Worn tire question
 

Hi all,

I recently bought a vintage bike from a local non profit bike shop and I was told the tires were new. I've ridden maybe 30 mi on it since I brought it home, but this morning when I went for a leisurely ride I noticed some wobble in the rear wheel, never had that before. I immediately cut my ride short and investigated. Looks like the tire sidewalls have frayed and there is a bulge in the tire.

My question is: did the tires just fail? Is it possible these tires were new to the bike, but not new-new and that made them fragile?

There is no identifiable thing that could be rubbing the tire sidewalls that I could see.

Curious if this is an experience others have had before. Thanks!

https://cimg3.ibsrv.net/gimg/bikefor...16d975d719.jpg

Could the brake calipers have so much flex that the shoes ride up onto the tire?

I played around with the brake shoes and didn't notice any shifting or flexing at all. But I can definitely take a second look. I don't know what else could be causing that kind of damage to what is supposed to be new tires.

Did you inspect the bike closely before purchase? If nothing has been changed since you bought it I suspect it was an oversight, or if the tire was underinflated at the time of purchase that damage might have occurred during your riding..

I inspected the bike but probably not closely enough... I was too focused on the drive train and frame that I paid little attention to the wheels and tires. So it could very well be negligence on my part.

That looks exactly like abrasion from a too-high brake pad. My guess would be that a previous owner installed a replacement set of brake pads and didn't position them properly.

Either that, or the the bike originally had 27" wheels that were eventually replaced by 700c wheels without readjusting the pads.

In any event, that tire should be replaced before the bike is ridden next.

The tread certainly looks new (or at least *unworn*); maybe they are actually old, and the gum sidewalls were waiting for an excuse to flake off. Under-inflation might do that, but the fibers look like there was some abrasion.
If that were my bike, I'd take the tire off, service the bearings as necessary, check the spoke tension/wheel alignment, and probably replace the tire.

Any evidence that there was a bottle-type dynamo attached to the seatstay at some point?

I have seen this kind of tire breakdown several times. I believe is is from the age of the tires.

Probably new old stock tyres, no wear but no life left - tyres have a finite lifetime even when stored unused in appropriate conditions. That's why motor vehicle tyres have a date code, manufacturers recommend replacing tyres over 5 years old and in some places it's illegal to use older tyres on some vehicles.

Agreed, not from brake rub, but from tire age. I have encountered this a number of times on customer's bikes as well as my own. Replace tires and forget.

It's a mystery worth writing about.
Reading about it, meh.

You can look up the bike by brand, model, and year. If that model came with 27" wheels and the wheels are now 700c, there's your answer: as mentioned earlier, it would mean that the wheels had been replaced without repositioning of the brake pads. The abrasion furrows are where they'd be expected to be after such a change.

Are the abrasions visible on both sides of the wheel(s)?

You'll probably never know the cause of the damage so not worth spending much time trying to figure it out IMO. Keep an eye on the sidewalls for tears or cracking on the tread and ride the tires until there is an issue and until then, just enjoy riding your bike.

The photo shows the brake blocks are reasonably aligned, assuming the caliper isn't super flexy.

The carcass is sufficiently degraded that the tyre has a lump, it's on borrowed time already.

They are still okay to ride until they finish determining whether they want to wear out or just let a road hazard take them out.

The fraying on there might also be from the tire not being sufficiently inflated and the rim is rolling on it. Other members have shown new tires that exhibit the same thing. Never has any said they had a bad experience with them. I'd ride them till they .... after I checked the tire pressure.

It's a local non-profit. You don't really want to beat them up on a set of tires on a used bike that they may have said were new, when possibly they just meant that they looked new to them.

The tires may not last as long as they should, but they'll have a good chance of lasting till you get tired of riding the bike. Unless unlike many people that get a bike, ride it a few times never to get on it again, you truly do get hooked on riding multiple times per week.

My speculation, spelled out:

1. The bike came with 27" wheels, with brake pads properly positioned.

2. A 700c wheel was then installed (as a replacement for a stolen wheel, perhaps [Edit: or, maybe more likely, after riding through a pothole with full body weight on the saddle, resulting in a damaged rim]), without moving the pads. [Edit: notice that the brake pad is at the bottom of the slot, which often indicates a wheel swap from 27" to 700c.]

3. Pads abrade the 700c tire, naturally.

4. Someone noticed that the pads were abrading the tire and repositioned the pads without replacing the tire.

That the wear is the result of riding the bike with the tires severely under-inflated is a possibility too, of course. But the exposed white thread seen just above the brake pad in the photo looks to me as if it was the result of abrasion from the pad.

In any event, the tire should be replaced as soon as possible.

the wheel got badly reinstalled during maint. and it was then ridden with the wheel out of position, and the brake pad touching the tire when engaged.
wheel then shifted when going over a bump or whatever, hiding the cause of the tire wear....
or the sidepull or centerpull caliper got knocked out of alignment, then went back to where it should be.

The tyre has already failed, there's significant distortion caused by the damage/degradation of the carcass, and it's ready to let go.

I'm not certain I see that in the picture. I thought the tire just looked underinflated.

Even if they are ready to let go, I've always taken the attitude that if it last just a few handful of rides longer, then that'll be more mileage till I have to replace the next set of tires.

Though if a ride that is coming up soon is something important to me such as anything I paid a entry fee for or is just a group ride where I don't want to bear the picking at in fun ridicule I get for holding everyone up, then I'd change it.

Any path the OP takes, I don't see a bad decision being made. Just personal preference.

From the OP: "Looks like the tire sidewalls have frayed and there is a bulge in the tire."

There's no upside to continuing to ride a tire that has already failed ("bulge" = significant carcass damage = failed) and plenty of potential downside.

This thread reminds me of previous ones where an OP asked whether it would be OK to just boot a nearly new tire with a 2" or 3" slash in the sidewall. Wanting to save a recently purchased tire is understandable, but reason should prevail over emotion in matters of safety.

What’s the maximum speed you do downhill? 😉

The OP hasn't shown a bulge. They only said a bulge, and not specifically where, what kind or how bad. Still, till it pops, I'd probably continue to ride it. Unless it is just too lousy a rolling tire. But not for the damage shown. Though those are likely crappy tires. And with tread on them which is virtually unnecessary for pavement. IMO, It's not a safety issue till the OP says they do something that might cause it to be a safety issue. Such as what is covered in the following.....

We don't have many long hills here. I top out about 50 mph give or take a few on the longer one I do somewhat frequently.

And your point? I suppose it's a blowout you want me to consider. Seeing how I don't do that hill frequently, I'd still ride the tire. I've had blowouts <30 mph and they aren't anything spectacular. Just let the bike slow down and don't do a panic stop. I've not had a blowout at a higher speed. But if the OP does do fast descents on twisty downhill roads, I suppose even I would put a much better tire on the bike at that point. But mainly because I wouldn't trust the grip of that tread on the tire compared to a slick.

As I said earlier, there is no wrong thing for the OP to do. It's just a matter of personal choice. Though perhaps I'll make a exception if the OP decides to take those tires on a screaming fast ride down a high mountain with lots of switchbacks and sheer cliffs off one side.

I once cut a brand new tyre on its first ride; I replaced the tube, fitted a tyre boot and tossed the tyre in the trash when I got home. It's just one of those things, I try to avoid riding bikes that don't steer or brake properly; sudden loss of tyre integrity is even less fun than a tyre that bumps on every revolution.