Need tire advice - heavy 35s or lighter 37s

matt1171

New member
I've got a 2012 Rubicon with 4.10 gears currently running 35" Toyo MTs and it's time to get new tires. I know all the debates about running 37 inch tires on the factory axles. But I keep seeing EVO promoting how Evolander is running 37s with stock axles, shafts and driveshafts and they wheel it pretty hard with no issues. So I'm curious... how much difference will it make to stick with 35" toyos which are heavy tires or move up to a 37" that is actually 10lbs lighter than the toyos. I live in Arkansas so most of my wheeling is in the national forest on trails a couple times a month and at the off-road park a few times a year running 3s and 4s on a 1-5 scale. What's going to matter the most - the larger rotational mass of the 37 or the added weight of the 35" toyo?

Let me have it.
 

TheDuff

New member
The toyo's are a great tire, if you like them in a 35 I'm sure you'll love them in a 37s. I personally wouldn't worry about the weight. I liked my 33 toyo's alot more than my 35 km2's. I would highly suggest a regear though, regardless of which 37 you choose, It's all about tire roll out.
 

tpietzsch

Member
I just went through this debate on my rig and I decided to go back to 35s and slowly beef up critical parts that in time will be up to the task of handling 37s. For me, the cost of a re-gear, wheels and hydro assist in addition to tire cost was to much. My plan is to beef up things like ball joints, chromoly shafts, tie rod ends etc before making the swap. 37s is like next level shit, in my opinion.
 

jedg

New member
I just went through this debate on my rig and I decided to go back to 35s and slowly beef up critical parts that in time will be up to the task of handling 37s. For me, the cost of a re-gear, wheels and hydro assist in addition to tire cost was to much. My plan is to beef up things like ball joints, chromoly shafts, tie rod ends etc before making the swap. 37s is like next level shit, in my opinion.


Eyup... that's the conclusion I came to as well.
 

Spudcannons

New member
I just went through this debate on my rig and I decided to go back to 35s and slowly beef up critical parts that in time will be up to the task of handling 37s. For me, the cost of a re-gear, wheels and hydro assist in addition to tire cost was to much. My plan is to beef up things like ball joints, chromoly shafts, tie rod ends etc before making the swap. 37s is like next level shit, in my opinion.

I agree. I am sticking with 35" tires and have been beefing up the week points(I could run 37s or maybe even 40s but I can't bring myself to replace tires with only 3k miles on them). I think it really depends on your wheeling style and willingness to beat on the rig. You could have no issues at all or brake something that first time you really hit the skinny petal. But I would definitely regear to 5.13 for 37s I'm running 4.88 on with 35s.
 
The weight makes some difference but not enough to justify the difference between tire sizes. 35s are cheaper to run and will have some better road manners too. It sounds like your rig is mostly a road warrior and does some trails. Personally I would stick with 35s if this were how I used my Jeep. We jumped to 37s on my Jeep and I don't regret it, but it did come with the need to do some other things like hydro assist. My Jeep is a family toy and not a DD though. Just my :twocents:
 

wayoflife

Administrator
Staff member
As mentioned, 10 lbs. is NOTHING and won't make a difference. Tire size is and will. If you're concerned with breaking stuff, I personally would stick with 35's.
 

Static83

New member
If you have the itch for 37s, you're going to end up doing it anyway. I know I did. Also ended up doing gears, RCV's, artec truss and c gussets while I was at it.
 

David1tontj

New member
The weight isn't going to matter nearly as much as the leverage that the larger tire has on everything.
Try tightening a bolt with your hand really close to the center of the wrench- then try sliding your hand away from the center of the wrench and see how much more leverage you get.... That is what the larger tires are going to do... They will put more stress on your axles and components simply because of this additional leverage.


Now- that being said- A fair compromise would probably be the bfg 37s. Bfgs run small- so it'll be more like a 36" tire, and it'll still be lightweight- yet you can still say you have 37s. 😁
 

sean.m.adams33

New member
I'm running 37's with the stock 4:10 gears and only some c's. No problems. As mentioned though, if it is that much of a concern then stay 35's so that you have that peace of mind. In the end you want to enjoy your rig.
 
Sorry if this is too engineerey ;)

A long time ago while pondering this, I calculated the torque requirement to accelerate a tire at a "normal" rate to 60MPH. The calculation work is long lost, but I do still have the result graph.

The blue bar is for the lightest tire I could find in that size. While the red top is for the heaviest tire. You will notice that while the tire weight does have an impact due to the increased inertia (which has an exponential effect) The tire size is far more drastic. You can see that with almost every tire size jump the torque requirement is nearly doubled.

The biggest place you will notice the difference in tire weight will be in sustaining speed. Heavier tires (of similar friction) will have lower fuel economy. Still not a huge difference, but one none-the-less. (My calculations were about 10% so maybe 1-2 MPG???)

Anyway I thought I would share....
Microsoft Excel - Tire Size.png
 

CrazyTrainJK

Caught the Bug
Sorry if this is too engineerey ;)

A long time ago while pondering this, I calculated the torque requirement to accelerate a tire at a "normal" rate to 60MPH. The calculation work is long lost, but I do still have the result graph.

The blue bar is for the lightest tire I could find in that size. While the red top is for the heaviest tire. You will notice that while the tire weight does have an impact due to the increased inertia (which has an exponential effect) The tire size is far more drastic. You can see that with almost every tire size jump the torque requirement is nearly doubled.

The biggest place you will notice the difference in tire weight will be in sustaining speed. Heavier tires (of similar friction) will have lower fuel economy. Still not a huge difference, but one none-the-less. (My calculations were about 10% so maybe 1-2 MPG???)

Anyway I thought I would share....
View attachment 149577
Thanks for the graph. I think I can even understand the graph:rock:
 

ParkCity

New member
This is what I was thinking. A 37 Cooper stt pro with D load rating weights about the same as a Toyo 35. It would sit closer to a 36 and the width is actually less. The 35 isn't available so I was looking into the 37x12.5 D rated.

Cooper 37x12.5 D load vs a Toyo 35x12.5 E... any thoughts on how similar these would be? Anyone made that jump from a heavy 35 to a light 37?
 
Top Bottom