Oversize tube?

[StreetCowboy]

I'm struggling to find the exact tubes that I want - 29" x 1.5" - 1.75" with the low pressure "thick" valves; anyway, the chap in the local cycle shop fobbed me off with a slightly oversize (1.9" - 2.25") tube.

Is that a recipe for disaster which is bound to end tragically? I'm planning on carrying the new tube as the spare, with old the patched tube as the duty, and if need be, I could replace the tube again once I get home. (This is following a lesson learnt the hard way; yesterday I replaced a punctured tube, only to find that a patch on the spare tube had come adrift in the few weeks the tube had been in my backpack. So I'm going to use new tubes still in the box for spares, and put the patched ones back on the bike.)

SC

[chiangmaiexpat]

An inner tube that is specified just a few mm larger than the actual tyre size is usually not a problem. Since the tube is a bit bigger, it creates folds easier, so you have to be more careful when installing it. Inflate the tube slightly before fitting and make sure it doesn't fold under the tyre. I likewise had some bad experiences with patched spares. I once had to re-patch my rear inner tube three times, because all of the old patches became pervious one after the other. In the tropical climate, the patches seem to hold only as long as the tube is under pressure.

Cheers, CM-Expat

[StreetCowboy]

 

An inner tube that is specified just a few mm larger than the actual tyre size is usually not a problem. Since the tube is a bit bigger, it creates folds easier, so you have to be more careful when installing it. Inflate the tube slightly before fitting and make sure it doesn't fold under the tyre. I likewise had some bad experiences with patched spares. I once had to re-patch my rear inner tube three times, because all of the old patches became pervious one after the other. In the tropical climate, the patches seem to hold only as long as the tube is under pressure.

Cheers, CM-Expat

 

thanks for that. I've probably just wasted my time patching a second tube, then. Maybe I'll stick it on the front, and recover the tube from there as a spare (I think it is an unpatched tube). How come it's always the rear tyre that gets the punctures (at least 4 to nil, at the moment).

SC

[el jefe]

 

An inner tube that is specified just a few mm larger than the actual tyre size is usually not a problem. Since the tube is a bit bigger, it creates folds easier, so you have to be more careful when installing it. Inflate the tube slightly before fitting and make sure it doesn't fold under the tyre. I likewise had some bad experiences with patched spares. I once had to re-patch my rear inner tube three times, because all of the old patches became pervious one after the other. In the tropical climate, the patches seem to hold only as long as the tube is under pressure.

Cheers, CM-Expat

 

thanks for that. I've probably just wasted my time patching a second tube, then. Maybe I'll stick it on the front, and recover the tube from there as a spare (I think it is an unpatched tube). How come it's always the rear tyre that gets the punctures (at least 4 to nil, at the moment).

SC

Rear tires carry a higher percentage of your weight than the front tire so they are more prone to punctures. On a road bike it's usually somewhere around a 10-1 ratio.

I agree with CM-Expat's theory that tropical weather doesn't agree with patched tubes. I spend several months a year in New York and have no problem riding on patched tubes and carrying them as spares, but in Thailand the patches have failed often enough that I won't patch a tube unless it's an emergency.

[StreetCowboy]

 

An inner tube that is specified just a few mm larger than the actual tyre size is usually not a problem. Since the tube is a bit bigger, it creates folds easier, so you have to be more careful when installing it. Inflate the tube slightly before fitting and make sure it doesn't fold under the tyre. I likewise had some bad experiences with patched spares. I once had to re-patch my rear inner tube three times, because all of the old patches became pervious one after the other. In the tropical climate, the patches seem to hold only as long as the tube is under pressure.

Cheers, CM-Expat

 

thanks for that. I've probably just wasted my time patching a second tube, then. Maybe I'll stick it on the front, and recover the tube from there as a spare (I think it is an unpatched tube). How come it's always the rear tyre that gets the punctures (at least 4 to nil, at the moment).

