and Im glad I did. I already purchased a 3.25 lift and 35's for my 14JKU. I had no idea about the gears...Thanks again!
Thank you excellent video! Are the 3.8 wranglers and outlier when it comes to this formula? According to the formula 35*4.1/32.1=4.47 Most of the charts I have seen recommend 5.13's.
Ugh, best video from this channel
Thank you so much for this video, I just got a 1985 Toyota pickup with 33" tires and the guy I bought it from change the gears and wrote it on the door pillar, I had no clue what it was, but now I know, you explain it in such an easy way to understand, thank you so much.
I've been waiting for you guys to do this video for a long time and I was NOT disappointed! Thank you this video was very well done and very helpful. Keep up the good work guys!
Good info. I have an 06 TJ with the 4.0L, Dana 30/35s, a 6 speed manual, with a 2.5 in. body lift on 33 inch MTs. Sixth gear is useless on the highway. I’ve started venturing out of state more often and need it to keep up with friends on the hwy.
Brilliant ! Really well done mate . Your knowledge and presentation skill is to be commended ! Thanks so much for all your effort putting these vids together , they are a great resource and I for one value them greatly !
Cheers from Australia
Hey mate! How much is a set of Maxxis tires down under 37x12.5r15?
Great segment, man. Hopefully by watching enough of these helpful vids, I can stop asking my brother-in-law every single question I have about Jeeps.
So incredibly helpful man! I've never messed with re gearing and this gives me so much ease of mind when I go to tackle my YJ!
You went with 4.88's right?
Yukon is actually China made now with lousy China bearings
I wish I had seen this video before regearing too low for my daily driver. Everything is subjective, and according to many commenters on the internet and a few local gear shops, "5.13 is the perfect ratio to run when you have a 35" tire on a JKU with the Pentastar." They must rarely run their rigs on the highway, because my 3000 RPMS at 60mph on flat highway disagrees. Using this equation, I should be running a 44" tire to best match up with the 5.13s. Conversely, the closest ratio using 35s is 4.10, based on the fact that my stock setup was 32s with 3.73s. A very expensive lesson that could've been avoided had I seen this earlier. Great video!!!!
SouthernFried87 A bunch of threads on the various Jeep forums. Yeah the 3.73s were definitely liveable. I just test drove a Rubicon with 4.10s and 35s to see if I should go that route. It didn't feel much different than the 3.73s. I'm pretty sure 4.56 is the right gear for me now.
This guy is so damn helpful.
+TytheBandit Thanks!
Tyler Bleepinjeep
Damn helpful!
I'm new to this off-road technicalities
I plan to get a Jeep Wrangler 3dr or 5dr sport since rubicon is so much and I'm not an extreme off-roader.
I plan to put a 35" tire with a 3inch lift
I'll be using this jeep as a daily commuter/occasionall off-roading.
Do I need to upgrade my gears? I would value your insights on this. Thank you
TytheBandit and apparently very cold.
Absolutely!
New to the Jeep community and don’t know much about cars but the way you explain this makes so easy to understand things. I bought a 2017 Jeep Wrangler Sport Unlimited with 35/12.5 tires lift 2.5
My gas mileage is horrible I get 12 mpg in the freeway and 9 in the city.
I knew something must’ve been wrong with it so I started to do some research and found out that I need to regear. I’ve watched so many videos and yours is one of the most informative. Keep them coming.
