MT ET street R bias

[Qtrhrse23]

Bias ply: Yea that 2.66 first with a 3.73 will want a 26" tall tire. A 28" tire is gonna be a BOG from a start, or even a 5-10 roll. A 28" tire will bog no matter how you leave, Im talking 5500 dump. 26" is what you want.

Stiff sidewall: 26" tire wont hold a 5k dump, maybe a quick release.

For best acceleration, go 26". 28" will make you more hamstrung in 1st.

Those 26x10 ET Drag biased are probably the best bet. Or easiest. Start at 17psi, lower .5 lb until you bog. On spray, start at 14psi.

 

[FastDriver]

Sounds like a plan. Torque box reinforcements soon, then I'll order the stiff sidewall 26s.

 

[Qtrhrse23]

Not STIFF sidewall. Rule of thumb you can ALMOST ALWAYS follow, stiff for auto, regular for manual. The manual SHOCKS or HITS the tires too hard, so more flex necessary.

 

[FastDriver]

It's the other way around, bud. At least from the research I did and from MT's recommendation. Stiffs for manuals and heavy cars. Mine is both.

 

[Qtrhrse23]

Soft sidewall ABSORBS the hard hit of the dumped clutch. Stiff sidewall cant flex-spins. Ive raced both, never could get the stiffs to hook unless you ride the clutch. Thats all I know. More research needed. Soft sidewalls give the most traction, but stiff sidewalls will drive/et better. The better straighter feel is what the stiff sides are ALL about.

How heavy? Less than 4000?

 

[FastDriver]

Soft sidewall ABSORBS the hard hit of the dumped clutch. Stiff sidewall cant flex-spins. Ive raced both, never could get the stiffs to hook unless you ride the clutch. Thats all I know. More research needed. Soft sidewalls give the most traction, but stiff sidewalls will drive/et better. The better straighter feel is what the stiff sides are ALL about.

How heavy? Less than 4000?

Yeah, race weight should be under 3,500 with me in it.

I get what you’re saying, and that’s exactly what had me going back and forth. Several guys made the same point that the regular sidewall can absorb more of the clutch hit. Mickey Thompson’s own construction guide says: “ST = Suggested for manual transmission (Medium compound – M5)” and “S = Stiff sidewall construction. Recommended for 4 link suspension cars, heavy cars (over 3000lb.), and ‘soft ride’ Rear Engine Dragsters. Can aid in quicker reaction times due to less tire distortion.” Mine is a stick car and over 3,000 lb, so that pushed me toward the stiffwall.

Where I landed is that if I just dump the clutch hard, I’m probably going to blow the tire off either way without a very sorted/tunable suspension. So I’m not really expecting the tire to do all the clutch’s job. I’m expecting to still have to work/slip the clutch some. Since I could see the argument both ways, the tie-breaker for me was the better/straighter high-speed feel and MT’s recommendation.

I noticed that these tires still wrinkle up on at least 1/3 of the sidewall, and I decided to run them tubeless. I'm not expecting a world beater, but if my 1.8x 60' on Nittos turns into 1.6 or better, I'd be very happy.

 

[Qtrhrse23]

Your 2.66 is gonna be iffy. I had a 98Z(LS1 6 speed), and that car was a bear to get off the line. It had the 2.66 and with Nittos it was almost always a bog. Best 60 1.91 ran 12.6s, and had almost 350Hp/350lbs at wheels(3500lbs). First gear roll was very nice though. Nice and straight.

My stock motored 92GT(full bolt ons) hit some 1.67s.68s on ET Streets Bias with 2.73s and a D1 5K dump not bogging. First gear math a little worse than yours 2.73x3.35, still in the 9s. Boltons NA 1.94s bog 5K dump. Back end walking.

On a different note, my friend let me drive his 92GT street car NOS(3400lbs all accessories roll cage) with 28x10.5 ET Drags. I got a 1.44 60ft. NOW THAT CAR HITS THE TIRES. Best the car has hit, and I weigh +80lbs. Back end REALLY WALKING.

No doubt those stiff sidewalls will drive better.

 

[FastDriver]

Those are all great data points. I'll be really interested to see how my dark blue car "Father Time" does off of the line. It already has 28x11Ws IIRC with stiffwalls and tubes on a 15" rim and has a fully adjustable suspension. It has 3.70s and a 2.9x 1st gear. So, the 28" tires make the overall ratio about the same, but it's a 331 turbo and I can run it over 7k on the launch if need be. I'm looking forward to getting to seat time.