Retrobike Forum Index

It is currently Wed Dec 07, 2016 9:55 pm

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 9 posts ] 
Author Message
 Post subject: 6 speed to 7 speed?
PostPosted: Fri Oct 04, 2013 8:25 am 
Retro Guru
User avatar

Joined: Tue Oct 16, 2012 9:45 am
Posts: 324
I have recently revamped an old Raleigh Equipe and it has had it's maiden journey on a 307 mile touring holiday to the TDF over the summer.

As with many people of this parish, I seem condemned to keep making upgrades wherever possible! After all, the job is never really finished it?!

Anyways, it's currently running a rather splendid 6 speed mega range freewheel at the back but I am tempted to see if it will stretch to a 7 speed? Does anyone know if this is possible without having to carry out some bending of the rear triangle? Or should it just slot in without much trouble?

My current shifters and rear mech are the original bog standard mid-80s indexed affair but they are crisp and very accurate and have given me no trouble whatsoever, which was a blessing on a lengthy touring holiday.

Any advice would be gratefully received!


Top
 Profile  
 
 Post subject: Re: 6 speed to 7 speed?
PostPosted: Fri Oct 04, 2013 9:18 am 
King of the Skip Monkeys
King of the Skip Monkeys
User avatar

Joined: Wed Nov 07, 2007 4:34 pm
Posts: 26174
Location: Moomin Valley
if there is room on the axle, a 7spd may fit but the last cog may also foul the stays


Top
 Profile  
 
 Post subject: Re: 6 speed to 7 speed?
PostPosted: Fri Oct 04, 2013 9:59 am 
Old School Hero
User avatar

Joined: Tue Jan 31, 2012 11:54 am
Posts: 157
Location: Cambridge, UK
Being a steel frame, if the rear drop-outs are too narrow then they will easily be persuaded to spread out a little to accommodate the wider rear axle.

You might find that the axle on the back wheel will also need an additional spacer on it so that the 7th sprocket doesn't foul the frame.

However, if you've got an indexed system that's working nicely, then you may find that the biggest problem is that it's a 6-speed indexed system which, simply put, doesn't have a 7th click to enable you to get that 7th ratio.

TBH, I don't really get the importance of 'upgrading' by one gear because the range of ratios is the key thing - if the large sprocket on the freewheel gives you a low enough gear and the smallest one enables you to maintain the top speed you're after then an extra ratio between those is unlikely to make all that much practical difference.


Top
 Profile  
 
 Post subject: Re: 6 speed to 7 speed?
PostPosted: Fri Oct 04, 2013 10:08 am 
Retro Guru

Joined: Sun Aug 07, 2011 10:55 am
Posts: 2920
Location: Dorset
I agree with S1m0nR, I have a Raleigh Clubman of 1985 vintage and I researched the gearing as above, I was struggling on the hillier climbs with the 13-24T 6 speed, I was lucky enough to locate a 14-28T 6 speed as a direct replacement and this has made hills easier.

It depends on the reason behind wanting the extra gear of a 7 speed as there are things that can be done to the setup you have already :)


Top
 Profile  
 
 Post subject: Re: 6 speed to 7 speed?
PostPosted: Fri Oct 04, 2013 3:01 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8212
Location: New Forest, UK
S1m0nR wrote:
However, if you've got an indexed system that's working nicely, then you may find that the biggest problem is that it's a 6-speed indexed system which, simply put, doesn't have a 7th click to enable you to get that 7th ratio.


It's more than that: 6 and 7 use a different sprocket pitch (5.5mm for 6, 5.0mm for 7) so the shifters are completely incompatible.

In the end, this upgrade-itis can lead you to refit the entire bike with 11-speed Campag Record, in which case you might as well buy a new bike anyway.


Top
 Profile  
 
 Post subject: Re: 6 speed to 7 speed?
PostPosted: Fri Oct 04, 2013 5:29 pm 
Old School Hero
User avatar

Joined: Tue Jan 31, 2012 11:54 am
Posts: 157
Location: Cambridge, UK
Oh, interesting - that's one of the reasons I read this forum. That pitch difference explains why I could never get my Mrs's bike's gears to index properly when I put a 6 speed freewheel on a 7 speed SIS system.

Cheers for the info.

So it's a resounding 'no' - leave the Equipe as it is, but if the ratios aren't to your liking just change the freewheel to one with as many speeds but different ratios, oh and make sure it's compatible with the indexed system...


Top
 Profile  
 
 Post subject: Re: 6 speed to 7 speed?
PostPosted: Fri Oct 04, 2013 10:00 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8212
Location: New Forest, UK
That's a pretty good summary. Alternatively, switch off the indexing on the lever - it'll work fine! People seem to have a perception that shifting is impossible without indexing these days. :roll:


Top
 Profile  
 
 Post subject: Re: 6 speed to 7 speed?
PostPosted: Fri Oct 04, 2013 10:08 pm 
Retro Guru

Joined: Sun Aug 07, 2011 10:55 am
Posts: 2920
Location: Dorset
hamster wrote:
That's a pretty good summary. Alternatively, switch off the indexing on the lever - it'll work fine! People seem to have a perception that shifting is impossible without indexing these days. :roll:


I ride non-indexed 8)


Top
 Profile  
 
 Post subject: Re: 6 speed to 7 speed?
PostPosted: Sat Oct 05, 2013 5:29 am 
Old School Grand Master
User avatar

Joined: Sat Oct 06, 2012 5:17 pm
Posts: 3775
Location: Norn Iron
MOrning,

There is an easy option (IMHO) - source an Ultra 7sp FW - it fits in the same space as a normal 6sp FW. You will have to go with friction shifting though - easy peasey!!!

Richard


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: keithglos and 12 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