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I bought my first bike few months ago, and it is old Raleigh 26" 1 -3/8 size. Every time I go with this bike through some bumps the rear tire and inner tube get punctured with large hole.

It is written in the tire that the maximum weight is 70Kg and I am 80Kg.

Is it the quality of the inner tube and tire makes it vulnerable to puncture? (we only have some cheap chinese tires and tubes in my country)

Or the size will not fit with my weight?
Or I can find a 26" tire and tube that could hold my weight?

  • Are you sure the maximum weight is 70kg? That's ridiculously low and would make the tyre unusable by most adults. – David Richerby Sep 8 '18 at 18:23
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    Does your air pump have a pressure gauge? If so, please tell us what pressure you're pumping your tyre up to, in PSI or bar or whatever unit. – Criggie Sep 8 '18 at 22:44
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    What is the air pressure you are putting in the tire. Your description of punctures when hitting bumps screams "THE TIRE PRESSURE IS TOO LOW!!!" – Daniel R Hicks Sep 8 '18 at 23:29
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    @AshrafAlmubarak - There are lots of variables. Depends on the bump, the shape of the rim, the thickness of the tire, and the material used in the tube. (But, basically, if, when you squeeze the tire with your fingers and you can compress it at all, the pressure is too low.) – Daniel R Hicks Sep 9 '18 at 11:15
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    @AshrafAlmubarak - A smaller tire needs a higher inflation pressure to safely carry the same load. This makes it more vulnerable to underinflation. – Daniel R Hicks Sep 9 '18 at 11:21
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  1. You are not putting 80 kg of weight on either tire; you're putting 80 kg + bike weight (say, 15 kg) on both tires combined, probably about 60% on the back, 40% on the front. So, about 57 kg on the back. In any case, I doubt very much that your weight is making you more susceptible to flats.
  2. The quality of the inner tube doesn't affect puncture resistance very much. The tire does determine puncture resistance. Some tires are engineered for light weight, some for flat resistance, some to meet a price point.
  3. One important cause of flats is under-inflation, which can happen with any kind of tire or tube. This permits the tire to bottom out against the rim when you hit a bump, causing what's called a "snakebite flat." So a first step towards preventing flats is ensuring adequate inflation. Here's an inflation calculator.
  4. The other main cause of flats, as you might imagine, is road debris. There's not a lot we can do about that other than try to avoid it. If I unavoidably ride through a patch of broken glass, I'll try to wipe down my tire with my (gloved) hand immediately after, but realistically, the damage is probably already done. If you think this is a likely culprit, you might try tire liners, which fit between the tire and inner tube and provide an extra layer of protection.
  • 3. The puncture occurred in the side wall of the tire. is this caused by under inflation too? – Ashraf Almubarak Sep 8 '18 at 16:31
  • 1. I have 3 times flat and all of them in the rear tire. Is it possible the design of the bike makes be put more weight in the rear tire? Because when I ride it I notice the rear tire is affected by my weight while the front doesn't do that much. – Ashraf Almubarak Sep 8 '18 at 16:34
  • All conventional bikes put more weight on the rear tire, and flats on the rear are much more common in general. A sidewall flat could be a snakebite flat. – Adam Rice Sep 8 '18 at 17:19
  • ok thanks I will maintain the right tire pressure and see the results. – Ashraf Almubarak Sep 8 '18 at 17:27
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    Sounds like it's time for new tires! – Adam Rice Sep 8 '18 at 18:10
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Minor point but you state the bike is old. There's nothing wrong with that, but its quite possible that the tyres and tubes are also old.

Sunlight, heat, and ozone do damage to rubber over time.

Rubber parts perish with age, meaning they loose strength. So a tube might inflate okay but not cope with the peak force of a bump.

  • If you can tear the tube using your arms, its old and needs replacing.

  • If the tyre has excessive cracking, looks dry or brittle, or you can see the canvas because of wear or flakes falling off, replace the tyres.

  • If your braking is bad, replace the brake blocks/pads. They can look perfect but be hardened and no longer provide predictable friction to the rims.

All these parts are "wear" parts, aka consumables. So if the bike fits you and is mechanically sound, is worth looking after it with basic refresh like this.

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    I changed the tire and tube 3 times with new one. – Ashraf Almubarak Sep 9 '18 at 9:17
  • @AshrafAlmubarak okay thanks - then this answer does not address the cause of your problems. Need a pressure reading - perhaps you can borrow a pressure gauge ? Does the local service station have one on their air pump ? – Criggie Sep 9 '18 at 11:36
  • I will try to find a pressure gauge that fits bike valve size, it is easy to find a pressure gauge for car tires. Bike tires pressure gauge will be very difficult. – Ashraf Almubarak Sep 9 '18 at 11:40
  • Until now I didn't get a clear vision to the problem. Most of people say it is under pressure may cause the puncture. But does under pressure cause a puncture of 10 mm size? Or it is caused by over pressure? Or just the tire quality is not ok? Or my weight don't fit the tire size? – Ashraf Almubarak Sep 9 '18 at 11:43
  • Get a pressure reading, lets figure out whether the pressure in the tyres is okay or too low. Perhaps try a bike shop, or ask a fellow cyclist in your neighbourhood? Or talk to your bike shop. – Criggie Sep 9 '18 at 11:59
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IMHO, its most likely a 'Snake bite', as covered by @Adam #3. Where are the holes? Does the tube have two holes or marks close together (hence the name "Snakebite" ).

The next most likely possibility is you have something sticking though the tire or rattling around loose inside the tire. When you remove the tire and tube, pay attention to where the tire is in relation to the valve (mark it if needed). When you find the hole, look inside the tire at this place for something stuck in the tire.

When you put the tire on, align a label with the tube valve so the tire/tube is in the same place. This is done so if you get another puncture, and its in the same place as an earlier one, you know you probably missed the thing causing the puncture.

Don't write off just plain old bad luck. I once punctured 3 times in less than 6km... Sometime it just decides that today is not your day....

  • The holes in the side wall of the tire and tube, and they are large holes. – Ashraf Almubarak Sep 9 '18 at 3:36

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