New Rims

CincinnatiFiero · Post by **CincinnatiFiero** » Tue Apr 01, 2008 5:07 pm

I am thinking about destroying these too

Atilla the Fun · Post by **Atilla the Fun** » Fri Apr 11, 2008 10:02 pm

what are your tire sizes, please? -Atilla

Series8217 · Post by **Series8217** » Mon Apr 14, 2008 7:13 pm

Atilla the Fun wrote:what are your tire sizes, please? -Atilla

205/50/17 front, 255/40/17 rear.
Stock 2001 Porsche Boxster sizes. They're about the same rolling diameter as stock Fiero stuff.

Atilla the Fun · Post by **Atilla the Fun** » Sat Apr 19, 2008 6:14 pm

is it possible you can get them to build you a new pair of rear wheels that are a half inch wider, instead of spacers? However, with spacers, you could try a 245/45 to better fit your rim and better fill the opening, IMHO.

Series8217 · Post by **Series8217** » Sat Apr 19, 2008 7:57 pm

Atilla the Fun wrote:is it possible you can get them to build you a new pair of rear wheels that are a half inch wider, instead of spacers? However, with spacers, you could try a 245/45 to better fit your rim and better fill the opening, IMHO.

I bought these rims because they were inexpensive and supported my desired tire sizes. I'm not going to have them widened..
Wheel widening is $150 per wheel and would have to be done past the lip, which is impossible with this rim design, the way the spokes come out close to the lip. They wouldn't be able to weld it.

The company that makes my wheels has an 18x9.5 and an 18x8.5, but I don't think they have those in 5x100. If I end up keeping my car I'll go with a widebody-style rear end or some nice fender flares, and get some 18x9.5s one way or another.

I'm not planning on running 245s. I'm going with 255/45/17 next time I need tires. The wheel gap looks big in those pics because the car is raised up in the back.

This is the exact same size tires, I just have the rear ride height set lower:

Notice the filled wheel openings.

I'll take some pics when I get my transmission back in and have the car lowered to the appropriate height.

Atilla the Fun · Post by **Atilla the Fun** » Fri Apr 25, 2008 3:46 pm

oh those tires are it! I might hafta go that way. Still, a 255 on anything less than a 9.0"? seems a 245 needs at least an 8.5. When your tread is wider than the rim, it hurts handling dramatically. I'll never do it again.

The Dark Side of Will · Sat Apr 26, 2008 8:07 am

Actually, tires are made to be a bit wider than the wheel... how much wider depends on how much sidewall you have. You can put a 245 on a 7" wheel if it's 60 profile. I've got 245's and 255's on 8" wheels in 50 profile. Doing it to the 90's, I'd put a 225 on an 8 inch wheel and 275 on a 10.

You'll actually hurt performance if you go much wider than that, because you're not giving the sidewalls the right kind of support.

Atilla the Fun · Post by **Atilla the Fun** » Sat Apr 26, 2008 1:52 pm

Tires, not tread. Real racecars use the widest wheel, rim way wider than tread, for maximum sidewall support. Look at the mid 80s vettes. they had 255/50-16s all around, with 8.5 inch front rim and 9.5 inch rear rim. The challenge series cars put the 9.5 all around. No, the narrow rim is for ride quality.
A 235/60 will fit a 7 or an 8 as normal, but you will get quicker steering response and more Gs on the 8. Put it on a 9, and it'll feel like a go-cart!
The viper put a 275/40-17 on a 10, while the vette used a 9.5 and the Z28 used a 9.0. Not only does the 10 look better, it works better.
This whole fat tire on narrow rim thing is people wanting fat rubber the easy way, not best results at any price. Think of what happens with the inboard sidewall when cornering, with say, a 295/50 on a 7 inch wheel.
I tried it on the rear of my Trans Am, and it was dramatically worse than a 245/60 on an 8.
Try back-to-back testing some time. Yeah, I had the advantage of working at a tire store, which also sold wheels, but we stuck with one brand and model of tire, and we did it based on what we learned from the Tire Rack. www.tirerack.com.

The Dark Side of Will · Sat Apr 26, 2008 4:57 pm

So the "Eurotuners" who run a 205 on a 9 inch wheel have it right? :scratch: Yeah, sure.

Corvettes ran 9.5's because they were $45,000 cars (Not sure what the current cars run). Vipers roll 10's because they are $80,000 cars.

Atilla the Fun · Post by **Atilla the Fun** » Mon Apr 28, 2008 9:40 pm

no, a 205 on a 9 is too much is still too much, but I guess we will have to agree to disagree on this one. If I had an 88-96 vette, and could put 17x10s on it, all around, then go 275/40, all around, I would. A 275 on an 11? I've seen it, I've ridden in it. Snap oversteer. Scary. These are my feelings and experiences. I know we all like to share these, to save people from repeating our mistakes. So, in conclusion, try it both ways, and do what's best for you.

The Dark Side of Will · Mon Apr 28, 2008 11:02 pm

275 on a 10 is very good. 275 on a 9 works, too.
Saying that a 245 REQUIRES an 8.5? Like I said, it depends on the sidewall. 245/50's work just fine on 16x8's. By that I mean that I've worn mine evenly. 255/50's are a teensie bit tight.

Just remember that there are 25 mm per inch when dealing with tires.

crzyone · Post by **crzyone** » Tue Apr 29, 2008 1:41 am

265/35r18s are slightly stretched in my 9.5" rims. A perfectly flat sidewall would require a 275 tire.

The Dark Side of Will · Tue Apr 29, 2008 6:57 am

Not all mfg's use the same mm's either.

Series8217 · Post by **Series8217** » Tue Apr 29, 2008 4:17 pm

Atilla the Fun wrote:oh those tires are it! I might hafta go that way. Still, a 255 on anything less than a 9.0"? seems a 245 needs at least an 8.5. When your tread is wider than the rim, it hurts handling dramatically. I'll never do it again.

You know the 255 is the overall width, right? It's from sidewall to sidewall. It's NOT the contact patch/tread width. That said, all tire treads are wider than the rim. I've never seen a car that came with tires that were smaller than the rim width. Even a 195 tire is almost 8 inches. Most cars have 6" wide rims. That's 150mm.
Have you ever actually looked at the tire manufacturer's recommended wheel size?

255/40/17 from most tire manufacturers is perfectly fine on an 8.5" wide rim. The Porsche boxster has 17x8.5s STOCK and comes with 255/40/17 from the factory.
255/45/17 is fine from most* tire manufactuers for an 8" wide rim.
245/45/17 are also fine for an 8" wide rim.

*some have different tolerance ranges because the tires are actually different widths at the rim. the "255" refers to the total width of the tire; not where it meets up with the rim. the actual bead measurement is always quite a bit less; an inch or more.

Atilla the Fun · Post by **Atilla the Fun** » Fri May 02, 2008 9:38 pm

not telling me anything I dont already know. That said, manufacturers nearly always go narrow. A 275/40 on a nine, like on some 96-02 Z28s, is not fun. My 95 z28 actually handled better after I replaced my 275/40s with the widest 245/45 I could find. But to get to the other end of the canyon in the least time, I should have ordered custom wheels, with a half inch more backspacing, and a half inch more front side. This would position the tires exactly the same as the SLP nines, but I couldn't afford that then. And while a 245/50-16 goes on an 8, if you ever find a 16x9, try that, as a back-to-back comparison. Same tires, same car, same driver, same surface, same fuel level, et cetera.