Flat tyre - again!

[272BHP]

I really don't know what I am doing wrong here but have just woken up to another flat tyre.

I have had the bike only a few weeks and have suffered 5 flat tyres now all in the same wheel. I was left stranded from home on Friday night with yet another one and it took a 90min run/walk to get home. At that point I ordered som new Schwalbe Marathon tyres and duly fitted them Sunday night. Next day after a short ride flat tyre again. I changed the inner tube again last night and checked the rim of the wheel but I can't find anything wrong. pumped the tyre up again and this morning I kind of knew what to expect and sure enough completely flat.

I do notice that I always end of bending the pin of the presta valve is this the likely cause?

[sociopath]

Pump the inner tube up and stick it in a bowl of water. Any air leaking out will be obvious.

[zasker]

If you’ve changed the tyres and the tubes have you fully checked the rim. Is the rim tape sat correctly and check there are no spokes sticking through the tape. Are you somehow catching the tube when you fit the tyre?

[upsidedownmark]

Bending the valve can be a problem depending on how severe. If you're using levers to get the tyre on, you're probably damaging the tube..

[BoRED S2upid]

Pinch flat?

Invest in tubeless and get them professionally fitted. I used to suffer a puncture once or twice year on average (I only do 2000km a year) moves over to carbon rims and went tubeless and no more punctured.

That or get some gaytorskins. Terrible tyres but you won’t get a puncture.

I imagine it’s incorrect fitting though rather than a puncture from anything picked up on the road.

[272BHP]

I will check the rim again when I do it again later but I didn't find anything last time. If it is not that then it is either the valve or me pinching the tube with the levers not sure how to get around that as I can't see how I can get the tyres on without them.

I don't bother with fixing inner tubes I just bin them and use a fresh one.

[272BHP]

BoRED S2upid said:

Pinch flat?

Invest in tubeless and get them professionally fitted. I used to suffer a puncture once or twice year on average (I only do 2000km a year) moves over to carbon rims and went tubeless and no more punctured.

That or get some gaytorskins. Terrible tyres but you won’t get a puncture.

I imagine it’s incorrect fitting though rather than a puncture from anything picked up on the road.

I don't think its the road no. I fitted Marathons to my last bike and went a year with no punctures. I think you are right and it is something I am doing wrong when fitting them

[fat80b]

272BHP said:

I don't think its the road no. I fitted Marathons to my last bike and went a year with no punctures. I think you are right and it is something I am doing wrong when fitting them

If you can't figure out why the last one punctured, then it will almost certainly happen again. - When you take the tube out after a puncture - make sure you find out where the puncture is on the tube and therefore tyre and rim.
I do this by removing the tube from the tyre keeping everything lined up together and then pumping it up, you should then find where the tube is punctured which narrows down the bit of tyre and wheel you need to inspect super closely.

I use gatorskins and they are pretty good at preventing punctures, but when they are worn down (2k km or so), they will repeatedly puncture and need replacing - the new ones have wear markers on them which helps a bit.

[BoRED S2upid]

272BHP said:

BoRED S2upid said:

Pinch flat?

Invest in tubeless and get them professionally fitted. I used to suffer a puncture once or twice year on average (I only do 2000km a year) moves over to carbon rims and went tubeless and no more punctured.

That or get some gaytorskins. Terrible tyres but you won’t get a puncture.

I imagine it’s incorrect fitting though rather than a puncture from anything picked up on the road.

I don't think its the road no. I fitted Marathons to my last bike and went a year with no punctures. I think you are right and it is something I am doing wrong when fitting them

What rims are you using? I found fitting new tyres to my carbon rims almost impossible and for the very small cost my mechanic charges me I don’t bother anymore.

[leyorkie]

272BHP said:

I will check the rim again when I do it again later but I didn't find anything last time. If it is not that then it is either the valve or me pinching the tube with the levers not sure how to get around that as I can't see how I can get the tyres on without them.

I don't bother with fixing inner tubes I just bin them and use a fresh one.

Yes but if you inflate them and put under water you can see the nature of the puncture. If there’s two holes that’s snakebite from under inflation if there’s a small leak and in the same area you may have a small thorn in the tyre which is not protruding but pressure will cause it to puncture the tube. I assume you are checking the tyre for foreign objects an that the valve is tight you maybe loosening the valve with your pump and the tubes are not punctured at all.

Don’t just fit a new tube without checking and taking care with the leavers or you may never be puncture free

[Hard-Drive]

What tubes and pump are you using?

