mattkime

I have a buillitt front loader cargo bike and today the rear tire failed - Schwalbe Marathon Winter Plus thats about 5 years old. The wire bead failed. Suddenly I felt the tire bottom out and I looked behind me to see that the tire had come off the rim. It had been inflated to 50psi - a very reasonable amount. I weigh 160 lbs and my 5 year old son was in the front but that certainly shouldn't be too much weight. The tire otherwise looked to be in good condition and I expected many more years out of it. When I went to put the tire back on so I could push the bike home thats when I noticed the broken bead.

Is there something I should keep my eye on to catch or prevent this?

bboy314

What was the failure exactly? Bead severed, sidewall torn, etc? 5 years is a pretty good run for a tire that gets used regularly on a cargo bike, I wouldn’t sweat it.

mattkime

Bead severed

Crankycrank

+1. How much does your cargo bike weigh? Those tires have a 95kg/210lbs limit which may have caused it to fail after 5 years but contact Schwalbe and see what they say.

mattkime

The bike weighs about 60 lbs, I weigh 160, my kid weighs about 40. We should have been well within the weight limit

veganbikes

Crankycrank said the weight limit is 210 and by your numbers you would have been well over it by 50lbs 160+40+60≠>210
You could reach out to Schwlabe but at this point I would just get a new tire and move on, the effort on a well worn 5 year old tire is not really worth it. Brand new tire failing yes 100%.

It is an old tire that probably got quite a bit of usage over the years and finally after years of use and abuse said I am done. You might look at the Pick-Up or Super-Moto-X which might serve you well for another 5 years!

mpetry912 

agreed if you got 5 years of service out of a tire, just replace it and move on

/markp

mattkime

Good point, I thought I could 2x that since there are two tires but in retrospect thats not how it works.

I'll pay more attention to weight rating in the future. I guess there is some variation depending upon configuration of the bike. Otherwise its pretty common to ride the bike near the weight limit of the tire. Of course, the intersection of studded winter tire, 26x2.0, and the weight requirements might be difficult.

Crankycrank

I goofed on the load limit of the OP's tires. I didn't specify a "26" tire in my search so Schwalbe have 3 widths in a 26". 1.75 is 100kg, 2.0 is 105kg, 2.15 is 115kg That's a big difference. Marathon Winter Plus | 55-559 | SmartGuard | Winter | Black-Reflex | 11159241 (schwalbe.com)

70sSanO

Well that is almost how it works. In your case you should probably determine a ratio of how much the cargo tire is carrying vs the other tire.

Maybe half your weight, 40lbs of the bike weight, and all, or almost all, of your kid’s weight. You don’t have 100% on one tire.

Cars and trucks have axle loads and high capacity trucks run dual rear wheels for hauling heavy loads and towing 5th wheels and the like. The weight is spread out over the tires.

John

pdlamb

I'm left to be the contrarian today.

Weight limit? Probably not excessive for the tire. It's all about distribution. Even if you add OP's weight to half the bike weight, that didn't grossly exceed the tire max load. And really, when was the last time anybody besides Cranky looked at a tire's weight limit? Given the robustness of Schwalbe Marathon Whatever tires, there's probably a safety factor on top of a margin etc. that OP never got near the engineering (not the legal department's) load limit.

Age? Again, probably doesn't matter. What might matter is how often the bike is used, and the total mileage on the tire. Bead failure is not a normal sign of aging tire failure; those would be tread wear and, perhaps, dry rot and flaking sidewalls.

Time for my entry into the guessing game: User error fixing a flat. Excessive enthusiam using a tire iron to lever the tire off the rim without manhandling the tire to create sufficient slack, or perhaps kinking the tire while it's off the rim. Second guess would be underinflation, perhaps in concert with finding a nasty pothole. That could have started as a puncture that the rider didn't notice, so the 50 psi at the beginning of the ride was 20 psi when you found the pothole.

From potholes to potshots! Comments/responses?

Trakhak

OP was not on a unicycle.

wheelreason

Five years is about right for a wire bead tire, sure some will last much longer, but there are several factors involved (I don't think weight is one in this case). See if there is a manufacturing date code on it, it may be older than five years.

mschwett 

cargo unicycle !!! the last untapped niche of cycling.

wheelreason

Is it metric? I'll bring the cutting oil...

Andrew R Stewart 

Actual wire bears breaking is a fairly rare cause of a flat. Far more common (and still no way near the usual reasons) with beds is the casing fabric is worn away from a brake pad not being well aligned and was rubbing the tire's side wall just above the rim. This acts much like a lathe tool cutting into a workpiece. Not what the OP describes at all.

After 5 years and what's likely many miles i agree with most here and will say the tire owes nothing. Well past any stated or unspoken warranty period. This is why it is the rider who bears the responsibility to monitor their bike. Had this tire been replaced after 4 years we would not be having this thread and the OP would still be happy. Andy

grumpus

Does he mean the bead itself broke, or that it separated from the cords? I've seen the latter in old tyres.ISTR manufacturers say that the expected life of a car tyre is as little as five years, even if it has no wear or visible damage. That's from the time of manufacture, not first use. Maybe bike tyres should be date coded.

FBinNY 

FWIW steel wire beads should last sometime shy of forever. But stuff happens, including minor damage to the tire at the bead during mounting. This can directly damage tire plies causing the tire to part from the bead, or it can allow water entry, rusting the bead leading to it's failure.

oldbobcat

It's done five years of duty on a cargo bike.

Rick

Schwalbe makes a cargo tire called the Pick-Up. It can handle more weight and appears to be very robust.

FBinNY 

FWIW overloading wouldn't cause a bead failure.

Overloading a tire would manifest different ways; pinch flats from bottoming or tread delamination and cracking from excess wall flex.

It would only cause blowouts or wall failure at the bead if you try to compensate with overinflation.

As noted above, tire liad ratings are per axle, so someplace between 30 and 70% of total weight depending on weight distribution.

However, all things considered, 5years service life for a tire isn't unreasonable, so replace and hope to do as well next time.

veganbikes

Yes of course we know that.

pdlamb

You may be right hinting at many miles, or maybe not. Was it ridden 200 times a year for a 10 mile round trip to child care and work? Or was the bike used at a summer home and then left inside, out of the weather? It might have 1,000 miles on it, a totally different case.

Nevertheless, as you and others have said, the wire itself rarely fails. While there's no need to perform a full fault tree analysis, if (as I suspect) the tire was damaged by something the user did or didn't do, it's worthwhile to point out Things Not To Do Next Time. Changing tires every 3-4 years might prevent the problem, or might not. Better care changing tires can prevent a recurrence either next year, or five years from now.

Trakhak

It was just a reminder to those who might have been misled by your post: the one stating that the rear tire was carrying the entirety of the weight of the bike/child/rider.

Leisesturm

Op expected "many more years of service" from that tire. I wouldn't normally get irate over how obtuse people can get sometimes but o.p. had their kid in the suicide seat on the run where the tire shook off this mortal coil. That should attract some unwanted attention.