Johnny Rad

...what's up?! Only happens at high speed, like +25mph. What do I need to check? I've swapped out the tube out for another and it's still doing it.

pharmboyrx

Did you lock up the rear recently for a nice skid? Might be a flat spot on the rubber.

Szczuldo

or could be a flat spot in the rim from a pothole encounter.

DannoXYZ 

Or as simple as an improperly mounted tyre. A lot of people don't check the tyre all the way around on both sides for a pinched tube before pumping it up.

Jeff Wills

If it's had lots of miles, this could be next:
https://home.comcast.net/~jeff_wills/...s/rites042.htm

AEO

imbalanced wheel?

Szczuldo

yeah make sure you don't have any wheel reflectors..those things imbalance the **** out of your wheels.

I've never had a pinched tube last past inflation...I don't see how people do it.

Johnny Rad

Thanks for the ideas!
* New rear wheel (Reynolds Attack); no reflectors
* New rear tire (Schwalbe Ultremo EVO)
* I replaced the tube (Vittoria ultralight, but not ultralight 55) and checked for pinched areas
* I wonder if it's the tire or wheel being out of round - seems unlikely, but I'm checking that next

canuck4levi

I had the same thing happen with a fairly new set of Neuvations. My rear tire or wheel (I was never real sure which one) made an irregular thump when I was at speed, and usually only after I had been out riding some miles. The darned thing got so loud that I could no longer sneak up on and quietly pass by some of the canines I normally passed by on my route. I had them eying me before I came and I didn't want to become a chew toy for this particularly nasty Doberman who lives on a corner I regularly go by. To try and quiet it up, I changed the tires over to brand new ones (I was using some Vredestein Fortezzas -- lasted several thousand miles, switched over to some new Maxxis Courchevels). Unfortunately, I still had the thumping noise, so I figured it was the wheel. I put the same tires on a set of Dura Ace C24's I had and the darned thing was as quiet as it was on day 1, so I figured it was the wheel. Sure enough, it was the tension of some of some of my wide aero spokes and the noise was actually occurring where the spokes crossed over too closely to one another near the hub. A few adjustments later and it is now quiet again. May be an idea worth checking out on your set.

deanp

Swap the tires and see if the noise moves to the front. If it does it is something with tire, if it does not then it something with the wheel.

Johnny Rad

Pop! Goes the tube in my back tire today. Ugh. Upon closer inspection, my rear tire has developed a tear at the kevlar (?) bead and the base of the sidewall. And it's only getting worse to the point that I got a few hundred yards before the replacement tube gave up the good fight (despite a wrapper stuffed in there to protect it).

This solves two mysteries. Why a rash of flats in the last two rides and why the thumping (I hope it solves them!).

So, now what do I do ... count it as a one in a million failure and buy another Schwalbe Ultremo EVO (or Ultremo R?!) or change it up?

The Carpenter

How old is the tire? If not too old you may be able to get a replacement, doesn't hurt to try.
Especially if the tire is "torn" not cut.

operator

This isn't a mystery. The tube was pinched or the tire was damaged in the sidewall one of which led to the blowout. Simplly spinning the wheel and looking down at the tire from above will usually tell when something is bulging/not seated correctly.

Johnny Rad

You're a genius.

halocon

oh snap!