car knocker

Most tires just have rubber in that area,where the rim bead touches the tire. Is there any way to add a cloth chafer strip? Conti Travel Contact had it but that tire is no longer available.Asking because my tires tend to wear really fast in that area, even though rim bead is not rough.

FBinNY 

Wear implies and requires movement. IME bead area wear usually results from under inflation, though it can be compounded by dirt and sand. Before trying to add a reinforcement there, I'd try to understand what was happening and deal with that.

If you ride in a sandy area, and especially including wet weather, take an old toothbrush and brush the bead zone on a spinning wheel to remove grit once in a while.

alcjphil

If your bike has rim brakes, check to see if the brake pads are able to contact the tire sidewall. If the pads are too high, they will cut into the tire

FBinNY 

Excellent point. In hindsight, I may have been giving the OP too much credit in assuming he would have known if shoes were cutting his tire.

car knocker

This has got me thoroughly stumped. I keep the psi at what the tires call for,usually 80. The bike gets cleaned regularly,though we do ride rail trails,after all,it's a piece of outdoor sports equipment.

Heres the damage
pretty much all around the tire. It's a Sun Rhyno Lite 26 inch rim. The hook bead is smooth and rounded. The tire has no more than 500 miles on it. It's on the front of our tandem .

FBinNY 

That looks classic for damage caused by the overhanging edge of a worn brake shoe.

Had you initially mentioned how fast it was damaged, any experienced mechanic would immediately have keyed on the brake shoe, even without the photo.

If nothing has changed pull the wheel and eyeball the shoes.

car knocker

No,I'm sorry,the brake pads squeeze below the top of the rim,they definitely don't touch the tire. The damage is where the hook bead contacts the tire. Perhaps we and the bike are too heavy for the tire?

FBinNY 

Question ---- is there similar damage on the other side?

If so, we're back to under inflation as a possible cause, though it seems awfully fast for that. Keep in mind that under inflation isn't a fixed number. It's a combination of pressure, width, and load.

FWIW, spoon feeding details like just now mentioning weight, without saying how much isn't constructive.

BTW I don't know the history, but is it possible the shoe rubbed at one time, and that was fixed?

Wear like this on one side only points to the brake shoe. On both sides to under inflation.

maddog34

additional info needed....

what is the Width of the tire? what is the Width of the rim?
and depending on HOW the pads are set up in the brake arms, they may move outward as they get squeezed harder under Use, but not so much on the work bench/stand.
also, please let us know the TYPE of brakes on the bike.

another thing to consider... extreme heating of the rims under sustained use on long downhills can melt the "rubber" and create the illusion of wear.... ;-)
a poorly centered brake can do the same thing...

Crankycrank

26" tires come in various actual diameters and the best way to check is look for the ISO or ETRTO (same thing, different acronyms) sizing on your rims and match the tire sizing which almost always has an ISO size on the tire as well as other sizing's. A good article on that here. Tyre Sizing Systems (sheldonbrown.com) To save yourself an evening of reading just look at the charts in the article and determine what you have. A longshot but this could be what's causing the wear. Sun Rhyno Lites look to have an ISO bead seat to bead seat dia. of 559mm and the Conti Travel Contacts appear to have the same 559 size so check your new tires.

grumpus

Rim brake? I'd suspect the rim is getting hot, and the bit with best contact, the bead hook, is softening the rubber and digging into it. But rail trails shouldn't do that, even on a heavy tandem. If this is the case (seems a bit weird, but it might be) you either want a disc brake or some sort of thermal barrier.

FBinNY 

One should consider Occam's Razor.

The simplest answer is the most likely to be correct.

The hot rim theory needs too many other factors, ie. weight, long descent, etc. While it's not impossible, it's also not likely.

Either way the tire itself is the best witness. If the damage is only on one side, it's pointing squarely at a high brake shoe.

Experienced mechanics see this so often that other causes are outliers.

To the OP---

Regardless of the cause, you won't solve the problem by focusing on the tire. Take the time to confirm the cause and focus on that.

grumpus

Indeed, but to me it looks a bit close to the bead to be brake block rub, and the OP stated the blocks aren't near the tyre. Of course the brake could be flexing enough that the block contacts the sidewall, but usually there's a ridge on the edge of the block where it's been hanging off the edge of the rim; if there isn't a ridge the block would contact the tyre further from the rim.

FBinNY 

So we've offered the OP three possibilities, and can't take it further based on the little info offered.

In the OP he mentioned tires (plural), then later weight, though without numbers.

A this point I would need specific details ---- rider weight, single or multiple tires, tire & rim width, one or both sides, hilly terrain?, etc. ---- to support or challenge the theories offered.