[Rich D]

Would like to use mickey thompson et street drag radials on car I'm working on. Info: car is a street / strip car but these will only be used for racing. What to use dot approved to run street classes. it's a stock weight LeMans with 495 inches. No roll bar so I will be running around 11.5 quarter times. Rear is a ford 9' with 3.50 gears so I don't want to use too tall a tire. Was going to use the 275/50 r 15's but I'm using 7 inch rally wheels and they recommend 7.5 to 9 inch wheel. My next option is go to 255/60 r 15 but it's 1 inch taller and I loose 1.4 inches of tread width per side.

So questions are: can I use the 275's safely? Would loosing almost 3' of tread make that much difference in traction and does anyone here use them and what are your results? What other options as far as tire companies would you recommend. Thanks for any help.

[Cliff R]

I've ran both on 7" rims and exact same results for 60' times, ET and MPH. The shorter tires just "buzz" the engine a little harder on top end. I went thru around 5300-5400 instead of 5100-5200rpm's.

Go with the 255's on 7" rims as they wear more evenly and you can run more pressure in them on the street and not knock the centers out of them.

I burned up two sets of the 275's right in the center before figuring this out. Another plus is that I gained some fender and shock clearance so no more rubbing on the street.

Bad news is that the MT ET Street radials require a decent burnout to work well, at least at my power level, so they don't last very long. I get about 40-60 good runs out of a set till the grooves are gone, then another 20-30 really good runs till the cords are showing.

Back when I used the bias ply version I could get about 300-400 runs doing the same thing. Bad news about them is that the car feels pretty "loose" up on the top end at 118-122mph. The bias plies also require very little if much of a burn-out at all, but they are like having two big rolls of tape back there on the street and throw every single piece of gravel you run over into the fenders. In contrast the radials drive more like a real street tire until you put some heat in them, then they act like a full race slick

I don't race my car that much these days, but I drive over to our local 1/8th mile track couple of times each summer, drop the pressure from 26 to 18psi, never shut the car off, do a nice 8-9 second burnout, roll into the lights, stage and blast off 1.59-1.61 60' times and bottom 7's at 95-97mph. Give them a few minutes to cool down, hit the gas station right outside the track on the way home and air them back up, and the car drives like it has plain old street radials on it and isn't throwing up every rock you run over!..........Cliff

[78w72]

i run the older version of m/t drag radial in 255/60, they are a great tire & ive got 4 seasons out of them doing mainly track use & they are just now at the wear bars & wore evenly with a little street use but no street burnouts.

but since you will only use them for track use i dont think the wear in the center matters. lots of guys use a 275 on a 7" wheel with no issue, just a little more rounded sidewall. & since you will only do track use you should check out the drag radial PRO or bracket PRO, they are DOT rated but strangely not legal for highway use, they are made specifically for DOT classes & are supposed to be the best hooking drag radial M/T offers, also says they dont require a long burnout. the PRO is basically a slick with just a few straight lines in the tread, not like the street version with the curved lines on the edge & more grooves in the center. the PRO is a 275/60 so its a little taller but wider than the 255/60. my next tire will probably be the PRO since they get great reviews & i dont use them on the street much if at all.

[i82much]

i have run 275/60r15 street radials on a 7 inch rally 2 wheel for years. Car drives fine but I do not drive enough miles to speak on wear patterns.

[Formulajones]

We run 275/60-15 MT drag radials on 2 cars here. Both very heavy A-bodies. We've been running them on both cars 100% of the time for more than 25 years, starting out with the first set of BFG drag radials back then. Been running the MT's since they first came out.

We log about 6-7,000 miles a year with each of these cars, and hit the track 2-3 times a year when possible.

Dad's car has used an 8" rim all this time, and for the last 5-6 years is making over 700hp and tq with a 571 Pontiac. They actually wear pretty well. Not even close to the wear bars yet and this set is going on 5 years old. It cuts 1.5x 60 foot times normally with a mild 455, and I expect that to drop a bit when it's fully sorted with the new found power, but at this point it holds the car well at the track and the street.. So as far as longevity is concerned, they actually hang pretty well for a soft compound tire.

Mine is a milder 600hp engine, and it's gone 1.5x 60 foot times fairly consistently too. I started out years back running an 8 inch rim on this one, but about 15 years ago I switched to a 7' rim. No difference in 60 foot times, and wear on the street has been perfectly fine. Didn't switch the wheel width for any particular reason other than I wanted a different set of wheels on the car and that's what I had at the time. Never bothered to change it since. Was worried at first about the narrow wheel for a 275-60 but it has shown to be perfectly fine. I think the current set on mine are actually 6-7 years old now with still plenty of life left. Might finish them off with another 2-3 trips to the track though which is fine because I tend to not like running tires on cars much past 5 years anyway and these drag radials have proven to last that distance for us with thousands of miles each year.

