Mickey Thompson ET Street question

Mike Puckett

SCCoA Member
My old tubeless Mickey Thompson Big End Street Drag tires are worn smooth and have become too inconsistent to run anymore so I've replaced them with new ET Streets that aren't "tubeless". I also got a pair of the 9553 tubes but the valve stems on the tubes are too big to fit the holes in the rims. So, I can either spend $200 to get the valve stem holes enlarged, drill them out myself and cross my fingers that I don't ruin the rim in the process, or run them tubeless. Mickey Thompson's tech rep said that it's Ok to run them tubeless but be careful if the car weighs over 3000 lbs. Well, I'm at 3500 lbs. It's not a problem to keep them inflated as I have a compressor and carry an air tank to the track with me. I just don't want to have to worry about tire failure during a run. So, the question is, how many of you guys run ET Streets without tubes? And, is there anything I need to be aware of when doing so?
 
I simply don't know what Mickey Thompson is saying regarding tubes. Tubes don't do jack for structure and I believe their recommendation came from issues with sealing and slow leaks with folks that actually drive them to the track.

I put my tires in the trunk.. typically bumping them up to 30psi before I go. Then at the track I put them on and drop the pressures.

i've run the M/T ET Street bias ply 10" tires on LX 6.5" wheels for a few years and other than a bit of the wiggles when I drop pressure to 12psi, no problems and no tubes.

If you want to do tubes, you could drill it. Just chamfer the inside edge so nothing sharp against the tube. Then get the wheel rebalanced.
 
I run my quicktime pros tubeless. The issue with tubes is so that the bead will still seal when you are running low pressures below 10 psi. I run my hoosiers at about 13psi without tubes and no issues.

When I first got them I was having issues with the tires spinning on the rims a little during the launch. Turned out that it was when I put them on myself and used a lot of dish soap to ease them on the rim with some spoons. The soap dried up and I haven't had any issues with spinning or leaking around the bead with low pressures. I trap over 110, and the car weighs 3800lbs and I've never had an issue.
 
Well that sounds good. Here, some of the racers run tubes and some don't, but their cars are all well less than 3000 lbs. One of the guys puts a little CocaCola in each one and sloshes it around real good so that when it dries out the sugar seals the rubber. I don't know if I'll do that or not. The M/T rep said use a little soapy water. The tubes came from Jeg's so I shouldn't have a problem returning them. I've been running 15 psi so I'll continue with that pressure. My old tubeless ones have a slightly thicker sidewall but otherwise look and feel the same. I went with the 27" instead of the 26" so I can get all the way to the 1/8th mi mark in without topping out in 3rd and having to shift.
 
another reason for running tubes is that a lot of people screw the tire onto the rim. You basically go right through the bead of the rim and the tire causing sealing issues. Running tubes solves that problem.
 
That's what I was gonna add.. It's on the back of most racers wheels that use tubes. The take sheet metal screws and screw the bead to the wheel. Then you need the tube to have any chance of keeping good air in there.
 
Just to update, I ran them yesterday with no problems. The air pressures stayed up with minor adjustments and there was no slippage on the rims. My 1st time trial had some spin but still managed a 1.883 short time. Then they faded to1.9 then 2.0 something. I ran back to back 13.65 time trials so I dialed a 13.62 and promptly ran back to back 13.74's gaining that 10th sec in the 60', losing one and winning one after a buy back. On my last pass I decided to do a dry burnout rather than roll thru the water. I noticed that I wasn't getting much smoke with a wet burnout. I got much more smoke with less engine effort dry and had a 60' time of 1.942 to get my e.t. back to a 13.66. Unfortunately I jumped the gun and red lighted while my Camaro opponent broke catastrophically on the line. Way to blow it:( Anyway I think I'll go back to going around the water and doing dry burnouts.
 
Interesting. All the printed material from MT says that the E/T Streets don't need much of a burnout during the course of the day. One good one to start off with and then pretty much a quick dry burn out after that. Something about how they hold the heat during the course of an afternoon.

I wonder now if that actually may be true, that you don't have to really heat them up before every run.


Ira
 
I would have to agree with them based on my experiences. Now that they've been scuffed in good, I shouldn't need to smoke them everytime and I'll stay away from the water and see what works best. I noticed that my trap speed was faster on that last run than earlier so I was getting better grip. Still, I was a mph slower for the same e.t. than with the 26" tires. We run again July 12.
 
Did the taller tire help you get to to the 1/8 pole as you hoped? And did you find you were running at 15lbs through out the day??


Ira
 
For certain, if you go through the water with them, you want them smoking nice and hot. I think the smokey burnout difference (when dry) is just going to depend on how long you wait between passes. The tires hold heat, easily gaining a couple PSI from cold to hot and stay sticky.

Hope they keep working out for ya.
 
You know, I was so busy concentrating on starting and hitting the gears I forgot to check at the 1/8th each time. I'd say to myself after each run, "Oops, forgot to check". At the end of the 1/4 my shift light didn't come on until I was past the marker so that's a good indication. I was shifting at 5400 and had plenty of room at the end.
Usually I have an hour and a half between rounds but that goes to 30 min in the later rounds assuming I get that far. Plus, it was 95 degrees in the pits all day, not much chance to cool down. I kept the pressure at 15 all day. I'm not sure if that's the best pressure but it seems to work. Since I'm not trying to get set record e.t. each time, I'm just wanting a good clean consistent launch without punishing the car.
 
Consistant. Makes sense. I would kill to be consistant :eek:

From my very little experience I have found that 15lbs does seem to give me the best launch. She does have a tendency to wobble at the top end though.


Ira
 
the thing with tubes is if u have enough hp and perfect grip that the tires might slip on the rim. thats usually around a 11.5 1/4 run car. and thats usually with a massive stall converter. i dont think you'll have any probs running tubeless. now if the tire is meant for tube im not sure if its ok to run without 1. however u say mt says it'll be fine, well get them to send that to u in writing so if something does happen they can pick up the bill.
 
I always have to smoke the tires real good (1st & 2nd gear to the rev limiter) to get them to bite. I can't go much lower than 18 psi are they feel like jello and it's difficult to steer.

Mike Siska said that his tires were much more stable on the top end since adding tubes last year. He said the slicks felt like drag radials...I'd like that.

David
 
Back
Top