I've been running the 27-10.50x15 Hoosier Quicktime Pro DOT's tubeless since I got them this spring. One of them has always lost more pressure than the other, but it's getting worse. It's leaking through the carcass, not the bead or stem. I'll be heading for Topeka tomorrow morning for the Division V ET finals, didn't want to hassle with air loss while away from home, so I had tubes put in today.

I've been running 19-20 psi in them, no problems with launch or 60', I suppose now I've messed up the combo and will have to change things. I'm assuming I'll need to drop the pressure a pound or two to account for the stiffer sidewall effect. I've had more issues with red lighting going on the 3rd yellow than I have bad lights, it'll be interesting to see if this picks up or slows the launch.

I'm sure the extra 4700' of air column won't affect the launch any, but. . .

 

Tubes are heavy and can be easily damaged.

Have you considered soaping the tires? Get some liquid dish soap. Put it on a rag and coat the inside of the tire. Let it dry completely then apply a second coat.

Under normal circumstances, this should stop any leaks through the rubber.

My current tires have tubes in them but my next set will be soaped. I remember a few years ago with my old MT tires , I could see air bubbles coming through the sidewalls when the car was in the rain. One leaked worse than the other. I've had no leaks with tubes except a tube got pinched and started leaking last year.

 

I can't say I've ever heard of soaping. I considered painting them, though.

I need to slow it down in Topeka to get over the 13.00 sec minimum dial-in anyway. And, if it slows it down off the line slightly, I should be able to cut more consistent lights.

The MT ET Drags I had on before the QTP's had tubes. I bought them used tires/tubes/rims. When they wore out and I mounted the first set of QTP's, one tube wouldn't hold air, so they took it out and mounted the tire tubeless. Of course, it was the 2nd tire they did, so the first one was already mounted and balanced with the tube. 6 weeks later, after I had gone out and had put the highway tires back on the car and the slicks were in the trunk, the 2nd tube failed, just sitting in the trunk - it was fine when I took it off. I was being watched over that day, for sure. One more burn-out or run on that tire and . . . well, it wouldn't have been pretty.

I won't be on the Board much in the next 6 days, but I'll let you know how it goes as soon as I can.

 

The tubes alone should slow you more than what you think...alot of extra weight if you use REAL drag racing tubes and not the POS tire repair shop-float down the river tubes LOL!! Yes they're spendy, but if a person decided to run tubes, these are the only way since they have the threaded valve setem lock to cinch it tight to the rim. I literally used 1 bottle of baby powder for 2 sets of slicks I used tubes in to make sure they would never get tacky and grip/rip each other. They killed the 60 and killed mph also, pretty amazing how just adding the weight of tubes affects things.

I think you'll find your psi will remian the same, I thought I would have to lower psi to compensate, but it was just business as usual. Heading to Topeka will undoubetdly make you change some things since the better air will make the car perform much better than your home track, so I would'nt put too much weight into what you find with your tubed slicks setting when you come over this way....make your true finding back home so you have a solid baseline number to compare to.


The one thing I did notice is in the hot racing season tires were less likely to gain psi between rounds when the sun beat on them...they stayed ALOT more consistant from morning to night when compared to tubless. They are a beeotch to balance though, so probably better to have it done with a bubble balancer then a centrifical.

I'll nver run them again, PITA and the extra eight slows ya down. Have the tire shop smear some bead glue/tire snot around the bead of the slick prior to mounting and your good to go without worrying about rim spinning.

 

Natural rubber tubes and baby powder is the way to go if you run tubes. I still have a big container of baby powder in my garage. The baby powder is sprinkled liberally all over the tube and on the inside of the tire. This will keep the tube from sticking to the inside of the tire. I think that's how I pinched a tube last year. Not enough powder. Got some sidewall wrinkling and it pinched the tube. I had a spare tube at home and quickly changed it for racing the next day. I can't remember if I ever got the tube patched.

