chain rings

General cycling advice ( NOT technical ! )
lotus 30
Posts: 38
Joined: 13 Mar 2017, 4:26pm

chain rings

Postby lotus 30 » 8 Dec 2018, 1:54pm

I have a williams Ab77 chain set and would like to get some larger ring gear for it say around 60 tooth which bolt holes do you measure to get the correct ring gear. a car wheel is diagonal but that prob will not work. Picture of a 62 tooth i have made an adapter for an old williams cotter pin chainset to a more modern ring gear
24068252_10155735178561063_8222126789204859928_n.jpg
DSCN2264.jpg
s-l1600-2.jpg

User avatar
Tigerbiten
Posts: 1612
Joined: 29 Jun 2009, 6:49am

Re: chain rings

Postby Tigerbiten » 8 Dec 2018, 3:11pm

Look up "Bolt Circle Diameter" for the correct distances.
Sheldon Brown's BCD crib sheet -> https://www.sheldonbrown.com/cribsheet-bcd.html

Luck ..... :D

thirdcrank
Posts: 27237
Joined: 9 Jan 2007, 2:44pm

Re: chain rings

Postby thirdcrank » 8 Dec 2018, 3:31pm

It's the same size as TA 5 pin as in Cyclotouriste equipment and also the adaptor (in your lowest pic.) as used with Stronglight 49D. Even standard sizes are now in rocking horse doodah territory. AFAIK, larger sizes like sixty teeth were only ever made to special order.

lotus 30
Posts: 38
Joined: 13 Mar 2017, 4:26pm

Re: chain rings

Postby lotus 30 » 8 Dec 2018, 4:12pm

Thank you people something to work with now. Merry christmas andy

thirdcrank
Posts: 27237
Joined: 9 Jan 2007, 2:44pm

Re: chain rings

Postby thirdcrank » 8 Dec 2018, 5:14pm

As a bit of a blast from the past, here's a compilation of some old TA ads.

http://www.classiclightweights.co.uk/co ... -comp.html

Of course, chain wheels wear out. Perhaps your main hope is that as devotees of older kit get older, they switch to lower gears: there may be more big rings surviving than smaller ones.
===============================================================

PS I see Hilary Stone has a 5pin Cyclotouriste outer with 57 teeth for £45. (Scroll down on this page.)

http://hilarystone.com/chainringstacyclotourist.html

User avatar
Mick F
Spambuster
Posts: 43213
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: chain rings

Postby Mick F » 9 Dec 2018, 7:14am

I have a 61t on my Moulton bought from Spa.
https://www.spacycles.co.uk/m2b0s113p17 ... -outer-61t
Mick F. Cornwall

lotus 30
Posts: 38
Joined: 13 Mar 2017, 4:26pm

Re: chain rings

Postby lotus 30 » 9 Dec 2018, 11:38am

Thanks for that link to SPA and thank you for the link to Hillary stone

fastpedaller
Posts: 1635
Joined: 10 Jul 2014, 1:12pm
Location: Norfolk

Re: chain rings

Postby fastpedaller » 9 Dec 2018, 1:28pm

What's the project? A small -wheeled bike, or an E-Bike ...... Or do you just have VERY strong legs? :lol:

User avatar
gaz
Posts: 13188
Joined: 9 Mar 2007, 12:09pm
Location: Kent, car park of England

Re: chain rings

Postby gaz » 9 Dec 2018, 2:16pm

Commercial adapter to 110 or 130BCD. I cannot confirm compatibility with a Williams Ab77 and I have no knowledge of availablility of suitable chainrings in either modern BCD.

lotus 30
Posts: 38
Joined: 13 Mar 2017, 4:26pm

Re: chain rings

Postby lotus 30 » 10 Dec 2018, 10:39am

fastpedaller wrote:What's the project? A small -wheeled bike, or an E-Bike ...... Or do you just have VERY strong legs? :lol:

Ha ha Its a Moulton special i have got a five speed sturmey archer hub i have built it into a new rim my first wheel build un assisted. i have machined some cogs and got two of them on the hub. and i have made an adapter for twin chainring on an old williams cotter-pin crank set. I have tested and it works fitted two sturmey archer bar end 3 speed levers. to operate the 5 speed. i shall fit twin levers on the down tube for the front changer and rear mech. I have got a period Benelux super sixty rear mech. so i will have a 20 speed touring moulton. Got to find a front changer yet i will prob go for another Benelux. Or a cheep campag.
IMG_3001.JPG
IMG_3001.JPG
IMG_2998.JPG
IMG_2997.JPG
20180509_141034.jpg

lotus 30
Posts: 38
Joined: 13 Mar 2017, 4:26pm

Re: chain rings

Postby lotus 30 » 10 Dec 2018, 10:44am

gaz wrote:Commercial adapter to 110 or 130BCD. I cannot confirm compatibility with a Williams Ab77 and I have no knowledge of availablility of suitable chainrings in either modern BCD.

That looks interesting chain set but i am ok for them i have kept mine from the 1960's when i was a school boy time trialist.
DSCN1931.jpg

andrew_s
Posts: 4541
Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: chain rings

Postby andrew_s » 10 Dec 2018, 11:03am

There are a couple of people making modern versions of the 49D/Cyclotourist chainset (e.g. Velo Orange, SunXCD), so new, off the shelf, chainrings and bolts aren't very difficult to find.

The main difference between the new versions and the originals is that there's a bigger gap between outer chainring and crank arm, so that the crank arm doesn't prevent modern, wider, front mechs from moving far enough to shift onto the big chainring.
This could also be a problem with your Williams chainset.

Long term , provided that it fits, using standard 110 or 130 bcd chainrings with a 5-arm SunXCD spider is likely to be cheaper than using 6-bolt 49D pattern chainrings.