Another great vid. I’m amazed how many times I see people with hard tyres off road. It doesn’t help with handling and grip but damages the track. Keep up the great work Matt. 👏👏👏
I use the old 4 psi rule on and off road. Works a treat with a tyre preasure monitoring system as you get real time feedback. I run a 2017 hilux, fully loaded with 20 in front, 25 in the rear
A bigggggg HI to you from Dubai!!!!!!. This is a beautiful advice Matt. We offroad in extremely soft sand in UAE/Dubai deserts. We keep a maximum of 15psi. Sometimes we drive at 6psi to counter the utmost softness of the sand. Putting a deadlock ensures that we avoid any pop-outs at such low pressures.
Thanks Matt, always great educational vids. my MY18 Dmax is heavy tourer (3200kg touring weight with GVM upgrade maximum of 3600kg from Lovells. Same Toyo Open Country AT II but in 245/70 R 16 on stock steel wheels. From Toyo Tech Mgr Steve in Victoria here pressures for my individual axle weights from Rim and Tyre Association charts are Highway F 50 PSI R 56 PSI (Cold pressures in PSI) Off road F38 PSI R 49 PSI Rocky F33 PSI R 44 PSI Sand F21 PSI R 27 PSI Speeds dropped down to 80kph off road, rocky appropriate and sand 30kph or appropriately lower. Pressure obtained from supplying Steve with the front and rear axle load weights.
Almost three minutes into your video, here, Matt, and good on ya to have mentioned "Cold Inflation Pressures" - This is important for those who're starting to become aware of how to manage their tires through pressures adjustments. It's critical, actually. ONE THING THAT HELP IMMENSELY these days in modern road-going rigs is TPMS and their pressure readouts in the instrument cluster! There, one can see the tires' "running" pressures, as Matt has demonstrated here. "Cold Inflation Pressures" are the base of your knowledge going forward (or in reverse when necessary) to manage your tire pressures when off highway, in the sand or in the bush (posting from the USA so please forgive my mangling of your slang). Matt! What Load Range are these tires? and might you do a vid or direct us to an explanation/translation of the AUS' "2-ply" vs "3-ply" tire construction? I am aware that 3-ply may infer the old 10-ply (cotton fabric ply) E Load Range standard here in the states... I'll soon be running a new Toyo ATIII 34 X 10.50 X 17 - D Load Range.
Contrarian view. On my XJ I run 33” BFG All Terrains at 35 PSI all the time. I do moderate off-roading/crawling here in the desert southwest US. Typically sticking to trails rated 6 and below. It is very rare that I need to air down to make it over anything. I quit airing down after several punctures and until a couple months ago I went years without one. This was the result of me channeling my inner 18 year old and no pressure setting was gonna save that tire. In short I may be giving up some performance and ride quality but I don’t think it is nearly as much as people think for either. But my tires last until they are worn down.
What sort of speeds would you do on the desert trails? I imagine rocks would puncture tyres at speed when deflated. Sidewall punctures or tread area punctures? Just trying to understand as highway pressures go against common practice here in Aust.
My special tracks are at 18psi front and 20psi back on my 110 defender that's my road pressure. Any more and I see center wear. Less than that and it chews the side lugs. Off road I don't drop them much most of the time. Usually down to about 12 or 15 up front and about and about 18 inthe back. No idea what I'd run on your rig. You've probably got it about right for you
The rule of thumb when I worked in the engine room on a submarine was 4 seconds when you put your hand on the item was equal to 104 degrees ferenhiet. When you get up to that temperature you starting to do damage.
