What Happened? (or, "Why Me?"

[scrooge]

I was out for a ride today and was going around a turn (slightly up hill, a lot of loose gravel., not pedaling that hard) when I suddenly hear a sickening crunching noise and my rear wheel slams to a halt. Looking down, I can see my R.D. is caught in the spokes. Not good. When I get off and look, I see that my Der.hanger is snapped, the R.D. is mauled, the chain is wedged between the casset and the spokes and has a twisted link or two, and several spokes have been ripped out of the rim (leaving a few sickening looking cracks/holes). So can anyone explain what in the world happened? Overshift? Loose stone kicked up? Just a mystery?

Yes, I know you can't know without being there, but I needed to vent. :crap: :crap: :crap: :crap:

On the bright side, a very kind woman riding a Murray mountain bike came upon the scene, went home and picked up here blazer, and gave me a ride the 20 miles back home!! Equally impressive is that she regularly (5 days a week) goes for rides of 25-30 miles on that Murray. I was impressed.

[David Kirk]

What brand and model of rear hub is in the wheel? what spoke pattern?

Dave

[JohnS]

What gear were you in? How long is your chain?

[Jeremy]

Hi Scrooge,

This almost always happens because of a inwardly bent hanger. If your bike has a replaceable hanger it is more likely to happen because most replaceable hanger designs are significantly weaker than a solid hanger. That being said it is not uncommon for a hanger to be misaligned from the start, especially if it is a replaceable hanger. An inwardly bent hanger will cause the disaster you describe. Why it seems to happen all of a sudden is that the bike will seem to be shifting acceptably, but when you shift to the low gear, it pushes the der cage into the spokes where it is promptly wrenched forward and ends up as you describe. It is always a good idea to visually inspect the alignment of the rear der. The cage should be perpendicular to the axle. Set screws can also work themselves loose so it is a good idea to check the high and low limits of the derailleur periodically. I'm sorry that this happened to you.

Jeremy

[scrooge]

Mr. Kirk--it's a Mavic Ksyrium Equipe.

I don't remember what gear I was in (was in the big one up front).

Bent der. hanger sounds like a likely bet to me too. Boy, a $3 part can sure screw you over!

Well, anyone have any wheel suggestions for a 6'8" 215 pounder? Want a good all around wheel--do long rides and be comfy but not be able to flex them when I'm hammering (as I could the Mavics when I stood--front wheel would rub on the brake occcassionally).

[slowgoing]

This happens a lot to mountain bikers. It can be caused by a lot of different things – bad limit on the derailleur, bent hanger, bumping the derailleur or chain into something as you’re riding by, etc. Once the chain is between the spokes and the cassette, something is likely going to break. Sometimes it’s the rear derailleur (I had one literally explode on me), saving the derailleur hanger. Other times, the derailleur stays attached but is driven into the cassette, bending or breaking the hanger. Sometimes they both break. It helps to learn how to temporarily make the bike into a single speed if you lose the rear derailleur so you’re not stuck walking your bike on the remaining uphills.

[jeffg]

I had heard a replaceable hanger was a good thing, but I am so glad that my Legend dropouts are as great as they are, and I wish I had the next generation Parlees that have 6/4 Ti dropouts rather than the AL replaceable one (that I had to replace after it was bent in the move to Europe) that my 2003 Hampsten has. As for wheels, if you go prebuilt I would go with Campy Eurus. I have a set I love, though Ksyriums are plenty stiff for me at 155 lbs. If you lived closer I'd consider trading you ... Eurus aree much smoother and stiffer but Ksyriums are easier to change tires on