UPGRADING to 8 speed

[nicmarsh]

As I have to get a new rear wheel for the 'winter' bike I thought it sensible to try and convert from the existing (screw on freewheel) 6 speed triple set up to 8 x 3. Existing parts feel well used, however I don't want to spend silly money as there are nicer projects lined up too!

I was considering:
1. Rear wheel built on new Tiagra hub
2. new 8 speed cassette and 8 speed chain (HG50 I think)
3. new Shimano 8 speed indexed downtube shifters
4. new long cage Deore rear derailleur

Any issues with this selection? Could consider upgrading front rings / derailleur too.....

[tim_f]

Why 8 speed rather than 9 speed ?

I would get a chain that uses a quick link rather than a Shimanio chain.

[bertbeerpot]

No issues, but how about nine-speed? You're going to be getting a new chain anyway, right?

Also, consider bar-end shifters? I just changed to bar-ends and find them very good. Not particularly cheap though.

[nicmarsh]

Why 8 speed rather than 9 speed ?

I would get a chain that uses a quick link rather than a Shimanio chain.

Point taken but I want to use downtube shifters, which I don't think I can get 9 spd indexed? Additionally will 9 spd chain be OK with existing chainrings if I don't replace them?

[fastpedaller]

At the moment you have 6 speed - is the OLN dimension 130mm?
Any chain will be ok on the front (if it's a triple it will be 3/32" rings)
I agree with your choice of 8 speed - I use 7 to get a stronger wheel, but the 7 speed are increasingly getting more difficult to source (especially as I like 'road' close ratio)
The industry pushing for more and more gears is something I don't like. If using a triple front, and carefully selecting the sprockets for the freewheel, most of us don't need many gears.
As an aside, if you do use bar end shifters these can be set to friction(rather than indexed), so it is possible to use them for other than 8 (but maybe not as convenient)

[531colin]

First question is why are you "upgrading"...?
With 8 speed cassettes, you can get lower gears, or higher gears, or both, or closer-ratio gears, if that's what you want.
You should get future spares availability, and less chance of bent/broken axles, if that's a problem.....but you might need to spread the dropouts, because a 8/9 speed freehub reduced to 126mm OLN builds an awfully-dished wheel.
You can get 9 speed indexed downtube shifters, and you can run an 8 speed chain on a 9 speed cassette (and also a 9 chain on an 8 cassette) , particularly running friction front shift, so no "trimming" issues.
You could keep an eye on cassette prices at Chain Reaction and Rose Versand, and buy a store of 8 speed cassettes, if you think they won't be made for long. (I think they will be available for a while.....if shimano stops manufacturing, I imagine SunRace will be rubbing their hands)

[531colin]

At the moment you have 6 speed - is the OLN dimension 130mm?
Any chain will be ok on the front (if it's a triple it will be 3/32" rings)
I agree with your choice of 8 speed - I use 7 to get a stronger wheel, but the 7 speed are increasingly getting more difficult to source (especially as I like 'road' close ratio)
The industry pushing for more and more gears is something I don't like. If using a triple front, and carefully selecting the sprockets for the freewheel, most of us don't need many gears.
As an aside, if you do use bar end shifters these can be set to friction(rather than indexed), so it is possible to use them for other than 8 (but maybe not as convenient)

Have a look here.....http://www.rosebikes.co.uk/products/bike-parts/cassettes/7-speed/7-speed/

[fastpedaller]

Thanks Colin - Yes difficult (but not impossible!) The last time I just got an 8 speed, and used the spacers off the old 7 speed - thus 'gaining' a spare 23 sprocket.

[531colin]

Thanks Colin - Yes difficult (but not impossible!) The last time I just got an 8 speed, and used the spacers off the old 7 speed - thus 'gaining' a spare 23 sprocket.

7 and 8 speed spacing is close enough to be interchangeable, if not exactly the same.....so you could just buy 8 speed and ditch a sprocket.

[[XAP]Bob]

You also could probably use existing d/t shifters in friction mode...

[nicmarsh]

The upgrade is brought about by needing a new rim AND a new freewheel, which would also mean a new chain.
I feel no desire for more gears, but switching to a free hub is to make the future easier; I've pretty much exhausted my own supply of screw on hubs and freewheels as I also use these on other bikes.
The frame is spaced @ 126 (steel) so will I probably start by springing the new wheel in at 130 and see how that hangs.
My main concern is will a new Tiagra hub be ok with 8 speed cassette ; the marketing men make you think you have to go 9/10 spd!
I don't mind replacing existing shifters as they are fairly worn and a little 'grumpy' at times anyway
I also run a bike with a 7 speed cassette so will take a look at stocking up on new cassettes there too!

[531colin]

8 and 9 speed cassettes are the same width.
You can fit a 7 speed cassette on a (8,9,10 speed) hub with a spacer.

[markfh]

Picking up a few points, two from the OPs posts and another from tim_f.

I use an 8 speed cassette on a Tiagra 4600 rear hub with no issues - its actually a SRAM 8 speed cassette cassette as I prefer the evenness of the ratios on their 12-26 8 speed cassette compared with Shimano's closest offering which appears to have at least one big step along the way.

Depending on the gear range and largest rear sprocket you want to run, you may want to consider a "road" rear dérailleur with a medium cage such as the Sora GS. It is nominally a 9 speed rear derailleur but I have been running one, all be it with friction down-tube shifters, for the last year with no issues and you may be able to get one for less than a deore unit.

Re tim_f's comments about using a chain with a link rather than a Shimano HG50, Chain Reaction currently have a KMC X8-93 8 speed chain (116 links) for £6.99 each. These normally come with a link but it might be worth checking with Chain Reaction as thier description does not specically mention a link although the (one) review does.

[nicmarsh]

thanks all for info

[nicmarsh]

re. a medium cage road derailleur , I see a Sora 9 speed can be had at reasonable price but there is little choice if looking particularly for 8 spd. (Claris)
Would I be OK with a 9 speed derailleur and 7/8 speed chain? I am wondering about jockey wheels.
I have already ordered the 7/8 spd chain (and 8 spd cassette) however I can always use the chain on another bike so it would not be a disaster to order a 9 speed chain but how would that fit with the 8 spd cassette?