I like that you're making me have a good think... It appears to me like the rear tyres are bagged out a little more than the fronts. This could be just the ground that each tyre is resting on making it look that way, but I have my doubts. I think that the 6 psi temperature induced pressure rise in the rears compared to the 2 psi rise in the fronts also suggests that more sidewall flexing is going on in the rears, but the extra weight in the rear will also contribute to this. Another consideration is what happens to the tyre over bumps or during suspension compressions, which momentarily compresses the tyre even further. Obviously, the sidewall flexes even further, so an allowance needs to be made for this. I think it may be ideal to increase the rear pressures a few psi, and possibly drop the fronts a touch further. That's what I'd try. Beyond that, I think it comes down to the feel of the vehicle - finding the balance between getting too squirmy and still being comfortable. I noticed another commenter mentioned about ground pressure and basically suggested having the tyres that are carrying more weight bag out further to keep the ground pressure more even between axles. I think that would be quite relevant on really soft surfaces to stop or reduce the tyres sinking into the ground, but on a relatively firm track, I don't think ground pressure is such a consideration... I really enjoy you content, and appreciate the time you evidently take responding to so many of the comments! Thanks Matt!
I've seen mentioned, more than once, that the 4 psi pressure difference test between cold & hot pressure is for non-Light Truck tyres. (passenger, highway tyres really). But for Light Truck tyres the difference should be 5 or 6 psi.
You have to take into account the side wall ply rating .Say a 10 ply you need to let more air out to get the same foot print as a 4 or 6 ply rated side wall. A 6 ply rated side wall you may need to take to 28 psi and 10 ply to 18 to get the same foot print.
I've been experimenting with 18psi front and back offroad but that's without a serious load. I'm very happy with that so far. I think the biggest concern is going below 16 psi because at 15psi you're pretty much at atmospheric pressure. Any lateral force will start to unbead your tyres at that point.
I run 33” mud tyres. Troopy weighs 3.2 tonnes fully loaded. I run 18psi (hot). I see the tyre temps reach a max of 70° (via TPMS) when doing 90-100kmh on dirt roads. May go down to 12psi when desert exploring. No punctures or tyre failures to report in 10-15 years of exploring. I only regard tyre life to be 4years and not actual wear as time degrades the carcass and causes issues after this duration. Great video.
That 70 series is a tough nut to crack because it is so cantalevered in the back. In the back you want to air down some so that it is supple enough when you hit obstructions, but not so low that it doesn't hold the extra load, potentially risking the tire getting pinched. I wouldn't lower the rear pressure much more than you already have it, maybe a 2-3 lbs. The front can go really low since so much weight is transferred to the back. You really don't want anymore weight transfer when the front tire strikes an obstruction. I would say you could lower the front another 5-10 psi. If the rear axle was back further, you could be more even front to back.
I'd guess 20-25 psi on that setup? I run about 20 psi off road on my rig with 37x12.50r17 tires but it weighs north of 8k lbs. The 42" tall 15" wide tires on my Jeep don't begin to belly out until they're down in the low single digits.
I just got my tyres done and the shop had the rears at 40 and the fronts at 37/38(my gauge isn’t super accurate but I’d say 38) So that’s what I’m sticking to until they wear a bit but I’ll be experimenting when I off-road, kinda just air up to 35 drive for a bit, see if I like it then compare to 40 again
Thanks Matt. Love your approach in delivering a lesson for the masses so gently by making it appear like a curiosity question - genius! Just an observation/guess about when a tyre hits a rock at 110km/h, I suspect that it is similar to an object hitting water at 110km/h - the water is very hard, so I imagine that momentarily, the tyre will respond as if it too is super hard pretty much regardless of the pressure. I don't think the tyre has time to conform to a rock at that speed - my guess is the tyre's shape remains intact and the forces are transmitted through the tyre to the wheel and then to the suspension. Mind you, we are talking about 110km/h, at 60km/h the compliance of the tyre will be much more apparent and I expect will deform appreciably to accommodate the impost of a 4" rock., but at 110km/h - I doubt much compliant deformation occurs. It makes one really stand back and marvel at the robustness of today's tyres! They've thought, tested, researched and developed solutions for this! You have to hand it to the engineers for the structural design and chemists for the compounds developed for off-road tyres.
