Retrobike Forum Index

It is currently Tue Nov 20, 2018 11:50 pm

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 7 posts ] 
Author Message
 Post subject: Calculating SS set up
PostPosted: Wed Jul 18, 2018 7:38 am 
Retro Guru

Joined: Tue Jun 03, 2008 4:31 pm
Posts: 794
Decided not to clip this on to the SS/Fixed thread that's going as I'll end up with an answer to fry my brain.
Is there a method/crib sheet that would allow me to work out what sprockets I need to SS a bike without trial and error? too lazy to keep swapping stuff and to tight to buy just to find out it's wrong.

I guess this would involve the chain stay length plus teeth on freewheel and chain set. I cannot visualise maths in my head so need pretty pictures or charts to look at and colour in.

Why? Bike I want to convert has vertical dropouts and fiddly alloy inserts for mech hangers so no filing.


Top
 Profile  
 
 Post subject: Re:
PostPosted: Wed Jul 18, 2018 8:01 am 
Retro Guru

Joined: Wed Dec 10, 2008 9:19 am
Posts: 2388
Location: Sheffield, top city
I'm not sure there is a formula.... or at least not an easy one for the layman.

Just a case of a magic gear (ie luck) given vertical dropouts, unless you have an eccentric bottom bracket.

A half link chain might help with fine tuning


Top
 Profile  
 
PostPosted: Wed Jul 18, 2018 8:05 am 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 9211
Location: New Forest, UK
Are you trying to get a magic gear?
See here: http://www.63xc.com/toddp/halflink.htm

But beware, as the chain wears you will need a tensioner or else the flappy chian risks un-shipping, which isn't terrific fun.
I've been riding singlespeed off road for 10 years and all this magic gear stuff always seemed too fiddly. In the end I swapped to a frame with horizontal dropouts and eliminated the tensioner.


Top
 Profile  
 
 Post subject: Re:
PostPosted: Wed Jul 18, 2018 8:45 am 
Retro Guru
User avatar

Joined: Mon Sep 24, 2012 9:10 pm
Posts: 1047
The whole point of the 'magic gear' is to avoid fitting the ugly chain tensioner. OK if you are prepared to fit a new chain every month.


Vertical dropouts really are a way of saying: "F@*k you, single speeders!"


Top
 Profile  
 
 Post subject: Re:
PostPosted: Wed Jul 18, 2018 10:15 am 
Retro Guru

Joined: Tue Feb 02, 2010 6:11 pm
Posts: 2113
Location: wellingborough
This is worth a look at http://www.bikecalc.com/gear_inches


Top
 Profile  
 
 Post subject: Re:
PostPosted: Wed Jul 18, 2018 11:00 pm 
Retro Guru
User avatar

Joined: Thu Jun 23, 2011 11:25 pm
Posts: 2071
Location: It's not easy being a dolphin.
Ages ago I saw and used a formula based on chainstay length which put you in the ball park if your preferred gear would probably work or not.

Practically though, measuring the
chainstay accurately is one thing, then buying stuff is still hit and miss due to manufacturing tolerances and varitions of wear if you will use
an old chain / chainring / sprocket.

Having a chsinstay a fraction too long is the best because you can file a flat (2mm at the very most)on the rear wheel axle to allow a
new chain to initially bed in.


Top
 Profile  
 
PostPosted: Thu Jul 19, 2018 11:34 am 
Retro Guru
User avatar

Joined: Thu May 17, 2012 11:04 am
Posts: 543
Location: manchester
http://www.sheldonbrown.com/singlespeed.html


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: Dale cannon, Erskine, Midlife, non-fixie, nonowt, Retro Spud and 18 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

About Us

Follow Retrobike

Other cool stuff

All content © 2005-2015 Retrobike unless otherwise stated.
Cookies Policy.
bikedeals - the best bike deals in one place
FatCOGS - Fat Chance Owner's Group

Powered by phpBB® Forum Software © phpBB Group