Wednesday, June 2, 2010

Preparing for a quick two-dayer

I've had a short dirt overnighter planned with some friends for awhile. It's in a couple weeks so the obsessing is starting in earnest now.

It's all dirt roads. Logging roads mostly. Lots of climbing. Hopefully some nice views. I plan on taking Phil's RB-T.

And I don't plan on making a bunch of changes. I put a Brooks on there last week and I've taken the bike for a few rides. It pretty much works out of the box. Since we'll be all dirt and I've guaranteed no rain to my friends, I plan on removing the fenders and putting fat WTB knobbies on it.

I thought of swapping out the bars, but they'll be fine. I'll put some different pedals on it. The shifting seems ok. If I was more thorough, I'd overhaul the hubs and the bottom bracket, but I'll gamble on those. I will clean and lube the chain. Otherwise it's good to go.

Question. What the hey is this:

I've never seen that before. Anyone?


Anonymous said...

Cable squeegee?

Pat S said...

I've never seen one either, but it looks like it's designed to keep krap from working its way into the housing via the cable. I can't tell for sure but I'm guessing the silver piece in the front has a set screw that locks it to the cable and the black tubing "accordians" as the cable moves? Those tubing clamps look to be the center punch-style. Whoa, serious hardware for serious business.

Traditional Bike Club Curmudgeon said...

Trailer hitch?

Dylan said...

It's to keep the junk out of your rear shift housing, since that shift cable runs next to the gunky chainstays.

I've seen homemade-jobbies like that on some older-school 'cross bikes.

Have a blast on the overnighter. I look forward to the write-up.

Willy said...

It's called a bassworm. It essentially adds spring tension to the cable so the deraileur will go into the higher (faster) gears better, in case you have a weak deraileur spring or gunked up cable housing. The cable runs through it and then you stretch it up the cable an inch or two and secure it to the cable with a tiny set screw. (which damages the cable, btw.) Originally used with early grip shifters mated to Shimano deraileurs. I'm surprised it's not dried out and broken, yet.

Willy said...

Just noticed the 217's, they're notorious for cracking at the eyelets. Better give them a good look before heading out on much of a ride.

OlyBikes said...

Willy is right about that being a Bassworm. SRAM's black gunk-guard was called the Nightcrawler.

Around 1993, Shimano must have gotten sick of losing shifter spec to SRAM's grip shifters, so they lightened up the derailer spring. Grip shifting don't work as well or as long with light action springs. Thus the Bassworm, to boost up spring tension indirectly. Oddly, I think Shimano screwed themselves over for two reasons:

- SRAM later developed their ESP line of matched shifters (both twist and trigger) and derailers which work very well (I prefer them to Shimano), and causing Shimano to lose rear derailer spec.

- The light action spring makes shifting to an 11-tooth cog pretty anemic. Perhaps that's what gave rise to Rapid Rise reverse action derailers (cable tension upshifts and the spring downshiftes). Recently, Shimano advertised that they are beefing up their derailer spring. Call in "the end of an error".