Wheel depth - difference?

Jay Levitt · 07-10-2002, 05:05 PM

While looking for new wheels to replace my slightly bent MM Spiders, I fell in love with the Abt A11. It is a 17x8 wheel. Unfortunately, it is no longer available, but its near-twin, the A23, still is. However, the A23 is only a 17x7.5 wheel.

I will be running 225/45 Bridgestone S-02PP tires. How much of a difference will I notice in traction between a 7.5" wheel and an 8" wheel? I know that the "height" won't change much, because of the steel belts, but the contact patch will still be wider with the 8" wheel.

ryoung · 07-10-2002, 06:08 PM

.
is the design rim for the 245/45-18 (anything from 7.0 to 8.5 is OK), so you will probably get better performance from the narrower rim.

In any case, though, the difference will be so small that you won't notice the handling difference. Just one psi off from the optimum pressure will have much more of an effect.

ex-quattro PETE · 07-11-2002, 01:21 AM

As far as looks - I think wider looks better though ;-)

Jay Levitt · 07-11-2002, 07:24 AM

I didn't know that the measured rim width/design rim width was actually important for optimal performance; it sounded from the Tirerack text that they had to pick SOME rim to measure the tire width, and assumed that the MRW was whatever size the industry uses for that size tire. Good to learn.

I'm not AS concerned about looks, width-wise - yes, wider looks better, but washed would look even better, and that hasn't influenced me lately...

it might be worth the $$$ importing the rims for performance, but not just for looks. Thanks.

Pelican Pete · 07-11-2002, 07:51 AM

Assuming that you would be using a 225 tire on either wheel, if the wheel is 1/2" narrower, that means you have 1/4" more curb protection (1/4" inside and 1/4" outside.)

The tire sidewall will flex to accomodate different width wheels, within a certain range. But the tread width will remain the same, hence your traction will be the same. So from a performance standpoint, you are probably better off with the narrower wheel -- it is most likely lighter too!

If you want the LOOK of the wider wheel, you could always use a 5mm spacer to push your wheels further out.
But before you do that, check the offsets of both wheels. If the 8" wheel is ET42 and the 7.5" wheel is ET35, then they will appear the same on the car.
If they are both ET35 wheels, then obviously the 8" will stick out slightly more, and have a more aggressive look. If the 7.5" wheel is ET42 it should still look good. If it is ET45, you might want to think about a spacer.

Cheers,
Peter

07-10-2002, 06:08 PM	#2
ryoung Elder Member Garage is empty, add now Join Date: Mar 2001 Posts: 11,968	I believe 7.5" ... . is the design rim for the 245/45-18 (anything from 7.0 to 8.5 is OK), so you will probably get better performance from the narrower rim. In any case, though, the difference will be so small that you won't notice the handling difference. Just one psi off from the optimum pressure will have much more of an effect. __________________ 2001 Audi S8 2007 Toyota FJ Cruiser

07-11-2002, 01:21 AM	#3
ex-quattro PETE AudiWorld Expert Garage is empty, add now Join Date: Feb 2001 Posts: 25,417	agree with ryoung - difference is so small that you'll not even notice it. As far as looks - I think wider looks better though ;-) __________________ n00b FAQ \| 2003 Official AudiWorld Postwhore \| Got questions? Audi Maintenance Schedules \| It's the truth!

07-11-2002, 07:24 AM	#4
Jay Levitt AudiWorld Member Garage is empty, add now Join Date: Mar 2000 Posts: 280	Interesting I didn't know that the measured rim width/design rim width was actually important for optimal performance; it sounded from the Tirerack text that they had to pick SOME rim to measure the tire width, and assumed that the MRW was whatever size the industry uses for that size tire. Good to learn. I'm not AS concerned about looks, width-wise - yes, wider looks better, but washed would look even better, and that hasn't influenced me lately... it might be worth the $$$ importing the rims for performance, but not just for looks. Thanks.

07-11-2002, 07:51 AM	#5
Pelican Pete AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 8,145	The narrower wheel will be better protected (more) Assuming that you would be using a 225 tire on either wheel, if the wheel is 1/2" narrower, that means you have 1/4" more curb protection (1/4" inside and 1/4" outside.) The tire sidewall will flex to accomodate different width wheels, within a certain range. But the tread width will remain the same, hence your traction will be the same. So from a performance standpoint, you are probably better off with the narrower wheel -- it is most likely lighter too! If you want the LOOK of the wider wheel, you could always use a 5mm spacer to push your wheels further out. But before you do that, check the offsets of both wheels. If the 8" wheel is ET42 and the 7.5" wheel is ET35, then they will appear the same on the car. If they are both ET35 wheels, then obviously the 8" will stick out slightly more, and have a more aggressive look. If the 7.5" wheel is ET42 it should still look good. If it is ET45, you might want to think about a spacer. Cheers, Peter __________________ New car: 2006 B7 A4 2.0TQMS, Prem, Tech, OceanBlue Sold: 1998.5 B5 A4 1.8T Quattro Sport Sept. 11, 2001 -- We will not forget. UrA4 -- 1998.5 1.8tqms GIAC 1 bar, APR exhaust, Turbo5 BPV, Neuspeed shifter, OEM Sport springs, Bilstein Sport shocks, AWE-DTS AWE VDO Nightvision Boost gauge, Euro projectors, Philips HID, Alpine V12 MRV-F357, DLS Sub, Focal 130K Oettinger RE 17x8, Toyo T1-R 225/45-17, ECS Tuning Stage II Brakes

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