As IHI mentions, running tubes will keep the tire pressures more consistant but they do add a lot of weight. Many tubbed out cars with the big slicks don't run tubes any more.

As for slowing your car down, the tubes should help with that. How about taking some timing out of the ignition? I'm assuming you're running the 57? Throw your tow vehicle's spare tire in the trunk

 

They are "real" MT slick tubes. Didn't do the baby powder, did do the bead goop. Since I'm not running them at 9 psi, they should be much less likely to spin on the rim than "real" race cars.

The elevation factor for Bandimere is .9276. I have found it very close in the past. Last time out here I was running 13.5's, which is 12.52 at sea level. Just for grins, I made one pass with it in drive and let the tranny shift - it shifted 1-2 at 5000, and the 2-3 was almost immediately after at 4500. I thought, "This isn't going to work, it's going to be way too slow!" Got the timeslip - 13.87. That's a 12.87 at sea level.

There are a lot of things I can do - full fuel tank, retard timing (those 2 are what I did at Pomona in 2004, with the old hydraulic cam), leave the floor jack in the trunk, and lengthen the throttle rod (I've got about 3/4" left). Or, I can just let it run at a 12.87 pace and fender race - probably what I'm going to do, the forecast for Sunday is mid-70's with a 10 mph cross-head wind.

 

Good luck with your races.

All this tire talk about tubes has me confused. I just got a set of MT ET drag slicks and the tire place didn't put tubes in them. I was going to go down tomarrow and make them fix it. Am I better off with out the tubes? I won't be running them at real low pressure as a 1.8 60' is about all I expect out of the car.

 

Most folks never run tubes no matter if it's a drag slick of DOT drag slick sine tire is essentially the same other than grooves in tread area to pass DOT inspection

But if you notice the slicks losing alot of psi between your driving times or between rounds, you can remove the slicks and "baste" the inside of the tire with dawn dish soap and this will help stop them from leaking air.

In a nutshell: DONT run tubes unless you have too, we've ran as low as 5psi tubeless with no bead troubles, it is squirrely on the top end, but can be done. tubes are headaches that slow you down.

 

Thanks alot for the info.

 

Well, back from Topeka. Not sure how much they slowed me down, if any. I did manage to spin the rims a little, about an inch, I think mostly during a weird burn-out - I spun them 'til the engine pulled down, gave it another second, let it go, like normal, then it apparently hit another patch of water left by a previous car. Gripped violently after hitting that patch. I switched them side-to-side for Sunday, and they slowly moved back as I went rounds. I need to re-goo them, as it didn't seem to take well. Or bite the bullet and put the screws to them.

Not sure if I'll get another run in at home this year. If so, I should get apples-to-apples data. From what I could tell, my 60's were down a tenth in Topeka compared to here, like they were 2 years ago. So, I don't think the tubes really slowed me down significantly.

 

hey guys ive got a set of hoosier 26x9x15's i have mounted tubeless on a set of weld draglites,they have the bead screws installed.There fine and all but it sux having to carry the extra set of lugnuts for those rims.infact last race i went to i forgot my lugnuts.so i was wondering i have my original 15 inch rs rims,is it ok to take those slicks off the weld rims and mount them on my rs wheels,or is that a no go since ive already got the screws in them?or would it be ok if i used tubes

 

i had a set of slicks on factory 15x7 rims that were screwed and no tubes, just used a little silicone on each rim screw and had to air them up almost everyday if I wanted to drive the car, but it kept a stock look no doubt. I even went so far to scrape off the M/T logo and the white paint to make them look like off brand tires to the casual observer.

 

Update:

I managed one more day at the track today. Earlier in the week I deflated the tires and siliconed the beads as best I could (couldn't actually break the bead from the rim).

As far as the tubes affecting the launch/times in apples-to-apples conditions - 60's same as before, ET's right in line with the weather station.

As far as the tires gripping the rims - one held, the other didn't. Looks like I've got myself a winter project.

Oh, held pressure within 1 psi over a 3 week period, during which time it got cooler. Gotta love that.