Personally, I generally run equal front and rear. I’m not a physicists, but the lower the pressure of the tyre, the lower the ground pressure that tyre pushes to the ground. If you put more air in a tyre to account for the load, then the ground pressure will go up as-well and you’ll get the negative consequences. That being being the case, having a higher load on the rear will mean the tyre will flex more and result is more heat build up. So, I actually put a lot of effort in to equalising the weight distribution across the vehicle to prevent this being an issue. It’s obviously very beneficial for handling as-well. Its gonna be hard to do that in a dual cab 79 though.
You’re 100% right about getting the load spread out and correct. I tried hard to do that but fought a losing battle. I’m not sure the equal tyre pressure concept makes sense if I’ve understood you correctly. Thanks for the comment.
@@MadMatt4WD basically… and I used to do it too… people often run higher rear pressure to make up for the extra weight over the rear axle. To create the same about of contact patch as the front. However, if the contact patch is the same, and the weight over the rear higher, then the ground pressure must be higher in the rear then the front, meaning the rear tyres will more likely dig in soft terrain compared to the front. I’m not suggesting that you should run equal pressures the way the truck is loaded, I’m just saying that ideally, you’d try to get as close to equal pressures as possible to improve off-road performance. You’d have more chance of achieving that in a wagon I reckon.
@@MadMatt4WD I guess another way to think of it is a truck… they use more tyres to spread the weight under the load. More tyres, more surface area = less ground pressure. The only way to get more surface area with a single axle is with lower tyre pressures, or have larger rear tyre, like a tractor.
When I explain to folks why lower tire pressure creates heat I remind them of bending a metal coat hanger wire and how it gets hot. This seems to click with most people.
Good information. You say 33” (dia.) but what is the actual size/profile of those particular tyres. I have found different tyre sizes require slightly different pressures.
First and foremost, the excessive overhang on the rear axle on most if not all dual cab vehicles are a poor design. The amount of leverage it has can easily be seen by the amount of excessive lift of the front suspension and less of a footprint of the front tyres. As for tyre pressures, when a tyre is cold, take note of what the pressures are on all four tyres, then after driving, for some time, for example 20-30 minutes, stop and check the now warmer temperatures, if the pressures have increased over 4psi, then you need to increase the tyre pressure to reduce the flexing of the tyre, which is the cause of the tyre increasing more than the 4psi. The Pirelle (not sure of the spelling) tyre company many years ago came out with this recommendation. I have personally used this recommendation for over 35 years now and have found that it works. Obviously it will take some time to find the sweet spot, for each different load and is also dependent on the road conditions (including road and air temperature) and last but not least, the vehicle’s speed, with heavy loads l prefer to keep the speed, well below 110kph.
front looks okay rear for the weight looks slightly a bit under deflated . but I think it's coz they are a all terrain not a LT mud terrain construction. they are softer .
There's many variables but a few thoughts for you. drop a third of your road pressures as a start point. Then see how you go if the car is struggling drop a little more. The biggest variable is the type of sand and how wet it is. You can safly drop to 15psi and you can go lower with caution.
I'm going to make myself unpopular here and say that rear axle and/or tyre is overloaded. If you're at 30+psi cold on a 33" tyre and it's bulging hardcore like that, and increasing by at least 6 psi hot then you're asking too much of it. Those Toyos are rated to about 1.4tonnes in a single tyre configuration but at that load they should be being used at close to their max inflation pressure to maintain sidewall stiffness and minimise heat buildup from constant flexing. Max tyre pressure for the 285/75 or 33" tyres is rated at 80 psi according to Toyo. I tend to feel that if you're going to load those tyres up that heavily, at pressures that low, 110km/h for hours on end is courting disaster. I could be wrong, and happy to hear arguments to the contrary.
