[torqjunki]

I am familiar with the formula that calculates predicted RPM for given tire height. Have also calculated (predicted) converter slippage for new converter. I would like to cross the finish line between 5800 and 6000rpm. The unknown factor is adding a 250 shot of nitrous. The converter was built for the nitrous and should be very tight, shooting for 3200 on motor and 4000 to 4200 on the gas. What tire would you experienced nitrous users choose?

130 mph on motor
T-400
3.73 gear
Max size I can use...30" / 10.2" wide

Should I wait and see what the converter does before purchasing tires in case the converter is a little too tight or loose? Thanks

[torqjunki]

I am familiar with the formula that calculates predicted RPM for given tire height. Have also calculated (predicted) converter slippage for new converter. I would like to cross the finish line between 5800 and 6000rpm. The unknown factor is adding a 250 shot of nitrous. The converter was built for the nitrous and should be very tight, shooting for 3200 on motor and 4000 to 4200 on the gas. What tire would you experienced nitrous users choose?

130 mph on motor
T-400
3.73 gear
Max size I can use...30" / 10.2" wide

Should I wait and see what the converter does before purchasing tires in case the converter is a little too tight or loose? Thanks

[Goatman]

Tallest tire possible at all times. Adjust everything else from there.

Chance favors the prepared mind.

[SCOTT ESTERLE]

I'm running 28x9's right now with 3.73 gears & i have killer sixty foots but no top end. I think my tires are to short so i'm going to try 29.5 x 9.

[6567GTO]

Which brand and tire are you going to try Scott?
Thanks

http://home.earthlink.net/~uptons1/ <~~some pics of my 65 GTO

[rumair]

i switched from 28x11.5 ET streets to 29.9x9 slicks and picked up .2 on the big end while the 60 ft. times stayed the same to within a few thousandths. i hope to be ditching the leaf spring suspension soon in search of more traction.

i couldn't be happier with the taller tire from a performance standpoint though...shifting at 6000 it goes through the traps at ~6200~ rpm weighing in at ~3800~ with a 4.11 gear. i'm not a math expert but i think the 29.5" tire turned the 4.11 into more like a 3.70 gear...

97 Trans Am WS6
Best ET: 12.13
Best MPH 114.6
74 Formula 455
Best ET: 11.83
Best MPH: 113

[basketcase70gto]

With a 130 on the motor I think you will over rev with a 28" tire. A 29.5 or 30" should be pretty close but with the n2o go with what Goatman said and put the biggest tire you can fit on there and you will probably still have to gear down.

[torqjunki]

Thanks for the advise guys...with the previous too loose converter and 28" MT's, I could not make it down the full quarter without getting on the rev-limiter at 6600rpm on 175 shot. Was'nt sure just how much the converter contributed to this. Probably go with the 29.5x10.50 MT's, but am considering running tubes in them to stiffen the sidewalls for the violent launch with stock suspension. Anyone experienced with running tubes with transbrake or manual trans cars, or just hard leaving cars in general? Still pics of car leaving show the tires squashed almost to the rim and wrinkled badly.

[WARPed]

I agree with Goatman, put as tall a tire you can get away with. Then adjust the gear if needed.

with out questions there can be no answers

1969 Grand Prix
[email protected](1.358)
[email protected](1.342)
WARPed Tepee Forums
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[SCOTT ESTERLE]

I'm going with Mickey Thompson slicks. Car sixty footed 1.44 with 28x9 Mickey's at Norwalk friday night. Torqjunki go with the Stiff Sidewall slicks & forget about the tubes.

[Ron]

Stiffer sidewalls will help. If the tire maker of your choice does not make a stiff wall tire in the size you want there are a few ways you can help yourself.

1. Run tubes in the tires

2. Run a wider rim. For instance; run a 10 inch wide slick on a 11 or 12 inch wide rim.

Good Luck,

Ron

[torqjunki]

My intention was to run a stiff sidewall slick, but I don't think the MT 29.5x10.50 is available in a stiff sidewall configuration, thus the idea to run tubes. Still thinking about some Goodyears also. Are they stiffer than the MT's?
Am told that the Goodyears will last much longer and possibly more consistant. Now that I have narrowed the search to a near 30" tall tire, I can search for the right compound and stiff sidewall. Want a med compound. Scott...1.44!!! That rocks Here is another question, slick related.
Keeping in mind that I am running a 8 or 8.5 wheel, and that I need a stiff sidewall, would it benefit me to run a 9" wide slick? Would the better match of the rim and tire width make up for the 1" less tire on the ground? Maybe the 9" patch would all be on the ground where the 10+" would not utilize the edges due to the 8" wheel. Thoughts...Seems to be working for Scott. All that delicate work on the inner wheel well with the sledge hammer for not

[Goatman]

NO TUBES.

Only benefit:

Extra rotating wieght.

Leave them out and get the 29.5x10.5W's. All you'll need.

Chance favors the prepared mind.

[SCOTT ESTERLE]

I would stay with the 9inch wide slick with the 8inch rim. If you go 10 inch definately go with a bigger tire.

[Torment]

I'm running the Phoenix 29x10.5 slicks. Not much choice but to run tubes with them, they leak air right out the sidewall They hook well and like alot of heat compared to others I've run. You're going to be on the rev limiter whichever height you choose, or damn close to it.

The secret to happiness is not getting what you want but rather, wanting what you have.

[torqjunki]

Goatman...would love to run the stiff wall "W" tire, but like I said, max size I can run is 10.2 wide.
Torment...Are the Pheonix tires a med or hard compound and how many passes can you get from them? Used them long? Why did you choose them?
Thanks

[SCOTT ESTERLE]

The Phoenix slick is 10.8 & F9 compound which is the Medium comp.

[Skip Fix]

Dave, You can trial fit my 29.5 radials and even make a pass or two with them if you want.

[torqjunki]

Thanks for the generous offer Skip. THe car is not near ready and I plan to have slicks ready to go before it gets finished. I have a connection for the MT's and can save quite a bit of money on them. Will probably end up using the 29.6x9.0 radial. If it is not stiff enough, I will try tubes. Second choice would be 30x9 Goodyear radials. Looking like I may show up to Nats in primer

[Skip Fix]

Dave, My Hoosier radials are DEFINITELY stiffer sidewalls than the M/T bias. They don't seem to be leaking any either.

I've got some Nittos and my car is finally old enough to get inspected!