You guys nailed it right on. I ran and 18/21 on stock power then to a bypassed then on my current 72v. Hands down if you plan to go this tire size you need to plan for a controller and battery upgrade. Also, adding a larger sprocket with a 72v will bring down your top speed and help you spin the additional weight with the 18/21. Gives you a little more acceleration. I know you guys also know this but maybe help someone scrolling through the comments. Great video and keep it up!
Check out our HUGE tire weight database here: chargedcycleworks.com/pages/sur-ron-tire-upgrade-specs-and-weights Slightly confused by your question, you shouldn't be running a 70/100-19 with a 80/100-21, the front is going to drastically overpower the rear in traction and make the bike handle badly. If you can still find Michelin Starcross 5 tires, those are some of the lightest and highest performing tires on the market. We still have a few left, but they are end-of-life and dissappearing quickly. chargedcycleworks.com/products/michelin-starcross-5-medium-terrain-front-tire
Just putting it out there that I have a 2020 XX black Friday Luna sale and have been slowly making it feel more comfortable. I just did a old version Fox 40 (used and cheap) and a 21/18 upgrade along with .75" riser. I put a 56 tooth on and I am more than happy with the XX power. 230 lbs rider, PNW single track intermediate skills. This bike feels more like my dirtbikes and less like a kids bike with plenty of power. It doesn't replace my gas bikes or my mtb's, just another toy. I will upgrade power when I blow something up and have to. Suspension and wheels has been more important for me.
XX has about 60% more power than an X. If you had a standard X you would not like the 18/21 nearly as much makes an already slow bike even slower. But with 8kw or more it hides the weight and gets pretty good. I agree, I’ll take suspension and great tires over power any day!
Hi guys, have you tried 19'' front wheel with a good MX tyre and 18'' rear setup? With MX front tyre your bike's geometry shouldn't change too much...? I have a Talaria and looking either 19/16 or 19/18 setup, I feel like the 16 inch rear wheel might make the rear end too low. Thanks for any feedback.
The problem with 18/19 is that an 18" MX tire was designed to work with a 21" up front. They are much larger diameter than the 70/100-19 tires on the surron. This will create a "stink bug" geometry where the rear end is taller than the front and causes odd body position and poor handling. If you keep a 19" up front the 16" rear is where it's at.
What rear suspension riser size works best for 18"/21" to maintain stock geometry? I'd have thought 1.5" riser as its aprox half the overall height difference but I hear of 0.75" risers being used?
That's a tough one, you certainly can do this but you'll find the front end lacks traction compared to the rear and your rear will be about 2" taller which throws off your geometry quite a lot. If you go this route definitely use a Dunlop MX33 70/100-19 up front, it's the largest tire of this size....doesn't fit inside an RST fork
The reason we prefer 18" rear is because 90/100-18 tires actually fit the surron and they are surprisingly light weight for their size. If you install a 100/90-19 tire you will have clearance issues and gain multiple pounds more weight.
Im looking at running 18/18 for better tyre choices and still trying to keep the same feel/look of the standard 19/19 setup, Do you recommend any tyres that would be more oriented towards daily commuting on the street and some off road at the weekend, May even consider a 19/18 wheel setup but not sure on wheel widths ?
You need to look to the Motocross industry and then you'll understand why we select the tire/wheel sizes that we do. 19 (70/100) and 21 are front tires and 18 and 19 (100/90+) are rear tires. These tires are designed specifically for front or rear application and this is why they are so popular on Surron. When we run 70/100-19 in the rear of Surron we are running front tires and the performance is not great, they were made to turn a bike up front not to propel it forward. There is no such thing as an 18" front MX tire, don't even go down that road. Find someone with a 16/19 and give it a ride, you'll be blown away with how it maintains the fun and nimble nature of the surron but provides massive traction and handling benefits.
@@ChargedCycleWorks I'm sure I seen Vividracing list a Kenda K270 2.75-18 front tyre on their website, But if a 21 will offer we better tyre choices down the line it seems like the better option
If you look at the thumbnail image of this video from Left to Right: 21, 18, 19, 16. The 21" is a monster sized tire which is part of the reason there is such a large weight gain and change in steering precision. The stock CST tires are not shown in this video and are much smaller than a normal MX 70/100-19 tire like the MX33, the diameter of them is about the same as a 90/100-16 rear tire. When we install 19/16 with a .75" linkage the bike is overall slightly taller than it came from the factory. With 18/21 like SurronSD said it's much taller, we've never taken an exact measurement, next time we have a stock bike in the shop we'll try to do that.
You guys nailed it right on. I ran and 18/21 on stock power then to a bypassed then on my current 72v. Hands down if you plan to go this tire size you need to plan for a controller and battery upgrade. Also, adding a larger sprocket with a 72v will bring down your top speed and help you spin the additional weight with the 18/21. Gives you a little more acceleration. I know you guys also know this but maybe help someone scrolling through the comments. Great video and keep it up!
I appreciate your guides and write up
Would happy buy from you but I'm in aus. The info has been extremely helpful
Great video, thanks. What about the Pirelli Scorpion XC 80/100 r21? Do you know its weight, please? I don't see any Pirellis on your site.
