22" pentagons?

Alright do you see professional race cars with low profile tyres? Pretty sure they wouldn't use 20 or 25 wall tyres.

 

Vongy is correct. In order for tires to work correctly you need some amount of sidewall flex to absorb the small undulations of even the smoothest road. Weather it's longitudinal or latitudinal grip, you need some amount of "shock absorbsion" within the sidewalls of the tire. I am not a fan of Top Gear Australia but they did make a very valid point a few years back where they ran the same car (HSV something or other) around their track changing only the tires from 20" to 18" (or 19??). It's on youtube somewhere. The smaller wheel was faster around the track by quite a bit.

If you look at virtually every racing category in the world where tire grip is important you will find relatively high tire profiles (unless the rules limit it). Like everything it's a compromise. The old 75 series tires were way too much tire wall whilst these days 20 series is not enough. Not to mention a lack of tire with such a low profile that will offer the load rating needed for a Commodore.

Reaper

 

Im pretty sure it was top gear uk testing the vaxhuall vxr8 an they went from a 20" to 22" an the car was faster on the 20".

 

NEW Top Gear Aus: Ep2 - HSV R8 vs Walkinshaw R8 - YouTube

 

Might have been - I just seem to remember the little weasel guy with the half arsed beard going on about it. Maybe UK did a similar thing??

Ahhh - thats the one. Thanks - illustrates my point perfectly

Reaper

 

Here you go.

 

No, you don't. Your first comparison was stupid though :thumbsup:

 

Mate in what way was it stupid? Drag racing needs grip as well, you didn't say anything about handling.

^ This was stupid. More rubber, more grip. Common sense.

 

Stoner - your out of straws. I'd give up whilst you are behind if I were you.

Actually that's not exactly right either. Within reason, 2 tires that are otherwise identical where one is (say) 205 and the other is 225 will produce exactly the same levels of grip to each other when fitted to the same corner of the same car (not at the same time obviously :bang. The difference will be the 225 tire will last longer in most cases. For more grip, you need to fit a softer compound which in turn will lower the longevity of a tire. Thus, bigger tire gives you a longer life with a softer compound which in turn gives you more grip. Of course there are limits to this, particularly on wheels that steer.

Reaper

 

Hmm I was thinking more of circuit and drag racing but i guess you're right. NASCAR do that when they race around a ring right?

 

lol at this thread. I have also seen replica pentagons in 22" for sale a while ago. they are out there but are replicas only

 

I was agreeing with him :thumbsup: