13" or 12" Rears?

[CuHead]

13\" or 12\" Rears?

Background:
I have learned alot recently about the assembly of wheels, and was suprised to find out that inner barrels typically only come in 8" or 10" depths (at leaset per iForged). Because of the Gen 3 rear calipers, the max outer barrel depth you can get is 4" without overly curving the spokes. So this results in the following wheel choices if you are trying to go 20" in the rears:

20"x13" = 10" inner with 3" outer => 3" lip
20"x12" = 8" inner with 4" outer => 4" lip

So, to get a nice fat 4" lip, you need to go with the 8" inner and end up with a 20"x12" rear wheel.

So, my question is, would I lose anything by going to a 12" wheel in the rears as long as I kept the 345/25ZR20 tire? At least in terms of actual tire patch? Hey, it should improve the rim protection at least!

 

[ILLSMOQ]

Re: 13\" or 12\" Rears?

So, my question is, would I lose anything by going to a 12" wheel in the rears as long as I kept the 345/25ZR20 tire? At least in terms of actual tire patch? Hey, it should improve the rim protection at least!

I assume your question is in regard to performance and handling. So the answer to that would be - not really. Going from a 19 to a 20 your ARE trading(loosing) performance for looks.

So I would tell you to get the one that YOU think looks better....that's the whole reason your doing it anyway.

My choice was the 13.

 

[CuHead]

Re: 13\" or 12\" Rears?

Yes, this is for street looks and the occassional goosing on the street. For racing, I am keeping my stock FE 5 spokes, although I may get some lighter wheels.

So I would like to revise the question to "For street use and looks". But I don't want to find myself sliding around turns a much more than I am already. I am wondering if the tire patch actually changes at all since it is the same tire. Just the sidewall angle would be largely affected, and this can even improve rim protection since the rubber would stick out a little more from the rim.

Thanks!

 

[ILLSMOQ]

Re: 13\" or 12\" Rears?

While I'm sure the 12" wheel looks wide the 13" has to look a bit wider from behind.

An inch fatter lip is cool.

I say go wider....but you may need to flip a coin to make up your mind.

 

[Scott_in_FL]

Re: 13\" or 12\" Rears?

Assuming the offset is going to look the same from the side (i.e. wheel is flush with upper portion of wheel well arch), the 12" may look nicer with the bigger lip. From the back, the car is so low it may be tough to really appreciate the width of the 13"er. If the 12" doesn't push out as far (to the be flush with the well), then pop on a 15mm spacer like they do on the compe coupe and you should be looking pretty good.

 

[2002_Viper_GTS_ACR]

Re: 13\" or 12\" Rears?

The tires wont know the difference, a 345 can work on a 13 or a 12 inch rim. (So I am not sure how people think you will be able to tell a difference from behind the car or whatever, because hte contact patch is going to be the same, and so is the overall size of the tire, that is not changing) And yes, you get a little bit more protection as the tire will finally be the part thats farthest out, instead of the typical 13 inch rear, which has the rim as the farthest most part hanging out.

Now all that being said, I agree with the part about giving up over all handly by going with a 20 vs a 19. I personally would prefer 18's all around for the best handling and biggest wheel size compromise. so If I was going to have the perfect set up, I think it would be:

18's all around
11 inch rim up front (315 front tire)
and 12 inch rim in the back (345 Rear tire)

Jon

PS. Good Luck with what ever you chose.

 

[jpas]

Re: 13\" or 12\" Rears?

I am running the Iforged Precision Series 20x12 on the rears of my SRT10. When I put the Iforged wheel beside the stock 13" rim with the tires mounted, there is only 1/4" difference in width. The tires actually fit the 12" rim better & they look less stretched then the 13" rim.

 

[ILLSMOQ]

Re: 13\" or 12\" Rears?

(So I am not sure how people think you will be able to tell a difference from behind the car or whatever, because hte contact patch is going to be the same, and so is the overall size of the tire, that is not changing) And yes, you get a little bit more protection as the tire will finally be the part thats farthest out, instead of the typical 13 inch rear, which has the rim as the farthest most part hanging out.

Well, I AM sure. The contact patch will be more or less the same, the side wall being stretched out more will make the whole package look wider. I have done this on other wheels so I actually know it looks different.

It will look great either way.


Now THAT being said I agree about 18's being best for handling.

 

[BADMOFO]

Re: 13\" or 12\" Rears?

CCW's 20x12.5

 

[KepRght]

Re: 13\" or 12\" Rears?

someone can confirm, but the 17" rear wheel in 96-98 had higher skid pad G's in testing then the 18" from 99 and on, i can only imagine a 20" would be that factor worse.

i think it went from 1G to .9G on the skid pad from 1998 17" to 1999 18".

so i guess you could say 19" would be .8G and 20" would be .7G before break away.

only a guesstimate based on other peoples data collection & i dont think it is all that accurate. No idea if it is from 1.0001G to .9998G or 1.0 to .90.

but, on the street where your not battling for .1 second off your lap time, i dont even think you will notice.

 

[2002_Viper_GTS_ACR]

Re: 13\" or 12\" Rears?

(So I am not sure how people think you will be able to tell a difference from behind the car or whatever, because hte contact patch is going to be the same, and so is the overall size of the tire, that is not changing) And yes, you get a little bit more protection as the tire will finally be the part thats farthest out, instead of the typical 13 inch rear, which has the rim as the farthest most part hanging out.

Well, I AM sure. The contact patch will be more or less the same, the side wall being stretched out more will make the whole package look wider. I have done this on other wheels so I actually know it looks different.

we'll agree to dissagree on the ability to dicern the difference visually. Maybe at best, side by side one could tell, but even then, probably not readily, as your talking 1/2 inch at most on each side.

Anyways, we do agree on ILL SMO Q looks good on any viper cuz mine is a few weeks away from delivery from the great state of IL.

Jon

 

[Qualitywires.com]

Re: 13\" or 12\" Rears?

hey Jon..

You're old buddy ab here...LOL!

What suspension do you have on your car? Is it stock?

 

[Viper TT/10]

Re: 13\" or 12\" Rears?

i have a pair of ccw billet aluminum 1/2 inch spacers for the viper if anyone needs them for clearance issues. i am sending them back to ccw if no one is interested. i ended up using a different size for my new wheels.

 

[ILLSMOQ]

Re: 13\" or 12\" Rears?

we'll agree to dissagree.

Wouldn't be the first time.

Anyways, we do agree on ILL SMO Q looks good on any viper cuz mine is a few weeks away from delivery from the great state of IL.

Jon

True...a lot of people get a kick out of it.