SC

Rear tires carry a higher percentage of your weight than the front tire so they are more prone to punctures. On a road bike it's usually somewhere around a 10-1 ratio.

I agree with CM-Expat's theory that tropical weather doesn't agree with patched tubes. I spend several months a year in New York and have no problem riding on patched tubes and carrying them as spares, but in Thailand the patches have failed often enough that I won't patch a tube unless it's an emergency.

You're cheering me up more and more.

I spent Wednesday afternoon patching a couple of tubes, and ended up sticking on about half a dozen patches. The tube that went back on the bike is still holding up, more or less; the other, I'll put on the front when I get round to it, maybe at the weekend.

I guess the tiny little bits of metal (they look like bits of broken staple) don't actually get driven into the front tyre, which just rides over them, but the rear tyre flexes so much it picks them up and they work their way into and through the tyre, and then burst the tube.

SC

[chiangmaiexpat]

thanks for that. I've probably just wasted my time patching a second tube, then. Maybe I'll stick it on the front, and recover the tube from there as a spare (I think it is an unpatched tube).

I am riding with both front and rear tubes patched several times. Not a problem. The patches become unstable only when you deflate the tube and store it.

The weight distribution depends very much on your posture and therefore it varies. This is an essential part of riding technique. For example, in mountain biking you have to "lighten" front and rear in order to clear obstacles. Mountain biking involves constant and rapid changes of weight distribution. Road bikers optimise their weight distribution for climbing and descending. A 1:10 F/R ratio would be pretty extreme and your front wheel would lose traction very easily. In neutral position, weight distribution should be between 50:50 and 40:60.

Cheers, CM-Expat

[el jefe]

thanks for that. I've probably just wasted my time patching a second tube, then. Maybe I'll stick it on the front, and recover the tube from there as a spare (I think it is an unpatched tube).

I am riding with both front and rear tubes patched several times. Not a problem. The patches become unstable only when you deflate the tube and store it.

The weight distribution depends very much on your posture and therefore it varies. This is an essential part of riding technique. For example, in mountain biking you have to "lighten" front and rear in order to clear obstacles. Mountain biking involves constant and rapid changes of weight distribution. Road bikers optimise their weight distribution for climbing and descending. A 1:10 F/R ratio would be pretty extreme and your front wheel would lose traction very easily. In neutral position, weight distribution should be between 50:50 and 40:60.

Cheers, CM-Expat

The approximate 10-1 ratio was for punctures, rear vs front. Sorry for the confusion.

And you may be right, that patches only fail when deflated and stored. But that means every time you puncture you have to change the tube twice. Once on the spot. Then again, before your next ride, you have to patch the tube and swap it with the perfect one so that the spare has no patches. It's easier just to buy a few spare tubes and have no risk.

[chiangmaiexpat]

But that means every time you puncture you have to change the tube twice. Once on the spot. Then again, before your next ride, you have to patch the tube and swap it with the perfect one so that the spare has no patches.

Yes, that's right... which is why I usually try to patch my tube on the spot unless the puncture is too small to find, or if I am riding with a group. One thing I am wondering about is whether an oversized tube is more likely to cause pinch flats. Honestly, I don't know, but I guess that would depend more on the pressure you are running. Personally, I have had the opposite problem more frequently, namely that I cannot find a wide enough tube, and I had to fit a slightly smaller one. Also not an issue, except that the slightly smaller tubes seem to lose air pressure a little bit faster.

Cheers, CM-Expat

[StreetCowboy]

 

thanks for that. I've probably just wasted my time patching a second tube, then. Maybe I'll stick it on the front, and recover the tube from there as a spare (I think it is an unpatched tube).

I am riding with both front and rear tubes patched several times. Not a problem. The patches become unstable only when you deflate the tube and store it.