Big tires come at a cost the weight costs fuel to turn them. Like the OP said you will be giving one for the other (low end crawling/acceleration or high speed fuel efficiency) your 9mpg city driving wont change much if any with a gear swap. If your daily driving a jeep with 35/12.5's your either rich or stupid. Pardon my dry straight forwardness...What did the jeep come with for stock size tires 225/75/16 (29.5in tire)? What rpms are you at when going 35 and 60mph.. how often do you off-road? Assuming your running MT tires due to size you gave also E rated more than likely. That's a 60-70 pound tire in place of a stock 30-40lb C-D rated tire. Fuel mileage costs of heavy rotating mass is way different than that of added payload mass. Tire size increases rolling resistance thusly reducing fuel mileage again. Lowering gear ratio (higher numerically) to give you proper acceleration decreasing fuel mileage yet again. Do you see where I am going with this? If you are daily driving going with a E-rated LT 265/75/16 AT would be 15lb lighter per tire with less height (not needing a gear swap) around 31.5x10.5 this only drops your ride height 1.75 inches . 10.5 section width reduce rolling resistance/friction increasing fuel mileage and still give 2.5 or so more section width over stock. This would also fit the stock wheels which are likely long gone just like your hopes of ever getting 15mpg. Prolly got wheel spacers in that mix to while running 70lb tires on a JEEP (0.O)… and by all means lets be thorough and add your likely running the wrong pressure for your vehicles carrying capacity like all the others with E rated tires on a jeep.. Hur hur "I run at the door jamb rated pressures or max rated of tire (on road) cause I never seen a tire pressure to load chart". Guessing you got aftermarket 18's to fit those 35's on... You also have to be aware that an E-rated tire carries less payload at the same pressure as your stock C-D rated passenger tires did (so if your running the door jambs stated pressure the E rated tires pressure is to low). You would then look at the door jamb (owners manual) for your weight requirements per tire should be around 2000lbs a tire then cross reference that weight to the corresponding rim size/tire size/load range on a chart like this one tirepressure.com/35x12-50r18-tire-pressure.... I see all this too many times over day in day out.... My suggestion if you want the 35's and regear the rig park it and offroad it or weekend it buy yourself another car. If you want to daily drive it take all that crap off go back to stock wheels on the tires I suggested the LT 265/75/16 AT tires like I said it will only be 1.75 inches lower ride height and way more fuel efficient getting you close to 16mpg HW and 12city. Good luck hope you took well the my prodding and learned something from it. Remember the OP isn't daily driving on a brighter note if your running 3000rpm on the highway like him your doing some serious carbon and catalytic cleaning in that process lol.
Who else wants to send him a space heater
Is that why the camera is so shaky? Brrr?
Do not forget a Heavier Tourque Convertor it totally helps ..
😂😂😂, poor guy is freezing.
good explanation however I learned something new last week about gear ratio's....I always thought that the tooth count on the R&P had to be the same regardless of the size of the R&P for example I have 4.56 gears front and rear, my front axle tooth count is 32/7 and my rear axle tooth count is 41/9 and the ratio is still 4.56, when I explained this to the guys in the gear shop he says as long as the ratio is the same it doesn't matter what the tooth count is. Here is the example he gave me which makes since...95+5=100, 90+10=100 , 80+20=100
7:30 the illustration there really helped it sink in and comprehend it. kudos
EXCELLENT Video and tons of great information delivered in a very understandable fashion.
May I make one slight observation? When you were discussing the ratio differences at the end you make the comment they were close enough in the THOUSANDS. Correction: The fist digit to the right of the decimal point is TENTHS. the second digit is HUNDRETHS and the third digit is the THOUSANDES on an Inch. I realize you must know that and it is easy to say what comes off your tongue. I know you know that difference with how informed you presented yourself in the rest of your video. I'm NOT SLAMMIMG YOU HERE. Anyone can make that slip of the tongue. Other than that tad bit you presented an awesome video and showed important information NO OTHER VIDEO I've come across of this type has. Your video has more content than some classes I've had to take for my job.
My hat's most definitely off to you Sir...Great Job!
Awesome video! I loved the formula you showed, as I have been wondering what gear ratio to go to in the future. Right now I am running 31" tires with 3.73 gears, and in the future I want to upgrade to 33"- 35" and have been wondering what gear to go with. With this formula, that question is now answered :)
+TxGamer13 I used 4:88 gears and 33" tires. Most guys will say that's too low. But I love it!! I bought my Jeep to run good at slow speeds in the dirt, and I was willing to sacrifice some high speed performance. You can go 65 on the highway at about 2600 rpm, but you don't want to go much faster. However, the low range is creepy crawly. It Is Awesome. I have a TJ with the 4.0 and the AX15 transmission.
(stock gear/stock tire)x(new tire)= new gear. choose the closest gear set numerically to the "new gear" number. So if you get something like 3.95 then you should use 4.1 because 4.1 is numerically closer than say a 3.73. If you get a "new gear" number that is smack dab in the middle like 4.33 (right between 4.1 and 4.56) then you can choose to either get more low end torque going with 4.56 or better fuel economy with a 4.1.
Your videos are a great additon to Matt's and the Bleepin lineup. Thanks!
As a world renown astrophysicist, you taught me more than I ever learned up till this point in my life.
on gear fudging, don't you mean hundredths, not thousandths
The difference is in the hundredths place (0.02), but the difference is about four thousandths of the base number (0.02 / 4.88 = 0.004 )
If you go to a machinist and ask him to cut one thousanths off, he will cut .001". If you tell him to cut ten thousandths he will cut .010". If you ask him to cut a hundred thousandths or one hundred thousanths he will cut .100". If you ask for a tenth he will cut .0001. I think that is why Mike asked the question.