I totally agree. When at high speed I was setting them at 50psi cold. The canter lever of the tray is the killer. I’d like to see the rtt on the cab. I tried to get as much weight forward as possible. It’s a common 79 problem apparently.
Hey Matt, I have been 4WDing a short while and fairly confident with pressures so far but I do have a question please. Can you give some advice regarding the trade off between lower tyre pressures on a track with loose rock, perhaps a bit slippery, bit of mud etc and therefore having the sidewall more exposed to sharp sticks, tree roots etc. I have Maxxis Razor at811 which have an aggressive sidewall adding some protection but this is deceased as the pressure is lowered. Of course I try and pick my lines and avoid anything sharp. Thanks.
Yes the sidewall is a consideration. I have the same tyre on the landcruiser. It will require you’re own assessment with watching the tyre perform. There’s no way I can tell you the right pressure to run
Back in the day you used to be able to get manufacturer data on load, temp,pressure. But even then you need to use your head. New vehicles are coming with very high pressures from the factory as that improves fuel for the manufacturers avg consumption figures. Only a car, but a direct example, vauxhall mokka comes with 44psi on eco settings and 28 on comfort. So manu figures not always useful for off-road vehicles. I've tended to use hand on surface as the test. Like you say too hot to handle - do something about it. Formula 1 use pyrometers to get the best from their tyres so it isn't stupid 🙂
@@MadMatt4WD Lay 2 sticks on ground at each end the contact patch or draw a line in the dirt and yes measure contact patch length . compare fronts to back tyres
Yes, in the shade. Not after sitting in hot sun for a while. Also you don't want to end up with different pressures on sunny side vs shady side of vehicle.
I can't believe you can put that much weight on a 5 bolt wheel. My Toyota 4Runner has 6 bolt wheels with 33" tires. Good video, you can't just say everyone needs to be at "xx" pounds of tire pressure. A heat gun might be a good method of determination of minimum tire pressure at whatever speed you chose.
Your Videos are so instructive. As a newbie at this off road sport, I really appreciate it. Thanks Matt!
Thanks Gary. I really do try.
Hey awesome seeing ya put out a new vid👍👍. Off road I run my 35" Toyo RT on 17's at 18 to 22psi
Ram 1500
Lake Havasu 🌞 Az USA
Cheers. We’re working on it.
Cheers. We’re working on it.
Another great vid. I’m amazed how many times I see people with hard tyres off road. It doesn’t help with handling and grip but damages the track.
Keep up the great work Matt. 👏👏👏
Thank you kindly Jack.
I use the old 4 psi rule on and off road. Works a treat with a tyre preasure monitoring system as you get real time feedback. I run a 2017 hilux, fully loaded with 20 in front, 25 in the rear
Yes that’s a great rule of thumb.
A bigggggg HI to you from Dubai!!!!!!.
This is a beautiful advice Matt. We offroad in extremely soft sand in UAE/Dubai deserts. We keep a maximum of 15psi. Sometimes we drive at 6psi to counter the utmost softness of the sand. Putting a deadlock ensures that we avoid any pop-outs at such low pressures.
I would love to come and drive your sand. It looks so soft. Yes beadlocks allow a whole nother level of capability.
@@MadMatt4WD would be glad to host you whenever you come here 😊👍
Thanks Matt, always great educational vids. my MY18 Dmax is heavy tourer (3200kg touring weight with GVM upgrade maximum of 3600kg from Lovells. Same Toyo Open Country AT II but in 245/70 R 16 on stock steel wheels. From Toyo Tech Mgr Steve in Victoria here pressures for my individual axle weights from Rim and Tyre Association charts are
Highway F 50 PSI R 56 PSI (Cold pressures in PSI)
Off road F38 PSI R 49 PSI
Rocky F33 PSI R 44 PSI
Sand F21 PSI R 27 PSI
Speeds dropped down to 80kph off road, rocky appropriate and sand 30kph or appropriately lower. Pressure obtained from supplying Steve with the front and rear axle load weights.
