I'm planning on upgrading wheels in the next month or so. I will probably buy something by Boyd Coddington. I keep changing my mind about the rear width though. I would like to get as much rubber on the ground as possible. I don't mind working the wheel well over extensively. I would like to run 315s on the back. Has anyone done this and wished they had gone with a narrower rim/tire?
Thanks for the input.
Kory

 

i've worked with them and to be honest sometimes i wish i had slightly smaller then my 10". the tires track pretty wide and don't hook much more then a good tire on a narrower wheel. they really affect drag on the car slowing you down and beyond looks do nothing for you. if your auto-x again this is a different story entirely.

you'll definately need to do some major inner fender work to keep them inside the wheel so they don't look like this...

 

10.5 wide is really the widest i would recommend which you could squeeze that size tire on without much problems. 295/35 is the widest i'm running which took some work but they fit inside the well perfect. remember it's all in your backspacing too. i'm running 6.75" on these rear wheels.

good luck with it...

 

I wonder if boyd will build me a 10.5" wheel? That would seem to be the best bet. So you think the 315 is more trouble than it's worth?
Thanks for the info Jeff.
Kory

 

i don't know if it's more trouble then it's worth but to be honest i'm running alot of power and my 295/35/18 bfg drag radials grip perfect at the track i can't see the need to go any wider and i'm running a 10" wide rim.

do it if you like, by all means as a wider tire definately looks cool but i can say comfortably that a 295 is much easier on the headache and looks just as cool.

 

for a 315 tire you will need a 12 inch wheel.

 

Um, no.

People run 315's ALL the time on 17x11's. Some even go to 335's.

Heck, I have 285's on my 17x9.5's.

 

but your not suppose too, that's all he was saying. to run them properly you should have a wider rim.

 

Come on guys.

What do you think came on the Corvette ZR1?

Yep, 315/35/ZR17 on 17x11 inch ZR1 wheels. I would think if "your not suppose too", they would not be the factory wheel and tire combination.

Just for you experts.

http://www.tirerack.com/tires/Select...5&autoModClar=

 

well if gm did it then it has to be right....

no one said it can't be done, is it the proper way....not really.

 

Dashboard noise, annoying headliner, crappy brakes, cheap interiour, leaking t-tops were stock/factory too.......

 

hmm.

well a 315 on a 11" wheel looks right....

and works right...

and handles right...

and has the proper contact patch...

and every factory 315 series tire is mounted on a 11" rim..


so what IS the proper, "right" way?

i mean, its a 12.4" tire on a 11" rim. thats .7 on each side.... the tire should be slightly wider then the rim.
i suppose if you wanted a exactly 11" wide tire on a 11" wide rim, you could stick a 280 tire on there.... but not only would that look a lil stupid, but the rim would be wider then the tire is. tires sidewalls are designed to support the weight while curving...

 

I agree. ANYTHING smaller than a 315 on a 11'' wide wheels looks bad a it folds in from the wheel.

Chris

 

Kandied and Graboid:

Please provide data to support your position, not just opinion.

(All tire data below based on Michelin Pilot data from Tirerack.com)

Kandied is running 295's on a 10 inch wheel, which has a section width of approximately 11.7 inches, leaving the tire cross section 1.7 inches wider than the rim.

The suggestion of running a 315 tire on a 11 inch wheel equates to similar math. A 315 series tire has a section width of approximately 12.6 inches, which leaves the tire cross section 1.6 inches wider than the rim. Are you suggesting that .1 inches of cross section is that critical?

I believe Graboid is running 285's on a 10 inch wheel, so here is the math for that one: Cross section of approximately 11.3 inches, which leaves 1.3 inches of cross section left over. Again, is .3 inches critical?

What cross section to rim width ratios are you gents suggesting then, and why are you suggesting ratios that are different than those you are running?

MrDudes argument is spot on here.

 

Here is a picture showing a 11" wheel with a 315 tire on it.....

 

I have 275's on a 10 inch rim and i think a 265 is better. There must be a reason BMW puts a 265 on the 10 inch rim on their M3 CSL.

 

probably from experience........

http://www.miata.net/garage/tirecalc.html

i'm sure not going to tell you what to do, when you ride in my car and wonder why it works so good then i'll let you know. it's pretty simple really though, fatter tire equals less handling and for some of us looks bad.

if you want the extra cushion it adds and like the looks then do so. i know i don't and i prefer how the car handles with the right tire.

