7/8 speed conversion

[Ajax Bay]

How about a picture of the Xtracycle @Andy in Germany

 

[si_c]

The length of cable means you have less leeway to get the indexing right, especially as it has to go through all manner of bends to get to the rear mech, and there's that bit more to stretch. It's a slight niggle with a longtail such as this. I should use a tandem cable really, but I discovered after a previous outbreak of poor organisation that a regular cable fits -just.

Aha, having never used either a tandem or a workcycle, I didn't know this. Good to know

 

[Andy in Germany]

How about a picture of the Xtracycle @Andy in Germany

@Ajax Bay I keep trying: it says it is loading but seems to get bored and stop. I blog on www.workbike.wordpress.com and you'll find pictures in there if you look...

 

[Blue Hills]

I always did have the idea that 8 speed chains lasted a tad longer than 9 speed. Isn't there also the issue that maybe an 8 speed chain is stressed a tad less as it is only moving side to side across 8 sprockets? If you choose to shoot me down, please be kind.

One thing i think is definitely the case - with 8 rather than 9, or god forbid 10 or 11, you will be fiddling with/reajusting your gears less once it's all set up. And you surely don't wznt, or need, a ferrari for your application.

 

[Andy in Germany]

How about a picture of the Xtracycle @Andy in Germany

HH_15 by Andy in Germany, on Flickr

 

[Andy in Germany]

Coming back to this queation: am I ight in thinking that if I change a 7 speed cassette to an eight speed, I need a new hub for the cassette to sit on?

I changed summer and winter wheels recently and I'm getting slippage in the top two gears, which makes me think the chain is worn. From experience that means a new cassette as well, so it seems a good moment to move to an eight speed cassette.

 

[Ajax Bay]

am I ight in thinking that if I change a 7 speed cassette to an eight speed, I need a new hub for the cassette to sit on?

Yes, you are ight. Assuming freehub is Hyperglide (one of the splines narrower) -
AASHTA
"Shimano Freehub Cassette Systems (and copies)
In general, all Shimano Cassette Freehubs will work with all Shimano cassettes, any number of speeds [up to 10]. There are a very few exceptions:

• 7-speed hubs won't normally accept 8-, 9- or 10 speed cassettes without modification. Click here for details.
• 7-speed cassettes fit fine on 8- and 9-speed (and most 10-speed) hubs if you put a 4.5 mm spacer onto the body before the cassette. Click here for details."

 

[chriscross1966]

Suntour's last stand was a 7-speed indexed down-tube system. It wasn't possible to upgrade this using Shimano or Campagnolo shifters because the pull ratios are different. But as long as you have same-same up front and on the derailer, then you are OK, it will work.
Everything remained compatible until Shimano's 10-speed Dyna-sys mountain groups came around. Then you again could not mix and match, which means you cannot use a road shifter with a MTB derailer and vice versa.

Campagnolo rear mechanism shift ratio (on the mech, not the cluster) stayed the same (at 1.5x pull IIRC) all the way from their early days up into the early 9-speeds, then changed (can't remember what to though)... that was around 2000, They might have changed again at 11. Weirdly if you fit a late 9 or a 10-speed Campy indexing shifter to an earlier derailleur it will work if you use a Shimano cluster appropriate to the shifter... Also if you ar etrying to mix and match speed ranges and component makers look at the JTEK Shiftmates and also the Hubub technique of changing the pull-ratio on Shimano mechs...