If you're bored with my bottom bracket incompetence, surf away before it's too late!
If, however, you take great joy in the misfortunes of others, have I got a post for you.
So I'd had issues with a cross-threaded BB cup (that I now know I can blame on Former Neighbor Steve for polluting my garage with his bad cross-threading juju), but I'd stolen a cup from another bike that (I thought) was compatible and (I thought) fixed the problem. Did a few rides on the bike, including a fast (for me) out-and-back 26-miler to Cumming, IA Thursday night. No creaks, no rattles, smooth spinning.
Then I saddled up for my commute home yesterday. Got about five blocks from work when things started feeling wrong. Pedals were wobbly underfoot, and each turn of the cranks made this awful grinding sound. Oh crap.
Stopped, assessed the situation, and realized that either a) the cup I thought was compatible actually wasn't, or b) I was too timid after the cross-threading adventure and didn't torque the cup down hard enough. Said cup had backed its way out of the frame far enough to let the cartridge BB rattle around (causing the wobbly feeling) and grind the chainring into the shiny, formerly-pristine metallic brown repaint on my right chainstay (thus the awful sound).
No way I can fix that by the side of the road, and no way I can ride it home. And my cell phone barely has enough juice to make one call.
In the words of the poet Homer, "DOH!"
I managed to get a quick "myphoneisdyingpleasecomepickmeupatthecornerofsecondandMLK" call to my wife and get rescued, but it was NOT how I'd hoped my day would end.
Today, I put in a different cup and torqued that sucker to "gorilla." We'll see if that does the trick.
Showing posts with label repair. Show all posts
Showing posts with label repair. Show all posts
Saturday, June 6, 2009
Monday, May 25, 2009
Homebrewed Tool Tip
I'm trying to get my mechanical hubris back after yesterday's debacle, so I thought I'd dig back through the old shop bag of tricks for a post.
Today's tip is the legendary Homemade Poker/Scraper Tool. I can't take full credit for it since I got it from Paul, my head mechanic when I wrenched in Iowa City. Paul was a hidden legend -- nothing mechanical seemed to faze him, from epicyclic hub overhauls to adding grease fittings to the ski-tuning equipment. He was also doing off-road single-speeding back in the mid-90s before it had dawned on anyone else. The guy could shred all of us on a junked-out warranty frame with one cog and a homemade chain tensioner.
The poker/scraper is one of the simplest homebrewed tools ever. One: Find a broken old spoke. Two: Cut off the elbow (assuming it's not already gone). Three: Lay one end on a flat metal surface and whang on it with a big hammer until a couple inches have been flattened. Four: Sharpen the other end to a point (a bench grinder is the quick way, but a Dremel or file will do the trick too). If you're feeling extra fancy, bend the resulting tool until it has a little loop in the middle for pegboard hanging... or you can just store it by poking it into a pegboard hole.
It seems simple to the point of useless, but you'd be surprised how often a flattened and/or sharpened hunk of spoke can help out while wrenching. The poking end is great for opening up the liner in a freshly-cut piece of brake or derailleur cable housing. The scraping end can get gunk out from between cassette cogs (proceed with caution, however, as the poking end can bite). Dirt clogging up your cleat bolts? Shard of glass stuck in a tire casing? Need to toast a marshmallow for s'mores? Reach for the poker/scraper.
(Hubris sidenote: Today's 20-mile TTT -- Touring Time Trial -- was delightfully creak-free, so it would seem that yesterday's debacle paid off and the teflon plumber's tape performed as expected. Either that, or it was a coincidence and I accidentally tightened up the problem bolt while I was doing all that disassembly and assembly. Either way, I'll take it.)
Today's tip is the legendary Homemade Poker/Scraper Tool. I can't take full credit for it since I got it from Paul, my head mechanic when I wrenched in Iowa City. Paul was a hidden legend -- nothing mechanical seemed to faze him, from epicyclic hub overhauls to adding grease fittings to the ski-tuning equipment. He was also doing off-road single-speeding back in the mid-90s before it had dawned on anyone else. The guy could shred all of us on a junked-out warranty frame with one cog and a homemade chain tensioner.
The poker/scraper is one of the simplest homebrewed tools ever. One: Find a broken old spoke. Two: Cut off the elbow (assuming it's not already gone). Three: Lay one end on a flat metal surface and whang on it with a big hammer until a couple inches have been flattened. Four: Sharpen the other end to a point (a bench grinder is the quick way, but a Dremel or file will do the trick too). If you're feeling extra fancy, bend the resulting tool until it has a little loop in the middle for pegboard hanging... or you can just store it by poking it into a pegboard hole.
It seems simple to the point of useless, but you'd be surprised how often a flattened and/or sharpened hunk of spoke can help out while wrenching. The poking end is great for opening up the liner in a freshly-cut piece of brake or derailleur cable housing. The scraping end can get gunk out from between cassette cogs (proceed with caution, however, as the poking end can bite). Dirt clogging up your cleat bolts? Shard of glass stuck in a tire casing? Need to toast a marshmallow for s'mores? Reach for the poker/scraper.
