Regular punctures

DiggyGun

Well-Known Member
Region
United Kingdom
City
Buckinghamshire
I’ve got a Raleigh Moutus GT and getting regular puncture.

The tyres are presently 700-42c Specialized Pathfinder Pro (Road and gravel tyre) and so far I’ve had five punctures in a short space of time.
1-Sharp stone pieced tyre and tube
2&3-Snake bite puncture on inside of tube where it sits on the rim
3&4-Single puncture on inside of tube where it sits on the rim

After each puncture the tyre, the rim was checked. Now have extra tape on the rim, they also have Kevlar tyre liners and they have been slimed, since No. 1.

1 is bad luck and after the repair, but learnt from this and added the Kevlar and Slime.
2&3-found out afterwards, due to under inflation. Tyre states 50-80psi, had at 50psi and increased to 60psi at front and 70psi at rear after No. 2, but then No. 3 happened.
4&5-could not find a cause for these

For information, I’m 95kg (14.96 stones) and have two panniers on the rear rack. Terrain is a mixture of road / cycle paths / hard tracks / gravel. My previous tyres were 700-42c Mitas Flash (Road tyre) and never had a puncture with them, but wanted to get better grip as they were a bit twitchy on rougher terrain). The type of riding and terrain is the same for both types of tyres.

I’m obviously doing something wrong as on Nos. 2-5, the Slime didn’t work, )added correct amount as per bottle and they still deflated).

Advice and tips please as to how to prevent punctures and why the Slime doesn’t appear to be working.
 

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See this thread under maintenance & repairs:
I average 1/2 puncture per year, that is every 4000 miles.
I don't use slime, tannus armor, tubeless tires, extra tape or liners. My kenda giant or sunlite knobby tires cost $26. I ride on road. I do change tires before the knobs wear down. I use $7 schwinn tubes.
I do debur my rims, stem holes, and spokes.
 
Snakebites usually come from either a bad job of putting the tire on and the tube gets pinched under the tire bead, or air pressure is too low and there's enough motion to get the tube kinked under the bead and poof same result. So yeah underinflation is often the cause, but just as often its human error. Are you checking the bead seat before inflating after getting the tube and tire back on? This would be happening with barely any air in the tube. Just enough to give it form but not enough to stop you from using your thumbs to press the tire away from the rim to look down at the bead.

Problems on the rim side usually mean... something sharp is rimside. Brilliant deduction, right? In addition to eyeballing every square mm closely for any sort or protrusion, spokes that are too long for the rim/hub could be intruding in to touch the tube and bang thats the end of that. It only takes a spoke thats protruding a mm or so past the end of the spoke nipple to make this happen.

Another bit of diagnosis: Where did the hole occur? Using your valve stem as the index point, you should be able to pinpoint exactly where the issue was on your rim. I hope you are patching your tubes yourself via a Rema style cold-vulcanizing patch and not replacing them every time?

Slime is not a magic bullet. It works great in many circumstances, but a circumstance where the tube is pressed up against a sharp metal edge? Nothing will fix that as metal will always win that battle.

I just recently had a rim built for me and somehow we wound up with the spoke lengths too long as described above. I used cloth rim tape and wrapped two full layers over the center channel. No issue. If instead I was using a rubber elastic strip or another synthetic solution I would not be anywhere near so confident. Old school cloth rim tape is tops for this sort of preventative.

Lastly... sometimes tubes are crap. Literally. You can get a bad batch. For the longest time Sunlite tubes have been prone to separating at the join of the valve stem to the tube. Especially on the thicker thornproof models. Maybe you don't have a problem at all. Bontrager tubes tend to be a little thicker at about 1.1 to 1.2mm. Oftentimes tubes come from the same factory in Thailand but the production batches may differ enough to make a material difference. If you are getting tubes from your LBS... step away and get a different brand.
 
Snakebites usually come from either a bad job of putting the tire on and the tube gets pinched under the tire bead, or air pressure is too low and there's enough motion to get the tube kinked under the bead and poof same result. So yeah underinflation is often the cause, but just as often its human error. Are you checking the bead seat before inflating after getting the tube and tire back on? This would be happening with barely any air in the tube. Just enough to give it form but not enough to stop you from using your thumbs to press the tire away from the rim to look down at the bead.

Problems on the rim side usually mean... something sharp is rimside. Brilliant deduction, right? In addition to eyeballing every square mm closely for any sort or protrusion, spokes that are too long for the rim/hub could be intruding in to touch the tube and bang thats the end of that. It only takes a spoke thats protruding a mm or so past the end of the spoke nipple to make this happen.

Another bit of diagnosis: Where did the hole occur? Using your valve stem as the index point, you should be able to pinpoint exactly where the issue was on your rim. I hope you are patching your tubes yourself via a Rema style cold-vulcanizing patch and not replacing them every time?

I’m patching, but the last two, after the patch the tube split further having to throw it away. No evidence of any problems with the tyre of rim.

I just recently had a rim built for me and somehow we wound up with the spoke lengths too long as described above. I used cloth rim tape and wrapped two full layers over the center channel. No issue. If instead I was using a rubber elastic strip or another synthetic solution I would not be anywhere near so confident. Old school cloth rim tape is tops for this sort of preventative.

You can feel lumps and bumps under the tape. The rim initially came with Red cloth tape and I put an extra Continental 18mm Black elastic strip on. How do I know what correct size tape to get?
 
Update on the punctures.

Did a very detailed inspection of the rims. And found that as I had put the plastic strap over the original tape, it had moved, slipped up the sidewall of the rim and was exposing the original tape. I think that this was also causing the tyre not to seat correctly.

I removed this and checked the original tape. And found that this had moved, leaving some sticky residue and exposed some of the spoke holes.

I have now removed the original tape, cleaned the glue and rim, ordered some new rim tape, going for some Velox Cotton Tape.

This should be arriving today, so I’ll do both rims, reseat everything and try again. Hopefully, this should stop the punctures.
 
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