superstring

Hi All

I'm thinking about "upgrading" my rims and tires from 16” to 17” on my 98 2.5RS and I’m looking for some help and advice!

I certainly like the look of 17" rims, but, from a performance standpoint, I'm concerned about a couple of things.

As far as tires go, I’m currently running 205-50/16’s and I'd like to fit either 205-45/17’s or 215-40/17’s on my new rims, which would maintain the same overall diameter and also appear to be the most popular sizes fitted in Europe. However I’m aware that apart from the Pirelli P-Zero, and the Dunlop SP 9000 there is practically nothing available in a max performance 205-45/17, while there are more choices in 215/40-17.

However.....

1. It seems the load capacity (load index) of most high performance 215-40/17's (with the notable exception of Toyo's T1s) is some 125 lbs. LESS per tire than Subaru recommends. This of course adds up to a car that is about 500 lbs. “under-tired” in this respect. Does anyone have any thoughts and/or experience with problems arising from this "issue"?

2. And again, from a pure performance standpoint, for those who have gone from 16" rims to 17's, has it been worth it? Prodrive's Mike Wood is on record as saying that moving from 16" to 17" rims (on the “Classic”/GC8) is a more important performance upgrade than changing suspension. But Prodrive recommends a 205-45/17 (preferred) or a 215-45/17 P-Zero. I presume that the 215-45/17 tire is recommended because of its' higher load rating.

I’m also thinking that, in order to maximize the contact patch of a 215 tire on a 17 by 7 rim, a little under- inflation is in order to flatten it out, and this may negate some advantages of the lower sidewall……

Maybe I’m better off sticking with my 16” rims!……….

Ideas, opinions, and educated guesses are all very welcome!!

Thanks.

Dexter@tirerack

First off, everyone needs new rims - my livlihood depends on it!

In all seriousness, load capacity is priority one. We recommend on your car the 205/50-17 which is a perfect fit with adequate load capacity. You can use a 215/45-17, but it will most likely require fender work.

It's not a necessity to go with larger wheels to get better performance. A "budget" upgrade would simply include better tires on your existing wheels. Upsizing wheels, however, usually offers a wider wheel with a more performance optimized offset and less tire sidewall to flex. So, to kill 3-5 birds with one stone, one might upgrade wheels and tires together.

superstring

Thanks for the reply, Dexter.

I know what you're saying and there are legal implications that come into play here, but maybe you could explain something for me? What reason could it be that, for the identical Subaru Impreza (old body style) in Europe (identical weight, that is), Subaru specified a 205/50-16 tire which has slightly less load capacity than the 205/55-16 spec'd on the old 2.5 RS in North America?

Just for the record, I've had absolutely no problems with my 205/50-16 Toyos and they are so much better in every performance aspect than the original 205/55-16 RE92s (but I guess they WOULD be, wouldn't they? )

If I were to fit 205/50-17s to my new rims, I would have (more or less, depending on the tire) the same sidewall height, flex etc. as I have now and therefore no performance advantage in this respect (Actually, maybe a bit less, as the car would sit slightly higher.)

John

mule2k

I may be incorrect, but I have read that Subaru uses the 205/55-16 in North America to give us a slightly more compliant ride. And also a little more sidewall and ride height, for winter driving.

Back in the spring, I was originally shopping for 17" wheels with 215/40-17 Goodyear Eagle F1 GS-D3, until Luke at Tirerack explained to me the importance of load capacities. I eventually settled on 16" SSR Competitions with 205/50-16 Yokohama AVS ES100s for my '00 Impreza L. The difference over the stock 15" steel wheels with RE92s was amazing. I'm glad I went with a lightweight 16 rather than a 17 that could have weighed twice as much.