My son and I took the Chevelle to a test and tune at Lebanon Valley Dragway yesterday.After reading all the posts indicating great success with drag radials I decided to try the set from our Turbo Buick which are M/T ET
STREET RADIALS P275/60R15.I set the tire pressure at 16.5lb cold hoping to heat them to 18psi after the burnout.When I attempted to launch the car off idle and footbraking it,the car hooked momentarily then blew the tires off.
I have not given up the idea of a drag radial and just think that the 275/60/15 is too small.What size drag radials are you guys fitting in the stock wheelwell of a 70-72 Chevelle.The drag slicks I run are M/T ET DRAG 29.5X10.5X15S.Thanks for any replies
Vinny

My son tried a 325/50 on his but it was a "very" tight fit. Didn't really hold the power very well either. It had some tire shake even after finding the best air pressure setting, leaving on footbrake. The car has been 5.95 @ 118 on regular 10.5" slicks in the eighth and could only muster 6.23 @ 114 with D/R on the motor.

I just tried a set of 275's on friday night. I couldn't get them to hook until I put 18 psi cold in them and did a massive burnoff. They went 1.64 60' to my normally on stiff sidewall slicks 1.58. I've got bone stock suspension, so I can't blame the radials, although, I'm going to keep them for street driving. I think you can get a 295/65/15, a friend with a 68 Chevelle runs thoughs and said he didn't have to cut anything. Maybe someone on here with first hand experience will no better though.

Matt

I have not given up the idea of a drag radial
You should!:yes:

Drag Radials will NEVER hook consistently with your power, nose weight, suspension and the tracks you run on!!:noway:

I have the same 275/60/15's on my '66. I was pretty disappointed initially, hooking for a few feet, then instantly into the rev limiter. After, what I would consider excessive burnouts, I finally had some success, running 60's of 1.62, 1.59, 1.61 (mind you, with 3.55 gears) consecutively. I am more accustom to hooking, maybe, 1 out of every 3 launches. A lot of this has to do with track prep. Because I don't meet NHRA tech for my E.T.'s, I can only race on nights open to the public (Midnite Mayhem/Madness). The track can be pretty neglected.

The massive burnouts have taken their toll on my current ET Street Radials. For a few weeks, I've been contemplating trying a different size, measuring repeatedy, however, still procrastinating. I'm afraid that the 295/65, despite being a wider tire, will only hurt my 60' times, because they are also 2" taller. The 275/50's would work better with the 3.55 gears, but, at the risk of sounding vain, would look goofy.

The only alternative, while retaining my current rims, would be the 325/50's. Close to the same height and over an inch wider. It would take some creative finesse and a lot of luck. I'm still straddling the fence. I'll have to decide soon.

This subject is very interesting to me.I am considering drag radials for my chevelle and thought that they hooked almost as good as a slick.I would love to see post from everyone who is runnning the drag radials.Im starting to lean to buying some cheap street tires and then get slicks for track.

Thanks for telling it like it is Footbraker,maybe drag radials are not for me!I thought since I had a set I would give em a try,thats why they call it test and tune.
What brand slicks are you guys running,my MT'S seem to loose grip after 50 passes even though there is plenty of meat left to the wear circles.I was surprised that my trap speed was only 6500 rpm's with the shorter tire and my mph was the same.
Vinny

You should!:yes:

Drag Radials will NEVER hook consistently with your power, nose weight, suspension and the tracks you run on!!:noway:

Aren't there guys running 7's on drag radials?:confused:I wonder if they are consistant or if their 60fts fluctuate with em.

this is just my thoughts,you can chew me up later .if you are a drag racer bracket or whatever you need to use drag slicks[ bias]unless your class requires others.it seems to me that alot of guys on here have some luck with the radials but always after alot of work to the suppensions,but the 60fts are not always as good or better than the bias slicks.for a car that is driven on the street i would probably use a street drag radial just to keep from changing tires when going to the track once or twice a year.vinny i wish i knew how many passes they are good for.i told my son we needed a new set of slicks at the start of the season and he said they had plenty of wear left in them.yesterday he was sick so i loaded up and went to the track.the 60fts have been going down hill but it is hot here.yesterday it was high upper 90s and my 60s were in the upper 1.57 to 1.59 .my 60 have always been in the 1.45 to 1.50s depending on track prep.there will be a new set of mickeys on there in 2 weeks to try before looking at the converter

I can assure you that whie D/R tires do hook well on the right setup, they are not a very consistent tire (assuming the cars making respectable power).

Now on slower/lowered power cars they may very well be OK for consistency.

I've run the D/R's for several seasons now and while I like alot of their attributes, consistency is not one of them, even on a fairly decent chassis setup.

As an example, on a good track, my car's 60's will vary maybe .03 throughout the day for no good reason. Dead hooking just fine, but the 60's still move around. I recently started trying a Hoosier stiff sidewall bias slick and even on a hot/greasy track, 60's varied in the thousandths at most from pass to pass (1.346 to 1.350).

