The extra click

[Captain Stupido]

I've currently got 4 retro steeds in action, all of which (rightly or wrongly) are set up with older Deore thumbshifters.

The oldest two bikes (a late 80s Dawes and a 1992 Orange clockwork) are very happy in a 6 and 7 speed setup respectively as originally intended.

My two newest bikes, a 1997 Clockwork and a 2000 Kona Hahanna also both have 7 speed thumbies, set up with 7 speed wheels/cassettes. For the time being they work just fine BUT, I have a surplus of wheels so could easily set them up as 8 speed - which seems more appropriate for the era of bike...

What are peoples views on utilising the extra click or no? Is having an extra cog worthwhile or does sticking with 7 make for more reliable shifting? I'm not sure I've ever tried squeezing an extra gear out of my favourite shifters...

 

[ishaw]

Re:

It isn't really an extra click, more shifting past the last official click. Works fine, I had xt 7 speed thumb shifters running nicely on 8 speed m739 running gear.

 

[legrandefromage]

Suntour xc pro thumbies are nicerer and propererere 8 spd

 

[Dr Dremel]

Re:

Yes, but Suntour has different spacing between cogs. I don´t know if they would work on a Shimano drivetrain.

I have an M900 drivetrain with 732 thumbies working flawlessly. This is on a Kona Explosif were this setup was stock. But I read in other posts that some struggle to get all the gears working.

The 8th detent in the shifter mechanism is really just a hole for a return spring. It does not have the EXACT same distance from the 7th gear detent as between the "official" detents for gears 1-7, but Shimano (at least Deore/XT/XTR) upper derailleur pulley bushings have a little play built in which accounts for that.

However I never thought to convert my other 7sp thumb shifter bikes to 8sp, plenty of gears to choose from. I can understand the urge to be PC, but I guess in 1997 there were no thumb shifters stock on any new bike either.

 

[Chris D]

Re:

Just do as I do. Run them across a nine speed cassette on friction

 

[legrandefromage]

7spd and 8spd shimano are 5mm and 4.8mm, it does get messy if not set perfectly.

Suntour is identical depending on cassette type. 5mm and 4.8

Shimano thumbies are set for the 7spd 5mm cassette spacing .Suntour would be set for the 8spd 4.8mm spacing.

 

[Dr Dremel]

I see. Looks like I accidentally set up the Kona perfectly then It is indeed my best shifting bike.

 

[Captain Stupido]

Thanks guys. Inclined to feel that reliable, perfect shifting 7 speed is probably better than clunky 8. 3x7 is more than enough anyway... And perfect setup is fine, but then, some margin for wear and error is probably more useful in the real world.

I think I'll just use the nicest/lightest wheels I have and see what happens. I think the Kona was 7 speed from new even though it's 2000. Low end tat.

 

[shedobits]

Re:

If you can climb OK with your 7 speed cassettes then there is no need for the expense of lower 8 speed cassettes. Any way what was ever wrong with clunky?

 

[ultrazenith]

I've been using 7 speed shimano thumbshifters with 8 speed cassettes for years and the shifting is fine, nearly perfect. The difference in spacing between a 7 and 8 speed cassette is only 4%, which means if the middle cog is perfectly indexed, then in the worst case of of the smallest and largest cogs, the misalignment between the indexing and the cog will be something like 15-20%, which ought to be well within the jockey wheel float.

I definitely need to try the 8 speed Suntour thumbshifters at some point