On 1/31/2018 5:24 PM, John B. wrote:
On Wed, 31 Jan 2018 13:45:17 -0800 (PST), jbeattie
wrote:

On Wednesday, January 31, 2018 at 7:25:22 AM UTC-8, sms wrote:
On 1/30/2018 8:35 PM, jbeattie wrote:

When I rebuilt the CX commuter with the new frame (after breaking the prior frame), I threw on a SRAM Red BB30 CF crank that I took off my broken SuperSix. This is what I hate about warranty replacements: my broken frame had a threaded BB, and the replacement is BB30, so I scavenged the BB30 crank off the SuperSix. That crank lasted six months on my commuter and then broke -- the pedal insert loosened and cracked through to the end of the crank arm. POS. I had an FSA do the same thing on another bike.

I just put on a $95 105 crank with Wheels Mfg. adapters. That's the fifth crank in the last 15 years on my commuter. I changed the original out because it was ISIS, and I was blowing through BBs. The second was an Ultegra, and it broke (crank arm while out of the saddle).

I thought I was reading a post from Joerg. You obviously are very hard
on your equipment. Broken frames, broken cranks, broken pedal inserts.
Have you considered a steel frame with more robust components?

Well, my commuter sees a lot of miles in bad weather. Plus I'm big and tend to mash up hills, and as for the crank pedal thread inserts failing, that's just a bad design. BTW, I've broken steel frames, too -- but when I break a Cannondale, I get a new one.

I'm not hitting my bike with a hammer or throwing it off cliffs, but I do subject it to a lot of fatigue cycles. Everything has a fatigue life.

-- Jay Beattie.

Didn't Brandt have a lot of problems with pedal to crank attachments?
I somehow remember that he solved the problem(S) in some manner.
Special bushing?

Right, like auto wheel lugnuts, the chronic precession
troubles were ameliorated by a conical interface. In Jobst's
case a pair of steel half-circles under the seat of the
spindle, fitting into a conical bore at the outside of the
pedal thread.



--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971