Advantages/disadvantages of 225/45-17 tires

[JJMorgan721]

I would appreciate input on the advantages and disadvantages of mounting 225/45-17 tires on the stock rims of my ND GT. I realize the speedometer will be off a bit and I imagine the gearing will downgrade the acceleration a slight amount. I am looking at Continental DW tires to replace the Bridgestones. Tire rack claims they can be mounted on the stock 7 inch rims. The are cheaper and only one pound heavier for the wider tire. Am I missing anything or is this a good idea?

[Brian]

I say don't do it.

They will mount up, but are taller than stock. I don't know if you might get some rub on fender liner over bumps when wheel is turned...but that is possible. Let's put it this way, I cannot think of a GOOD reason to do it and saving a few bucks is not a good reason. Assuming no clearance issues the bad includes slower car, sloppy in the turns because that is a 9 inch wide tire on just 7 inch rim, so contact patch is round instead of flat, and is not well supported. If the goal was to make a sports car handle like a 70's Caddy that would be a good first step because you will be adding some of that 'wallowy' effect. But if the goal is softer ride then I expect it will be softer at same tire pressures as before.

[KirvenS413]

Brian,

For those of us who have to budget out our upgrades (I want to do exhaust, tune, spring and/or sways first), would you recommend 215/45/17's instead? I'm thinking of moving to a bigger tire when mine wear out but can't quite swing the wheels I want yet. I'm not auto crossing (yet).

[Brian]

215/45/17 works great on 7.5 wide wheels, that's what we did on my wife's NC with Enkei 17x7.5 wheels.

On stock 7 inch wide wheels still some of same issues noted above. Just don't fool yourself into thinking car is 'faster' with 'more grip' because you stuck wider tire on the same 7 inch wheel. If goal is softer performance, more comfort, it will work well. To get same level of performance with tire not as well supported could run higher pressures, but then the extra comfort part goes out the window.

[Paddie]

To follow up on this discussion I would like to purchase Advanti Racing Storm S1 to put on my ND. The car will not be tracked but just for fast road use and will have lowering springs and no other suspension mods. I like the look of the Advanti and would like a roadholding improvement.
As the Advantis do not come in 7.5 width I would get the 17x8. What is the best tyre width on this rim for my use?

[Brian]

Yes, for grip improvement 17x8 version will put more tire on the ground for you. Best grip with that 17x8 would be using 205mm wide tire, because that would be 8 inches of tire on 8 inches of rim and straight sidewalls give sharp turn-in response. Downside of that combo is risk of curb rash is high, ride quality would take a hit, every choice is a tradeoff. And 215mm wide tires on that same 17x8 would give a bit better ride than 205mm, 225 would be a bit better still on ride and offer quite a bit more curb rash protection, not near as sharp turn-in response, etc.

[KirvenS413]

How would 235/40x17s on 17x8 wheels?

[Brian]

I have a set of 235/40 on 17x8 Tungsten 6UL wheels, works great. Lots of pics of that setup on our site, just visit the product description for that wheel.

[jamaican_tuner]

Chiming in on this thread since I think it is relevant.

Brian, based on your experience, which is the fastest tire (size and brand) one could use on stock 17x7 wheels for road course use. Mx5 cup ran 225 45 17 bfg R1. Is there a faster setup since 225 45 is not the ideal size?

[jamaican_tuner]

5 mins later I may have answered my own question. Hoosier makes a 225 40 17 R7 and A7. $1100 a set though. Assuming a 235 r comp on 17 x 9 would be as fast if not faster for $400 less a set.