Aren't there guys running 7's on drag radials?:confused:I wonder if they are consistant or if their 60fts fluctuate with em. Mostly Mustangs that have a 101" wheelbase and weigh very little. If you can find a way to kill bottom end power and then bring it back in downtrack they can be made to work, but they are always a hit or miss thing with lots of power.

Aren't there guys running 7's on drag radials?:confused:I wonder if they are consistant or if their 60fts fluctuate with em.
I would't say running but rather have run high 7's and few at that!

Further, those doing so at least on a national level ARE not only purpose built race cars with NO expense spared, they ARE also using timing computers read traction control and some are using ACTIVE traction control units that cost upwards of $10,000!!

That said, those that are running 9's and 8's on the local scene are doing it with much lighter RACE cars AND are blowing the tires off more than you know and more than they care to disclose!!

Big heavy car with big powerful engine = Hoosier C07 stiff wall slicks.:thumbsup: You may lose a little et, but if you have a good suspension, these slicks will hook and run consistently.

Is the Hoosier D07 a medium compound slick?Although my 60's have slipped to the high 1.48's low 1.49's at least it is consistent.The rear suspension is Hotchkiss with adjustable uppers,pinion angle is neutral and running air bags with stock rear shocks.
I am going to go to negative 2 degree pinion angle,adjustable rear drag shocks and an HR anti roll bar with a new set of slicks.I believe I can get a mid to high 1.30 60foot with this car.
Vinny

FYI a local racer here Brian Rock with a 65 GTO has been featured in CarCraft/Hotrod and Pontiac Hi-Performance runs M/T drag radials year round. His times are 10.5@125mph N/A. I look at his car all the time and see how consistant he is. His supesnsion is in stock location,no transbrake and nothing fabricated to make his suspension unique,just bolt ons. I think its in his launch technique.

He raced and won the Naturally aspirated class at Dragweek last year with 295/65R15 MT's. For some it might work and others it doesn't. Why? I dunno,but I've seen them work consistantly on his car and am impressed with the outcome.:thumbsup:

Vinny,
I misquoted. I meant to say C07, not D07. I run the 18155 (medium compound stiff wall). These slicks and the HRParts anti roll bar have been the best two things I've added to my car for consistent 60ft. times.

FYI a local racer here Brian Rock with a 65 GTO has been featured in CarCraft/Hotrod and Pontiac Hi-Performance runs M/T drag radials year round. His times are 10.5@125mph N/A. I look at his car all the time and see how consistant he is. His supesnsion is in stock location,no transbrake and nothing fabricated to make his suspension unique,just bolt ons. I think its in his launch technique.

He raced and won the Naturally aspirated class at Dragweek last year with 295/65R15 MT's. For some it might work and others it doesn't. Why? I dunno,but I've seen them work consistantly on his car and am impressed with the outcome.:thumbsup: Mid ten second cars are still in the power range that a D/R can be made to work consistantly well. Some of the bigger Chevy engines here make 200 more lb. ft. of torque over that level and run speeds of 140 MPH or more, so you have an apples and oranges comparison here.

let me throw my 2 cents in on this issue
i have ran hoosier slicks on my chevelle for years and just recently changed to a set of m/t 295/65/15 drag radials my car runs consistant 1.39 or 1.40 60 foots on the slicks on alcohol i may add, now my car is on gasoline and drag radials and it went 1.4311 60 foot and no worse than a 144.34 out of 6 passes that only .3 difference and that could very easily be the difference between alcohol and gas. and the way they drive down track is awesome no swaying like with slicks, so to me i like the drag radials,my car is a small block 383 with a weiand 177 supercharger at 7 p.s.i on gas 10.35@ 129 with only 32* of total timing.........Mike
http://i128.photobucket.com/albums/p184/fast1971chevelle/dragradials.jpg

Hi Vinny
We run same STREET RADIALS P275/60R15.on 3600lb camaro.Had exactly same problem with tire pressure at 16.5lb cold. ( hoping to heat them to 18psi after the burnout.When I attempted to launch the car off idle and footbraking it,the car hooked momentarily then blew the tires off.) Went down to 14.2psi cold + bigish burnout then tyres worked well (1.47 - 1.55 60ft) No spin at all, same technique as you.

Well, I use the MT/DRs275/60/15 on a 66 chevelle with about 411 hp and 450tq to the rear wheels with a 4sp and I love them. Granted I don't get the same 60ft as some of you do but my last time out I recorded a 1.7 60ft and that was with a bad clutch that caused me to get a Cen. DF. I get just about a full revolution on launch but hook well after that. To echo the same as some others have said, tire pressure is key with the DRs. I launch at 4000 rpms with 14lbs and like the way they hook.
BTW, the time to break in a new one is killing me and can't wait to get back to the track.
Good luck
John H.