DOT tires ??

70 Challenger w 4 speed and Caltracs.
4.10 Dana.
Roughly 3400 w me in it.
527 inch 440 w roller.
We have a street race coming up in a few weeks at Crossville/I-40 and they require DOT tires.
What do you guys run?
In your expertise, what will work.
I have room for 10.50 W Hoosier on 11 inch wheel now.
The DOT stuff is what I am unfamiliar with.
Jerry

Just double check the tire requirements. I've done the DOT tire race and was disqualified when it was pointed out to me, radial DOT tire. Other than that Hoosier DOT are the most forgiving and hook under less than ideal track conditions.

With a stick I'd run a bias D.O.T. tire.

Make sure you're running DOT's on the front too ... sometimes, they get finicky during tech inspection and you won't pass without DOT's all the way around. It's probably an insurance thing ....

Yeah, we have a silly rule here locally at one of our street races where a drag radial has to have tread to the outside edge of the tire or is considered a slick! Nevermind I drove my car to the race and everybody else trailered theirs!

the front has to be DOT as well. I hate the rule but have been told to go home or get new front tires in the past, so I stick to slicks and front runners and stay away from the Radial world, I'm not fast enough anyways.

Getting the clutch right is usually the biggest part of getting radials to stick with a manual transmission. Too much clutch will knock the radials loose and make things very difficult.

When the clutch has more torque capacity than what the engine is putting out, that clutch pulls the engine down when you dump it, which in turn releases inertia energy from the rotating assy. For example let's say an engine is making 600 ft/lbs but the clutch has 800 ft/lbs of capacity. When you dump that clutch on the starting line, it will pull an additional 200 ft/lbs of inertia energy from the engine's rotating assy, and the net result is that the transmission's input shaft sees the full 800 ft/lbs of torque that the clutch can hold. If that 800 ft/lbs is enough to overpower the radials, they will get knocked loose with little chance of a quick recovery.

When dead hooking, that excess clutch capacity is also what determines how quickly the engine loses rpm after launch. If that 600 ft/lb engine above had a clutch with only 700 ft/lbs of capacity instead of 800 ft/lbs, the clutch would slip twice as long. The net result from that is the car has more time to gain speed before the clutch locks up, which in turn means the engine will only bog half as much as compared to the 800 ft/lb clutch. Not only does a closely matched clutch improve bog rpm, it also improves recovery rpm after WOT shifts.

Bottom line for radials- the better matched your clutch is to your engine, the more average power your engine will make, the easier your chassis will be to set up, the easier it will be to dead hook your radials, and the quicker your car will run.

All that said, my Clutchtamer eliminates that downside to installing a clutch that has more clutch capacity than you need. It basically makes it possible to temporarily dial back that excess capacity for a good launch. For me personally, it allows me to use a clutch that holds the torque when i'm spraying, but then allows me to dial back the hit of that same clutch for an effective NA launch at a zero prep event.

I'm a radial guy with a firm belief in dead hooking over wheelspeed, but this stuff can work with slicks as well.

Grant

Off topic a bit, but how do Hoosiers QTP's (bias ply)do on a street car with a stick? Summit's site says not meant for street use.
Also, what the heck do you use for a front tire with a bias ply rear if you have wheels wider than 4"?

Not running a stick in mine. But went from Mickey Thompson Sportsman Pro to Hoosier Quicktime Pro Dot. Was big difference in how the car hooked. Running 440 with an 8-71 on it. Idle to floor with Mickey would spin them easily. Idle to floor with Hoosier car hooks and goes. This is with no warming tire up. So far 40 miles on them and little new tire hairs are just starting to disappear. Summit says that to cover their rears. I talked to Hoosier before I bought mine. He said no problem on street. Jegs had them cheaper than Summit and was free shipping from Hoosier. Do not know if this helps you any.

I have the M/T ET streets and no way in any gear can I go from cruise at 25-3500 rpm to WOT and NOT blow the tires off.I can roll into it hard in 2nd but NO stompin!

I forgot to mention though that I am running 18.5 wide tires on mine. The narrower tires may spin easily compared to mine.