7 speed to 9 speed conversion for a Galaxy

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Bowak
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7 speed to 9 speed conversion for a Galaxy

Postby Bowak » 18 May 2013, 7:54pm

Hi,

I have a '97 Dawes Galaxy that will need a new cassette and replacement chain rings within the next year. I'm planning on taking advantage of this to change the ratios to better suit my current use. I've spent the last couple of weekends researching bits and pieces and I want to check that what I've come up with makes sense/doesn't have any glaring errors. I've done a search for RSX on the forum so I hope I'm not duplicating an existing thread.

The bike currently has RSX bar end shifters and derailleurs, front chain rings of 52-42-30 and a 7 speed rear cassette of 14-28.

This isn't the original gearing as I had larger chain rings added a few years ago when I was only using the bike for commuting on the flat. Even this setup is slightly lacking at the top end (as is to be expected for a tourer and something I can easily live with), but it noticeably requires an extra gear or two on the bottom for any hills whilst the panniers are loaded. I now live and commute in a hilly area and I'm planning some short tours in the Highlands in the near future.

I'm thinking of adding Deore chainset of 48-36-26 - FC M590, a 9 speed rear cassete of 11-32 - Shimano HG80 and of course a new 9 speed chain. This would give me extra range at the top and bottom, though I need to confirm that the useable gears on each chainring are right for me too. I'd replace the RSX bar end shifters with Dura Ace 9 speed bar ends. One bike shop I spoke to recommended Sora STIs but I can't see any particular advantage to them as I've been using bar ends for nearly a decade now so I'm used to them and they're £60 cheaper.

From what I've read I'd also need to replace the rear RSX derailleur which I'd use Deore for again. I don't know what the difference is between the Normal & Shadow variants. Is either more suited to a tourer? I haven't seen anything yet to suggest that the front would need replacing too as it's still a triple ring, but can anyone confirm this?

I've also seen it said that a 7 speed wheel isn't compatible with a 9 speed cassette. Is this a definite incompatibility or does it depend on certain factors and if so what are they? The rear dropout spacing is 135mm.

All in the parts should cost approximately £240ish at today's prices if a new wheel's needed. This seems a reasonable amount considering how much is being replaced and for a bike that does 3,000+ miles per year.

Any advice, pointing out of errors or suggestions for alternative parts would be most welcome.

Thank you, John.

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Redvee
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Redvee » 18 May 2013, 9:35pm

One way of reducing the cost could be to change the freehub and have the wheel redished.

Brucey
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Brucey » 18 May 2013, 9:38pm

135mm rear hubs fall into two main categories; 7s and 8/9/10s. A 7s freehub body has splined freehub length of ~31mm, and the other sort is 2-3mm longer than that. Just because you have 7 sprockets it doesn't mean you definitely have a 7s hub; it is possible to fit a 7s cassette to an 8s hub using a spacer to the left of the cassette.

If you have a 7s hub and don't want to splash out on a new wheel, you can fit 8 from 9 onto a 7s cassette hub, provided you get a cassette without a carrier and you are happy to remove rivets etc. Your existing rear mech should work with 9s, but it just won't work as well as a 9s one. The important thing is to get enough capacity in the rear mech for the range of gears you will have.

BTW if it isn't worn out yet, I'm not sure I'd necessarily upgrade to 9s; most folk can get a wide enough range, close enough together with a 3x7 setup. 9s stuff is going obsolete too.....

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Bowak
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Bowak » 18 May 2013, 10:14pm

Thanks for the information.

Just checking that when you say the spacer would be to the left of the cassette, is that with looking forwards? ie the spacer would be between the spokes and the cassette.

I have to admit I'd been looking at 9 speed after seeing what recent year's Galaxys have been geared with. I've just had a quick look and seen that it's only about £12 for a 12-32 7 speed cassette. For that price I have to give it a try and I'll discover soon enough if it provides the correct gears for both commuting and touring. My current chain's only a couple of months old so should be fine with it. It'll also give me a chance to finally use my cassette locking tool and it's always good to learn how to change another part.

If 9s are going the way of the dodo are they being replaced by 10s? I've seen 11s for sale too and it seems to be getting out of hand. How long until 15s are the in thing?!

Brucey
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Brucey » 19 May 2013, 6:28am

Bowak wrote:.....Just checking that when you say the spacer would be to the left of the cassette, is that with looking forwards? ie the spacer would be between the spokes and the cassette.....


yes that is right. IIRC the spacer will be about 3mm wide if you have one.

BTW if you have a 7s 135mm hub, the wheel will be noticably stronger than one with a similar 8s 135mm hub, because of the reduced dish.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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Erudin
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Erudin » 19 May 2013, 7:37am

On my Surly LHT build I used Shimano Deore M590 9spd components originally with 7 speed downtube shifters/cassette/chain, and more recently with 9 speed bar-end shifters on Retroshift levers and 9spd chain/HG50 cassette.

I went for a 48/36/26 M590 triple chainset and changed the inner chainring to 22 teeth for a wide range of gears that works on/off-road. With a 32-11 cassette the 26t inner still gives a good low gear. The only problem I've had is the original bottom bracket bearings felt rough from new and died after a few weeks, but since replacing them facing the bb I've had no problems.

