32
votes
Accepted
Why does the manual for the inner tube say the maximum pressure is 4.5 PSI?
Most likely this low number refers to inflating the tubes without the tire, as a balloon.
When installed inside a tire, the majority of air pressure is held by the tire casing, not by the tube.
A ...
- 14.3k
32
votes
Accepted
Tyre exploded while riding
TLDR answer: you ran over something
Given the ding/cut in the rim itself that aligns with the cut in the tire, you ran over something metal that was sharp enough to cut your tire and even dig into ...
- 10.8k
28
votes
Accepted
What might cause an inner tube to "behave" flat in a tire?
When you inflate a tube that is not inside a tire, even if it balloons up a huge amount, you are only getting maybe 1-2 PSI (7–14 kPa). A tube that is not constrained by a tire will increase in size ...
- 641
23
votes
Why is my inner tube not distributing air evenly in it?
If you are just inflating a tube alone, it will be uneven above a certain pressure. It is not supposed to hold significant pressure on its own. It is used inside a tyre. If you did not overstretch it, ...
- 16.8k
22
votes
Accepted
How to find punctures in inner tubes?
Do whatever works, really.
The problem with the container of water approach is that it requires a container of water. It won't damage the tube. Also, if you need to patch the tube, you have to wait ...
- 46.4k
22
votes
Tyre exploded while riding
Definitely a cut - the damage to the rim and the fact that the rubber and carcass fibers are clean cut through confirm that. If the tire burst from over pressure you'd see ragged edges. Also, from ...
- 75.9k
21
votes
Does anyone patch inner tubes anymore?
Yes, some people still patch their tubes
I've worked sales at a bike shop for three years, and patch kits are still one of the most common small items for us to sell. It still makes sense from an ...
- 410
20
votes
Unable to get a tube replacement to last
There is a mark in the middle of the valve stem as if something has pressed against it:
Given that it was a fresh new tube, it likely means that it had been installed with the valve protruding at a ...
- 14.3k
20
votes
Unable to get a tube replacement to last
Check that the rim tape (tape or liner that sits in rim bed) is not loose or spinning. I had an identical issue where a brand new tube would be ruined after a 10 minute ride. The rim tape spins on ...
- 6,208
19
votes
Presta Valve Keeps Ripping From Tube
The usual causes for this:
Presta valve in Schraeder hole without proper reinforcing grommet.
Valve crooked, or being forced crooked at the expense of extra stress on the tube/valve joint by riding ...
- 87.2k
19
votes
Accepted
New wheel. Does it need that little rubber lining between it and the tube?
Yes, you will need a rim tape to protect your inner tube from the spoke holes or the spokes in your rim. There are a few exceptions we come to later.
The rim is the outer part of your wheel. Along ...
- 9,808
18
votes
Accepted
Why using a puncture repair kit instead of a new inner tube?
You have to remove the wheel to replace the tube. A repair can be done in the frame.
On older bikes without quick release, and with current gear hubs, electric hubs, Nuvinci hubs, belts etc, you need ...
- 1,068
18
votes
Can I pump my MTB tire to max (55 psi / 380 kPa) without the tube inside bursting?
It can't burst the tube, because the tube is completely surrounded by the tyre and rim.
Bear in mind, though, that higher pressures don't automatically mean a faster ride. There are two competing ...
- 17k
18
votes
Accepted
Unable to pump air in my bicycle tube
I think its worse than that - your valve core is not there, but the thinner thread where you connect the airhose is there.
That tells me the shaft of the valve core broke off, the acorn nut was lost, ...
- 129k
17
votes
How to find punctures in inner tubes?
To follow up on what Batman says, what you use to find the leak depends a lot on the circumstances.
If you get a flat by the side of the road (and you don't have a spare tube) then you obviously can'...
- 53.9k
17
votes
How can I patch a hole on the underside of an inner tube?
It does not matter on which side the hole is, the process is exactly the same anywhere on the tube. Be sure to let the glue become more viscous and sticky by waiting for a while before applying the ...
- 16.8k
17
votes
Are 26'' wheels and tubes a thing of the past?
The sheer number of bikes in the world with 26" wheels means finding a tire is unlikely to be a big problem for a long time, if ever. Plenty of BSO's being sold are still 26" and there are ...
- 52.4k
16
votes
Accepted
Technique for self-adhesive puncture repair patches
This kind of failure is basically the reason sticker-type patches have a reputation for not being reliable.
Scrupulously sanding the area and getting it as clean as possible (ie, with alcohol or ...
- 87.2k
16
votes
Why does the manual for the inner tube say the maximum pressure is 4.5 PSI?
It is common to inflate a tube just a little bit before you install it in the tyre. This gives it some shape and helps prevent it getting twisted or pinched, with a little care from the user.
This is ...
- 12.9k
16
votes
Why did my road bike tire patch fail?
Bike shops don't patch tyres because at $60-100 per hour its not worth their time compared to a new tube.
Road tubes can absolutely be patched, however its harder with thicker patches - try and get ...
- 129k
15
votes
Accepted
New high quality tire doesn't sit evenly on the rim
The tire sidewall is just hung up on the rim a little. It’s a common problem.
Deflate the tire until you can deform it a little with your hands, rotate the wheel so the problematic section is at the ...
- 75.9k
15
votes
Accepted
Why is my inner tube not distributing air evenly in it?
Tubes aren't designed to be stretched; they are simply there to hold the air while the rim and tire contain the pressure.
Consider what happens when you blow up a long thin balloon.
First, the loose ...
- 647
14
votes
New high quality tire doesn't sit evenly on the rim
Sometimes I've found that pumping up the tyre to the rated pressure (or a little over), deflating most of the way, and pumping up again does the trick. You can chuck some water on the bead while its ...
- 61.4k
14
votes
Does anyone patch inner tubes anymore?
Yes - absolutely, though not on the roadside.
Here's a spare tube out of what was my main commuter. I counted and it has 15 patches applied, though some of them are snake bites and get two.
Presuming ...
- 129k
13
votes
Accepted
New inner tube bulges near the valve when inflated
Unless the tire bead (the re-enforcing wire around the edges) is damaged your tire is simply not seated on the rim properly near the valve and has popped off as the tube was inflated.
Tube size seems ...
- 75.9k
13
votes
Technique for self-adhesive puncture repair patches
I believe pre-glued patches were always intended to be a temporary fix to get you home. When they first came out on the market I remember explicit warnings that these were not a permanent fix.
...
- 30.7k
13
votes
Unable to pump air in my bicycle tube
You seem to be missing the valve core in your Presta valve. Perhaps you removed it? It is the most important part, it must remain in the valve.
If you no longer have it, you need a new one or a new ...
- 16.8k
13
votes
Quality check for donated tubes
Here’s what I would do when testing patched tubes:
Inflate the tube outside of a tire just a little past the point where it starts to expand. Let sit over a night or two. If it’s still got air, you’re ...
- 4,552
13
votes
Accepted
Is zip tie a durable way to carry a spare tube on a frame?
It depends on how long the spare has been wrapped up and how much freedom of motion it has. And whether it sees a lot of sunlight/UV.
Abrasion will cause damage to a spare tube over time. If your ...
- 129k
12
votes
What does vulcanizing solution in patch kits consist of? Can I buy it?
For those that are curious what the difference is between "rubber cement" and "vulcanizing fluid", here's a summary of the chemistry.
The actual process of vulcanization of rubber (Thank you Charles ...
- 2,277
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