Cycling UK Forum

Hi,
I'm looking for a 6 speed freewheel block for use with vintage Campagnolo friction bar end levers. I'd like a 14,16,18,20,22 & 24 block but can only find this spread of sprocket sizes in an indexed block. What are the difficulties I may find if I use an indexed block? I presume both types use a 3/32" chain.
Many Thanks... Alex

I am usually wrong but ..... i thought the derailleur was indexed not the block ?
Do indexed blocks have a different gap between the gear cogs than non indexed ?

BITD some six speed blocks were "compact" with narrower spacing than you'll find on a current indexed block.

If you are running a "compact" you may need to redish or respace your wheel to run an indexed block.

Aside from that, nothing to worry about.

I only remember a very old Shimano derailleur that would have the indexing right there, pretty much everything else would have the indexing in the shifter. The block is not exactly "indexed".
And I cannot recall many indexed 6 speed shifters, perhaps some thumb-shifters?

I won't advise to spend time faffing around with cog spacing, etc. to match an indexed shifter, especially if the existing one does not have missing parts. No reason to replace it, IMO.

Btw, I've not tried with a 6sp block, but I've always had great results using the venerable Campagnolo C9 chain with 7sp Maillard and Regina blocks, either friction or indexed it works very well indeed, even if it's formerly a 9sp chain.

landsurfer wrote:I am usually wrong but ..... i thought the derailleur was indexed not the block ?
Do indexed blocks have a different gap between the gear cogs than non indexed ?

The blocks I've been looking at on ebay are described as indexed or non-indexed. I think the indexed ones have some machining on the teeth to help the chain to shift but I don't know if the spacing is the same or not, or if they need a different chain.
Cheers... Alex

1942alexander wrote:

landsurfer wrote:I am usually wrong but ..... i thought the derailleur was indexed not the block ?
Do indexed blocks have a different gap between the gear cogs than non indexed ?

The blocks I've been looking at on ebay are described as indexed or non-indexed. I think the indexed ones have some machining on the teeth to help the chain to shift but I don't know if the spacing is the same or not, or if they need a different chain.
Cheers... Alex

I don't think that can be called "indexing", rather a "tooth profile" and that is made to -arguably- improve the shifting whether you will use and indexed shifter or a friction one.
Maillard used to make the "split tooth", while Shimano did the "twisted tooth". I'm not sure if any of them would really improve the shifting, but the shape of the Maillard sprockets makes a very nice noise with the Campagnolo chains

Thanks for clearing that up, Gattonero.
Much obliged... Alex

Blocks or freewheels are produced with spacers between the cogs to equal the amount of shift produced by the index levers and derailleur and will differ for different number of gears and for different manufacturers, even though there is the same spacing for certain gears, eg Campag 7 and 8 are the same spacing. Freewheels produced for non index gears, could have different spacer width between the cogs and will work with any derailleur, or non index levers.
I do not know, if there was a reason for the random width of spacers, or was it just the way the cogs fitted together .
As far as I know tooth profile is there to make the changes smoother, but the cogs wear out quicker from my experience.

I've got a couple of pairs of black indexed 6 speed DT levers. One set came off a late Raleigh Sprint. Shimano I think.

When indexing was in its formative years the purpose of the various tooth profiles was to encourage the chain to engage with the sprockets rather than to skate along the top of the teeth. IIRC Shimano's twisted teeth were known as Uniglide. The teeth were all of a uniform shape and height.

A short time into the development of indexing Shimano introduded Hyperglide. Teeth were of different heights and shapes with ramps in the sides to improve shifting.

Current indexed freewheels use the Hyperglide style. Whilst many are budget items quality models are also available. Current non-indexed freewheels will likely have full height teeth, no ramps and are mostly aimed at the bottom of the market.

1942alexander wrote:... What are the difficulties I may find if I use an indexed block? ...

I think the answer is "none." (OTOH, the other way round, the indexing might not work.)

Thanks to you all for the replies. I'm buying what they describe as an "indexed 6 speed 14/24 freewheel" and will update if any problems are found.
Cheers... Alex

I think you will be fine but there are a few things to note;

1) a standard 6s (5.5mm pitch) freewheel will only fit to a 126mm hub (or wider) if the wheel is dished in the usual way. If you have a 120mm spaced hub then you would need to default to a 5s freewheel or a now-rare 'compact' ('ultra' in suntour-ese) 6s freewheel. The latter has basically the same sprocket spacing (~5mm pitch) as 7s and 8s systems.

2) If you have a 126mm rear hub, arguably you may as well fit a 7s freewheel. These fit into the same space as a standard 6s more or less.

3) If you use a standard spaced 6s freewheel pretty much any 3/32" chain (up to ~9s rated) will work OK. If you use a compact 6s (or 7s) freewheel then you need to use chain that is 7s, 8s or 9s rated. Not that they are very common these days but 'standard 3/32" chains' won't work on 7s systems (or compact 6s).

BTW Uniglide evolved over the years; I don't know when this feature first appeared, but the final versions had one or two short, untwisted teeth on every sprocket bar the smallest one.



This was presumably intended to help the shifting performance and hinted at the way ahead with hyperglide. I quite liked uniglide sprockets; in their original incarnation they could be reversed so that you could get double the wear out of them.

cheers

Hi,
Not sure about the rear cogs but that feature was called "W" cut on the chain wheels.

Rear derailleur indexing was called "Positive shift mechanism" an notched plate which coincided with the cog spacing, you felt a notched resistance in the DT lever. early eighties, just before SIS.

http://velobase.com/ViewComponent.aspx? ... 7&Enum=108

1942alexander wrote:Hi,
I'm looking for a 6 speed freewheel block for use with vintage Campagnolo friction bar end levers.. What are the difficulties I may find if I use an indexed block?

None.

With friction levers you can use any mech and any block, just about.
Possible problems are that the lever might not pull enough cable for a wider 8/9/10/11 block, so you could lose top or bottom, or that with 10/11 you would change too many sprockets until you had re-educated your fingers. If you are swapping 6 for indexed 6, there won't be any problem.