The weight distribution depends very much on your posture and therefore it varies. This is an essential part of riding technique. For example, in mountain biking you have to "lighten" front and rear in order to clear obstacles. Mountain biking involves constant and rapid changes of weight distribution. Road bikers optimise their weight distribution for climbing and descending. A 1:10 F/R ratio would be pretty extreme and your front wheel would lose traction very easily. In neutral position, weight distribution should be between 50:50 and 40:60.

Cheers, CM-Expat

The approximate 10-1 ratio was for punctures, rear vs front. Sorry for the confusion.

And you may be right, that patches only fail when deflated and stored. But that means every time you puncture you have to change the tube twice. Once on the spot. Then again, before your next ride, you have to patch the tube and swap it with the perfect one so that the spare has no patches. It's easier just to buy a few spare tubes and have no risk.

 

the whole saga came about because I was struggling to find a 700 x 38/43 tube with a low pressure fitting; and if I fit a tube with the high pressure valves, the tube fails around the edge of the hole in the rim, in my experience (perhaps could be sorted by more tightening the knurled ring, or not tightening it) (or perhaps by putting in a little home-made grommet from a piece of old inner tube - I have several of those now) so anyway, I patched all my old tubes as spares.

the bike is a mountain bike, and it's maybe supposed to be run with bigger tyres, but I am 98% on tarmac, so I wanted road tyres; they're still the widest tyres I've ever had; maybe I'd get less punctures with skinnier tyres; but I don't think so, my neighbour who rides a proper road bike is always regaling me with tales of two punctures in one ride.

SC

[chiangmaiexpat]

The roads here are often dirty and there is lots of glass, small metal pieces, sharp stones that can cause punctures. You get the least punctures with knobby tyres on an MTB, because the knobs keep the small stuff from penetrating the tyre. Unfortunately, they are not the most power efficient types of tyres, so if you most of your cycling life is spent on the road, it probably makes sense to put on thinner and slicker tyres. Have you considered going tubeless?

Cheers, CM-Expat

[StreetCowboy]

 

The roads here are often dirty and there is lots of glass, small metal pieces, sharp stones that can cause punctures. You get the least punctures with knobby tyres on an MTB, because the knobs keep the small stuff from penetrating the tyre. Unfortunately, they are not the most power efficient types of tyres, so if you most of your cycling life is spent on the road, it probably makes sense to put on thinner and slicker tyres. Have you considered going tubeless?

Cheers, CM-Expat

 

I'm frightened to go tubeless - fear of the unkown. But surely anything that has pierced the tyre sufficiently to make a hole in the inner tube would let air out of a tubeless tyre as well?

I might just resign myself to replacing the tube twice - once with a new tube on the street, and then again after I've patched it; or just scrap the punctured tubes - they're only a few quid anyway, and I'm still nervous about the integrity of the patches - though they seem to be bearing up well to date (famous last words!)

SC

[bobfish]

 

The roads here are often dirty and there is lots of glass, small metal pieces, sharp stones that can cause punctures. You get the least punctures with knobby tyres on an MTB, because the knobs keep the small stuff from penetrating the tyre. Unfortunately, they are not the most power efficient types of tyres, so if you most of your cycling life is spent on the road, it probably makes sense to put on thinner and slicker tyres. Have you considered going tubeless?

Cheers, CM-Expat

 

I'm frightened to go tubeless - fear of the unkown. But surely anything that has pierced the tyre sufficiently to make a hole in the inner tube would let air out of a tubeless tyre as well?

I might just resign myself to replacing the tube twice - once with a new tube on the street, and then again after I've patched it; or just scrap the punctured tubes - they're only a few quid anyway, and I'm still nervous about the integrity of the patches - though they seem to be bearing up well to date (famous last words!)

SC

Cowboy,

3 out of my 5 [don't ask] mtb's are running tubless. Its not 5/5 because the other rims aren't tubless compatable [i've avoided the "ghetto fix"...]. My experience of tubeless is great. Sure, I've bent a rim and 'burped' the odd tyre, but as far as small punctures go, generally you don't notice the leak and it self seals...... It's only when you change the tyre that the amazing number of self sealed holes becomes obvious.....

