Bicycle Mechanics - Tourer/fixed flip flop
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03-15-03, 08:14 AM
I am almost finished converting my Miyata 1000 tourer to fixed.
I am building new 700 C wheels to replace the 27" 40 spoked wheels, and have installed a shimano 1710 (I think) BB (109 mm.)
to replace the 125 mm cup-and-cone system that went with the Sr triple crank. The SR has been replaced with an old Dura-Ace track crank with ancient 151 BCD 1/8" rings.
Question: I do not want to swap out the new 109 mm BB, but want on occassion to return the bike to touring duty with 3/32 cogs and rings. I have the old 27 " wheels put aside for this reason. Will I be able to find a light weight touring crank
set that will work with this BB (triple or double)? I want to stay with the low "Q"of the new BB in the touring set-up. Thank You.
If the new BB spindle gives you enough drive-side clearance to install a chainring on each side of the spider, you will be fine.
03-15-03, 02:53 PM
It seems like it may be nip and tuck with a spindle that short, but as John E says, if it will fit it will fit. Your best bet might actually be to try a double crankset with 110 BCD or smaller so that you can put on a smaller inside chainring which might give you the clearance you need if a 39T won't do it. This could be a positive for touring. With 110 BCD you can go as small as 34 teeth, giving you smaller gears than normally available with a double. I have a 48/34 on one of my bikes. It works great. On my normal flat riding I am always on the big ring, but I have that tiny one to handle even pretty serious hills if I put on a 28T or even 34T cog in back. A 94 BCD would allow you to go even smaller, but I don't know if doubles come that small.
I am not too up on the model numbers, but is that a cartridge bb? If you used cup and cone you could just purchase a longer spindle from someplace like HarrisCyclery.com which could be swapped in a matter of minutes without completely replacing the bb. But then swapping a cartridge bb is probably just as easy.
Still another, even simpler, compromise depending on the terrain you might be touring one would be to put on one smaller ring up front. With a relativlely inexpensive XT rear der you could spin on a megarange 11-34 7sp freewheel. With a single 42T chainring this would give you 7 gears from a pretty low 33 inches to a pretty darned big 103 inches. There are also 13-34 and 14-34 which offer more cruising options but lower high gears.
There are many ways to approach a solution. These are just a few alternatives.
03-15-03, 07:34 PM
Thanks Raymond and John E.
Raymond-the BB is a cartridge. I wanted to get a good match for the track crank that I came upon, so I sent it to Business Cycles in Florida to get a suitable BB. I am hoping that I will get a good chainline with the same vintage Dura-Ace track hubs, I was also influenced by the low Q concept. So, I have already taken out the BB, ( had a hell of a time on the drive side of course.) As I mentioned the spindle length reduces from 125 mm to 109. Found a lot of rust in the BB, I guess I haven't serviced it for many years. That solution of 110 BCD may just be the ticket. Don't know that I need a triple, and anyway that may be out of the question with the 109. I kind of like the idea of a convertable bike, and I don't mean "top down". I mean a good road/off-road fixed which can change in a phone booth to an equally good tourer. I guess I find something offensive about the idea of a different bike for every task, kind of disloyal in a way. But the way the dollars are adding up, I may have been ahead by bying another dedicated bike.
03-16-03, 11:31 AM
The 110 mm BCD gives you quite a bit of flexibility. That's why I like them.
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