|
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
"Compact Double Crank" = "Touring Bike Crank"
David Huggins-Daines wrote:
I wonder why the move to integrated granny spacers happened. I can't see any benefit in it, for the consumer at least. There are several benefits: Easier to change chainrings, because you don't need to deal with loose spacers. Better thread engagement for the mounting bolts. You can use shorter mounting bolts. Probably also permits the spider arms to be made thinner and lighter since the holes don't go as far through them. There is also a drawback; it makes it harder to customize the spacing. For instance, my "Brown" has a nice old Sugino AP130 crank (this was, I believe, the first 130/74 crank ever. I recall being very excited when I got it because if finally allowed me to do a triple with full-sized Biopace chainrings. (It is set up with 52-42-28.) I wanted the chainline of the two big rings to be in the normal range for a double crank, so I used much thinner than normal spacers to attach the 28 tooth chainring. The idea is that 99% of the time I ride it as if it were a 52-42 double, but when I'm really up against it I have the 28 ring in reserve. For many years I rode this with a 12-22 6-speed freewheel. The 28 tooth chainring could only run smoothly with the 2 or 3 largest sprockets, but there was no reason to ever use any of the other sprockets with the 28 anyway. The skinny spacers (and a Phil Wood adjustable bottom bracket) allowed me to get the crank in very close to the frame for usable chainline in all combinations using the two larger rings. This could be difficult to do now, because I'm not sure any modern front derailer has sufficient leftward travel to shift it, but the old Sun Tour Cyclone handles it OK. Sheldon "Breaking The Rules" Brown +----------------------------------------------+ | Check out my wife's tale of her experience | | in the 1975 Paris-Brest-Paris at: | | http://harrietfell.com/PBP1975.html | +----------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide http://captainbike.com http://sheldonbrown.com |
Ads |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
May 6 NYC NBG Day to Honor Fallen Bike Activist | Cycle America | General | 0 | April 11th 05 04:15 PM |
19 Days to go: NBG Mayors' Ride Excitement #5 | Cycle America | Recumbent Biking | 0 | March 30th 05 07:32 PM |
Convert Hybrid to Touring bike | Willy Smallboy | Techniques | 23 | March 26th 04 01:03 PM |
aus.bicycle FAQ (Monthly(ish) Posting) | kingsley | Australia | 3 | February 24th 04 08:44 PM |
How old were you when you got your first really nice bike? | Brink | General | 43 | November 13th 03 10:49 AM |