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I have a cross bike which I use for winter road bashes and touring. I find that BBs are lasting own average 300-400 miles. On the last tour the plastic cap on the chain set fell off during an offroad section and, as a result, the left crank arm fell off. Without the cap the cank arm kept falling off and I eventually had to give up and cycle with one pedal...(luckily had SPD's!)
Anyhoo...having cycled mountain bikes for years, and never had such issues, what is recommended for a cross / touring bike which is more reliable? Currently running 105 chain set on ultegra BB.
As it looks like you don't get on with external BB's go square taper. You will never find their limits, they last for thousands of miles and you have choice of chainsets from dirt cheap to extortionate. Look at Spa cycle for their own models.
What he said. New UN54 or 55 and cranks off of ebay.
400 miles out of a BB? WTF are you doing to them? An Ultegra BB should be capable of several thousand miles without missing a beat (mine are).
400 miles out of a BB? WTF are you doing to them? An Ultegra BB should be capable of several thousand miles without missing a beat (mine are).
My Ultegra cranks on my touring bike are up to about 8 -9000 miles. No issues at all.
Are you using the plastic preload 'bolt' to hold the crank on? What's going on with the two Allen keyed bolts that clamp the crank arm to the axle?
Yes that is what I would expect in terms of miles...
I went on eBay and found myself some last generation XT Octalink cranks for 35 quid. They last forever however its getting more difficult to find the BBs. Lovely cranks though, wishing I'd kept them.
Trick with Octalink is to keep on top of the bolt tightness for the first few rides, any loosening will happen then. Once you've got them bedded in you never need to think about them again.
So are there any cranksets that come with a metal cap as opposed to a plastic on of the off drive side? Like 2009 XTR and Duracell stuff.
The endcap is only there to preload the bearings, and shouldn't be very much more than finger tight. The crank is held onto the axle by the two 5mm headed bolts, which should be tightened evenly to 12-14nm (expect them to come loose again if you've damaged the splines by riding with them loose).
Coatsey....what I don't understand is why once the cap,was gone the crank would not stay not. The bolts were not threaded and I was able to fiully tighten them..