Spedley - But aren't you less likely to lose traction with the taller tire in the first place?

 

Generally. Some times crawling something just doesn't work and you have to use some throttle and wheel spin to get up it no matter what size tiers you are on.

 

to be clear, I'm looking at the BFG MT KM2's in 37x12.50 which are D rated tires. Don't really like the idea of going to C rated on a 4 door myself. It just so happens the MT MTZ is one of the heavier tires out there.

BFG MT KM2
Part# Tire Size Rim Width Range (Min/Max) Section Width (On Measuring Rim Width) Overall Diameter Tread Depth (in 32nds) Max Load, Single (@PSI) Tire Weight
29037 LT345/75R16/D 9.5" - 12" 13.6" on 9.5" 36.4 20 3750@50 76.59
28483 LT365/75R16/C 9.5" - 12" 14.3" on 10" 37.6 20 3195@35 79.39
38371 35x12.50R17/D 8.5" - 11" 12.5" on 10" 34.8 20 3000@50 66.42
99782 37x12.50R17/D 8.5" - 11" 12.5" on 10" 36.8 20 3525@50 70.86
23241 38x14.50R17/D 10" - 12" 14.7" on 12" 37.8 20 3195@50 81.79
10977 40x14.50R17/C 10" - 12" 14.7" on 12" 39.8 20 3195@35 81.7

 

Not an expert in physics but from what I remember from college, inertia (resistance of any physical object to a change in its state of motion or rest) it what causes the axles to break.

With tires we're talking about rotational inertia, and mass (tire weihgt) and how far that mass is from the axis (tire size) is what determines the tire's inertia.

So by reducing the tire/wheel weight you could run bigger tires reducing the chances of braking an axle. Now, to know how many pounds of tire/wheel weight per inch of tire diameter increase you have to reduce, I'll let the experts in physics chime in.

 

Bottom line. Buy what you want. C rated tires would give better performance on the street. And E rated tires would give better performance on the trail. So I would say that the D rated tires are a good compromise.


I believe that there is a little more to it than that. Force plays in there somewhere. Like another poster said. Larger diameters = more force.

I though that bigger tires allows easier traversing of larger obsticles?

 

Yea but they don't have a magical compound that sticks to mud,moss or water. Even sometimes dry rock can be a challenge.

Here is 4 40" tires spinning.

http://www.youtube.com/watch?v=5509hYSiIsI

 

I didn't know that tire size and tire grip was related?

 

I agree with this. I plan on going light weight 37 on my d30 with gussets and sleeves

 

I give up.

I said sometime you spin the tires and then they hook and you replied larger tires traverse obstacles easier. I showed that larger tires still spin so your point of them traversing obstacles easier isn't true in all cases. Sometimes nothing gets grip and you just need to spin the tires.

But actually a larger tire has a larger contact patch so yes it should have more grip. That doesn't mean it will climb without spinning though.

You should step away from the computer and go wheeling some time.

 

Don't give up, bud. We're just talking. And we're talking about risk factors for those of us who just can't throw cubic money at potential problems and stuff D80's under both ends.

It's all good.