Friday, October 15, 2010

Bridgestone MB-6 Project, Part 2


I visited the powder-coater with the bare frame this week, and was a bit taken aback by their new pricing. Really, the price is reasonable considering the work it takes, and to tell the truth I haven't been very satisfied with the work done for 200 kr. 800 kr, the current asking price, includes bead blasting and clear coating, luxuries previous junk bike projects have gone without. This is a vanity paint job more than anything, since it's not covering up any frame modifications. But the original paint was in such bad shape, I think I'll go ahead and do it. I'm going to blast the frame myself though, and save a bit on the total cost. They even had a pink, RAL 3015, which seems a popular color for bikes.

It seems a shame to spring for a new paint job without doing any frame modifications. The most obvious route, since it's going to be a singlespeed anyway, would be to put on some track ends. That way I'd avoid the trouble of gimmicky chain tensioners and whatnot. Still, I have a feeling this bike will live to experience another build, and I may want that derailleur hanger in the not-so-distant future. Also, the dropouts feature a couple fender/rack mounts, which will probably come in handy, and which are generally lacking from track ends if you don't drill and tap some of your own.

Another nice feature for a future build would be down-tube shifter mounts. These would add flexibility to any geared arrangement with derailleurs, and would allow the use of cheap and plentiful friction shifters either on the frame or on the bars. But again, the current build plan is to go singlespeed, and exposed and unused shifter bosses are even worse than exposed and unused canti-bosses, in my mind. So I think we'll forgo any additions or removals from this frame.

Is this frame really worth the trouble I'm putting into it? Of course I think so, for a number of reasons. Since I salvaged the frame, and am building the bike largely with the detritus of parts bins, my total cost won't be anywhere near that of a new bike, especially of the quality of this one. I believe any sort of adaptive reuse is a better solution for an old bike than the landfill, but there are particular bikes which represent especially good candidates for these types of projects. Road bikes from the 70s, 80s, and early 90s are widely appreciated. Quality, especially mid-market and up, was particularly good, industry standards still in use today were solidifying, and the geometry favored by builders was appropriate for a number of applications beyond that of road-racing.

Perhaps less appreciated today are the mountain bikes of the early 90s. There was a golden window, when mountain bikes were at the height of their popularity, that a number of factors came into play:

1 Geometry was more racing-oriented than that of most mountain bikes that came before, which means these bikes ride well over a variety of terrain. Also, they were not yet "suspension-specific", meaning the gap from bottom of the headtube to the tire falls is reasonable-appearing with normalish tires and fenders.

2 Standards in use today became firmly established: gone were the oddball U-brakes behind the bottom bracket and E-stays. Also, modern headset sizes (threaded 1", threadless 1 1/8") were common. Watch out for oddball headsets though! A good shop can help with things like facing a JIS-standard fork for industry standard races, but stems for threaded 1 1/8" forks or threadless 1" forks or anything 1 1/4" are hard to come by!

3 Taiwanese construction was established and relatively good by modern standards. Preferable exchange rates meant Western countries could buy relatively high-quality frames at low cost. Tube sets of complete double-butted chromoly and nice investment cast fittings were the norm even on mid-level bikes like this one. The aluminum bikes that stormed the market a few years after these are fine bikes, but they can't be as freely modified or repaired as bikes with steel frames.

4 Suspension forks hadn't yet entered the mainstream at the mid-level pricepoint, which automatically made these bikes a better all-around value than those that followed. Not having a suspension fork reduces the overall complexity of modifying these bikes for other use, as you don't have to spend time searching for finding out-of-production replacement parts. Fortunately, there are plenty of rigid replacement 1 1/8" forks available for those stuck with an obsolete fork.

The Bridgestone frame I am working on with this project benefits from all of the above. 26.2mm seatposts don't grow on trees, but otherwise almost everything on this frame is relevant today. The 1" threaded fork means I can pick from a variety of interesting stems, and cantilever brake bosses open up the world of modern and vintage cantis and V-brakes.

All that being said, it's not a lightweight:

Frame: 2342g
Fork: 882g
(with original paint)

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