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I know this has been dicussed before, I just can't find it. I will listen to suggestions, both pro and con, on whether I am out of my mind proposing to use rear tires on all four corners rather than skinny tires on the front and wider on the rear.

John
CFR fv42

Are you trying to fix something?

I've used (and enjoyed) the wide fronts/short rears on all four corners at our local track (very tight, technical track with a relatively short front straight), but I don't think I'd use the full size rears up front.. Seems like way too much tire for our needs, heavier, bigger..

When the Runoffs were at Topeka, many drivers tried the short rears (21.5x5.5) to achieve lower gearing and ended up chasing rear grip. As Tiago asked, what are you trying to accomplish? You will loose top end speed on the longer straights so drag reduction is a zero sum game. Lower gearing will come at a cost of reduced cornering. I know some folks at Topeka made them work but still gave up something.

That said, short rears on the front are another issue. I ran them for years with great success to reduce push. They feel much heavier in the steering wheel and will last a bit longer if your car is sliding the front. The downside seems to be in top speed. While I could never measure a significant difference in my data, many say that the top speed will be reduced with wide fronts. I would imagine that a track like Road America, the wide fronts will be a liability.

Regarding the two tire brands, last I looked GY did not have short rears. Having run both the current Hoosiers and Goodyears I think the GY's have a bit more front grip. That's not to say they're better, it's just that on my car, the balance is better. I have felt that the Hoosiers inherently have higher grip in the rear tires that translates into a push for me when stickers are installed.

Wasn't trying to "fix" anything. Was just wondering if putting 5.5 inches of tire at all four corners would help or hurt?

John
CFR FV42

First you define the problem and then you look for a solution. What you are asking is babble.

Brian

I've played around with 4 same-size tires on a Fv. I even tested that configuration for Hoosier almost 20 yrs ago.
My conclusion was that it made no difference to grip/balance but changed the characteristics of turn-in. My interpretation was that the width of the contact patch was so narrow that the extra tire width was insignificant in steady-state cornering. Different size/width tires will have different constructions which will effect the feel of the car and the reaction on turn-in.
My conclusion was supported by several others who experimented with different width fronts, including a certain 3-time champ.
I regularly ran with 4 large rears on the car in the mid-90s when front tire life was 2-3 sessions. I was used to the car on F1200 tires (same size) and found it was more economical on slicks too.

John, go for it!


PS ............ For the purposes of this discussion ................ Babble Babble Babble

Thanks to all.

John
CFR FV42

hardingfv32-1 wrote:First you define the problem and then you look for a solution. What you are asking is babble.

Brian

"Manners maketh man"

Hi jmattox,
I would go for the "rears all around", It will make for eazy tire management! rotate, flip, rotate!

One of my "tintop" racer friends suggested I use really tall tires so that if I flipped over I could just keep going like a hot wheel.

John
CFR FV42