Ayuda ! Hacéis envíos a España ??
Little late seeing the video… but what is the correct size for the 21 inch Michelin Starcross tire? Planning it for a Talaria Sting.
Awesome.
Whats is most lightweight set 70-100-19" rear, and 80-100-21" for enduro?
Check out our HUGE tire weight database here: chargedcycleworks.com/pages/sur-ron-tire-upgrade-specs-and-weights
Slightly confused by your question, you shouldn't be running a 70/100-19 with a 80/100-21, the front is going to drastically overpower the rear in traction and make the bike handle badly. If you can still find Michelin Starcross 5 tires, those are some of the lightest and highest performing tires on the market. We still have a few left, but they are end-of-life and dissappearing quickly. chargedcycleworks.com/products/michelin-starcross-5-medium-terrain-front-tire
Just putting it out there that I have a 2020 XX black Friday Luna sale and have been slowly making it feel more comfortable. I just did a old version Fox 40 (used and cheap) and a 21/18 upgrade along with .75" riser. I put a 56 tooth on and I am more than happy with the XX power. 230 lbs rider, PNW single track intermediate skills. This bike feels more like my dirtbikes and less like a kids bike with plenty of power. It doesn't replace my gas bikes or my mtb's, just another toy. I will upgrade power when I blow something up and have to. Suspension and wheels has been more important for me.
XX has about 60% more power than an X. If you had a standard X you would not like the 18/21 nearly as much makes an already slow bike even slower. But with 8kw or more it hides the weight and gets pretty good. I agree, I’ll take suspension and great tires over power any day!
Hi guys, have you tried 19'' front wheel with a good MX tyre and 18'' rear setup? With MX front tyre your bike's geometry shouldn't change too much...? I have a Talaria and looking either 19/16 or 19/18 setup, I feel like the 16 inch rear wheel might make the rear end too low. Thanks for any feedback.
Would a 18/19 still feel nice ? I’m abit shorter and already for 2/3 inch riser bars
The problem with 18/19 is that an 18" MX tire was designed to work with a 21" up front. They are much larger diameter than the 70/100-19 tires on the surron. This will create a "stink bug" geometry where the rear end is taller than the front and causes odd body position and poor handling. If you keep a 19" up front the 16" rear is where it's at.
What rear suspension riser size works best for 18"/21" to maintain stock geometry?
I'd have thought 1.5" riser as its aprox half the overall height difference but I hear of 0.75" risers being used?
Do you have an idea when you will be getting those 18" rear tires back in stock? Looks like they are sold out everywhere :(
If you buy a wheelset from us we have tires for each wheel, but the supply chain is so bad on them we do not sell them individually.
What about using a 18 rear 19 front until I’m ready to upgrade the battery. I don’t want to go to a 16 then have to get a 18. Thanks for any advice
That's a tough one, you certainly can do this but you'll find the front end lacks traction compared to the rear and your rear will be about 2" taller which throws off your geometry quite a lot. If you go this route definitely use a Dunlop MX33 70/100-19 up front, it's the largest tire of this size....doesn't fit inside an RST fork
Any issues with 19/21? With the upgraded controller and 72v obviously
The reason we prefer 18" rear is because 90/100-18 tires actually fit the surron and they are surprisingly light weight for their size. If you install a 100/90-19 tire you will have clearance issues and gain multiple pounds more weight.
Im looking at running 18/18 for better tyre choices and still trying to keep the same feel/look of the standard 19/19 setup, Do you recommend any tyres that would be more oriented towards daily commuting on the street and some off road at the weekend, May even consider a 19/18 wheel setup but not sure on wheel widths ?
You need to look to the Motocross industry and then you'll understand why we select the tire/wheel sizes that we do. 19 (70/100) and 21 are front tires and 18 and 19 (100/90+) are rear tires. These tires are designed specifically for front or rear application and this is why they are so popular on Surron. When we run 70/100-19 in the rear of Surron we are running front tires and the performance is not great, they were made to turn a bike up front not to propel it forward. There is no such thing as an 18" front MX tire, don't even go down that road. Find someone with a 16/19 and give it a ride, you'll be blown away with how it maintains the fun and nimble nature of the surron but provides massive traction and handling benefits.
@@ChargedCycleWorks I'm sure I seen Vividracing list a Kenda K270 2.75-18 front tyre on their website, But if a 21 will offer we better tyre choices down the line it seems like the better option
Is 18/21 taller than 19/19? And by how much?
Yes it is taller by about 1.5”
If you look at the thumbnail image of this video from Left to Right: 21, 18, 19, 16. The 21" is a monster sized tire which is part of the reason there is such a large weight gain and change in steering precision. The stock CST tires are not shown in this video and are much smaller than a normal MX 70/100-19 tire like the MX33, the diameter of them is about the same as a 90/100-16 rear tire. When we install 19/16 with a .75" linkage the bike is overall slightly taller than it came from the factory. With 18/21 like SurronSD said it's much taller, we've never taken an exact measurement, next time we have a stock bike in the shop we'll try to do that.