Tpu tubes problem

[Seph]

I have a few tpu tubes aside for spares, today I had to change one since got rekt in a race and I noticed something.

Two in er tubes feel a bit too long for a 700c wheel, and I'm not able to insert the tyre since the tube is going to get compressed.
The other one just stay tight to the rim, and I'm able to put the tyre whiteout any problem.

Ofc I use a bit of pressure before installing, and yes the pressure is the same.

Here an image how the "longer tube" looks like.



Also I have to admit that the tubes are never used.
Can be fixed in any way?

Ps. If someone is interested to know how the race ended, I just lost my 10th rank. The inner tube failed after a pot hole at the last 1.5km and I had to run toward the finish with my bike on shoulder.
At least I was able to close at the position 17/29.


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[Steve Curtis]

Any tube will expand if you inflate it outside of the tyre. I don't understand your problem?

[Seph]

Any tube will expand if you inflate it outside of the tyre. I don't understand your problem?

I can understand that my question probably sounds very stupid.
But reading the instructions tubes must be inflated a bit before installed.
Now take a look at those images

1-

2-

Those are two different tubes inflated just a bit for the installation itself.
One is completely flat against the rim and the tyre installation can be done easily.
The other one is almost impossible since the tube folds on itself making it impossible to install correctly without pinching.
Note that both tubes are newer, fresh from package.


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[Steve Curtis]

They need a very small amount of air to install.

[MikeD]

What brand of tube? Maybe yet another problem with these cheap tpu tubes.

[Seph]

What brand of tube? Maybe yet another problem with these cheap tpu tubes.

RideNow

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[Mr.Gib]

As noted above, you may be overdoing the pre-installation inflation. IMO the best way is to just blow enough air in with your mouth to stop the inner tube from lying flat. Just so it won't crease or fold during the installation. Makes the install easier than a "full" inner tube. Most inner tubes end up bigger than the rim with enough air in them to hold a fully round shape. Certainly latex will. It shouldn't be a problem. Let some air out and stuff it in.

I do admit that the incosistency is a bit troubling. So if you want to be extra careful, throw it out and install a good one. Fortunately they are not expensive.

[BigBoyND]

If the tube holds its shape like that, it's too much air.

[usr]

Any tube will expand if you inflate it outside of the tyre. I don't understand your problem?

TPU do this expansion in a plastic way, not in an elastic way, that's the P in the name. It means that once they expanded, they will never shrink.

There's also a tiny bit of elasticity, so perhaps the one in the picture can still be used, but inflating TPU outside the tire can easily destroy them, long before they are anywhere close to bursting.

Just don't preinflate tires. It's a merely speed hack to make the mounting require a tiny bit less care, not a mandatory step in the process. I find it mostly counterproductive with any tube material, I actually consider preinflated to nut require less care but different care and I'm far more comfortable with the kind of care required without pre-inflation. I use gravity to find the exact spot to start with on the point opposite to the valve.

[Steve Curtis]

Any tube will expand if you inflate it outside of the tyre. I don't understand your problem?

TPU do this expansion in a plastic way, not in an elastic way, that's the P in the name. It means that once they expanded, they will never shrink.

There's also a tiny bit of elasticity, so perhaps the one in the picture can still be used, but inflating TPU outside the tire can easily destroy them, long before they are anywhere close to bursting.

Just don't preinflate tires. It's a merely speed hack to make the mounting require a tiny bit less care, not a mandatory step in the process. I find it mostly counterproductive with any tube material, I actually consider preinflated to nut require less care but different care and I'm far more comfortable with the kind of care required without pre-inflation. I use gravity to find the exact spot to start with on the point opposite to the valve.

I know this. The OP over inflated and "stretched" the tube prior to installing.

It's why the instructions are pretty specific if the user cares to read them.
Also if they're used in a tyre - 32mm, as an example, they can't then be used in a 25 as they've stretched to fit the shape of a 32.

Some people don't know how to use TPU, but it's never user error, and always "cheap" TPU tubes which are to blame.