115 replies to this topic

[Mr. Haney]

svt13, the reason I'm not considering a 305/35-20 is Michelin doesn't offer a Pilot Super Sport in this size.

[Mr. Haney]

dave 316, on 25 November 2012 - 06:42 PM, said:

mr.haney, were you offered offset options?

No, I gave them the tires sizes I wanted to use and they told me whether or not they could build a wheel to fit that under the car. The 315 in the rear aren't going to be a problem. They were not willing to say I could use the 285 in the front and recommended a 275, but I'm hoping I can get the 285 to clear. It is going to be very close from all the stuff I've looked at and may come down to a few millimeters in clearance when done. They were willing to build the front wheels with a few more millimeters in backspacing, but said if the tires rubbed the  outer fender lips that it would be my problem.

[Albino500]

Mr. Haney, on 26 November 2012 - 03:43 PM, said:

The 3.90 is looking very attractive to me when I consider the difference in the tire diameter of the 315/35-20  when compared to 285/35-20 with the 3.73 gears. The only problem is I'll have to purchase that gear set from someone other than FRPP, as they don't offer it. My gut is telling me to go with the 3.90 gear with the 315 tires increased diameter..........I need to sit down with a road speed calculator to figure out the differences between these combos. I just haven't gotten around to it. In my mind I doubt the difference would be more than a 3% change in top speed with the 315/ 3.90 combo versus the 285/ 3.73 combo or the 295/35-20/3.73 combo. The difference in the two smaller tires isn't much at all, as the revs per mile difference is only 6 between the 295 and the 285.

Mr. Haney if you can find out the individual gearing in your trans you can go to Tremec's website and plug in the info to the application chart and get a full break down on speed at any selected RPM . PM me if you want to pursue this. KP

[Mr. Haney]

jerseygator, on 25 November 2012 - 06:48 PM, said:

This how it starts on every thread...

LOL..........I'm in a civil mood this evening, but I understand exactly what you mean

[Mr. Haney]

Albino500, on 26 November 2012 - 03:53 PM, said:

Mr. Haney if you can find out the individual gearing in your trans you can go to Tremec's website and plug in the info to the application chart and get a full break down on speed at any selected RPM . PM me if you want to pursue this. KP

I will do that, thank you.

[Mr. Haney]

http://www.tremec.co...alculators.html

After playing with this nice tool a while. I thought I would share it. Everybody that finds this as a neat tool to use, please thank Albino500

the transmission gear ratios for a 2013 GT500 are

1st: 2.66
2nd: 1.82
3rd: 1.30
4th: 1
5th: 0.77
6th: 0.50

[svt13]

Mr. Haney, on 26 November 2012 - 02:59 PM, said:

I want a 315 on the rear of the car to gain as much forward traction as I can. To increase the rear tire size this wide and try to maintain the same handling balance of the car, the front tire needs to increase in width also. If I go with a 255 or 265 in the front while increasing the rear to 315 the car will gain understeer.The 285 will be close to the same split in tire sizes as the car was stock with a 265 front and 285 rear. If the car pushes slightly more in the corner with the 285 or 275 I will still be able to tune the rear suspension with a roll bar. If I go much smaller in front tire size with a 315 rear tire I doubt that any roll bar will bring the handling back to a neutral feel. I have always driven performance cars hard, but I want them to be able to be predictable a the limit. One thing I've learned is these cars can jump up and bite you hard with snap oversteer, if you don't lift on corner exit when the rear tires start spinning. Increase the rear tire size to put more power to the ground then the smaller front tires get pushed to there limit and the car doesn't want to turn, so now you need to increase the front tire size for more grip there too.

The Kenny Brown upgrades have made my car much more predictable with a very neutral feel and I want to keep it that way.

Well that all makes sense. I remember Hamedi saying if they went with a bigger rear tire that would increase understeer so they would have to then go to a larger front tire to match. But then what I am wondering is why don't other brands have huge front tires? Why are they usually no bigger than  265 and then the rears are like 295s to 315s. I'm wondering since I was playing with the idea of a wider tire but I like the neutral handling of this car. I just want it to be able to handle the power better though but still want it to be nimble so I think 335s may be a tad too big.

[Albino500]

svt13, on 26 November 2012 - 07:12 PM, said:

Well that all makes sense. I remember Hamedi saying if they went with a bigger rear tire that would increase understeer so they would have to then go to a larger front tire to match. But then what I am wondering is why don't other brands have huge front tires? Why are they usually no bigger than  265 and then the rears are like 295s to 315s. I'm wondering since I was playing with the idea of a wider tire but I like the neutral handling of this car. I just want it to be able to handle the power better though but still want it to be nimble so I think 335s may be a tad too big.

Are you referring to mid - engine or rear mounted engine cars when you say " other brands" (like your beloved Porsche or K car)? (here we go AGAIN)

Edited by Albino500, 26 November 2012 - 07:28 PM.

[HyperStangs]

Mr. Haney, on 26 November 2012 - 02:59 PM, said:

I want a 315 on the rear of the car to gain as much forward traction as I can. To increase the rear tire size this wide and try to maintain the same handling balance of the car, the front tire needs to increase in width also. If I go with a 255 or 265 in the front while increasing the rear to 315 the car will gain understeer.The 285 will be close to the same split in tire sizes as the car was stock with a 265 front and 285 rear. If the car pushes slightly more in the corner with the 285 or 275 I will still be able to tune the rear suspension with a roll bar. If I go much smaller in front tire size with a 315 rear tire I doubt that any roll bar will bring the handling back to a neutral feel. I have always driven performance cars hard, but I want them to be able to be predictable a the limit. One thing I've learned is these cars can jump up and bite you hard with snap oversteer, if you don't lift on corner exit when the rear tires start spinning. Increase the rear tire size to put more power to the ground then the smaller front tires get pushed to there limit and the car doesn't want to turn, so now you need to increase the front tire size for more grip there too.

