Latex installation / removal PSA
So, I've had 3 flats on latex tubes in the last year that just did not seem to make sense to me given the conditions that they occurred in. I did some digging into it an a whole big ST thread later, I'm pretty confident I've reached my answer.
My errors were twofold, both in installation, and specifically in removal. First, when installing, the general consensus I got is that supplementing the tube's modest amount of powder that should come on it new is highly advised. I got all sorts of advice from placing the tubes in a zip lock bag full of baby powder, to actually coating the inside of the tire itself with baby powder before installation.
This detail is pretty important, because I believe the powder plays a pretty big role in preventing the latex tube from 'sticking' to the inside of the tire during use. Why this matters is less about using a new tire, and more about what happens if you ever have to remove your latex tube and plan to use it again.
When removing a latex tube from a tire, you have to be extremely careful not to pinch the tube itself with your tire lever, something that is basically impossible if your latex tube has stuck itself firmly to the inside of the tire wall. The tire lever rubbing along the length of a latex tube creates a weak spot across the entire circumference of the tube. In all of my cases, there is no visual puncture, however this weak spot may become thinned just enough to the point where it starts to become permeable and basically becomes a ticking time bomb that may seemingly spontaneously fail with no puncture or special conditions that would typically lead to a flat.
The takeaway is that you need to be extremely careful with your installation and specifically removal of latex tubes if you plan to re-use them in a race scenario. Latex tubes that have been damaged by your tire lever during removal look like this, and I would be very cautious about re-using them.
The whole thread is here, http://forum.slowtwitch.com/gforum.cgi?post=4599263, and specifically see the post from Maarc about 3/4 of the way down for a step-by-step of cautious latex installation with pictures
Comments
To make it a little easier, here's some pictures / advice extracted from the ST thread:
Be sure that every thing is clean at first
I also use baby powder as someone said earlier!
I put some powder inside to reduce the chance as much as possible the chance to pinch the tube inside because latex tubes are very fragile. Having said that, if well installed, there's no problem at all in the future. I have never had any problem with mine for every bike I ride.
Do not hesitate to put some powder too on the tube itself and take care not to pinch the tube.
Well, now I can say, in my opinion, that tyres which are very tight and hard to instal are not the best candidates to receive latex tubes inside
When installed, you start to inflate. Stop inflating at 1 bar, remove your pump at press the tyre everywhere to be sure there is no twist inside. Hernia can be frequent on latex tubes if you don't take any precaution. Then you pump until your expected pressure and then go to ride under the suuuuuun!
Thanks for posting the pics from ST!
Since I got a flat 2 weeks earlier at AmZof, I put my spare in my tire. When I was replacing it in the freezing cold, the bead was the tire when I hit it with my CO2 and I had to deflate it, fix the bead, and immediately use a 2nd CO2 which "double froze the rubber near my valve stem. Fast Forward to the day before Quassy. I knew I was going to be trashing my race tires after the race (because I always get a new pair before an Ironman and then just continue to race on them the following yr). So I looked into my tire/tube drawer and there were several Latex tubes that I had used in previous races. I didn't think it was a big deal, so I just grabbed a previously used one and added my extender and installed it, figuring I would save the new ones for Placid. It turns out this was probably a bad idea (So thanks for your PSA). And since I had only used my spare for one bike loop at AmZof and the following weekend of training, I simply put it back under my seat after I replaced it with the used latex tube. I'm guessing that hitting it with the CO2 again was probably too much for the tube to take after becoming a bit brittle after the double shot of it previously. It's the only reason I can think of that it literally blew a big hole in it right near the valve stem.
So... What lessons did I learn:
1) Forget the extra baby powder... I will only be using NEW latex tubes while racing from now on and if I ever need to take them out of my tires, they will go in the garbage.
2) I will only be using NEW butyl tubes as spares for all races.
A few dollars for new tubes is just too small of an amount to worry about conserving given how much time and money I spend on this sport. I just ordered a bunch of new tubes so I will have a healthy supply going forward.
Thanks Trevor.
Just to add to the confusion. I assume one would want to use talc type powder preferentially. I think most baby powders are corn starch. I assume corn starch would work ok but you might get things growing in your tire?
I wasn't sure about that, people kept saying to use 'powder' and when I asked about talc vs baby, people didn't seem to have a hard stance on one over the other. Baby powder certainly is a lot easier to find these days than talc, and seems to work OK based on the responses I got, but I'd probably go with talc as well.
@John, I'm with you. I really wanted to know what was going on with these flats because the flat I got at Ironman last year was on a 'new' tube, only I had removed it to re-tape my rim (flo-rim tape recall) like 2 days before the race after only riding on it a few times.
From now on, I'll most likely only ride brand new tubes for races and just leave them in after the race. I've been doing quite a bit of my training on latex recently to kind of get a good feel for their durability. Another thing I've heard often anecdotally is that if you do remove your latex tubes and plan to re-use them, storage is really important. Cool place, out of direct sunlight, all that jazz, but I've heard store them in a ziploc bag with as much of the air removed as possible to keep the latex from drying out and getting brittle.