That’s some great info. Cheers
@@MadMatt4WD I have the weights on each axle to determine individual wheel and tyre weights.
Almost three minutes into your video, here, Matt, and good on ya to have mentioned "Cold Inflation Pressures" - This is important for those who're starting to become aware of how to manage their tires through pressures adjustments. It's critical, actually. ONE THING THAT HELP IMMENSELY these days in modern road-going rigs is TPMS and their pressure readouts in the instrument cluster! There, one can see the tires' "running" pressures, as Matt has demonstrated here. "Cold Inflation Pressures" are the base of your knowledge going forward (or in reverse when necessary) to manage your tire pressures when off highway, in the sand or in the bush (posting from the USA so please forgive my mangling of your slang).
Matt! What Load Range are these tires? and might you do a vid or direct us to an explanation/translation of the AUS' "2-ply" vs "3-ply" tire construction? I am aware that 3-ply may infer the old 10-ply (cotton fabric ply) E Load Range standard here in the states... I'll soon be running a new Toyo ATIII 34 X 10.50 X 17 - D Load Range.
Great comment. I’ll look at doing a video on tyre ply and construction. I have access to a Maxxis tyre engineer.
Contrarian view.
On my XJ I run 33” BFG All Terrains at 35 PSI all the time. I do moderate off-roading/crawling here in the desert southwest US. Typically sticking to trails rated 6 and below. It is very rare that I need to air down to make it over anything. I quit airing down after several punctures and until a couple months ago I went years without one. This was the result of me channeling my inner 18 year old and no pressure setting was gonna save that tire.
In short I may be giving up some performance and ride quality but I don’t think it is nearly as much as people think for either. But my tires last until they are worn down.
G'day America, good to see you.
@@glenwillson5073 Thank you, sir.
Interesting. This certainly goes against the common principles but if that’s what works for you go for it
What sort of speeds would you do on the desert trails? I imagine rocks would puncture tyres at speed when deflated. Sidewall punctures or tread area punctures? Just trying to understand as highway pressures go against common practice here in Aust.
35 psi is not aired down. I run 33 psi on the pavement. 14 psi to 16 psi is aired down. 35 psi you need a new spine.
My special tracks are at 18psi front and 20psi back on my 110 defender that's my road pressure. Any more and I see center wear. Less than that and it chews the side lugs.
Off road I don't drop them much most of the time. Usually down to about 12 or 15 up front and about and about 18 inthe back.
No idea what I'd run on your rig. You've probably got it about right for you
The rule of thumb when I worked in the engine room on a submarine was 4 seconds when you put your hand on the item was equal to 104 degrees ferenhiet. When you get up to that temperature you starting to do damage.
Sorry I didn't convert it to Celsius for you.
That’s cool.
Lol we can cope with that but usually Americans can’t cope the other way.
I like that you're making me have a good think...
It appears to me like the rear tyres are bagged out a little more than the fronts. This could be just the ground that each tyre is resting on making it look that way, but I have my doubts. I think that the 6 psi temperature induced pressure rise in the rears compared to the 2 psi rise in the fronts also suggests that more sidewall flexing is going on in the rears, but the extra weight in the rear will also contribute to this.
Another consideration is what happens to the tyre over bumps or during suspension compressions, which momentarily compresses the tyre even further. Obviously, the sidewall flexes even further, so an allowance needs to be made for this.
I think it may be ideal to increase the rear pressures a few psi, and possibly drop the fronts a touch further. That's what I'd try. Beyond that, I think it comes down to the feel of the vehicle - finding the balance between getting too squirmy and still being comfortable.
I noticed another commenter mentioned about ground pressure and basically suggested having the tyres that are carrying more weight bag out further to keep the ground pressure more even between axles. I think that would be quite relevant on really soft surfaces to stop or reduce the tyres sinking into the ground, but on a relatively firm track, I don't think ground pressure is such a consideration...