If your tubes have removable valve cores, they may not be screwed in properly (get a valve core spanner or bodge it carefully with pliers), or you may be unscrewing the valve slightly when you remove the pump if you are using any kind of screw adaptor (some Lezyne pumps are known for this). You can always use a dab of Loctite on the valve core threads too...

[shouldbworking]

What's your approximate weight and what psi are you inflating to? What type of bike is it?

[ukbabz]

One point to bear in mind, when putting the tyres on then line up the logo to the valve.

Not because it looks 'pro', but if you puncture again you can take the tube and find the hole in the water and then work out where it's going to be on the tyre / wheel.

[272BHP]

Just standard rims that came with the bike, branded Alexrims 626X19. I will inspect the inner tube and rim again once I take it off later.

The tubes are Bontrager 700 x 28-32c with 48mm presta valve - pump is a Beto alloy barrel from Amazon. I am about 85kg and I pump the tyres to about 80psi

Tyres are brand new Schwalbe Marathons 700x32c

[BrundanBianchi]

Check the rim tape for problems. Have a look to see if there are any obvious breaks in it, especially where it covers the spoke holes, and where the valve hole is. Run a piece of cotton wool around the entire circumference of the rim, looking to see if it snags on anything.

[272BHP]

ukbabz said:

One point to bear in mind, when putting the tyres on then line up the logo to the valve.

Not because it looks 'pro', but if you puncture again you can take the tube and find the hole in the water and then work out where it's going to be on the tyre / wheel.

That's a good tip thanks

[272BHP]

BrundanBianchi said:

Check the rim tape for problems. Have a look to see if there are any obvious breaks in it, especially where it covers the spoke holes, and where the valve hole is. Run a piece of cotton wool around the entire circumference of the rim, looking to see if it snags on anything.

Yep It all checked out ok to me, slightly proud bit where the rim join is but nothing serious I wouldn't have thought. I have put another inner tube in now and pumped it up carefully so will see how this one goes.

The inner tube I extracted had a small hole in it but It didn't correspond with the rim join above.

[upsidedownmark]

272BHP said:

I will check the rim again when I do it again later but I didn't find anything last time. If it is not that then it is either the valve or me pinching the tube with the levers not sure how to get around that as I can't see how I can get the tyres on without them.

I don't bother with fixing inner tubes I just bin them and use a fresh one.

It's hard to describe, but it's a bit of a knack. Firstly, you need to pinch the walls together on the opposite side to make sure they drop into the 'well' of the wheel, and that the 'slack' (such as it is) is worked up to the top. Personally I'd forget having ANY air in the tube as it makes this difficult, but some swear by having some air in. I put the bottom of the wheel against my gut, with the last bit to put on farthest from me. Grab the tyre in an overhand kind of grip. I'm using my right thumb to push the bead upwards (towards the tyre tread) and my left thumb to push the body of the tire inwards towards the other side of the wall a bit past where the bead crosses the lip of the wheel. Basically you're trying to roll the bead around the lip of the wheel. Inch it on a little at a time.

Some tyres are easy, some are hard, some are absolute b*tards. The downside of having chosen marathons is that being a heavy tyre they're probably harder to fit. Using levers to put the tyre on without damaging the tube is extremely difficult - sorry, but I'd bet on that being the cause.

Tubeless brings it's own set of problems - set up, and anything that doesn't actually seal are a major PITA, but smaller cuts self seal. It has benefits but isn't a panacea. I reckon I get about 1 puncture in 8k on GP4000's, and it takes 10 mins to change a tube, so... By far the biggest indicator of punctures is sh*gged tyres, more so than even what tyre you ride. As for gatorskins, I'd rather have a flat than a broken collarbone. Evil things

[272BHP]

Thanks for that guide. I can see it being a knack, I was very careful this time to make sure every thing was seated correctly and I moved around the tyre after fitting to make sure everything looked ok. It has been 3 hours now and it is still up so looking good so far. If it goes again I will try and follow these steps.

Thanks for the tips everybody.

[272BHP]

ukbabz said:

One point to bear in mind, when putting the tyres on then line up the logo to the valve.

Not because it looks 'pro', but if you puncture again you can take the tube and find the hole in the water and then work out where it's going to be on the tyre / wheel.

I did try that, however after it was all pumped up it appears to have moved a few inches so I guess all my manhandling of the tyre has shifted it. Oh well, I will remember for next time.