(Hubris sidenote: Today's 20-mile TTT -- Touring Time Trial -- was delightfully creak-free, so it would seem that yesterday's debacle paid off and the teflon plumber's tape performed as expected. Either that, or it was a coincidence and I accidentally tightened up the problem bolt while I was doing all that disassembly and assembly. Either way, I'll take it.)
Sunday, May 24, 2009
Rookie Mistake
This just in... mechanic defeated by his own hubris.
I'd pulled off a pretty slick repair on our tandem so it would be ready for the farmers' market yesterday. I was feeling pretty good about myself. There was even some mention of my candidacy for the coveted Greatest Living Bicycle Mechanic in Central Iowa title.
Not so fast, slick.
I've been chasing a creak around my main ride, eliminating possible causes through a slow diagnostic process. Today, I had enough time to pull the cranks and bottom bracket. The plan was to grease the shoulders of the bottom bracket cartridge where they sit in the cups and wrap the cup threads with Teflon plumber's tape. It's an old trick from my days as a Cannondale mechanic, since a dry BB install would invariable make a small creak that would resonate through those big aluminum tubes until it sounded like a door opening in a horror movie.
That was the plan, anyway. And it worked for a while. I got everything out, cleaned it all up, greased up the cartridge, wrapped up the cups, and got the right side cup back in the frame, straight out of Sutherlands.
So, I started the left cup. And it felt a little snug. Before you ask, yes, I did know which cup had left-handed threads. Straight out of Sutherlands, remember?
"No biggie," I figured. "The Teflon tape makes it tight." So I kept cranking.
And it got even more snug. "Man, I must have put too much tape on that thing," I figured. So I grabbed a bigger adjustable wrench, clamped that bad boy on my BB tool and kept cranking.
It got even more snug. I could barely budge the thing, and it was barely a third of the way in. Only then did Mr. Fixit think, "Huh, that doesn't seem right." So I started backing it out again.
Cross-threaded. The aluminum cup was absolutely shredded where I'd ham-fisted it sideways into the steel bottom bracket shell. This is a family blog, so let's take the "edited for TV version of Snakes on a Plane" approach and pretend that I said, "I'm such a monkey-fighting idiot, cross-threading this Monday-Friday bottom bracket."
Proof that someone or something up there is looking out for morons and klutzes, at least it was an aluminum cup that sacrificed its life for the steel bottom bracket shell. If I'd needed the BB threads chased late on the Sunday of Memorial Day weekend, I would have been stuck. And I made a decent save by pulling a cup out of my fixie that just happened to fit despite being an entirely different brand of cartridge bottom bracket. So, the fixie's down until I replace the cup, but at least my daily driver is going again.
I'd pulled off a pretty slick repair on our tandem so it would be ready for the farmers' market yesterday. I was feeling pretty good about myself. There was even some mention of my candidacy for the coveted Greatest Living Bicycle Mechanic in Central Iowa title.
Not so fast, slick.
I've been chasing a creak around my main ride, eliminating possible causes through a slow diagnostic process. Today, I had enough time to pull the cranks and bottom bracket. The plan was to grease the shoulders of the bottom bracket cartridge where they sit in the cups and wrap the cup threads with Teflon plumber's tape. It's an old trick from my days as a Cannondale mechanic, since a dry BB install would invariable make a small creak that would resonate through those big aluminum tubes until it sounded like a door opening in a horror movie.
That was the plan, anyway. And it worked for a while. I got everything out, cleaned it all up, greased up the cartridge, wrapped up the cups, and got the right side cup back in the frame, straight out of Sutherlands.
So, I started the left cup. And it felt a little snug. Before you ask, yes, I did know which cup had left-handed threads. Straight out of Sutherlands, remember?
"No biggie," I figured. "The Teflon tape makes it tight." So I kept cranking.
And it got even more snug. "Man, I must have put too much tape on that thing," I figured. So I grabbed a bigger adjustable wrench, clamped that bad boy on my BB tool and kept cranking.
It got even more snug. I could barely budge the thing, and it was barely a third of the way in. Only then did Mr. Fixit think, "Huh, that doesn't seem right." So I started backing it out again.
Cross-threaded. The aluminum cup was absolutely shredded where I'd ham-fisted it sideways into the steel bottom bracket shell. This is a family blog, so let's take the "edited for TV version of Snakes on a Plane" approach and pretend that I said, "I'm such a monkey-fighting idiot, cross-threading this Monday-Friday bottom bracket."
Proof that someone or something up there is looking out for morons and klutzes, at least it was an aluminum cup that sacrificed its life for the steel bottom bracket shell. If I'd needed the BB threads chased late on the Sunday of Memorial Day weekend, I would have been stuck. And I made a decent save by pulling a cup out of my fixie that just happened to fit despite being an entirely different brand of cartridge bottom bracket. So, the fixie's down until I replace the cup, but at least my daily driver is going again.
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