There's different systems and your LBS could sort it for you - no mess and money well spent imo.

[StreetCowboy]

 

3 out of my 5 [don't ask] mtb's are running tubless. Its not 5/5 because the other rims aren't tubless compatable [i've avoided the "ghetto fix"...]. My experience of tubeless is great. Sure, I've bent a rim and 'burped' the odd tyre, but as far as small punctures go, generally you don't notice the leak and it self seals...... It's only when you change the tyre that the amazing number of self sealed holes becomes obvious.....

There's different systems and your LBS could sort it for you - no mess and money well spent imo.

 

When you talk about small holes, how big do you mean? Two of my recent punctures have been from small metal shards less than a millimetre in cross-section and maybe three to five millimetres long; another was a pin bigger than a drawing pin; and the first was a square concrete drain edge - a drainage channel across the road about 200 mm wide for which the cover was missing, and when my back wheel hit the square corner, the tube burst - a split almost 10 mm long.

SC

[villagefarang]

In my last 5000 km I think I have had one flat while riding and a couple more slow leaks I discovered the next day. I don’t carry spares and was able to find someone to patch my tube the one time I was out on a ride when it went flat. My rides are usually between 50 to 70 km and a mix of road and dirt so I am wondering why I don’t get as many flats as the rest of you.

[StreetCowboy]

 

In my last 5000 km I think I have had one flat while riding and a couple more slow leaks I discovered the next day. I don’t carry spares and was able to find someone to patch my tube the one time I was out on a ride when it went flat. My rides are usually between 50 to 70 km and a mix of road and dirt so I am wondering why I don’t get as many flats as the rest of you.

 

I think mine are mostly construction-traffic related. Big knobbly MTB tyres would have avoided the two small metal shards puncturing the tyre; and the missing drain cover, well, if it had not been dark in the underpass, if I'd not been doing over 30 kph, maybe I could've shifted my weight better...

SC

[StreetCowboy]

 

 

In my last 5000 km I think I have had one flat while riding and a couple more slow leaks I discovered the next day. I don’t carry spares and was able to find someone to patch my tube the one time I was out on a ride when it went flat. My rides are usually between 50 to 70 km and a mix of road and dirt so I am wondering why I don’t get as many flats as the rest of you.

 

I think mine are mostly construction-traffic related. Big knobbly MTB tyres would have avoided the two small metal shards puncturing the tyre; and the missing drain cover, well, if it had not been dark in the underpass, if I'd not been doing over 30 kph, maybe I could've shifted my weight better...

SC

 

Just to expand on that - the underpass is two concrete boxes under the expressway for each direction, at the bottom of a fairly steep hill. The lighting in the underpass is failed, and I think the drain pumps are failed as well - maybe they never got round to running out the power supply. The first time I went through, I noticed the cars were pulling over to the right-hand box. The second time, I was first one down the hill, and I didn't fancy swinging out in front of the other traffic, and I never knew why the cars preferred to go through the right-hand box... Until too late. That was Christmas morning, I think, but luckily the bike shop on the way home was open and I got a new tube there. That was my first puncture, after about four months;and I've had three since.

Anyway, next time I went that route, the drains had been covered with concrete (maybe filled in - when I went there on a rainy day it was flooded a few inches deep)

SC

[bobfish]

A good tubeless system will stop the tyre deflating with the punctures described. You may lose a bit of air while the goop seals...

[bobfish]

Apologies, all punctures except the type StreetCowboy encounters!

Be warned, if you keep riding with a front tyre leak while the sealant is still weeping, you can soon start looking like a porn star

[moonoi]

+1 for going tubeless, I run Hutchinson Atom Galactik 23mm on my road bike with 60ml of sealant, works really well. My only problem is finding replacement tyres, as it seems Thailand isn't joining in on the tubeless road bike tyre revolution!