19" Or 20"

[96ET]

Hey Guys,

I was hoping use could help me out.

I want to get some new rims for my G6ET and I cant not decide 19 or 20inch ?

I dont want to buy 20" if the only pro is that they look better.

I would prefer 19" but think they may look small.

The main purpose for this car is just street use and the odd run down the quater as I continue with more mods.

Your advice will be greatly appricated.

Thanks,

Matt

[Bellato]

Only advantage to 20's they look better lol. FG's have huge guards and 19's don't quite fill the guards but if your not after looks then go staggered 19's

[Bonjaz]

I was in the same basket a month ago, I threw it in the too hard basket and ordered 2 new 18" tyres

[Oni]

If you assume that most of the mass in the wheel is in the rim not the spokes, no doubt some may argue against this, then the 20s are killers for the 1/4mile so get 19s. The moment of inertia for a wheel will be that for a cylinder and all other points being equal the difference of the squares in the radius is the only difference. Therefore for 19s the radius is 9.5 and that squared is 90.25 but for 20s the radius is 10 and therefore we end up with the moment for 20s being ~10% more difficult to get going than 19s! It's about 19% for 18s.

So, 19s better for performance but 20s look better. Yes the overall rolling diameter is the same depending on profile but I'm sure the mass of the wheel is the key to the problem not the tyre.

All of this is from my long distant memory so may be wrong in several ways

Cheers

Geoff

Edited 07/11/12 09:56 AM by Oni

[96ET]

Wow great info thanks mate