[mtbtuc8700]

Ok, so I have have been running homemade tubeless on Singletrack rims for a while now with no problems with IRC Trailbear tires. I also have a bike with Bontrager Race Disc Tubeless wheels. I have been running Michelin Hot S tires on these wheels with the homemade mixture (water, liquid latex, slime). I have no problems getting them to seal or anything, I have been running them for a few months now with no problems. I usually run around 35 to 40 psi max. So like 2 weeks ago it was like 85 degrees or so out and I had the front wheel in my backseat and it blew while I was driving and scared the crap out of me. Anyway it stretched the bead and the tire was done.
So moving on to this weekend I had a 24 hour race and had just finished my last lap and was getting things packed up and the rear tire just blows hanging on a stand. It was only like maybe 80 out. Again stretching the bead.

I can understand the first blow out it was probably kinda hot in the back of my car and blew but, I don't see how it went from like 35 psi to whatever preasure it blew at in like 30 minutes. Same with the bike just sitting in a stand under a tent. Oh, and one more note I have used these tires on the singletrack rims with no problems tubeless, but it was never really this hot out then.

So what do you think the problems is. Is there some kinda reaction with the homemade tubeless mixture and heat. Or can the tires just not hold that much preasure? Do you think the Stans mixture would help, or do I need to use a tubeless specific tubeless tire? Would the stans strips solve the problem? I know that Mike from Stans is on here all the time and thought he or some of you other guys might have had some of the same problems or might have some ideas. I am not really looking for someone to just tell me to get the stans system, I am interested to know what you think the problem is. I have heard stretched beads being a problem with michelins in the past with heat, but I would like to know what some others think.

Thanks for any help you can give me, and sorry this was so long.

Later,
Tucker

 

[D_D]

Heat can make tyres do funny things. I would check the around the rim where the tyre bead sits and look for any imperfections, bends etc.
Also check that the rim strip is ok.

If the bead is stretching there is a serious fault with the tyre. Steel beads snap and take a lot to snap them. A decent steel bead would proberly destroy the rim before snapping. I have seen this happen before and it was seriously loud and the rim was destroyed.

Unless the tyre has a kevlar bead. If that is what is causing the problems I would get a steel beaded tyre and throw the kevlar one in the bin.

 

[Softy]

My geuss wuould be , some kind of VOC is caused by a reaction in your mixture. Maybe simple organic fermentaion. Champagne corks pop.

 

[oldfart]

There are several posibilities. I have no idea if your mixture is affected by heat. Most tires will take 2 times the max pressure recomendation. I wouldn't think even the back of a car that heat would increase the pressure that much. There is a lot more volume in a tire that size as oposed to a road tire. maybe there is a junior physicist out there who can answer that for us?

Kevlar does not stretch. That's why kevlar tires are often a little more loose than an equivalent steel bead tire. They do get more loose with use but I think that has more to do with the bead settling into the rubber of the tire and the rubber getting looser. Its possible that a standard tire with goo in it is not compatible with your particular rim and strip. Its OK at standard operating pressures but a little too much pressure from an overheated environment and BOOM. I know I had a road rim, I think open pro cd which would blow certain tires off the rim if I wasn't really careful with my mounting.

D_D: I'll bet that the tire which you thought destryed the rim was actually a rim which failed because the brake track was worn down, it cracked failed and the tire blew out as a result. I've had that happen several times. In North Van its rather wet most of the year and we go through 4 or 5 rims a year due to wear of the brake track. Ceramic rims and disc brakes are cost effective alternatives.

 

[mtbtuc8700]

Well thanks for the responses so far! I am still kinda looking for more info or more ideas. I would still like to hear from other with Tubeless ecperience and see if they have ever had any similar problems. Mike B if you read this I would like to hear what you have to say also.

Thanks again for the help.

Later,
Tucker

 

[speedbump]

How about this for an experiment:

Take your homemade mixture and put some in a jar. Stretch a latex glove over the top of the jar. Put it someplace warm and wait for awhile. If the glove inflates dramatically, the mixture is probably reacting in some way and giving off fumes of some sort that gradually increase the pressure in your tire until .........Kaboom!!

 

[Mike B.]

Well, first off, I like speedbump's idea of performing the experiment to see if there is maybe something in your home formula that's causing a problem.

My second thought is that the Michelin XC tires have been a problem running tubeless (or even with tubes) from the very beginning. We discussed the issues with the Michelin engineers and they told us that they intentionally use less kevlar in their beads than others as a means of saving weight and cost. In all of our testing with the Singletrack, it has proven to be one of the best rims available for the tubeless conversion (with the Stan's kit of course) this is backed up by the fact that Chumba Wumba uses the Singletrack for DH with NoTubes inside. Not knowing how your strip is constructed, that may in fact be contributing to your difficulty.

Whoever mentioned that kevlar doesn't stretch missed the mark a little because when used in small quantities like tire beads, it can and most certainly does stretch. We've done extensive testing with kevlar beaded road tires where the tire will blow off the rim by stretching the bead and in some cases, snapping the bead. It's also possible, as someone mentioned, that you have a small defect in the rim that may have damaged your bead or did not allow the tire to seat properly. A little over a year ago, I had a 2.4 Motoraptor blow off the rim while the bike was propped against a wall because the kevlar bead snapped. After further investigation, I found a small cut in the tire right above the snap that seemed to indicate I had damaged the bead while riding.

My recommendation would be to try another tire, maybe a Kenda, Hutchinson, Continental, Specialized, etc which are all known to work very well to pinpoint whether the system you are using is at fault. I can't say for sure that buying Stan's kit will fix your problems but it can't hurt right

 

[mtbtuc8700]

Thanks everyone.

I like the experiment idea it makes since and seems to be a good idea.

Thanks Mike B. that is pretty much what I wanted to know, and I had an idea of it with some michelin's in the past.

Thanks again for everyones help.

Later,
Tucker