Weird Tire Seating Problem
 

I recent put some commuter tires on my mountain bike. They are Vredestein Monte Carlo. I also put new 26 X 1.25 tubes to match the tires.

Once they were mounted, the seating wasn't even, causing the tire to wobble. I deflated it, reseated, and reinflated countless times, but still the same uneven seating. The weirdest thing is that the seating is uneven on both sides, causing a depression in the tire. This is happening on both the front and rear tires.

I am thinking that it has nothing to do with the tire, but rather that the inner tube is not inflating evenly all the way around. Perhaps the place where there is a depression in both tires is a spot where the tube is not inflating as much as elsewhere. That's my theory, any others?

Also, any ideas on how to fix it?

You could try powdering the tube with baby powder (talc).

The rims may be too wide for 1.25" tires. Check Sheldon Brown's page on tire sizing.

It is not an inner tube problem. I guarantee that with 80-100 psi of air pressure, your tube is conformed completely to the inner cavity of the tire/rim. If not, there would be a big hole in it. Your problem is the bead of the tire is a little small compared to the rim. You may be able to get it to pop into place by lubricating the bead with soapy water and overinflating the tire. You can also try whacking the tire against the driveway on the side of the tire where it's low to help "pull" it out. There's also a tool that grabs around the tire to let you help pull it out.

Make sure the rim-tape is seated in the well of the rim and doesn't get up on to the shoulder at any point. I had this happen to a rim on my Schwinn - it had a Velox rim-tape which was sticky on one side and over a long period the tape had moved from the centre of the rim slightly up onto the shoulder (or perhaps it was never fitted correctly) - anyway, the result was that I always had a problem getting tyres to seat on that particular rim, and the result was exactly as you describe, the tyres had difficulty in moving onto the shoulder where there was tape. The solution was to use an Exacto knife to remove the tape from the shoulder. Result - no more seating problems!

- Wil

sounds like this to me too

Only pump it up to 1-2psi so that it holds it shape, but you can still move the tyre around on the rim. Push up on the part that's depressed into the rim. You'll want an even border at the rim/tyre interface. Then do the other side. Spin it to make sure it's even. Then gently install the pump-head and give it about 10-pump. Spin it again to make sure it's even. Then pump it up the rest of the way.

The 26" tyre and rims have a lot of tolerance, so it's possible to have a lot of play and when that play all stacks up on one side, you get the wobbles.

Thanks for the replies. I have tried all these suggestions, but the problem is still there. I did the soapy water thing and overinflated it. No effect. I ended up blowing the tube, so I took the tire off and put a new tube on and the wobble is in the exact same place, which says it has to do with rim in that spot. The rim has a kind of black plastic strip along the outer edge on both sides in addition to the rim tape. However, I don't see any difference in the tape or the plastic strip that would cause the seating problem. Maybe the tool that pulls the tire out will work, but I don't have one, so I would have to take it to an LBS.

BTW: Never noticed any problems with the 26 x 2.25 mountain tires that were on it previously, but then again, big tires probably have more tolerance for such things, making it unnoticeable.

I will try riding it and see how much effect it has. As for the rim size, the rims are 559x17, so they should mount 26 x 1.25 tires.

There are two types of seating problems:

1. Tire bulges out.

B. Tire dips in.

1. When the tire bulges out, it is often tube related, typically the tire bead is sitting on top of the tube somewhere. This is especially common near the valve, where there's a reinforcing patch around the base of the tube. It's also common if the tube is a bit too big for the tire.

With a "bulge" type mis-seating, the tire is at risk for blowing off.

B. When the tire dips in, it means that the tire/rim combination is a particularly tight one. This seems to be particularly common on German tires. Continentals, in particular, are somewhat noted for this.

There's an easy fix for this, however, once you manage to get the tire onto the rim---overinflation!

Sometimes I will actually lubricate the edge of the tire by spraying Windex or alcohol down into the gap between the sidewall of the un-inflated tire and the rim. Then I inflate it way hard, disregarding the desired pressure for actual riding.

At some point, the "dip" will snap into place with a loud "pop" and the tire will suddenly be perfectly seated.

Once this has happened, you can reduce the pressure to the desired riding pressure and everything will be hunky-dory.

Sheldon "More Air!" Brown
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| A custom loathsome to the eye, hateful to the nose, |
| harmful to the brain, dangerous to the lungs, and in the |
| black, stinking fume thereof, nearest resembling the |
| horrible Stygian smoke of the pit that is bottomless. |
| |
| Herein is not only a great vanity, but a great contempt |
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| corrupted by this stinking smoke. |
| --King James I of England and VI of Scotland |
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I took it out for a 20 km ride today. The wobble is more noticeable on the workstand than on the ride, although it is noticeable. The tires are rated for 55 psi, so I did as you suggested and inflated to 80 psi. Nothing has popped into place as yet. Is the extra 25 psi enough or should I overinflate even more?

If they haven't popped into place, you have not "done as I suggested."

Sheldon "More Air" Brown

OKAY. I deflated the tire, put WINDEX, AND pumped to nearly 100 psi. "as suggested," but the tire is still the same. Anyway, the bike's out of commission for a couple of weeks. The bolt that holds the crank on the bb broke today during my ride. Amazing the junky components coming out of Asia these days. I have a couple of 30 year old bikes and never had that happen before. This bike has less than 500 miles on it.

Like I said, "more air!"

All the best,

Sheldon

Thanks for the advice. I finally got around to working on my bike again, since I had a number of distractions (like a trip to Peru - see my other posts). Anyway, I did the windex thing again and this time inflated the front tire to 120 psi and it popped into place. The rear tire was more intractable. I inflated to 150 psi and it was still warped. Then I blew the tube. I put a new tube in. This time I sprayed the entire tire with windex and when I got to 130 psi, it popped into place. Now it is ready to go.

When you said more air, you sure meant it...But the important thing is that it worked. Thanks again!

Apologies for resurrecting an old thread. So what do you do when the tire bulges out? I've just got myself a pair of Mavic Open Pros and Michelin tires and tubes to put on them, and I simply cannot figure out a way to get the tire to stop bulging out at the valve. I've let out the air and can see clearly that the reinforcing patch for the tube is indeed getting caught under the bead, but I cannot finagle it over so that the bead sits lower down. I'm using 700x23 tubes for 700x23 tires. Is there a special technique for doing this, or should I just get 700x20 tubes?

Thanks
R

Bump. Is this a commonplace issue, or am I perhaps missing something obvious? Subsequent web searches have been fruitless. Both wheels have exactly the same problem as described in my previous post, so it would seem to me that there's something I'm not doing right, but try as I might I cannot figure out what that might be.

I've tried massaging the tire and tube with no air in it, or with only a little air in it, or with more air in it, and I simply cannot get the reinforcing patch to move over to let the bead of the tire sit properly. I'd be grateful for any words of wisdom on this.

When this happens to me, I push the valve back through the hole in the rim prior to inflating so the reinforceing patch is inside the tire and the bead can seat. Then I start to inflate so the air pressure pushes the valve back out to its normal position.

Well, went to the LBS today and they put smaller (700x20) tubes on, and that did the trick. Lesson learned: Mavic Open Pros don't take Michelin 700x23 tubes.