Keep pop'n latex tubes
 

So I just got my order in for new tires and tubes. I am planning on trying my first bike race this summer, and have my old '88 Prologue I planned to put some better tires on and clip on aerobars.

I got Veloflex Master 23's, and many reviews for them suggested to pair with latex tubes. I don't mind spending a few more bucks for better ride and lighter weight for like $4 more seemed like a no-brainer, and I got Michelin latex tubes.

Now I am still relatively new to road biking (started last year). I changed the tires on my Letour a couple times, and I also took off and put back on the cheap Kendas that where on the Prologue. So I have changed tires just a few times. The Veloflex where very difficult compared to the others, but I managed to get them on. However the tube blew out on the rear shortly after hitting ~110 PSI. After taking it all back off I inspected the rim around the area and it all seemed smooth. I put the one spare latex tube I ordered on, and re-inflated. That one held for a few more seconds, but blew again around 110 psi. My ears were ringing (was in my living room). Frustrated, but once again I pulled the tire off this time I'm out of latex tubes and put the old bontrager tube back on it. Held ok. I've done 2 rides on it now, with the Michelin latex up front and the old tube in the back.

Are these tubes super sensitive or what am I doing wrong? Is there really an advantage to using latex? Its mainly just going to be a race/ fast training bike used on paved bike path with the Veloflex pumped up pretty high. I don't mind spending a few bucks more for a better product but I hate blowing +$20 just trying to get them on!

At least I was pleasantly surprised how well the new tires were. Both speed and cornering were night and day better than the Kendas!

More than likely there was some damage done to the tubes during installation. It's really easy to get a part of the tube pinched between the tire bead and part of the rim. Even a pinch between the edge of the tire bead and the bottom of the rim will lead to a blowout. Adding a small amount of air to the tube before mounting can help a lot. What I can blow into a tube using my mouth is about right. Too much air can add to the difficulty.

Tubes only blow out when there's someplace for them to blow out too. When things are right, the tube is constrained to the closed space within the tire and rim and cannot blow out.

So step one is to consider whether the space within the tire is a truly closed chamber. Possibly you have a hollow double wall rim, and the holes aren't covered properly (most common reason).

Step 2 is to look at the location and shape of the blowout. Belly side, near valve, long slot, or short pucker, etc. Compare that to the location on the rim and tire and see if it makes sense.

If the tape is in good shape and the blowout is a long slot, and the rim is narrow, then the issue may be that the tube is sticking within the tire and when initially inflated, stretches across the gap between the beads. Then with more pressure, that narrow strip stretches more as it blows down into the gap below. This is a common issue with narrow rims. See sketch and consider the effect of the area across the gap id the tube forms a circle, stretching down to fill the rim as shown.

There may be other causes, such as not properly seating the valve, but as I said, the process begins with looking at the tube to see where it's failing. That may tell you how and why.

That could very well be it. The new Veloflex came flat and were a bit difficult to get tubular shaped profile at first. The tubes, which I did put a little air in, really did not want to seat within the rim but kept spilling out. The rims are slightly narrower than the 23mm tires, I'd guess maybe 19ish? They are Weinnman aero rims from the late 80's I assume. I also seemed to have a bit of excess tube on the opposite end of where I started.


Thanks for the great info FB. When they blew, they knocked the tire bead right off the rim. Or is that what allowed them to blow? Is it possible the virgin Velo's which come perfectly flat where just not used to the shape yet and slipped off the rim? Is there some kind of break in needed before going to full pressure?

When I put the tubes in, I start at the valve stem and work my way to the opposite side. Both times the blow out was on the opposite side, where I ended (and had the greatest difficulty getting the tube to stay in, and the final bead in place. Both blow outs left a long straight tear on the tube, the second one actually left two that were a couple inches long each and separated by about an inch. As far as the tube sticking, how does one prevent that? Do you use soap or something to lube it? Could be just me being inexperienced and trying to tackle a tough combination of tires rim and tube.

Tubes don't blow the tire off the rim from pressure. As FB rightly points out, there needs to be an escape route first before a tube can explosively blow out. Either tube or rim strip was underneath the bead when inflated or (less likely) the tire is defective. A blowout never has anything to do with a tube problem, whether it be damage or defect.

I had a Michelin latex tube blow out after being installed for over a hundred miles of trouble free riding. It blew the tire bead off the rim. I had had the tube and tire on and off a few times in the past so I assume I had damaged the tube somewhere along the way. I can tell you with 100% certainty that the tube wasn't under the bead when I inflated it. I checked every inch on both sides.

I bet you're pinching the tube between the tire and the rim, and not realizing it, latex is much easier to that then regular tubes. You need to cover the tube with baby powder then put just enough air into the tube to give it shape before installing.

I tried using latex tubes on and off over the years and end up going back to butyl. Latex flats just as easily which is contrary to what is told in the world of tubes, they are about as easy to repair as butyl but have to make your own patches, cost more, but they do feel like you're riding with about 15 to 20 psi less than you actually are, they also have slightly lower rolling resistance but you can't feel it but could be important if your racing.

