Suntour 6sp/7sp block
- Thread starter DaveyA
- Start date
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raleighnut
Legendary Member
- Location
- One of the 'Elite'
It depends if you have room on the hub.
mjr
Comfy armchair to one person & a plank to the next
- Location
- mostly Norfolk, sometimes Somerset
If it's an ultra6 then no, but I think otherwise usually yes if the wheel is dished for 7 - I think you can tell if there's space between the end of the sprockets and the frame (I think that's what @raleighnut is saying). Both regular 6 and 7 are 126mm OLN IIRC.
raleighnut
Legendary Member
- Location
- One of the 'Elite'
Ajax Bay
Guru
- Location
- East Devon
We have to assume the wheel is not dished for 7, though.
Sheldon offers dimensions to inform any decision. The 7sp block would be 2.4mm wider. This would not fit on my 6sp wheel: it would screw on but not fit between the dropouts.
raleighnut
Legendary Member
- Location
- One of the 'Elite'
I think it's whether the hub is a 5-6 or a 6-7, I've shuffled axle spacers around on hubs to get clearance but it either means getting the wheel 're-dished' or as in my case ('s) rebuilding the hubs to get new rims laced on ( I love Maillard 'wide flange' hubs)
mjr
Comfy armchair to one person & a plank to the next
- Location
- mostly Norfolk, sometimes Somerset
Why do we? It might be. My 5 speed wheel took a regular 6... although I had to reshuffle a rack-mounting bolt to clear the chain.
Ajax Bay
Guru
- Location
- East Devon
Well you don't have to, but most trying to give good advice will, because the OP says:
Why would an old wheel be dished for 7sp yet have a 6sp fitted?
Most old style 5sp blocks can be successfully replaced by a regular 6sp as the distance between the small sprocket and the dropout allows this - as you discovered (reported above).
mjr
Comfy armchair to one person & a plank to the next
- Location
- mostly Norfolk, sometimes Somerset
Well, why would an old wheel be ready for 6sp yet have a 5sp fitted? Yet that's what I had, the rear dropouts were 126mm (6sp) not 120mm (5sp or old SA AW) and I understand that's not so unusual. Looking at the thing is probably the best way.
mjr
Comfy armchair to one person & a plank to the next
- Location
- mostly Norfolk, sometimes Somerset
Other way round: if you had ultra 6 already, a 7 speed probably wouldn't be an option. Ultra 6 fits in the space of a regular 5 speed. http://www.sheldonbrown.com/gloss_u-v.html#ultra
Ajax Bay
Guru
- Location
- East Devon
The OP's freewheel has a 6sp fitted.
With a 126mm OLN a 'bog standard' 6sp block can be screwed on instead of a 5sp with no complications so quite likely the block has been replaced at some time, given it is of a certain age. As I said upthread there is space (with a 126mm OLN) for the extra 2.4mm block width (5 > 6sp): you don't need an 'ultra' 6sp block (to replace the 5sp) unless the OLN is 120mm.
