Pics attached. I’ve been getting big, sudden flats for about a year. Typically, I leave my bike in my garage. First time it was summer in AZ, so I assumed heat caused it to blow up, didn’t think much of it, and changed. Happened this way a couple more times but also in the winter.
Happened once or twice while biking. Big sudden flat. I live in a new neighborhood, there’s nails and glass, so walked it home and switched it up.
I started checking where the hole was. It was consistently around the nozzle. Figured I got a bad batch of tubes, so got some new ones. Same thing kept happening.
Right now, I think the rim tape is moving and basically slicing the tube around the nozzle.
What do you think? Pics attached. Can I just remove the tape?
by Away_Engineering_613
22 Comments
The rim part is part of the problem, however, it is just a symptom as well.
What’s the tire pressure?
Are you possibly over tightening the rim nut on the valve stem?
Looks like that your tube is touching/rubbing the bare metal arround the hole .
i would put one or two layers small patches of duck tape ontop and then poke it and strech the hole with a pen or what ever fits in there , from the top excatly how you put in your tube
i think this will fix it
I would replace the tape. While you’re at it, use a file to smooth the hole in the rim.
And last, make sure you’re not applying sideways force to the valve while you inflate.
That looks like metal burrs at the valve hole. Smooth that out, retape the rim, and dont use the valve nut
i think your theory is right that the bunched up rim tape is wearing a hole on the inside of the tube. Change out the rim tape. A lot of people like Velox cotton rim tape. Seems to stick in place pretty good, and it might be softer than what you have.
>I started checking where the hole was. It was consistently around the nozzle.
This can be caused by (over) tightening the knurled jam nut on the valve stem. It sometimes pulls the tube through the hole in the rim.
The solution is to remove the nut and throw it away. It isn’t needed.
One or both might cause this :
1. The rim tape shifted and no longer cover de sharp edge of the valve hole. It needs to be replaced. (tube might too small if it shift whith the rim tape).
2. The valve hand screw was probably too tigth. Pulling the tube into the sharp edge of the rim’s valve hole. It’s a hand screw for a reason : it’s not supposed to be tigth, just barely holding in place and hand screw once in a while whne it gets loose.
Replace the rim tape.
Since it seems to be happening right over that, spoke to the immediate right. I check and make sure that spoke isn’t sticking out and that the nipple on the inside is not rough.
That looks like a rim strip, replace with a new one or even better in my opinion just take the rim. If you’re not running timeless the rim strip/ tape only exists to prevent your spoke nipples from puncturing the tube.
Check the inside of your tire to make sure whatever is giving you punctures are taken out before installing the new tube.
Make sure your valve stem isn’t moving around , tighten the nut on the outside if you need to , I’ve never had to go more than finger tight.
Run the correct psi, too low will make your tube move around inside more often than not resulting in a tear exactly where yours are occurring . My money is on this, but trial and error is the only way to confirm.
Don’t mind me as I state the obvious. You keep getting flats because you keep riding it
I’d do a thorough check for burrs around the valve hole and smooth any out with a file + check the tire for any glass / thorns etc that might be stuck.
I’m guessing it’s likely a combo of some burrs near the valve hole and possibly incorrect tyre pressures allowing the tire to move more than it should and slice the valve base Here’s a good tyre pressure calculator to check you’re in the right range: https://www.veloi.app/tools/tyre-pressure-calculator
Retaping over the valve hole would also help and you could also consider some TPU tubes – they’re pricey but a lot more puncture resistant
Something in your rim, guaranteed. Remove your rim tape, check the whole rim surface and around the valve stem hole using your non-dominant hand (old bodywork trick), you’ll feel any imperfections in the surface much more quickly.
I had a valve completely separate from the tube this way. Turns out I overtightened the ring nut. Recently bought a new bike which did not have a ring nut installed, now I know why.
Are you skidding at low pressure?
Don’t use the valve/rim nut. Also, you might be running the tire at a pretty low pressure and causing the tire to slip under torque and put side pressure on the valve stem.
Doesn’t look like a puncture.
Rim tape, as a rule, can’t really slide unless the tire/tube slides with it, due to the pressure inside the tire.
> I think the rim tape is moving and basically slicing the tube around the nozzle.
That isn’t rim *tape*. It is a rim *strip*. When they’re old and brittle they can cut into the valve stem. Rim tape won’t do this.
The valve nut is only so you can put the pump head on and not push it through the rim (if the valve is short) it doesn’t need to be tightened down. If you have a long valve you can remove it. If not keep it loose.
Tire is sliding around the rim and dragging the tube with it, putting stress on the valve.
valve hole in the wheel may have burrs and rough spots
3rd pic is a torn stem
do not use the rim nut things!
or the hole is too big and you are ‘wallowing it out’ by pumping somehow
adn the hole is too sharp