Running shorter tires in the rear of an SRT/10?

[Gforce]

Curious – does anyone out there run the same height tire in front and back?

Kai - what do you run?

All that discussion about tourque, gearing and tire sizes got me to thinking (I know – kind of dangerous )

I am not certain what the official size of the SRT/10 stock tires are but lets say the fronts are 25.5” tall and the backs are 26.5”.

Wouldn’t I be faster running a 25.5” tall tire in the rear (versus the 26.5)?

I have the foregline wheels from the viper racing league. Anyone know if the 25.5” tall tire would fit?

Cheers –

J

 

[Viper Specialty]

doing so would increase the cars accelleration at any time in a given gear, but it functions exactly the same as a different rear end ratio would. The car accellerates HARDER in any gear, but it does so for LESS TIME in each gear. That is part why SRT's are deceptively fast compared to a gen-2. The cars put down about the same amount of torque at the wheels than a gen-2 (actually higher in ft/lbs, but we arent measuring at a 12" radius in both cars, we are measuing a difference of about .75" between the two) the SRT accellerates at the same "harshness" as a Gen-2, but it does so LONGER in each gear, allowing the car to be faster, without actually "feeling" like it is.

For example, a Gen-3 car is overall geared equivalent to a gen-2 car with a 2.93 rear end ratio. Even though both cars run a 3.07 with the same trans ratios, the taller tires on the SRT make it effectively taller, when campared to a Gen-2.

Also, for another comparison, a Gen-3 with a 3.55 rear end will behave like a gen-2 with 3.33's in the rear end. This is in part why the 3.55's are such a good gear in the gen-3's, but slightly too tall in the gen-2 for many applications.

 

[Kai SRT10]

At the track, I run 18 inch wheels all around with Michelin Sport Cup tires.

Compared with my stock street wheels and tires, the car has less "rake" fore and aft.

Sport Cups are 26.3 diameter rear (345/30/18) and 25.2 diameter in the front (295/30/18)

Stock Pilot Sports are 27.4 diameter in the rear (345/30/19) and 25.7 diameter in the front (275/35/18)


I have noticed that the car pulls a little harder with the 18 inch rear wheels than with the stockers, and I have to shift noticably sooner than with the stock wheels. I think that the 18 inch wheel size is just about perfect for road racing on tight tracks, as it allows me to pull out of most slow hairpins in 2nd gear, whereas before, I needed to use 1st gear. With the 18's I only have to shift down to first on extremely slow, tight turns.

The only downside to running 18 inch rear wheels on a SRT-10 is that you have to alter the parking brake with the Archer kit to make it fit.
I'm pretty sure that the Comp Coupes are all running on 18 inch wheels.

 

[Gforce]

Thanks Kai.

I am also running 18" tires all around. I am using michelin slicks off of Don Roberts comp coupe. I was expecting the wheel+tire to be shorter (than the stock 19" wheels + runflats)in height but after installing them, turns out that his tires are the same height as the stock ones (less metal, more tire).

I am considering switching from the full on slicks (presumably 27.4 inches tall) to something like the sport cups (around 26").

In case it helps, I loved the 3.55 gears on the GTS. Perfect for portland international raceway (which is where I drive most of the time).

Don't know if I want to give up the grip from the michelin slicks but sure would like the pull of the 26" tires.

thoughts?

 

[Kai SRT10]

Where can you find these Michelen slicks?

What wheel sizes will they fit?