I really enjoy you content, and appreciate the time you evidently take responding to so many of the comments!
Thanks Matt!
I glad it makes you think. We’re all learning here.
I've seen mentioned, more than once, that the 4 psi pressure difference test between cold & hot pressure is for non-Light Truck tyres. (passenger, highway tyres really).
But for Light Truck tyres the difference should be 5 or 6 psi.
As a start point either would work.
As a start point either would work.
You have to take into account the side wall ply rating .Say a 10 ply you need to let more air out to get the same foot print as a 4 or 6 ply rated side wall. A 6 ply rated side wall you may need to take to 28 psi and 10 ply to 18 to get the same foot print.
Totally agree
I've been experimenting with 18psi front and back offroad but that's without a serious load. I'm very happy with that so far. I think the biggest concern is going below 16 psi because at 15psi you're pretty much at atmospheric pressure. Any lateral force will start to unbead your tyres at that point.
Every tyre and situation is different. On my Bundera I can go down to 12psi in rock.
Incorrect, 15psi is double atmospheric pressure. The tyre has one atmosphere inside when it's deflated.
I run 33” mud tyres. Troopy weighs 3.2 tonnes fully loaded.
I run 18psi (hot). I see the tyre temps reach a max of 70° (via TPMS) when doing 90-100kmh on dirt roads. May go down to 12psi when desert exploring.
No punctures or tyre failures to report in 10-15 years of exploring.
I only regard tyre life to be 4years and not actual wear as time degrades the carcass and causes issues after this duration.
Great video.
Great comment. Thanks
That 70 series is a tough nut to crack because it is so cantalevered in the back. In the back you want to air down some so that it is supple enough when you hit obstructions, but not so low that it doesn't hold the extra load, potentially risking the tire getting pinched. I wouldn't lower the rear pressure much more than you already have it, maybe a 2-3 lbs. The front can go really low since so much weight is transferred to the back. You really don't want anymore weight transfer when the front tire strikes an obstruction. I would say you could lower the front another 5-10 psi. If the rear axle was back further, you could be more even front to back.
The canter lever element makes it very difficult Offroad.
I'd guess 20-25 psi on that setup? I run about 20 psi off road on my rig with 37x12.50r17 tires but it weighs north of 8k lbs. The 42" tall 15" wide tires on my Jeep don't begin to belly out until they're down in the low single digits.
You raise a good point. Tyre size and wall along with vehicle weight all play a part
I just got my tyres done and the shop had the rears at 40 and the fronts at 37/38(my gauge isn’t super accurate but I’d say 38)
So that’s what I’m sticking to until they wear a bit but I’ll be experimenting when I off-road, kinda just air up to 35 drive for a bit, see if I like it then compare to 40 again
Infact just went and gauged it seems I’m at 37 rear anyhow lol
Must have done it dodgy
Well done.
Thanks Matt. Love your approach in delivering a lesson for the masses so gently by making it appear like a curiosity question - genius!
Just an observation/guess about when a tyre hits a rock at 110km/h, I suspect that it is similar to an object hitting water at 110km/h - the water is very hard, so I imagine that momentarily, the tyre will respond as if it too is super hard pretty much regardless of the pressure. I don't think the tyre has time to conform to a rock at that speed - my guess is the tyre's shape remains intact and the forces are transmitted through the tyre to the wheel and then to the suspension. Mind you, we are talking about 110km/h, at 60km/h the compliance of the tyre will be much more apparent and I expect will deform appreciably to accommodate the impost of a 4" rock., but at 110km/h - I doubt much compliant deformation occurs.
It makes one really stand back and marvel at the robustness of today's tyres! They've thought, tested, researched and developed solutions for this! You have to hand it to the engineers for the structural design and chemists for the compounds developed for off-road tyres.
Thanks mate nice pick up. I’m not well known for my subtleness . I’ve pondered the speed element as well but don’t know. Yes they are amazing.
