Sunday, May 22, 2011

Nothing but Rim

"Given the conditions of the flat, a trip to Bike Gallery to discuss brake adjustment/modification options should be considered.  And I guess I'll be getting to try out those Soma Xpress tires somewhat sooner than I planned."

The flat occurred because the drive-side rear brake rubbed on the tire.  The brake could not be adjusted to not rub on the tire.  I didn't notice it until a month ago, when I was giving Sweetpea a good clean.  It didn't seem to be a problem.  At least until yesterday, a few miles from home.

The hole in the tire

See where the brake rubs?

The brakes are Tektro R556, purchased on-line, on sale in the fall of 2008.  Perhaps there was a reason they were on sale.

I couldn't decide what was up - I've got supposedly the Very Same Brakes on Bleriot (also a 650B bike), and there is still room for adjustment on that side.  The Silvers are the Rivendell-branded Tektro brake.  I bought the Silvers in winter 2007.

Now that I knew what was going on... ack.  Big ride next month, didn't need a tire flatting because of this. I understand there are many other reasons a tire will flat out there in eastern Washington, and indeed, a friend riding a 400k out there yesterday had a ton of flats, as did the folks she was riding with.  They had a flat-patching party in the Safeway in the middle of the night to repair all their tubes.  No, don't need more opportunities to get a flat tire, especially with the amount of wrestling it takes to get tires off the Aerohead rims.

Took the bike into Bike Gallery this morning, and had a long conference with Mechanic Tim.  (for the record, I prefer working with Mechanic Tim, Mechanic Mark, or Mechanic Michael.  I am sure the other mechanics are competent, but these guys completely understand what my bikes have to put up with)

We stared at it for a good long while.  He thought the brake arm might be a bit short.  I did, too, but a cursory once over with a precision measuring instrument didn't seem to indicate that.  He suggested I try the rear brake from Bleriot, to determine once and for all if it was the brake.

Went home, hauled out the repair stand, cable and housing cutter, third hand, allen wrenches, little bag of ferrules and crimps, some tunes and a cup of coffee.

Rivendell Silvers on Bleriot

Pulled both brakes, and compared them side by side.  The Tektro did look shorter.  Hmm.

Put the Silver on the Sweetpea, dropped the brake pad to the bottom of the notch.  Nothing but rim.  Relief!  Got everything adusted, put a new crimp on the cable, one down.

The Silver rear brake on Sweetpea

Then, put the Tektro on Bleriot.  Nothing but rim; no adjustment needed (good, because there was no more adjustment to be had).  Finished that up.

The Tektro rear brake on Bleriot

Called Mechanic Tim to let him know all was good.

Now just waiting for the new tires to arrive.


Janice in GA said...

Huh, that's really interesting. Do you think there's an eensy bit of difference in the brake-mounting bosses? Or was the one that caused the flat just the tiniest bit shorter than the other one?

Amyway, glad you got it fixed.

Fully Lugged said...

Those 650B Aeroheads are cool rims. I stay with kevlar bead tires on mine and can mount and dismount them barehanded if I need to, although I usually use a pry bar. Wire bead takes a pair of levers.

lynnef said...

If only the Aerohead rims were not made of unobtainium. I had to buy currently available tires. A first in a long time. Michelin Axial Raids and Michelin Megamiums were my preferred tires.

Anonymous said...

For my own amusement I just spent some time looking up "long reach brakes".
The reach specs are all over the place. Apparently the term "long reach" means whatever the mfgr. wants it to mean.
When I built my bike last year, I bought the brakes before I brazed the brake bridge. The brakes did happen to fit the fork.

orc said...

When I first built up my rando bike the year before last, the tektro bigmouth brakes I used (I first built it as 650b) weren't quite long enough to fit the rear wheel, so I took a dremel tool and ground the slot about 1/8th inch longer so the silly thing *would* properly adjust down to the rim.

It may not have been the best idea for durability, but that brake lasted longer than the 650b wheels on that bicycle (and since then has spent its time braking the rear wheel on my xtracycle, which also has issues with brake reach.)