The way I patch which seems to work better than standard glue on patches or glueless which didn't work at all (but are fantastic with butyl tubes) is to take an old latex tubes and cut 3/4" round circles for patches. Then use rim glue like Pastali which works better than patch glue, and wipe a thin layer of glue on both the patch and the tube covering an area slightly larger than the area of the patch, then press on immediately firmly and flat for about 30 seconds. Butyl patches will work but the patch material won't stretch when inflated the way the latex patch will and this is why a lot of regular patches on latex fail or don't last long. Of course you have to remove all the powder from the area of the tube you'll be patching so carry some alcohol towelettes.

.. in the mean time.. I expect you dont "need" latex tubes ...

More common Butyl tubes suggested , till your installation skills improve..

It would have helped if you mentioned that the Tire blew off straight away, instead of the "tube popping".

Describing the issue as you did, is analogous to someone asking for help with a dog who keeps escaping the yard, without mentioning that they come home to find the dog gone and the gate open. Not mentioning key details has people looking at the wrong things, like holes under the fence, vs. a possible problem with the gate latch, or maybe kids who don't close it positively.

As you suspect, you have the cause and effect backward. The tire jumps over the rim at high pressure, allowing the tube to expand into the gap and burst. To be 100% clear, a tube CANNOT blow a tire off the rim, it's the tire blowing that allows the tube to blow.

Odds are that you're the victim of poor mounting technique, and the tire was not securely "latched" under the rim's hooked edge, so it worked it's way off when the pressure was high enough, or as sometimes happens over time.

After mounting, fill tires to 10-20psi and slowly rotate the wheel watching the reference line molded into the tire just above the rim. It should be the same distance above the rim all the way around, and it's often necessary to bleed air and massage the tire home before inflating to full pressure.

Often the tire won't seat evenly because some tube is trapped under the last section you pushed over the rim. This is one of the reasons I prefer to mount ending at the valve. Before inflating, I push the valve deep into the tire to pull out any section of tube that may be trapped, then push it back into place from the outside (do not pull the valve on thin tubes). Then to the partial inflate and check before going to full pressure.

With a bit of experience, the partial fill and check become unnecessary, but Murphy's Law applies, and once you get so comfortable with your own skills, that'll be the time you should have checked.

+1. Andy.

FB, when my latex tube blew, it also blew the tire off the rim. It was a Challenge Strada 700x30mm tire with about 1000 miles on it. The tire fit very tightly to the rim. In fact I had to use tire levers to get it on because of the "open tubular" type construction. The same tire has gone 400 or so more miles trouble free with a butyl tube and I'm still riding it.

I repeat, The tube cannot be responsible for blowing a tire off the rim. The air inside does that, but not the tube itself. If the tire blows off it's because it wasn't seated properly (or was the wrong size or type, or was defective), and when the tire blows off, it causes the tube to explode.

If in doubt, I challenge anyone to try and pump more than 5psi into a tube that isn't inside a tire.

So, I can't say why your tire blew, but I can say with confidence what didn't cause it.

Well, it was seated properly, it isn't damaged, and it isn't defective. I put a hundred miles on it before it blew. It appears we are at an impasse.

Stuff happens.

Yes that is probable. I was having issues with the tube getting stuck between the bead and rim as I was trying to get them on. I thought I got them in but very possible it wasn't all the way (or could have been damaged by the pinching already. The butyl tube had no pinching problems at all though, perhaps its the rigidity difference between butyl and latex. I'll try the baby powder trick next time.
Agreed. I didn't think that I "needed" them anyhow, just that they might help weight, ride quality, and speed on the bike I'm setting up for racing. Although I realize the difference is probably minor, just wanted the best for this bike.

Well since you called me out on the order I mentioned things(and only the reason is I did not know the order of importance when it comes to bike tire failure, unlike your escaping dog analogy which would be much more obvious to the average Joe even), I'll call you out on one of my big pet peeves on forums is folks responding without reading all that was posted. Its annoying enough when something is posted in a follow up and missed, but especially so if the OP clearly explained it. But thank you for your detailed response. I was not aware of a reference line on tires, that will help immensely in the future. I was careful to seat it, and after the tire bead was on (extremely difficult for the final bit, that part was not necessarily done what I would call carefully) I inflated to 15 psi and gently massaged the tire as I slowly rotated it around all the way. The valve are of the tire was clearly having trouble seating and was popped up, I actually let a little air out of the tube and squeezed it a bit narrower and pulled it up a bit and massaged back down to get the tire to sit in the rim properly.

I may practice with the old butyl tubes putting on and taking off if I get some free time, before trying another latex tube. I'm however very busy at the current time and might just leave it the way it is until after the race I have planned in July but we'll see. Thanks everyone for the help! I just want to learn from my mistakes so I know better for next time.