The Kenny Brown upgrades have made my car much more predictable with a very neutral feel and I want to keep it that way.

Only real downside is that 285's will probably want to wander quite a bit.... they'll bite every little pucker and undulation in the road.  Daily driving just becomes more work... worth it?  Probably.

Edited by HyperStangs, 26 November 2012 - 07:40 PM.

[Albino500]

HyperStangs, on 26 November 2012 - 07:28 PM, said:

Only real downside is that 285's will probably want to wander quite a bit.... they'll bit every little pucker and undulation in the road.  Daily driving just becomes more work... worth it?  Probably.

NOT TRUE ! You need to understand what scrub radius is for 1 and what causes wander . Along with what the variants in overall diameters are acceptable to the ABS and TCS systems regardless of the changes to the speedo calibrations.

Edited by Albino500, 26 November 2012 - 07:37 PM.

[HyperStangs]

Albino500, on 26 November 2012 - 07:33 PM, said:

NOT TRUE ! You need to understand what scrub radius is for 1 and what causes wander .

Ewww, gosh... are we really going to get into that?

[Albino500]

Naw - we'll just agree with the 285/35 on front

[svt13]

Mr. Haney, on 26 November 2012 - 03:51 PM, said:

No, I gave them the tires sizes I wanted to use and they told me whether or not they could build a wheel to fit that under the car. The 315 in the rear aren't going to be a problem. They were not willing to say I could use the 285 in the front and recommended a 275, but I'm hoping I can get the 285 to clear. It is going to be very close from all the stuff I've looked at and may come down to a few millimeters in clearance when done. They were willing to build the front wheels with a few more millimeters in backspacing, but said if the tires rubbed the  outer fender lips that it would be my problem.

Hmmm so I was thinking a 295 315 combo when I decide to go wider but then after seeing this I'm guessing a 295 would have major problems being in the front?

[svt13]

Albino500, on 26 November 2012 - 07:27 PM, said:

Are you referring to mid - engine or rear mounted engine cars when you say " other brands" (like your beloved Porsche or K car)? (here we go AGAIN)

Well "here we go again" you have no one to blame but yourself with that remark your just trying to bait me but I won't bite. But if you want a front engine example well the new viper is 295 front and 355 rear. The c6rs by pratt and miller is I believe the same. Though I don't think any amount of modifying would allow us to put a 355 on the rear of a shelby without that wide body kit. I'm just wondering why those 2 cars along with other brands have such a huge gap between front and rear tire size when cars like the zl1, zr1, shelby, and GTR don't. If its because it creates understeer thats fine but a lot of those cars like the viper or c6rs don't have that huge understeer problem so I'm wondering how they fix that.

I personally would like a neutral handling car with maybe a tad of understeer for safety purposes.

Edited by svt13, 27 November 2012 - 07:41 AM.

[patrickshelby]

[Mr. Haney]

svt13, on 27 November 2012 - 07:37 AM, said:

Hmmm so I was thinking a 295 315 combo when I decide to go wider but then after seeing this I'm guessing a 295 would have major problems being in the front?

295 will not fit, unless you use a offset strut assembly with a smaller diameter wheel/tire combo

[Mr. Haney]

The reason other manufactures can get away with offset tire sizes front to rear is they engineered the car to handle properly with this offset in tire sizes. One of the things that the suspension mods I did was to significantly lower the rear roll center. By doing this I was able to remove the rear anti-roll bar while still keeping a neutral handling car. Now as I increase rear tire size I can install an anti-roll bar on the rear of the car to adjust the unbalance that the offset tires will create. I also have an adjustable bar on the front that will allow me to fine tune it. This is similar to what the car manufactures do

[svt13]

Mr. Haney, on 28 November 2012 - 05:25 AM, said:

The reason other manufactures can get away with offset tire sizes front to rear is they engineered the car to handle properly with this offset in tire sizes. One of the things that the suspension mods I did was to significantly lower the rear roll center. By doing this I was able to remove the rear anti-roll bar while still keeping a neutral handling car. Now as I increase rear tire size I can install an anti-roll bar on the rear of the car to adjust the unbalance that the offset tires will create. I also have an adjustable bar on the front that will allow me to fine tune it. This is similar to what the car manufactures do

hmmmmm. The only thing I have that will be adjustable is my front sway bar. Steeda has a 31mm rear bar thats adjustable but I thought thats way way too thick on the rear and will create way too much oversteer. Though maybe I could balance it out with a crazy ass tire combo like 265 front 315 rear though I don't want to play the R&D game with my car.

Maybe I'll just stick with a 295 in the rear on the alcoas if I can get away with it. Some say 295/30 works but I'm still waiting for someone with a 295/35 michelin PSS to talk about it.

[Tob]

HyperStangs, on 26 November 2012 - 07:28 PM, said:

Only real downside is that 285's will probably want to wander quite a bit.... they'll bite every little pucker and undulation in the road.  Daily driving just becomes more work... worth it?  Probably.

For what its worth, I ran a pair of stock size  285's up front for a while. No wander and no more effort than stock.

[patrickshelby]

Mr. Haney, on 28 November 2012 - 05:18 AM, said:

295 will not fit, unless you use a offset strut assembly with a smaller diameter wheel/tire combo

Right!
That's what UBB does to fit 305/35/18 all around.
http://www.ubbmustang.com/index.cfm