To be honest the 9 speed upgrade did not add much apart from a wider availability of cassette choices. I'd recommend getting the matching M590/M591 front and rear mechs, I've had no issues with gear shifting such as chain unshipping even on rough tracks off-road on Dartmoor.

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Sweep
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Sweep » 19 May 2013, 9:27am

Bowak wrote: I've just had a quick look and seen that it's only about £12 for a 12-32 7 speed cassette.


Can I ask where that is?

I have a 7 speed bike hybrid/cum tourer and am always on the look-out for sources of 7-speed bits - getting to be a bit of search these days.

Currently have an 11-28 on the back which with a 22T granny ring gets me up most hills unloaded - more of a struggle with a full load at times.
Sweep

Bowak
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Bowak » 19 May 2013, 10:30am

Here's the 12-32: http://www.tredz.co.uk/.Shimano-HG20-7- ... _43086.htm

and here's a whole set of options, of which the 13-34 is probably the most suited for me: http://www.rosebikes.co.uk/article/shim ... tAodmFkAxQ

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meic
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby meic » 19 May 2013, 11:12am

I don't know what the difference is between the Normal & Shadow variants.


The shadow variants have a different design which means that they dont stick out as much to avoid getting torn off on MTB trails but more importantly they can take rear cassettes with more teeth on the largest sprocket (ie 36 teeth) the non-shadow ones can not go as far and it is best to check if they can take a 13-34 before buying them or the cassette.

As an aside, personally I would stick with the seven speed and when the front chainrings need replacing, I would get a narrower range cassette (12-32, 12-30, 12-28) and smaller front chainrings.
You can fit a 24 tooth inner ring on your chainset which will make it unnecessary to have the large gaps between gears that for example a 13-34 will give with only 7 cogs.

Note if you keep your 7 speed freehub not all of then can use cassettes with 11 teeth sprockets on them anyway.
Yma o Hyd

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georgew
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby georgew » 19 May 2013, 11:23am

If you do go with the Shadow variant then note that they do not have the cable adjuster usually found on other models. This means you will need an adjuster on the Gear lever itself.

Bowak
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Bowak » 19 May 2013, 11:35am

Thanks very much for all the advice here. I've been persuaded to stick with 7 speed for now.

One last thought I've had - I still plan on getting the smaller chain rings, which has made me think if it might be a good idea to have two separate cassettes for commuting and touring. Say just for example while this idea's fresh in my head, a 12-28 and a 12-32. I'd only be likely to take the bike out fully loaded with camping gear 2 - 4 times a year, so it's not as if I'd be changing them round too often, or would repeated changing increase the risk of damage making it more sensible to just have a second back wheel with the touring cassette on?

Presumably in this scenario it'd also make sense to have a second chain so the cassette and chain wear together?

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Erudin
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Erudin » 19 May 2013, 12:24pm

I've had no problems changing cassettes over, I do this to clean/inspect them or for different gear ratios, each cassette has its own chain for wear purposes and chain length difference.

Bowak
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Bowak » 2 Feb 2014, 11:22pm

I'm back to thinking that 9 speed 11-32 with 44-32-22 chainrings is the way to go for me, almost certainly Deore.

I want to stick with bar end shifters and know that I can get Dura Ace in 9 speed. My question is is there any reason why my current RSX 7 speed shifters won't work in friction mode? Presumably a 9 speed cassette still has to fit in the same width on the hub so it'd be shorter gaps between gears and not a longer cable pull overall? If so, this would be fine with me as I've been using friction shifting for most of the last 16 years.

I've managed to find enough posts on other forums that show 9 speed friction bar ends work fine with a 7 speed cassette, but no luck for the other way round.

If I have to get the 9 speed shifters it's not the end of the world, just 1 more month of saving before the upgrade :-)

Brucey
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Brucey » 2 Feb 2014, 11:40pm

you probably need to do a bit more research;

FYI;

a) a 9s cassette won't fit a 7s hub. You need an 8s hub for this (same as 9s and many 10s in fact)

b) Barring cable mount mods etc, 9s shifters will only work a 7s system properly in friction mode. [ If you look hard enough you can find any flavour of B.S. you like on t'interweb...].

c) almost any friction shifter will work almost any system. The exceptions are when you run out of cable pull with some lever/mech combinations. I think your proposed setup will work OK.

To address a) think about an 8-from-9 cassette. Just remove one of the sprockets from a 9s cassette. Many 9s cassettes can lose the (fairly useless) 11T sprocket and then use a different lockring to secure the (usually) 12T cog you are left with.

cheers
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Bowak
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby Bowak » 3 Feb 2014, 12:13am

Just to be sure, are you saying I could make a 9s cassette fit on my 7 s hub by removing one of the cogs to make it 8s, or would I need to get a new rear wheel with a more modern hub?

I'm glad to see that my current shifters should hopefully be ok.

There's definitely a lot more to take into account than I thought there would be when I started seriously considering making changes to my bike.