Jay M

I posted the other day about bad traction at the drag strip. The cheapest solution would be to use drag radials when I race.

But I think I would prefer a more permanate solution. I don't know how wide street tires need to be to keep a grip with 540#s of torque, but I looked at a web sight with a bunch of exotic car specs and saw that the quickest cars have really fat tires.

Ferrari Enzo 484.6 ft lbs at 5500 rpm - R 345/35ZR-19 - 0-60 3.5 seconds
2003 Viper SRT/10 - 500.0 ft lbs - R P345/30ZR-19
2001 911 GT2 - 457.4 ft lbs - R 315/30ZR-18 - 0-60 4.0 seconds
2001 Corvette Z06 - 385.0 ft lbs @ 4800 rpm- R 295/35ZR-18 - 0-60 4.2 seconds

I don't know how heavy my car is but I am guessing 3600 pounds.

The Viper looks like the closest match for weight and TQ. So I think 345 tires would be nice on 17" rims.

Will these fit using offset trailing arms? That would be 13 1/2 inces wide!!

I don't want fender flares, or the tires to stick out!

Any thoughts?

thanks,
~Jay

Twin_Turbo

the offset trailing arm doesn't give that much increase in rim/tire width you can use, the frame is the next obstacle. I'm guessing that 315 is about the largest you can run without resorting to fender flares.

Jay M

I had another thought..
I read that tire height makes a huge difference too. Right now I have 26" tires, would taller tires fit? Maybe 27" on 18" rims? Would that look silly with the 17" rims with 26" tires in front?

~Jay

Gordonm

And each one of those cars can't really hook up with the power they have. It helps to have wide tires but if you want to really hook it up Drag radials or slicks are the only way. I've driven a Z06 and if you even nail it from a roll the tires go up in smoke.

Twin_Turbo

the enzo and the GT2 have traction control if I'm not mistaking...that sure helps a lot.

Let 'er eat!

73 Vet

Jay, I don't know how wide you can go, but, if it's traction you're looking for, have you checked out http://www.dragvette.com?

Nixxa

Good question.....w/o offset and w/ offset what is the widest tire that I could put on.......?

norvalwilhelm

I ran MT sportsman pro's in size 12.5 x 28 x 15 and they absolutely filled the wheel well from frame to modified inner lip. You will not get bigger then that. My existing 305's are slight smaller and fill nicely but with offset trailing arms.

LiveandLetDrive

Keep in mind, given one type of tire, the front-to-back length of the footprint is what really matters. There's a point at which more width won't do much of anythign for you in a straight line. Decreasing tire pressure and increasing radius will help make your contact patch longer. For your kind of power... time for slicks and breaking parts :D

-Chris

HUGEsidepipes70

I think there is a different trailing arm that will allow for wider wheels. I think I remember something about that when I bought my '70 from the previous owner. Not sure if that helps any. You can check with any of the major aftermarket dealers and they could tell you about it I'm sure


[Modified by HUGEsidepipes70, 2:55 AM 4/27/2004]

Stingy74

How wide were the wheels? My 28x9.0x15 ET Drags on 8.5" wheels (3.5"b/s) came very very close to the end of the leaf spring. With the car bouncing around on slicks you can't help but think about how close the sidewall is coming to the end of the spring. I'd hate to tear a slick. I guess a shortened spring would help.

tshort

Jay,
There was a lengthy discussion about this probably about a year ago or more. There were some very scientific formulas and approaches presented and, at least for me, I was convinced that tire width is not how you gain traction. It is all about the optimum pressure and rubber compound. You really need to consider drag radials. I am running drag radials permenately and it has been good so far. I haven't had them long but if you don't mind the shorter life and taking it VERY easy in the rain then they are great. Or you could also buy a cheap set of wheels with slick on them and have those strictly for the strip. I actually went that route at first but the wheels I bought (Cragars) won't fit without spacers. In fact I still have them if you want them for very cheap but like I said would need a spacer. They have some MT's slicks on them but are a little dry rotted. Probably only safe for some good burnouts.
Back to the point, if I remember correctly, wider tires only help a lot in road handling, not straight line performance.

aharte

I can't help you with your tire problem, but comparing torques between various cars doesn't mean anything. Peak torque is a meaningless number since what reaches the ground can be made arbitrarily large with the right gears. That's why people talk about hp when comparing engines, although its certainly not a perfect measure either.

Jay M

I don't quite understand that. If you put any car on a chassis dyno it will still give a Torque figure relative to it's engine dyno figure (usually about 20% less) regaurdless of what gears it has. If I were to change the gears in the rear end, the chassis dyno would still give very similar numbers wouldn't it?


As for tires, I think I am going a little overboard with the size. When I left work today I had the road to my self in the indusrtial center. So practiced a few launches. I think that track was especially bad the night I was there because I had a lot more control tonight on the street. I was also wearing a helmet at the track which really impares your senses.

For a short time I had some used 275s on my 8" rims. They looked a little funny (too wide for the rim) but they got a ery good grip.

Maybe a good sticky 295 would be a good compromise. Great grip on street, and a nice safety cussion at the track.

I'm a little affraid of drag radials on the street. sometimes the rear end gets a mind of it's own. I would imagine drag radials would compromise cornering a bit.

I guess I should just be content, but I can't stand the fact that an AMG mercedes can beat me at the track!

~Jay

aharte

Dynos measure power, not torque. They then use the rpm measurement to derive torque from the measured power. Power doesn't change with gearing (in a perfect world at least), but torque does. That's why you can break your tires loose in 1st gear but (probably) not 4th. The torque to the ground is very different in those two cases.

Solid LT1

The biggest tires for stock wheel wells would be 275/50/rears and 255/60 fronts. My 275/50/15 Drag T/A's require me to remove my rear sway bar and stick out about 1/2" outside the wheel wells. I run 255/55/16 street tires ans 26X10.5/15 Drag slicks but, have run 26X11.5/15 with the slicks hanging out from the wheel wells. Here is a picture of my street set-up I think it looks JUST RIGHT!

427V8

People run 7's on 10" drag radials.

you don't need Fred Flintstone tires to go fast.

tshort

:iagree: 100%

Suspension and tire compound play huge roles in traction.
:leaving:

groovyjay

Here's 295 tucked under stock 79 body lines with stock trailing arms, the parking brake cable has been relocated to the top of the trailing arm