[kabob]

OK wanted to talk about this, whats more important when it comes to stressing axles, the weight of the tire or the size?

My toyota has had a set of 37x13x15 boggers on it forever and has been wheeled pretty hard with no real problems those tires weight in at 86# (no wheel) I was thinking about moving up to the 40" MT-r kevlar which also weigh in at 86ish pounds, Will I be ok? with the larger rotating mass?

 

[qumanchew]

I would say for wheeling/rock crawling the leverage of the larger diameter tire will exert more force than the extra weight would. If you're doing a lot of high speed stuff (pre-runner) the weight might become a larger factor.

 

[fordtrucknut77]

Ehhh I would go with the weight is an issue,
My buddy runs a wrangler that until recently had 37 boggers on it And I run a ranger on 38 tsls (much lighter than the bogger obviously) and HE would snap yukon chromoly shafts like they were pretzels. Me on the other hand I have been running the same set of alloy usa chromolys for 4 or 5 years. This is ofcourse just my theory, I am not an expert by any means!

 

[kabob]

yeah I dont know???? but I do know I would love to have the 40's and most all of my riding is rockcrawlin and trail riding no high speed stuff....

 

[theydontstop]

Both. A tall tire that weighs the same as a shorter tire for instance: the center of mass of the taller tire is farther away from the center of the hub, increasing the leverage on the axle shaft. Assuming the rubber is proportionally distributed in the same places on the tires.

 

[CRUISINFJ60]

They both play a factor for sure. Not sure what is a bigger factor tho...

lets say you have a 37 that weighs 100 lbs and a 40 that weighs the same 100 lbs even when crawling you sometimes have to bump it or throttle up stuff. On the 37 the mass is closer to the inside of the tire center since not as tall so if it does grab traction or you are trying to get it to spin there is less force due to the smaller diameter. now take a 40 at the same 100 lbs when it comes time to spin that tire it will be more stressfull for 2 reasons. 1 it is taller to leverage is affected and 2 even tho the same weight the weight is now further out from the center of the tire taking more torque to get to move, when that is added with the taller diameter (again same exact weight) it is more stress on the axle components. now if you had a 37 that weighed 120 vs a 40 that weighed 90 I would say similar stresses, but lets be honest, its hard to go bigger and not weigh more. Both are factors, keeping weight down will help but when they get taller it is more rotational force no matter what.

Clear as mud? Makes sense in my head even if bad examples.