@@MadMatt4WD I didn't say subtle, I said genius! :)
Personally, I generally run equal front and rear. I’m not a physicists, but the lower the pressure of the tyre, the lower the ground pressure that tyre pushes to the ground. If you put more air in a tyre to account for the load, then the ground pressure will go up as-well and you’ll get the negative consequences. That being being the case, having a higher load on the rear will mean the tyre will flex more and result is more heat build up. So, I actually put a lot of effort in to equalising the weight distribution across the vehicle to prevent this being an issue. It’s obviously very beneficial for handling as-well. Its gonna be hard to do that in a dual cab 79 though.
You’re 100% right about getting the load spread out and correct. I tried hard to do that but fought a losing battle. I’m not sure the equal tyre pressure concept makes sense if I’ve understood you correctly. Thanks for the comment.
@@MadMatt4WD basically… and I used to do it too… people often run higher rear pressure to make up for the extra weight over the rear axle. To create the same about of contact patch as the front. However, if the contact patch is the same, and the weight over the rear higher, then the ground pressure must be higher in the rear then the front, meaning the rear tyres will more likely dig in soft terrain compared to the front.
I’m not suggesting that you should run equal pressures the way the truck is loaded, I’m just saying that ideally, you’d try to get as close to equal pressures as possible to improve off-road performance. You’d have more chance of achieving that in a wagon I reckon.
@@MadMatt4WD I guess another way to think of it is a truck… they use more tyres to spread the weight under the load. More tyres, more surface area = less ground pressure. The only way to get more surface area with a single axle is with lower tyre pressures, or have larger rear tyre, like a tractor.
Ah now I understand what your getting at. I’d agree
Also, the sidewalls are not designed to flex at the lower pressures so it's a bit hard on them.
That would be an interesting question to ask the tyre engineer.
When I explain to folks why lower tire pressure creates heat I remind them of bending a metal coat hanger wire and how it gets hot. This seems to click with most people.
Now I like that. Thanks
Very educational. Thanks
Glad it was helpful!
Good information. You say 33” (dia.) but what is the actual size/profile of those particular tyres. I have found different tyre sizes require slightly different pressures.
I agree. 285/75-16
Great information!! Thanks!
My pleasure.
First and foremost, the excessive overhang on the rear axle on most if not all dual cab vehicles are a poor design. The amount of leverage it has can easily be seen by the amount of excessive lift of the front suspension and less of a footprint of the front tyres. As for tyre pressures, when a tyre is cold, take note of what the pressures are on all four tyres, then after driving, for some time, for example 20-30 minutes, stop and check the now warmer temperatures, if the pressures have increased over 4psi, then you need to increase the tyre pressure to reduce the flexing of the tyre, which is the cause of the tyre increasing more than the 4psi. The Pirelle (not sure of the spelling) tyre company many years ago came out with this recommendation. I have personally used this recommendation for over 35 years now and have found that it works. Obviously it will take some time to find the sweet spot, for each different load and is also dependent on the road conditions (including road and air temperature) and last but not least, the vehicle’s speed, with heavy loads l prefer to keep the speed, well below 110kph.
front looks okay rear for the weight looks slightly a bit under deflated . but I think it's coz they are a all terrain not a LT mud terrain construction. they are softer .
Yes
what is average pressure u use on average beach not a tourer just a ute i use beach fishing
There's many variables but a few thoughts for you. drop a third of your road pressures as a start point. Then see how you go if the car is struggling drop a little more. The biggest variable is the type of sand and how wet it is. You can safly drop to 15psi and you can go lower with caution.
Thanks for the video✊🏽 I’m new to 4WD but would the pressure of the tyres be dependant on the weight distribution of the car?
Absolutely. I believe I mention that in the video
Awesome content ! Can I run 285 70 17 tires on my 17"x8.5 rim ?
