Outer Limits 4x4 Board

This is why meeting each other out wheeling on weekends or at comps is important, some one u thought was a d*ck is more than likly a really good bloke that cant be botherd typing a fancy post to keep everyone happy so just types what he thinks, and sometimes it comes across wrong.

This is why talking to people face to face is so much better.

So when is every one coming over to WA???

I think its obvious why one tyre is out preforming the other. One has a higher side wall than the other. This gives it more flex, hes its better able to maintain contact/grip with the surface.
Why are manufactures going to 17" rims ? Solly to fit bigger brakes inside the rims. Will that be good for crawling ? Only time will tell.
Peter.

PS, Tim, keep the report coming.

Zute wrote:I think its obvious why one tyre is out preforming the other. One has a higher side wall than the other. This gives it more flex, hes its better able to maintain contact/grip with the surface.
Why are manufactures going to 17" rims ? Solly to fit bigger brakes inside the rims. Will that be good for crawling ? Only time will tell.
Peter.

PS, Tim, keep the report coming.

Geez, i feel like i shouldn't reply. Just in case people think i am cutting them down.

Anyway, a smaller sidewall is better for (competititive) Rockcrawling. By smaller i meen larger rim diameter. So in fact a larger Rim Say 17", 18" and 20" (on a 40" tyre) are very good.

The reason most Rockcrawlers aim for a larger Rim and less sidewall is to reduce the amount that the tyre will roll under the rim when turning and especially turning in an off-camber situation. It actually keeps the face of the tread in contact with the ground longer rather than the tyre rolling under and slipping. This is also why Radials are all the rage against Bias ply tyres.

Sorta like Low profile tyres on race cars.

Like you said it also has an added bonus of using alot larger disk brake set-up which helps alot in crawling.

Hope that makes some sense.

Cheers!

Ok most importantly, what are they worth? Thinking about 35x13.5, what will they cost me and from where in vic? Cheers.

Good reply. I still disagree with the low profile tyre.
Low pro' tyres work well on flat smooth race tracks, but on uneven rocks surfaces the tyre needs to conform to the surface.
If the tyre is rolling off the rim, than presses need to be increased.
Side walls also need to match the weight of the car, so they flex. Cooper stt would not work well on a Zook, but MTR's do seem to flex more readily, and be the better tyre.
As a point of interest, F1's use a 13" rim (as per rules) and use a high side walled tyre. The designers have used this rule to design a tyre that flattens out under braking to give a larger foot print for more grip. The flexing also allows it to curb hop without having to build in more suspension travel.
Also watch a drag car's rear tyres, there not a low profile.

Zute - F1 and drag cars dont sit on a 45 degree side angle on the sidewall of their tyre

Too much sidewall WILL hurt your performance. Notice I said "too much". Obviously you need some but it becomes a game of negative return once you reach a certain point. 15" rims have been fine with the 35" tyre brigade - even up to 37s. But once you get into the 40"+ range - bigger rims are the better performers They are more stable.

Think of it this way. A 35" tyre on a 15" rim gives 10" of sidewall. A 40" tyre on a 17" rim gives 11.5". So you can see the bigger rim and tyre still gives a similar amount of sidewall

EDIT - Oh yeah, having said all that, Im still running 40" tyres on 15" rims