Thursday, June 25, 2009

Clive's Rear Derailleur

This, friends, is a tale of an embarrassment of riches—of my struggle to choose between two very fine Mavic rear derailleurs.

Originally my plan was to use a Mavic 851 rear derailleur that I had picked up for no particular reason on eBay. I knew from the beginning that I would be using friction shifting. Weight was also a concern; and of course aesthetics are always in my mind. So why, I thought, use anything else? The Mavic 851 is a friction derailleur, is unbelievably light, and is for me unequivocally the most beautiful derailleur (nay, component!) ever made.

Well, the answer began to suggest itself when I tried actually using it. I installed in on my Fuji one day last spring just to "make sure" that it worked as well as the Campagnolo Centaur derailleur I'd been using. At first it didn't work at all; it simply wouldn't shift onto the big (24 & 26) cogs. Eventually I was able to figure out how to slide the cage to allow it to wrap around the 26—but then I lost all chain tension. So I took it off. Recently I gave it another try, and figured out the chain tension issue. But even perfectly set up it (1) couldn't take up all the slack on my 48/32 13-26 setup; (2) still skipped around on the big cogs; and (3) shifted really, really badly compared to the slant-paralellogram Centaur.

By this time I had grown very attached to the idea of using a Mavic derailleur. And though I knew the 840 existed, I wasn't very enthusiastic about it. For one, it seemed needlessly heavy and bulky compared to the 851. For another, new old stock 840s were going for $200+ on eBay. And though I liked it strange-looking cage plate, I didn't find it very attractive. This was especially evident in comparison to my very special 851, whose previous owner (a kindred spirit!) had taken the time to disassemble it, strip off all the clear anodizing, and polish the aluminum parts.

This dilemma resolved itself in three steps. First, I got over the weight issue and resolved myself to the fact that slant-parallelogram derailleurs work really well and I need one. Secondly, I found some poor soul who couldn't spell "derailleur" and whose listing for a "Mavic derrailer" (along with a nice pair of Mavic/Modolo brake levers!) attracted very little attention and came to me very cheaply. Finally, I disassembled the derailleur and sanded and polished the silver parts.

The result is a beautiful, functional derailleur in whose beauty I have a hand. Being involved in the "production" of one's posessions—rather than just "consuming" them—always adds enjoyment.




Ian wrigley(karrimor@OYB) said...

I have a very similar mavic derallieur to your 851 which i bought new in1987 and used for several years dispatch riding in london, mine has a longer cage so far as i can see and worked perfectly the whole time i had it fitted, sorry i cant recall the ratios used as i switched to a single freewheel after it got knocked into the wheel one time, only ever used three ratios regularly anyhow. As i recall, at the time, cages were available in different lengths/sizes to accomodate different ranges of ratio and this model could be fitted to the most extreme MTB ranges as a result. The cage on mine has a white detail on the anodising. As testament to the quality of build it is still serviceable, the only damage being a small gouge where the mounting bracket dug into frame end pivot block. The steel bracket bent.

Ian wrigley(karrimor@OYB)) said...

Just in case you are wondering the bike was built around a lightweight road frame-double butted 531- which i presuaded the makers(condor cycles of london) to add cantilever braze-ons to. They were none too keen and thought i wouldnt be able to control the bike under braking. They were wrong,and soon were fitting them to all of their touring frames, if not the road race frames. The gears were therefore road/race in range so twin front rings(? 52/48) and i'm guessing just a standard cheap six speed freewheel(it was going to wear out too quickly to spend loads on for work) I still have the bike and use it occasionally in the form i used it for dispatch, single speed freewheel,ratio 50/17 on 700c rims &track hub, for 8 yrs, including 1yr in edinburgh. Hills were a killer.

AH said...

Yeah, I'm sure these worked extremely well with a closer ratio on the back, and especially with less of a jump between front chainrings (48/32 is pretty huge!). I'll certainly hang on to the derailleur and try it out on a 52/42, 13-24 setup or something similar. I'm sure some people are able to get the 851 to work well with larger cogs and front chainring jumps; setup does require skill!