 

I wonder why in the US of A, driver of imports have the better feeling for tire/rim combination. I am speaking of the weels, not the general appearance of their rides

 

probly because it doubles the value of their cars.

or it could be because of the extremely limited options they have. (size wise)



im not talking about the usefulness, fitment(of the wheel as a whole) or anything else like that.

just pointing out the proper size rim for a 315 series tire..

the rest is up for debate... yes i personally like it.

i know it'll make the car understeer even worse.
i know it wont help much on the street, and almost none at all compared to a slightly narrower tire.
and i know you have to bash the car some to make them fitting while tucked in.

but it looks cool IMO, so i like it.

 

The Lamborghini Gallardo comes from the factory with 295's on an 19x11" wheel.....

 

An 11" wheel is more than 11" wide from rim edge to rim edge.

I'm pretty sure that 11" is measured where the tire's bead is supposed to seat on the wheel.

 

true, but then again, a 275 tire has more than a 275 mm overall width (at japan products, such as bridgestone, yokohama, dunlop etc)

 

yeah I know.

the BFG g-Force KD 315/35-17 has a 10.4" tread width but a 12.6" section width.

 

315's on a 11" looks the best, the Lambo with 295's on 11" just looks stupid. You want the tire to stickout a little to protect the rim from the curb or damage.

Anything where the tire is not wider then the rim makes it look stretched, which is stupid and wrong.

 

i guess in your eyes it might look stupid, like the 315 looks stupid to me. But if it really WAS stupid, i don't think the lambo people would do it that way. There is the possibility that they know a bit more about highperformance cars than GM......
The Gallardo is a sportscar without compromises and a new concept, while the ZR-1 is old cake and not as radical and sproty as the lambo.

 

The 315 and 335 series tire is awesome....for a car that was designed to use it....our cars...not really designed to use it, however, that is not saying it can't be done successfully.
So, do what you like best mang:rockon:

 

and the wheel looks pretty stupid too...

 

beauty is in the eye of the beholder....

 

if only i could trade my thirdgen in for a payment....

:lala:

 

well look at the tire (and the tire itself) and you'll see what i mean.

pay attention to the sidewall...

 

like it should be. These are hardcore italian racers (factory owned by germans). The people who are responsible for the tires and wheel combo know more about it than the average thirdgenner, and have performance in mind. But in the land of pot holes and scary curbs it makes more sense to choose the 315/11inch combo like GM did for the ZR-1........

 

I dont have 11" rims, 9.5" for me. But personally im either going to use 275/35/18's which is 10.8" on a 9.5" tire. .65" overhang on either side.

Or, 245/40/18, section width is the same size as the rim. (well actually its 9.9" according to my tire company) And the tread width JUST over 9.5".

my buddy did this (only with 19's tho) its a harsh ride. but it handles beautifully (even tho he had better tires on before , he has yokohoma's now, he had so-2 potenza's) and the tire width is same as stock, just got rid of all the side wall rolling. He has an audi a4 (the wagon one tho)

reason im thinking of this is 1, tire is cheaper, 2, stock width tire is what the suspention was designed for, and 3, improvements in handeling are more importaint then straitline traction to me.

ofcourse i may not, it would be nice to have SOME buffer between the road and I.

 

oh, and gm chose the 315's on an 11" rim because 1, 95% or all 315 tires have stiff as hell sidewalls, great for corners, bad traction. ( the idea is that the tire is so wide anyway the it will still have more straitline traction then a smaller tire, but ALSO have the cornering stiff sidewall) and 2, they wanted the extra bubble so the car can squat a bit more and gain some extra strait line traction.


since you guys are always asking for proof
i have an artical here in that explained that, and proved it with tests, let me find it. ill post later

btw, im not saying thats the reason GM did the 315 thing, it could be wrong, but thats was several respected magazines belived. it makes sense. they might have done it for shear shock value. who knows really.

 

Chevy High Peroformance feb 2004.

has an actical about 3rd gen camaro suspention upgrades...near the end of the artical they compare 245/50x16 stock tires against the new 275/40/17 kdw's, Even with the old 16" tires they beat the 275's in the quater by .06, if the 16's were the same tires, and new, im sure it would be close to if not beyond a full tenth in the quarter, btw, the 16's were worse at braking, slalom and skidpad.

So you have to choose what you want to do with your car, drag or drive....I wanna drive.