@@lockcracker I work in an engine remanufacturing company and train machining parts and assembling engines. You are correct and so many people get that confused
I have been thinking of adding airlocks, carrior brake was something I did not know.
Your demo is excellent, your articulation “tops”
I learned something new today.
Thank you
5 years later..still relevant..AWESOME!!!!
Wow! Great video. I have not learned that much about anything in such a short while. Thanks a lot.
First thing I did when I finished watching this video was to like and subscribe! Clear and concise explanation on how gear ratios work. Thanks
Only you and George Costanza have a coat that puffy. Love this video. Thank you!
I don't understand how it took .e long to find this comment about the coat lmao
BleepinJeep, thank you so much for this video! I'll just be honest and say I am a total noob to 4x4 trucks. I was planning on just putting a 6 inch lift and 35 inch tires on my truck and calling it good. You just saved me alot of headache down the road!
finally, someone I can understand when explaining that...
thanks
4:16 The full laden weight of the vehicle is also factored into choosing the diff ratio.
Very helpful I was considering going from 33' to 35" on my dodge ram, now I know what gear ratio to go to. Thank you for making this easy to understand,
Just want you to know I'll probably never ever have to use what you just did but now I know how my rear end and front end work I leave it all up to the professionals like you thanks for the video very cool
Straight up awesome info. I knew most of this but not the formula for figuring the gears/tire size. Thanks, belatedly!
This is brilliant man. Thanks for this! My son has his eye on a used Wrangler with huge tires and I wanted to make sure it was set up properly. You just armed me for my research!
Fantastic info. Just answered my question on gears wanting to run 37s.
Here is one other thing to keep in mind that I didn’t hear you discuss. Wh A 3.07 gear will turn the tire more revolutions then a 4.88 gear. However a larger tire will travel more road distance per revolution than a smaller tire.
Thus you could have 3.07 gears with a smaller size, and 4.88 gears with a larger tire travel the same road distance per revolution of the drive shaft feeding the differential.
Using the same tire size… 3.07 gears will have a higher top speed then 4.88 gears for the same engine rpm’s.
Other then the fact it takes more energy to turn a larger heavier tire then a small one. The 4.88 gears with larger tires will generally help gas mileage some when placed with lower gear ratios. But it isn’t a linear graph due to the fact that larger tires are generally heavier.
Thanks. This made things a lot clearer.
89 k1500 heavy half 4x4 gmc came stock with 3.07 rear end gears...this is definitely helpful in making the right choice in gears...
If the rear is 3.07 how can you figure out what the fronts are or do you just do the same gearing for both axles?
Great stuff man! I own a Tundra, but you’re knowledge of 4x4 related material is unbeatable. Thanks for posting!
In talking bout tires you omited the the radias if the specified OEM wheel all those factors were designed to. The talker wheel is traveling the same distance( speed) at a lower Rpm if the engine and gear set . All factors of the equation.Dandahermit
awesome video man now I understand axle gears I had no idea before watching this so thank you.
Excellent presentation! It was very clear & concise. Your voice cadence & explanations made the content easy to follow and comprehend . Thank you!
Great stuff, ty. One little technical point just because I'm an engineer. You mean 20 thousands not 2. Keep up the great work.
He meant 2 hundredth. Mathematically the same. But easier for non-math peeps to understand than 20 thousands. No trailing zeros needed here.
Currently running 37” tires on stock 3.73 gears on my 2016 Wrangler JK. Debating between 4.56 and 4.88 for gears for my Dana 30. But I may go down to 35” tires next time I get them. Do you think going with 4.56 gears is the smarter choice? (Especially if I go down to 35s)
I'd go with the 4.88's
Thank-you. Very well explained.
Carrier is the case (often referred to as a ‘dif case’)… it carries the differential which holds the ring gear, Hope this helps. FoMoCo Sterling Axle Plt engineering
Love the content!! Awesome resource! Thank you for posting!
wow I would run at least a 4:10 with 33 inch tires
That was GREAT ! I hate to admit it but I've never had a clue about gear ratios ! Thank You ! All I knew is that when I was a kid most of us guys had cars with either 3.73 's or 4.10''s . . . late 60's early 70's . Nice to finally understand ! Wish I had some of those cars back too ! LOL.
damn dude, you live on Hoth or what? thanks for informative vid. I'm going from 3.21 to 4.88 on my JK with 35s soon.
It sure feels like Hoth when the temps go below zero. You're going to love the 4.88's. Your jeep will feel like a brand new car.
