Problems with tyres

[londoncycler]

Hi - I'm new here, though not new to cycling.

I have a Claud Butler Urban 200, and ride through London on fairly standard roads (an infuriating mix of smooth and bumpy tarmac). I get punctures more regularly than I think I ought to.

The specifications of my wheels (and what tyres/tubes I should be putting on them) are a bit of a mystery to me. Can anyone please help??

Tyres: Michelin 622 700 x 23C.

Tubes: Specialized fits 700 x 20/28C.

Wheels: Vuelta Crosser(?) Trekking wheels, ETRTO 622 x 21 DIN, Alloy 6063 T6.

One shop told me that my tyres are not wide enough for my rims. Not sure whether this is what is causing the problem, and if so, what size/brand tyres I should get to improve reliability.

I would be so grateful if someone more knowledgeable than me can see through this murky set of numbers and give me some advice. Thanks!!

[Retro Grouch]

You need to examine your flatted inner tubes to analyze what is causing your flats.

Holes on the inside circumference of your inner tubes indicate a rim tape, protruding spoke or rim burr problem.

Holes on the outer circumference are punctures. Sometimes a piece of glass or a thorn will hide in your tire and continue to cause punctures in exactly the same place.

Two parallel slit holes indicate impact flats. They are generally caused by insufficient air pressure but can also be the result of using a too narrow tire for your rim.

[londoncycler]

You need to examine your flatted inner tubes to analyze what is causing your flats.
Thanks very much for the reply. I have had experienced the two holes before (is this sometimes called a snakebite?), but most recently, both tyres seem to have gone flat while the bicycle is totally stationery. This is the second time this has happened - and the previous time there were no holes in the tubes. Anyway - I will examine the tubes, thanks for the tip-off.

I think my problem is compounded by a problem with my tyres. I suspect, though I'm not sure, that they have become warped in some way from direct sunlight. They don't pull off the rim as easily as they used to. The rubber seems transformed or otherwise affected in some way. It has also been difficult to inflate the tyres to the correct pressure, as if there could be a problem with either the tube, or the tyre in allowing the tube to expand to the correct size.

Do the specifications that I posted indicate that the size of the tyre in itself is not compatible with my wheel size? Should I also measure the rim width, or is that figure already in the above numbers somewhere? Does any of this make sense?

[kdelong]

Wheels: Vuelta Crosser(?) Trekking wheels, ETRTO 622 x 21 DIN, Alloy 6063 T6. ETRTO denotes the sizing system being used. 622 is the diameter of the wheel in millimeters. 21 is the approximate tire width. The rest is the rim material.

Tubes: Specialized fits 700 x 20/28C. 700 is the tire diameter that the tube is designed for. 20/28 means that the tube will fit tires that have a with within the range of 20mm up to 28mm. The "C" indicates the width of the rim that this tube is designed for.

Tyres: Michelin 622 700 x 23C. 622 is the diameter of the wheel that the tire will fit. 700 is the actual tire diameter measured tread to tread. 23 is the width of the tire. The "C" indicates the width of the rim that this tire is designed for.

According to Sheldon Brown (who is the most knowledgable person on earth when it comes to bicycles), your tires are too small for your rims. On his webpage http://sheldonbrown.com/tire-sizing.html#iso , there is a chart that shows the rim size and compatable tire sizes. According to the chart, you should be using tires that are between 35mm to 50mm.

Using tires that are too small for your rims will cause all kinds of tire problems like you have described. Unfortunately your tires and tubes are probably no longer serviceable and I would have your LBS check out the rims just to be safe. I would also go to them to get the right tires and tubes. You will find that the wider tires are going to increase in rolling resistance, so you could talk to your LBS about replacement wheelsets for the type of riding that you want to do.

[londoncycler]

...
Thank you so much for your help! This all makes sense now! :)