gonutz

I own a 1999 A6 Avant and recently purchased a set of the 5-spoke 4.2 forged wheels (17x8) - I love the look of these wheels.

The wheels came with a set of Bridgestone Potenza S-03 tires in a 235/40-17 size. I understand that this is a slightly smaller rolling diameter than my stock 16" wineglass wheels with 205/55-16 tires. The recommended replacement calls for a 225/45-17 tire. The tires are in excellent condition (1 has a little scuff) and at >$200/ea, I'd like to give'em a go!

Question: Can I get away with the 235/40-17 size without causing an unsafe condition? Doing a side-by-side comparison with my current wheels/tires the difference is very minimal - but I don't want to do something foolish.

Some of the issues I am concerned about are load rating and screwing up any onboard engine management systems like timing or the like.

Any thoughts/comments/lessons learned are greatly appreciated.

BTW - I tried to do a search on this and couldn't find any resolution.

gonutz

Stock: 205/55-16

205 mm = 8.07 in

[(8.07 x 0.55) x 2] + 16 = 24.87 in

New Setup: 235/40-17

235 mm = 9.25 in

[(9.25 x 0.40) x 2] + 17 = 24.40 in

Difference of 0.47 in.

Gary@Tirerack.com

Although this isn't enough of a diamter difference to cause any issues with engine management, the load capacity is a bit of a concern. Bumping the tire pressure to 36-41psi might be a good idea until you're able to get a more proper tire size on the car. 225/45R17 will work well, but I'd probably use 235/45R17 if it were me.<ul><li><a href="http://www.tirerack.com/a.jsp?a=AR8&amp;url=/tires/index.jsp">tires</a></li></ul>