Retrobike Forum Index

It is currently Thu Dec 08, 2016 7:15 pm

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 7 posts ] 
Author Message
 Post subject: Eight of nine on seven
PostPosted: Sun Nov 02, 2008 11:12 pm 
Old School Grand Master
User avatar

Joined: Wed Feb 20, 2008 12:21 pm
Posts: 5785
Location: Lost in Translation
Rainy here yesterday, so I got me to fettlin'.

I want to put thumbshifters on my '92 Stumpjumper Comp.

Image

http://www.retrobike.co.uk/forum/viewto ... 2&start=30

I put the thumbies on, and they look very nice just sitting there on the bars, but they probably need to be connected to something. So, on with the mechs.

I'd planned to run 2x8 with eight ninths of a 9-speed 11-32 cassette, leaving the 11 off, and 42 29 at the front, friction shifting.

The rear hub's a Phil Wood cassette hub that came from eBay years ago. I've been running it with spacers and a single DX BMX sprocket since then, but I'd assumed it would take a 7-speed (and therefore eight ninths of a nine speed) cassette. It doesn't. The splines aren't quite long enough, and with the lockring snugged down, the 12 doesn't have any engagement.

Plan B: a dished Ritchey 33t 2x9 sprocket, then build up the rest of the cassette with loose sprockets. No go: the tolerances don't match, and the Ritchey sprocket won't fit the Phil hub.

So, what to do? I could use 7 8-speed sprockets, but I want the 12 and the 32, and that means bigger jumps than I'm happy with. I could go triple at the front, and run a 12-24 8-speed spaced 3x7, but I'd need a longer bottom bracket and I like the low Q of my 103mm WTB Greaseguard unit. I could probably get someone to machine a couple of millimetres off the back of the cassette spider, but the Mavic rear mech already comes pretty close to the spokes, and I'd rather not tempt fate. I could build up a new wheel with an old XT 7-speed hub, but I've got more than enough wheels kicking around, and the Phil suits the bike very well.

One idea that came to me is that maybe somebody makes a 12 and 14 tooth combo 9-speed double sprocket machined in one piece with splines running the full length of the unit. That would get me the spline engagement I need. Anyone ever heard of such a thing?

Any other ideas?


Top
 Profile  
 
 Post subject:
PostPosted: Mon Nov 03, 2008 8:38 am 
Gold Trader
Gold Trader
User avatar

Joined: Mon May 19, 2008 10:30 am
Posts: 1729
Location: colchester
possible surly do a combined cog? seem to remember summing like that...


Top
 Profile  
 
 Post subject:
PostPosted: Mon Nov 03, 2008 8:49 am 
Old School Grand Master
User avatar

Joined: Wed Feb 20, 2008 12:21 pm
Posts: 5785
Location: Lost in Translation
hoegaardenadds1 wrote:
possible surly do a combined cog? seem to remember summing like that...

On the right track, but the Dingle is threaded for track hubs:

http://www.surlybikes.com/new/dinlgecog_pop.html

What I really need is a splined 12-14 pair with 9-speed spacing, a full-length spline and a knurled face for the lockring. Asking too much?


Top
 Profile  
 
 Post subject:
PostPosted: Mon Nov 03, 2008 11:26 am 
Retro Guru
User avatar

Joined: Thu May 08, 2008 4:18 pm
Posts: 2336
What shifters are they? 'cos old XT/Deore ones won't work with nine-speed spacing anyway.


Top
 Profile  
 
 Post subject:
PostPosted: Mon Nov 03, 2008 12:31 pm 
Old School Grand Master
User avatar

Joined: Wed Feb 20, 2008 12:21 pm
Posts: 5785
Location: Lost in Translation
MikeD wrote:
What shifters are they? 'cos old XT/Deore ones won't work with nine-speed spacing anyway.

They're Deore II, that I planned to run as friction (as I wrote above). Are you saying that they won't reliably friction-shift 9-speed spacing, or just that they won't index?


Top
 Profile  
 
 Post subject:
PostPosted: Mon Nov 03, 2008 12:50 pm 
Retro Guru
User avatar

Joined: Thu May 08, 2008 4:18 pm
Posts: 2336
Oh aye, missed the friction bit :-) As you were...


Top
 Profile  
 
 Post subject:
PostPosted: Mon Nov 03, 2008 1:11 pm 
Old School Grand Master
User avatar

Joined: Wed Feb 20, 2008 12:21 pm
Posts: 5785
Location: Lost in Translation
No worries. There's always a set of Forge thumbies in the spares box if it comes to it.


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: Giom6, WandsworthRouleur and 41 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