Tuesday, July 28, 2020

Another day, another bike I'd never heard of

It was too new for Classic Rendezvous, but still from the "screwed and glued" aluminum era. Its worn decals seemed to say Prism, but a web search on Prism bikes, bicycles, cycles turned up nothing that resembled it.

Little letters on the frame and fork said SR Litage. That seeming subtitle brought up the bike and its kin from the late 1980s.




 Componentry said early 1990s to me. Later the owner told me she got this one in 1993. That headset looks particularly annoying to adjust and keep set. Crap like that is a large part of what made threadless headsets seem like a good idea. I was glad that the bike wasn't in for a full tune. It only had a shifter problem with the 8-speed Campagnolo Ergopower brifters. They were jammed.

The bike had a weird mix of parts: Campy drive train and rear hub, Shimano Ultegra brakes from back when they still said "600," and that Mavic headset. ITM bars. The rear brake cable enters the frame, but the housing is continuous. Shift cables are external. Shift housing stops are mounted to downtube shifter bosses.

I figured that the shifters had jammed because the index springs had broken and fragments had wedged in the ratchet rings. I detached the cables from the derailleurs to see if I could free anything up. The shifters then pulled the cable perfectly well, with no crunching or excessive play. Maybe the derailleurs themselves were stuck.

Nope. I could move them easily by hand.

I reconnected the cables and everything worked perfectly. So I test rode the bike. It didn't want to shift to the big ring. Then it dropped the chain inside, where it stuck behind the tabs on the inner ring. I carried the bike back inside to pull the crank and extricate the chain. This led me to discover that the bottom bracket was unscrewing itself. An early cartridge model, as it migrated to the right it pulled the left side in after it. The cartridge never felt loose as the crank migrated sideways away from the front derailleur.
It hadn't gone far enough inside to pull the left crank arm against the chainstay on the way around.

An exploded view in one of our old Campy parts catalogs showed the Athena bottom bracket with what look like serrated washers that are supposed to go in the cups on either side. I would presume that these are supposed to enhance the grip of these unflanged cups against the cartridge with the bearings in it so that they can be securely torqued into the bottom bracket shell. The axle also measured shorter than the triple crank supposedly requires, but the chain line was almost too far out, even with the BB restored to its proper position. I torqued it as securely as I could. The only way to get those missing washers would be with a time machine.

In eternity, all nows are equal. Every moment exists and could be reached if we were not stuck experiencing time in a linear flow. I think of this every time I look through our old Quality catalogs at all the componentry I wish I'd stocked up on.

If I had needed to open up the shifters I would have removed them from their clamps and worked on them off the bike rather than unwrap the bars and lose the vintage Celeste green cork wrap. Even if it didn't have aggressive adhesive backing, so I could get it off without shredding it, it never lines up exactly the same. The shifters seemed miraculously cured, as if they were only trying to get the rider to bring the bike in to have the bottom bracket apprehended before it escaped completely. If they malfunction again, we do keep index springs on hand. Campy being Campy, they still use the same springs in the same basic design.

8 comments:

John said...

Time travel... If only. =)

Steve A said...

I confess that I used Locktight on the bb. The bike was crap anyway.

RANTWICK said...

Speaking of BBs, question: I am installing a new external bb in a "normal" english threaded, "modern" setup. I have always preferred to just use good grease (I like automotive bearing grease) on the threads. A bikeshop I use prefers antisieze compound for this. Opinion? Also, gave I asked you this before?

RANTWICK said...

*have

cafiend said...

@Rantwick: I just use grease unless I'm working with titanium. Plenty of grease and proper torque should do the job.

Normal English threaded is the way to go.

I don't remember if you've asked me before or not. If so, it's been a while. Anyway, I'm glad to be of help.

RANTWICK said...

Yay grease! Thanks fiend.

ktache said...

Does the Mavic headset use needle bearings?

I seem to remember setting up a Roberts mtb for a mate, full groupset setup, and the top of the mavic had needle bearings, bottom normal balls. the bottom race was loose to, centre punched little dents all the way around to add a little more to the friction fit. and a bit of treadloc.
No lockring on the top, grub screws.

cafiend said...

I didn’t delve into the headset, but needle bearings in the top and ball bearings in the bottom is so bass ackwards. Needle bearing headsets are the absolute best for durability, which is why no one makes them anymore. I have them on most of my bikes. The one on my road bike is a Stronglight from back in the 1990s (I think). The others are the old FSA Orbit UF, with needle lower and ball bearing upper. FSA changed the UF to 36-degree angular contact cartridge bearings a few years ago. And the UF was not available when I built up the current version of my mountain bike, so I don’t have needle bearings in that. They are particularly good in the lower race where most impact is absorbed.