Retrobike Forum Index

It is currently Mon Dec 05, 2016 1:37 pm

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 21 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
 Post subject:
PostPosted: Thu Apr 16, 2009 7:52 am 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8204
Location: New Forest, UK
No this is the whole point!:roll:
The freehub body isn't longer.
Because 6 speed has the cogs further apart, a 6s cassette fits in exactly the same space as a seven. There has never been a different freehub body length for 6s or 7s. The only difference is that uniglisde ones fitted the cassette with a screw-on smallest cog, whereas the later hyperglide (7s and up) ones had a lockring. By the time HG came out, UG was obsolete so there were no HG 6s cassettes made. So you have a 7s freehub with a custom made 6s hyperglide cassette.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 16, 2009 9:09 am 
Retro Guru
User avatar

Joined: Sun Mar 09, 2008 7:43 pm
Posts: 557
That's an interesting setup.

Pics of the different freehubs here, along with compatibility:
http://www.sheldonbrown.com/k7.html


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 16, 2009 12:37 pm 
Retro Guru

Joined: Sun Dec 14, 2008 2:11 pm
Posts: 303
hamster wrote:
No this is the whole point!:roll:
The freehub body isn't longer.
Because 6 speed has the cogs further apart, a 6s cassette fits in exactly the same space as a seven. There has never been a different freehub body length for 6s or 7s. The only difference is that uniglisde ones fitted the cassette with a screw-on smallest cog, whereas the later hyperglide (7s and up) ones had a lockring. By the time HG came out, UG was obsolete so there were no HG 6s cassettes made. So you have a 7s freehub with a custom made 6s hyperglide cassette.


Which would be convenient were it true. From your measurements a seven speed cassette will measure up at 31.85mm outside edge to inside edge, a six will measure 28.35mm, assuming a 1.85mm sprocket thickness. Lets call it a 3mm difference, which is curiously enough the same as the difference between a 7 and an 8 IIRC. To fit a 7 speed to an 8 speed body you need a 3mm spacer. Shimano only got wise to keeping the casette width the same when they moved from eight to nine speed.

There is no additional spacer on my setup.

Furthermore sprockets 5 & 6 have built in spacers so if they came from a seven speed unit they would need additional spacers to index properly, they do not have additional spacers and they do index correctly. Obviously number six can't have come from a UG set because it's not threaded, it's splined. Converting from splined to threaded wouldn't be too hard, the other way wouldn't be so easy.

Shimano did make quite a few parts that were only ever available to OE manufacturers, not retail. Among them were cassettes with unusual combinations of sprockets. Maybe this is another of those strange items available only to OE? Maybe it made sense to some manufacturers.

I don't know what bike this was originally intended for as it's not the original wheel.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 16, 2009 12:47 pm 
King of the Skip Monkeys
King of the Skip Monkeys
User avatar

Joined: Wed Nov 07, 2007 4:34 pm
Posts: 26157
Location: Moomin Valley
this is a perfectly formed genuine 6spd cassette freehub...


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 16, 2009 12:59 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8204
Location: New Forest, UK
For uniglide there always had to be a bit of extra on the outboard end of the freehub for the smallest cog to screw onto before it got tight. That's the difference between the two cog stack heights.

Shimano's floating jockey wheel patent does absorb a lot of inaccuracies, and the first click (from gears 6-5) also has a slightly longer pull, designed to pick up cable slack.

The only other thing I can think of is that somebody filed down the end of the freehub body to ensure the lockring then went tight.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 16, 2009 1:15 pm 
King of the Skip Monkeys
King of the Skip Monkeys
User avatar

Joined: Wed Nov 07, 2007 4:34 pm
Posts: 26157
Location: Moomin Valley
hamster wrote:
For uniglide there always had to be a bit of extra on the outboard end of the freehub for the smallest cog to screw onto before it got tight. That's the difference between the two cog stack heights.

Shimano's floating jockey wheel patent does absorb a lot of inaccuracies, and the first click (from gears 6-5) also has a slightly longer pull, designed to pick up cable slack.

The only other thing I can think of is that somebody filed down the end of the freehub body to ensure the lockring then went tight.



Why?? then re- tap the thread?? ITS A 6SPD FREEHUB

accept it

it exists

low end groupsets had all manner of weird shit - dont let worry you...

javascript:emoticon(':wink:')
:wink: :wink:


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 16, 2009 1:43 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8204
Location: New Forest, UK
No need to shout.

I was just trying to puzzle it out.

I'm sorry that my contributing to a forum offends.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 16, 2009 1:54 pm 
King of the Skip Monkeys
King of the Skip Monkeys
User avatar

Joined: Wed Nov 07, 2007 4:34 pm
Posts: 26157
Location: Moomin Valley
hamster wrote:
No need to shout.

I was just trying to puzzle it out.

I'm sorry that my contributing to a forum offends.


Nope - re-read my post, definitely nothing stating 'contributing to forum offends' written anywhere even when using Google Chrome as a internet browser that seem to go ape at spellchecking...

and used LOADS of shouty things like: :wink: :wink: :wink:


:D


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 16, 2009 3:08 pm 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8204
Location: New Forest, UK
It's just so ODD! (me shouting now)

Usually the tat cheap stuff seemed to use freewheels and didn't bother with freehubs at all.

Mind, there are a lot of STX hubs around with 130mm spacing, I guess for hybrids. I've been stuffed by that one on ebay before.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Apr 19, 2009 11:54 pm 
Retro Guru

Joined: Sun Dec 14, 2008 2:11 pm
Posts: 303
It sure is odd, but it's definitely as it came out of the box. You can tell that the freeehub body hasn't been tampered with, and for all it's filth it doesn't appear that the cassette has been messed with either. Either way it would be far too much work to convert low end seven speed to a six, much easier just to stick with seven sprockets and change the shifters. I could see it being worth the trouble if it was a high end group, but Altus? Nah.

It is a curious thing, but if you search all sorts of forums for content on six speed cassettes there's always somebody on there willing to swear that they are not genuine.

Anyway I'm intending to keep it as an oddity, unless it turns out to be worth money (which I strongly doubt) in which case it's going on the bay. :wink:


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 21 posts ]  Go to page Previous  1, 2, 3  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: CBguy, markyp and 13 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