 

if you believe everything that magazines have written you have alot to learn.....

 

I believed them when they said your car was cool

 

you knew what i meant...

 

Hmmm, again the same debate as Nolan's thread. Tires have a range of wheel widths that they fit on. No right or wrong answer here when the tire falls within that range. Its a personal preferance. As for me, I plan to experiment with 11" or wider in the rear with my next set of wheels. Now that I've had my Boyds for a while I've been able to do some measurements. I'm gunning for 19x9.5" wide in the front and 19x11" in the rear. Very very tight fit, possible rubbing issues, but if my tire selection works out like I want then it should work good (notice how that tire sidewall sits on that pic of the lambo hehe) ... nothing ventured, nothing gained right? Just gotta sell my current Boyds ... hmmmm heheheh

 

i say go for it...roll the quarters, bang the inner fender and have at. watch out for those lava rocks.



if only there were a 19" wheel that really was lightweight.

 

What I've been playing with is the idea of doing is running a set of Volk Racing wheels or Racing Hart CP-035s with some custom adapters from Skulte.

Import oriented, yes I know, but pretty much the lightest there is that isn't a dedicated racing use wheel. Most are forged.

They're about as light as it gets for any size, plus they have some suitable widths originally intended for Supras/Skylines/etc.

Like these TE37s, they've got 10-10.5" widths for 17" and up:

http://www.group5motorsport.com/cgi-...alogno=VR-TE37

more volks:

http://www.group5motorsport.com/cgi-...Racing%20Wheel

the RH CP-FTunes, ultra-light:

http://www.group5motorsport.com/cgi-...alogno=RH-CPFT

check out the CP-035s at the bottom, kinda like Z06s but ultra-light:

http://www.racinghart.com/wheels_rac.asp

 

If I had the money, I'd run 17 or 18" volks, 10.5" rear, with decent negative offset for a little spoke dishing, the have adapters compensate for the different lug pattern and offset.

Then some BFG g-Force KDs or...

Eagle F1 Supercars:
http://www.tirerack.com/tires/tires....le+F1+Supercar

 

or maybe the Yokohama A032R:

http://www.tirerack.com/tires/tires....ireModel=A032R

if people saw a 315-width one of those on the back of a Camaro, they wouldn't know what to think.

it's such a rare tire (really, a competition tire, but streetable) it almost looks styled or something.

 

The ZR1 had a wide tire mainly for looks,but also because the car weighed so much. Notice the C5 and C6 use a narrower tire and they pull decent skid pad numbers. I like a wide tire but there is going to far. I second Kandis opinion and thank it would better to go with a 265,275 at max.

 

Nothing wrong with running Volks, they are great wheels. But running adapters, hmmm maybe a bad idea if you have enough power to warrant 315's. If you want those type of wheels (streetable lightweight 3 piece racing wheels) in a direct bolt on fit, maybe check out SSR. I once priced a set of 19's made custom for a 3rd gen, came out to $3200 (without tires hahaha).

 

I've heard that adapters need to be re-torqued once in a while, but for a high g-load application are they really at risk of letting go or something?

Is it just because they are aluminum?

I've always questioned adapters, how far they push out wheels from hubs makes me wonder if there is too much bending torque from being out so far.

 

plenty of people race with them.....i had them for one season with my z06 replica wheels and couldn't stand the feel of the car myself though.

 

Kandi- Did they autocross then or just drag? The only ones I have seen break have been on cars drag racing,but I think they were put on with a impact and stressed the studs. The adapters will be just as strong as a wheel. The only thing it does do is increase the tires scrub radius. Which is what you were feeling. Thanks for letting us know that. I am glad someone could tell the difference. I think I will just find/or have someone make me some wheels that dont require them.

 

cdh67 - mind explaining what scrub radius? Im about to fit wheels on my car with adapters, and would like to know what to expect. thanks.

 

Scrub radius is defined by SAE as kingpin offset, which is the distance between the two points created by the inter- section of the wheel centerline (centerline of tire patch) and the steering axis with the ground plane. The steering axis is determined by the kingpin index angle, which is the plane projected through the upper and lower ball joints and the wheel shaft joint. A zero scrub radius exists when the wheel centerline and the kingpin index intersect exactly at ground level. Positive offset occurs when the wheel centerline is located laterally inboard from the steering axis at the ground plane, while negative offset occurs when the steering plane intersects the wheel centerline above the ground plane.

 

Picture for reference: