Tyre Sizes and Puncture Question

[DeSelby]

Hello,

Normally posting in the mountain bike section but my commuter bike is a road bike so here I am.

I bought a set of Wenimann DP 18 wheels recently to replace my old wheels, since changing over I have had three punctures, two on the back and one on the front. Now the front one looks as though it was my fault because the tube was twisted. Strange thing is there seems to be a mark like a skewer has been put through the tube. There is no marks on the tyres or lose spokes so not sure what caused this and since replacing the tube the front has been fine.

The back however had a puncture a couple of weeks ago which I just pumped up at first and managed to ride 11 miles home to fix the next day. Now this morning I was riding in and the tube went bang, I removed the tyre which is now ruined as there is thread showing round the bead. The tube had a split on the bit that looks like the tube seal but then I also noticed a pinch flat mark or snake bite mark. I am assuming when the tyre burst the sudden pressing down of the rim onto the tube caused the snake bite mark. Is this possible? If the tube failed on the seam part do you think this is because the tyre was pumped to high? I pumped it to 80 PSI and managed to do 6 miles before it burst. I normally run the front and back and 80 PSI but have been reading I should maybe pump them up some more.

I have the Specialized Nimbus Armadillo Tyre 700 x 28 the tubes that I have been using are 700 x 20/28 while looking at tubes online today to try and find a cheaper alternative I found a well known supplier selling 700 x 18-23c tubes. Im a bit confused as the place I bought the ones I'm using now dont sell the ones the other place does, are 700 x 20/28 and 700 x 18-23c both suitable for use with the 700 x 28 tyre?

Sorry for all the questions I just dont understand why since getting the new wheels I am having Major problems with punctures / burst tubes. I am riding to work to try and save money so cant really afford to go through this many tubes.

Any advice will be greatly appreciated.

Thanks for your help

Jamie

 

[Jonny69]

I don't think you can use 18-23 tubes in a tyre that wide. I couldn't physically get the ones from my old 25mm tyres in my new 23mm tyres so I think there is quite a difference between the next size up tube. You want a 700 x 25/28c. Raleigh ones are good and hold their pressure well. So that's probably problem 1.

I've also heard that Armadillos aren't great for puncture protection, so you might have also got unlucky going over some sharp stuff. It does sound like a pinch puncture though. For reference, on my fatter tyres (32mm) I run about 80-90psi in the back and 70-80psi in the front. The narrow 23mm tyres have 110-115psi in the back and 100 in the front. Keeping the pressure up like that seems to make them quite immune to rough roads and potholes.

 

[DeSelby]

Thanks Jonny, Seems like a lot of pressure but from what I have been reading seems the way to go so I will give this a try. Left the bike at work over the weekend with the intention of fixing Monday night before the ride home.

Jamie

 

[Simon Daw]

What type of rim tapes are you using? Is there any chance that the tubes are pushing into the spoke wells under pressure?

Adhesive tape (Velox, e.g.) has always been my favourite, but nowadays many plastic ones are fine, too. Nonetheless, it's worth checking, especially if the wheels didn't come with factory-fitted tapes.

 

[DeSelby]

Guys I have been informed its more than likely the pressures that I have been using, however just to check I have purchased some new rim tape, cloth type, Inner tubes and fitted a replacement rear tyre. Since these changes fingers crossed I have had no punctures.

For some reason I run the last wheels and tyres at 80 psi for six months and never had a puncture. With the new wheels I have. After speaking to a guy outside of one of the bike shops in London I am now pumping to 100 psi. Feels like a lot to me but from what I have been reading its the way forward.

Feel like bit of an idot now.......

Jamie

 

[Simon Daw]

I'd be very, very surprised if running the tyres at 80psi caused your problem. Much lower than that and you'd get poor handling (especially with 28mm section tyres on quite narrow rims) and a greater risk of pinch-type punctures (though on tyres of the section you've described the risk of this is reduced), but 80psi should be okay, even if not optimal.