Quite possibly but check with your tyre store
I'm going to make myself unpopular here and say that rear axle and/or tyre is overloaded. If you're at 30+psi cold on a 33" tyre and it's bulging hardcore like that, and increasing by at least 6 psi hot then you're asking too much of it. Those Toyos are rated to about 1.4tonnes in a single tyre configuration but at that load they should be being used at close to their max inflation pressure to maintain sidewall stiffness and minimise heat buildup from constant flexing. Max tyre pressure for the 285/75 or 33" tyres is rated at 80 psi according to Toyo. I tend to feel that if you're going to load those tyres up that heavily, at pressures that low, 110km/h for hours on end is courting disaster. I could be wrong, and happy to hear arguments to the contrary.
I totally agree. When at high speed I was setting them at 50psi cold. The canter lever of the tray is the killer. I’d like to see the rtt on the cab. I tried to get as much weight forward as possible. It’s a common 79 problem apparently.
Matt, are you trying to pressure us into talking about tire pressure? 🤣 Good video 👍
Lol
Start with 40psi F, 50psi B, on the black top. Drop 15psi on all for gravel. Drop 24psi for sand. Monitor it suck it and see.
Yep.
Hey Matt, I have been 4WDing a short while and fairly confident with pressures so far but I do have a question please. Can you give some advice regarding the trade off between lower tyre pressures on a track with loose rock, perhaps a bit slippery, bit of mud etc and therefore having the sidewall more exposed to sharp sticks, tree roots etc. I have Maxxis Razor at811 which have an aggressive sidewall adding some protection but this is deceased as the pressure is lowered. Of course I try and pick my lines and avoid anything sharp. Thanks.
Yes the sidewall is a consideration. I have the same tyre on the landcruiser. It will require you’re own assessment with watching the tyre perform. There’s no way I can tell you the right pressure to run
Does anyone know if the modern heat reading thermometers for humans would be OK for tyre heat reading?
I would think so
Back in the day you used to be able to get manufacturer data on load, temp,pressure. But even then you need to use your head.
New vehicles are coming with very high pressures from the factory as that improves fuel for the manufacturers avg consumption figures.
Only a car, but a direct example, vauxhall mokka comes with 44psi on eco settings and 28 on comfort. So manu figures not always useful for off-road vehicles. I've tended to use hand on surface as the test. Like you say too hot to handle - do something about it.
Formula 1 use pyrometers to get the best from their tyres so it isn't stupid 🙂
Very interesting. Thanks
Matt show the stick trick to get the foot print even front and back
As in using it like a ruler
@@MadMatt4WD Lay 2 sticks on ground at each end the contact patch or draw a line in the dirt and yes measure contact patch length . compare fronts to back tyres
Ah yes I’ve used that. Usually it easy to see.
Cold in the shade on a cool surface?
Generally first thing in the morning is how I think of it.
Yes, in the shade. Not after sitting in hot sun for a while. Also you don't want to end up with different pressures on sunny side vs shady side of vehicle.
What is a good tire pressure on gravel roads?
A very rough rule of thumb is drop 1 third of the pressure you run onroad as a starting point. Then monitor tyre temperature.
I can't believe you can put that much weight on a 5 bolt wheel. My Toyota 4Runner has 6 bolt wheels with 33" tires.
Good video, you can't just say everyone needs to be at "xx" pounds of tire pressure. A heat gun might be a good method of determination of minimum tire pressure at whatever speed you chose.
Old Jeep M 715 1.25 ton trucks had 5 lug wheels. My Jeep CJ has Dana 60 axles with 5 lug wheels and 42"x15" tires.
I get you on the 5 stud thing but it works. Engineers are very clever some times.
@@MadMatt4WD I guess I did see a class A motorhome with a 6 bolt wheel. A giant bus of a thing.
The 6 bolt Toyota hubs use 12mm studs. The 5 bolt Toyota hubs use 14mm studs. The larger fasteners make up the difference.