ISO: 50.4 BCD outer chainring
06-06-23, 10:36 AM
#1
Myrtle Beach Crab
Thread Starter
Join Date: Nov 2012
Location: Newport RI
Posts: 824
Bikes: enough one would think, but thinking isn't my strong point
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 271 Post(s)
Liked 541 Times
in
214 Posts
ISO: 50.4 BCD outer chainring
looking for a chainring in the mid 30's.. i'm running a 44t single right now with a 4 speed 14-22 4 speed rear and my legs doth complain. 3/32
06-06-23, 01:54 PM
#2
Senior Member
You can buy new TA rings, but it looks like the smallest outer is 40 teeth. Two sources are https://www.veloduo.co.uk/collection...nt=34104480583 for 25 pounds or TA itself - https://specialites-ta.com/pro-5-vis...denture,40-dts, 40 euros.
I bought a TA ring from Veloduo Cycles a few years ago, and the transaction was fast and clean.
I bought a TA ring from Veloduo Cycles a few years ago, and the transaction was fast and clean.
06-06-23, 02:56 PM
#3
Myrtle Beach Crab
Thread Starter
Join Date: Nov 2012
Location: Newport RI
Posts: 824
Bikes: enough one would think, but thinking isn't my strong point
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 271 Post(s)
Liked 541 Times
in
214 Posts
You can buy new TA rings, but it looks like the smallest outer is 40 teeth. Two sources are https://www.veloduo.co.uk/collection...nt=34104480583 for 25 pounds or TA itself - https://specialites-ta.com/pro-5-vis...denture,40-dts, 40 euros.
I bought a TA ring from Veloduo Cycles a few years ago, and the transaction was fast and clean.
I bought a TA ring from Veloduo Cycles a few years ago, and the transaction was fast and clean.
06-06-23, 03:40 PM
#4
Phyllo-buster
Join Date: Jan 2010
Location: Nova Scotia
Posts: 8,847
Bikes: roadsters, club bikes, fixed and classic
Mentioned: 133 Post(s)
Tagged: 0 Thread(s)
Quoted: 2298 Post(s)
Liked 2,054 Times
in
1,254 Posts
Or you could go triple. 
06-06-23, 03:56 PM
#5
Senior Member
Even simpler and cheaper - go double. The same sources (and others) sell inner/middle rings in even numbers from 26 to ...um... 52.
Likes For cocoabeachcrab:
06-06-23, 06:44 PM
#7
Myrtle Beach Crab
Thread Starter
Join Date: Nov 2012
Location: Newport RI
Posts: 824
Bikes: enough one would think, but thinking isn't my strong point
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 271 Post(s)
Liked 541 Times
in
214 Posts
looks like Bob at freewheel spa has a solution to my old legs.. a custom freewheel to fit my 4 speed spacing and hub.
Likes For cocoabeachcrab:
06-07-23, 03:29 AM
#8
Senior Member
Join Date: Feb 2020
Posts: 2,819
Mentioned: 49 Post(s)
Tagged: 0 Thread(s)
Quoted: 1106 Post(s)
Likes: 0
Liked 1,327 Times
in
783 Posts
Get a crossover-sprocket from a tandem drive (30T pictured, I've seen mention of 34):
Last edited by oneclick; 06-07-23 at 03:33 AM.
06-07-23, 05:57 AM
#9
tantum vehi
Join Date: Jul 2008
Location: Flathead Valley, MT
Posts: 4,440
Bikes: More than I care to admit
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 1167 Post(s)
Liked 992 Times
in
491 Posts
Brilliant idea with the tandem chainring suggestion.
Bob’s also a brilliant idea.
__________________
1970 Gitane TdF; 1973 Gitane TdF
1979 Trek 710; 1981 Trek 412; 1981 Trek 710
1984 Specialized Stumpjumper Sport; 1985 Specialized Allez SE; 1988 Specialized Sirrus; 1989 Specialized Rock Combo
1984 Ross Mt. Hood
1988 Centurion Ironman Expert
1991 Bridgestone RB-1
1992 Serotta Colorado TG
2015 Elephant NFE
1979 Trek 710; 1981 Trek 412; 1981 Trek 710
1984 Specialized Stumpjumper Sport; 1985 Specialized Allez SE; 1988 Specialized Sirrus; 1989 Specialized Rock Combo
1984 Ross Mt. Hood
1988 Centurion Ironman Expert
1991 Bridgestone RB-1
1992 Serotta Colorado TG
2015 Elephant NFE
Likes For mountaindave:
Likes For cocoabeachcrab:
06-10-23, 01:38 PM
#11
Senior Member
Join Date: Apr 2011
Location: Maryland, USA
Posts: 2,433
Bikes: Drysdale/Gitane/Zeus/Masi/Falcon/Palo Alto/Raleigh/Legnano
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 983 Post(s)
Liked 632 Times
in
403 Posts
I've seen, but usually unavailable, some adapters to use a 50.4 BCD crank arm with chainrings of a different BCD (larger); no ideal what the lower T limit is on those, however. But I suspect it would look cool (lots of chrome bolts).
__________________
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
Likes For tiger1964:
06-14-23, 07:33 PM
#12
Senior Member
Join Date: Dec 2015
Location: San Diego
Posts: 703
Bikes: 1978 Bruce Gordon, 1977 Lippy, 199? Lippy tandem, Bike Friday NWT, 1982 Trek 720, 2012 Rivendell Atlantis, 1983 Bianchi Specialissima?
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 345 Post(s)
Liked 175 Times
in
107 Posts
09-07-23, 02:42 PM
#14
Junior Member
Hi, I'm wondering if you sorted this out because I am in need of a 44 TA outer (50.4) to make a half step double out of. I know yours is a single but I could probably drill it. Thanks.
09-07-23, 04:06 PM
#15
Senior Member
Join Date: Feb 2020
Posts: 2,819
Mentioned: 49 Post(s)
Tagged: 0 Thread(s)
Quoted: 1106 Post(s)
Likes: 0
Liked 1,327 Times
in
783 Posts
The Simplex 5-to-3 bolt adaptor gets you to 36, sorry don't have one, the pics I see are associated with large figures in front of dollar signs.
If you are going to spend money you might find a hobbyist who would do this (is a 54 but it'll go down to 28):
09-08-23, 04:58 AM
#16
Senior Member
Join Date: Apr 2011
Location: Maryland, USA
Posts: 2,433
Bikes: Drysdale/Gitane/Zeus/Masi/Falcon/Palo Alto/Raleigh/Legnano
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 983 Post(s)
Liked 632 Times
in
403 Posts
And a quick look shows rings down to 34T, I do not know the lower limit: RING
__________________
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
09-09-23, 11:59 AM
#18
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,784
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3587 Post(s)
Liked 3,400 Times
in
1,934 Posts
