School me on wheel diameter.

[808toy]

I did a search and found a few threads that were pretty vague. If anyone can point me in the direction of thread specifically on this, thanks in advance. At any rate, a buddy of mine was debating between a 15, 16, 16.5, and 17 beadlock wheel and was curious as to what the pros/cons of the various sizes and more specifically, what would fit his application. He has a 80's Toy pickup with about 300 lbs of added weight, including cage and gear.

Reading through some of the threads, people tend to gravitate towards the 15" wheel with tires 36" and below and then increase wheel diameter with increasing tire diameter. Considering the use of a single (outside) beadlock and a 36", what are the theories of using a bigger diameter wheel vs. smaller and vice versa? Also, what are you folks running and what quirks (offroad) have you noticed? Thanks in advance.

[StockChevy]

I like the smallest diameter wheel possibe (15") simply because of the larger sidewall area. My 44's are on 15" wheels and I love it.

Ya, sometimes you have to do a little grinding to make them fit, but I would not have gone any bigger.

[edubreuil]

The trade off on small diameter wheels, with large diameter tires, is side wall roll. On a side hill running reduced tire pressure, the weight of the vehicle tends to roll the tire. Even with beadlocks, this causes stabiliity problems. Large diameter wheels reduce sidewall height. I have seen a general thumb rule for off road tire/ wheel size ratio of 2:1. That being said, I run 37's on 15" wheels. I do notice the sidewall roll at very low pressures, but it is liveable.

[87YJ]

The overall market move toward larger wheel diameters is driven mainly by two factors. 1) wheels look cooler than tires - most people think larger wheels look better. 2) Larger wheels are required as brakes grow larger.

For your buddy, I'm guessing (hoping if you're posting here) that mall crawler looks aren't the priority and he's prolly on stock brakes that will fit in a 15 wheel.

For 36's, a 15" wheel will work well and give you more options. There will be plenty of sidewall to flex and shouldn't have stability problems if you stay with a good quality tire.

Stay away from 16.5's and 16's won't give many options either. 17's are generally going to be more expensive but it would be the best route if another upgrade using the same bolt pattern axles may be happening in the future.

[808toy]

Thanks guys! Yes, my friend doesn't take this truck out much except for the trail runs we make and to tote his dirt bike to the track. I was thinking along the lines of what Edubreuil mentioned regarding the sidewall roll. Things have been mentioned in the past about this and how this could possibly have negative effects on traction and the tire itself. His truck does have the stock brakes and would physically fit the 15" wheels and is what I would consider a light to medium weight rig. At the weight he is at, I think he could possibly roll the sidewall over and would probably want to stay away from that. Are there any other issues similar to sidewall roll that would point him in the direction of a larger or smaller diameter wheel? Thanks

[Krusty]

stay with "15 rims and go 36" tires- the side wall 'roll' is not enough to be concerned about !
there is a lot of flex to a 36 with 6-7# trail pressure. Better traction, less chance of a puncture on a sharp rock and the sidewall will take up most of the bumps on a motorcycle cut whoops dirt road. The price and availability of rubber is a factor to also consider. IF you want BLING-- bolt on some spinners to the 15" wheel !!!

[conny3737]

as long as you aren't going to go with some kind of bigger brake setup, stay with 15's. especially since you're going with beadlocks, you can air down and get a nice footprint without worrying about popping bead.

[Old Scout]

The overall market move toward larger wheel diameters is driven mainly by two factors. 1) wheels look cooler than tires - most people think larger wheels look better. 2) Larger wheels are required as brakes grow larger.

For your buddy, I'm guessing (hoping if you're posting here) that mall crawler looks aren't the priority and he's prolly on stock brakes that will fit in a 15 wheel.

For 36's, a 15" wheel will work well and give you more options. There will be plenty of sidewall to flex and shouldn't have stability problems if you stay with a good quality tire.

Stay away from 16.5's and 16's won't give many options either. 17's are generally going to be more expensive but it would be the best route if another upgrade using the same bolt pattern axles may be happening in the future.


Two factors? Better add more traction due to less tread squirm! :shaking:

[808toy]

Two factors? Better add more traction due to less tread squirm! :shaking:

Can you explain the "tread squirm"? Thanks in advance.

[Old Scout]

Can you explain the "tread squirm"? Thanks in advance.
There is too much side wall movement when aired down at the contact patch A wrinkle will develop in the tread contact area and the tire will have less traction because of it.