[ta man]

I suggest the 275/60/15 ET PRO, not sure how your track is but for less than ideal tracks you want the largest best tire you can stuff under the rear. I've had no issues with uneven wear and I've gone through a few sets.

[78w72]

Originally Posted by ta man

I suggest the 275/60/15 ET PRO, not sure how your track is but for less than ideal tracks you want the largest best tire you can stuff under the rear. I've had no issues with uneven wear and I've gone through a few sets.

& the radial pros broke his driveshaft too!

[Formulajones]

One thing I'll mention Rich when running a small drag radial like this and looking for optimum traction, I've found they really like being hit pretty hard on launch. Fair amount of instant center to push the tires (rearend) into the ground has produced more consistent 60 foot times.

[Rich D]

Thanks for all the info guys. The question about using 275's and 7 inch rally wheels has been answered. That brings me to another question. If you use a 275/ 50 tire on 7 inch wheels can you still get a full foot print of the tread on the ground for launching? Also any problems with fitting under a 70 a body? Thanks

[Cliff R]

If you lower the pressure down far enough they will eventually flatten out and get most of the tread on the pavement for launching.

The 255's will do that w/o having to go lower than 18PSI on 7" rims.......FWIW......

[Navy Horn 16]

Different tires, but I went from
275/60/15 Nitto 555s on a 7 inch Rally 2, to
275/60/15 Mickey Thompson ET Street SS' on an 8 inch snowflake..
And I picked up over an inch and a half of overall width.

The 8 Inch Snowflake is also 4 pounds lighter than the steel Rally2.

[Formulajones]

Have to keep in mind the MT tires are bigger than the competition, which is why they are favored in the radial classes because they push the rules to the limit. Not all 275 60's are created equal

Even though they are both 275-60's,

The Nittos are only 11.1 section width.

Those MT Pro's are 11.4 section width.

The MT's are also taller at 28.2 inches

While the Nittos are 27.76 inches.

[Cliff R]

Correct, AND one thing that has hasn't changed in this hobby is rim width vs tire cross-section vs the actual tread width.

IF you are using 7" rims you are pretty good to about 9" tread width without loosing some "footprint" at "normal" air pressures. If you go wider the narrow 7" rims pull the sidewalls in and reduce footprint. At 18psi you get at least as much as if not more tire on the pavement with 255/60-15 MT's as you do with the larger 275-60-15's.

I even ran one set of the 275-50'-15's and same thing, had to lower the pressure down pretty far to keep from knocking the centers out of them. I ended up running the 255's at normal pressure and got better and more even wear out of them........and even better exact same 60' times as the bigger tires without any clearance issues.....FWIW.....

[Rich D]

Thanks guys. So far all the posts are refering to the 275/ 60 tires. I was looking at the 275/ 50's. Here are the spec's on that and the 255/60's :

275/ 50 r 15 = 26.4 O.D., 11.1 sec., 10.2 tread, 83.0 cir.

255/60 r 15= 27.3 O.D., 10.1 sec., 8.8 tread, 85.7 cir.

By using the 275/50 over the 255/60 I'm gaining a total of 2.8 inches of tread if aired properly, only 1 inch difference in center section, the 275/ 50 is .9 smaller od and 2.7 smaller cir. Since I have 3.50 gears I thought the smaller tire would help keep the rpm's up a little for more power. These tires will not be used on the street, only at the track.

[AG]

What RPM do you want to be at going across the line?

[Lee]

Have you had your engine on a dyno? You talk like 3.50 aren't much. But with 495 inches, that is actually rather steep (unless you have a HUGE cam). My old 469 ran the 275/60's and 3.42 gears, yet I was crossing the finish line within 200rpm of my shift point - so those gears/tires were about perfect.

Also, in contrast to other's experiences, I've always ran my DR's around 24-25psi at the track. I've also done rather light burn outs - 2nd gear, and let off a second or two after the smoke turns white. I've logged a bunch of 1.5x 60' times that way.

[Rich D]

according to what I found I should be around 5400 at the end allowing 5% converter slippage. The motor is getting built now and unfortunately the cam card is at the builders also. I was thinking as long as I keep it around 5800 or so it should be still pulling at the end. The heads are kauffman d ports that flow around the 300 mark. Sorry no flow sheets on them either. Trying to keep the car around 11.50's because of no roll bar.

[Navy Horn 16]

I'm right there with you. I'd like to get kicked off the track at some point. Life goals.

[Scott65]

Its not as much fun as you think... You still wanna go faster, and you still don't wanna cut up your classic... My experience anyway...

[Formulajones]

Originally Posted by Scott65

Its not as much fun as you think... You still wanna go faster, and you still don't wanna cut up your classic... My experience anyway...

DItto....