Thursday, February 26, 2015

Friday, February 13, 2015

Broken Crank

I had to walk the last 1/2 mile or so on Wednesday because my crank broke. Yeah, that's right, snapped right off. 7000 series aluminum crank. I had come to a stop. Light turned green. I hopped on the saddle, did about 2 revolutions and clunk. That's about the sound it made. Nothing so dramatic as Eric's carbon fiber crank breaking with it's huge snapping noise on the last mile of Courage Classic.

I sent a picture of the crank to Velo Orange and told them, "I guess your cranks only last about 13,000 miles." There reply email stated that they've never seen anything like that before and to what address would I like my new replacement crank sent to? Very cool of them. They are replacing it for free. They've even sent it via 2 day priority mail.

Now I've done quite a bit of research and apparently all cranks have a lifespan however cranks of this type should last many thousand miles longer then that. So I'm not sure if this is a manufacturing defect. My bike has fallen over a few times but I've never been in a crash. The start of the break is right along a machining line where the crank arm tapers up to the spider assembly. Very hard to spot with the chain rings on, etc. The dark, thumbnail looking section of the break is where it originally cracked, probably several weeks/months? ago. It's darker because of dirt and oxidation occurring over a longer period of time. The much lighter area of the break is where the final snap occurred as the crank couldn't take the strain anymore. There's a good article on how this happens here -
There are many pictures of cranks that have failed (all probably under differing circumstances and mileages) here -

Thinking back over the last 6 months or so I do seem to remember an occasional "tink" sort of sound and feel in the downward stroke of the right crank. Could this have been a tell tale sign of the crank cracking ever so little bit more? I couldn't think of anything else in that area of the drive train that would cause this. Bottom bracket, chain ring bolts, etc. were all buttoned up nice & tidy. Needless to say, I will be doing routine inspections of my cranks for cracks in the future.

Brooks Saddle for New Build

Picked up a new Brooks B17 in blue for a new build. More on that to follow. I was comparing how stiff it was compared to my old B17. That saddle that has over 16,000 miles on it. In the process, one thing I noticed about the old saddle is the Brooks logo stamped on to the sides wearing off. I realized that when I sit on it, now the sides flare out a little. This is causing them to rub on my thighs and wear the logo.
There's two ways I can take care of this. One is to adjust the tension bold on the nose. The other would be to punch a few holes in the sides and lace underneath as Brooks does with some of their other models. Now there's a lot of mysticism when it comes to people's opinion about adjusting the tension bolt on a Brooks. Most say 1/2 turn a year would be a lot. Some people say not to ever adjust it and just do the lace. And then there's a lot of talk about weather you rode it in the rain or not. The rule, as I understand it, is not to ride it wet. It's OK if it gets wet. Just let it dry but if you ride it wet you WILL stretch the leather. Well, I live in Seattle. It rains. I commute every day. For the most part the saddle is dry. Sometimes when it is really coming down the nose of the saddle will get a little wet and sometimes it's received a few sprinkles and been rode on. So I'm sure it's stretched over the years.

Also I think there's a few more factors that come into play here. You can't just say adjust your Brooks 1/2 turn every year or so. I ride more in two days then many of my friends do all year. So you've really got to look into the time put in on the saddle. As of right now I know there's at least 1100 hours on this one. That's 45 days I've sat on that seat! Not to mention, not everyone cares for their Brooks the same way. I only use the Proofide but people use all sorts of stuff and the saddles will break in differently because of it.

So I did the unthinkable. I adjusted the tension bolt. And not just a little. I turned it 30 times. Now that's only thirty 1/4 turns but most Brooks owners would be freaking out. I adjusted it until the stiffness of the bolt and the saddle started to match the new saddle. That's just about 3/8th's of an inch. It seems like a lot but the saddle still has some flex/give.

Tuesday, February 10, 2015