Tyler Bleepinjeep I love the 4.88s! wish I'd done it sooner
RDubya73 lol
im going to 4.56s from 3.21s in my jk on 35s. i about went 4.88s lol
Tyler Smith my 85 Chevy came factory with 4:56 my top speed is no more than 60mph....M-1028
My dad once showed me how to determine gear ratio by turning the tire and counting rotations of the driveshaft but I don’t remember it exactly, but it was a spot on way to determine without opening the diff.
super helpful
Your video was very helpful. I learned something today, which is a good thing. Between my son’s calculations and your’s, i know i need 4.56 gears in my 97 TJ.
I think I’m more impressed with those kick ass iPhone gloves!
I have an 05 TJ, and it had 3.73 from the factory. I’m running 33s, and changed my gears to 4.56. GPS reads 2 MPH slower than my speedometer. A Dana 44 will accommodate a 3.73. I put a E-locker to run the 4.56.
I am so thinking about this because of the mods my Taco is always searching for gears? I'm not a Jeep guy but great video! voodoobluetacolife19
Very helpful thank you for your time .... I have a 1968 gladiator jeep truck with a 12 valve Cummins with a NV 4500 with 37” tires ... I’m thinking 4:10 would be the best but I’m not sure
Awesome Video. I'm just getting into and preparing to start off-roading (again after years away from it) and will be 'building my own' Jeep. This has been extremely helpful. And delivered in a wonderful way = smart, down-to-earth, not at all condescending (and there is zero sarcasm here which is Abby Normal for me).
Thank you. Really just an EXCELLENT video demonstration.
From doing research on forums, a lot of people were saying 4:56 for 35's then another fellow that really seemed to know what he was talking about to me, he said you don't want it exactly way it was from Factory because of the added weight of the tires, And that 488 would only bring it up a couple hundred more RPM, so... I installed 488, I ordered some dip switches and solder to my speed sensor spent days finding out the binary code, it shifts right, well it did until I blew the gutless Tbi i350 up in my 93 Chevy, it now has a 6.0 LS in a 4 L 80 e Terminator X Max, but I digress, for a daily driver, I should have gotten 456 . I could just put 37's and that would be killer, except for its IFS, I know I know boo! You can't climb Boulders with those, just passed along a little hopefully helpful information that's all. If you really want a boo I'm considering putting a 9.5 IFS I saved out of the donor truck and Putin a locker in it 🤯because I can't afford to SAS, especially when the truck spends 75% of its time on pavement and my only ride/ but if I could afford to spend as much on front suspension as the whole rest of the truck I would be all over it about it and jumping off the top of it 🤞come on LOTTERY
Thank you, that was interesting. I learned how to calculate the tire size, Carrier brake and gear fudging. All good stuff I can teach to my students. I have one question and one comment. I have never seen carrier brake specification when purchasing a new case. How can I find that information? When you spoke about gear fudging you said the gear ratios need to be withing 2 - 3 thousandths. That is: .002 - .003 and I believe you meant to say between 2 - 3 hundredths written .02 - .03 such as 3.73:1 and 3.70:1 gears are withing 3 hundredths of each other.
I'm going to be putting 215 85R16 tires on my XJ and this makes me feel good about having already decided on going with 4.10 gears. According to this the ideal ratio is 3.96 but I plan on doing some hauling and towing so I think the 4.10s will do nicely.
HOOLY CRAP, this is one awesome gearing video!
I've got a 2016 Willys Wheeler, and it came with 3.73 gears. I upgraded the suspension to 3.5" and tires to 35"; it does feel pretty sluggish coming off the line, but is fine after getting up to speed...but the mileage is crap at about 12-13mpg! I'm now kicking around different options to help with horsepower/torque, and was pretty much a noob when it came to gearing.
Thanks for the schooling!
Thank you so much for the video. God bless you! Your knowledge will help many others, like myself, got ripped off previously due to my lack of knowing how.
thank you!! your the only one i’ve seen who mentions the two different carrier sizes in the dana’s . i bout a 5.13 foolishly and am now finding out i have a 3.21 gear set stock.
Yup just swapped to 30inch tires for winter and noticed on the highway it’s hard for my Jeep to find a gear between 65 and 70 during the summer I have 32 inch tires so now gotta watch more for my ratio need
That's hundredths not thousandths 18:28...math can get exhausting.
Why so many dislikes this is so helpful? Liked and saved this.
I did 4:56's on a stock 4.7 tundra pretty good increase in rpm gets it's power down to the ground but it's definitely not a good highway truck.