7 speed to 9 speed conversion for a Galaxy

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

Postby Brucey » 3 Feb 2014, 12:20am

Bowak wrote: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.


-yes, that is pretty much it. If you have a 7s cassette hub that is....

Just be sure of what you have now before you start buying new bits; see the relevant Sheldon Brown page (or check with your LBS, or post photos here) to identify cassette vs freewheel, type of cassette etc.

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

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

Postby Bowak » 3 Feb 2014, 12:33am

Cheers.

It's definitely a cassette hub so that's something.

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

Postby Grumbleweed » 3 Feb 2014, 7:52am

There are a few places online selling 9 speed freewheels that will index with sti no problem. if your wheel is dished for 7 speed it will take these narrow blocks no problem.

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531colin
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Re: 7 speed to 9 speed conversion for a Galaxy

Postby 531colin » 3 Feb 2014, 6:39pm

Grumbleweed wrote:There are a few places online selling 9 speed freewheels that will index with sti no problem. if your wheel is dished for 7 speed it will take these narrow blocks no problem.


A standard 8 or 9 cluster is around 3mm wider than a 7.
As Brucey says up-thread, if you discard one sprocket from a 9 cassette, the remaining 8 will fit a 7 speed hub. (If you discard one from an 8, it becomes a 7.....the spacing is comparable)

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

Postby Bowak » 3 Feb 2014, 6:57pm

Thanks for the help. I think I'll probably go for a new rear wheel when I buy the other parts. It'll put the cost up a bit but not excessively so.

Just to check that I'm not missing anything else blindingly obvious:

1. If I change the front derailleur I need to check if my current one's top or bottom pull for the cable routing.

2. The rear derailleur will need to be long cage to cope with a 32t or 34t cog.

3. I'll need a new 9s chain.

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

Postby Brucey » 3 Feb 2014, 7:13pm

apologies if any of this is B.obvious but

-an 8/9/10s wheel's hub will usually be wider than a 7s wheel's hub (or the same width and a bit more dished, i.e. weaker) so you may well have to spring the frame slightly.

- the front mech will need to be the correct swing, the correct clamp diameter, the correct capacity, and the correct pull ratio (in shimano, road or MTN depending on which index shifters you want to use, but friction will do either).

- not all long cage rear mechs have the same capacity; check to be sure.

- yup you will need a 9s chain.

Before you shell out for a new wheel, ask yourself if you really are going to use the topmost gear or not with the new setup. If the answer is 'no' or 'not often' ( it will probably be a stupidly high gear that you will only use going downhill, if ever) then you may as well go with the 8-from-9 approach. You can always do something different later on if you want to; a decent quality 'keeper' wheel would be the most expensive item for most people.

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, 7:35pm

No worries about potential obviousness. My bike maintenance knowledge largely comes from the common everyday things that need doing such as tube/tyre/brake block replacement. I'm determined from now on to start learning how to replace/fix the rest of the parts, partly for cost savings but mainly out of wanting to understand my bike better.

I've measured the rear dropouts to be 135mm so from what I've read I think the frame should be fine. I'm also 90% sure that the bike was 8s when I bought it, but I had the gearing changed early on to make it more suited to flat commuting so my memory might be playing tricks.

For the front arm, if I buy a Deore derailleur to go with a Deore crankset will that be fine, or do I need to measure the tube diameter to get the right clamp size?

I hit my top gear often enough that I'd like to keep it or something similar. Whilst I mainly commute on hilly ground and I'm changing my gearing to be suitable for touring, a couple of times a month I end up on fairly long stretches of flat between Durham & Newcastle or Middlesbrough and whichever direction gives me wind assistance that day leaves me spinning out in top for a few miles. If I went for the full 9 my top gear would change from 50-12 to 44-11 which is a small enough change.

That said , it can't hurt to try 8 from 9 first to see what I think and also get some practice in at messing around with the cassette.

Another reason why I like the idea of changing the back wheel when I do this is that nearly all of the major parts (wheels, gearing, saddle) would then be under a year old and while not cheap, it'd still be significantly cheaper than a brand new tourer. As I have a 64cm frame I don't have much choice in potential replacements so I'm maybe prepared to spend a bit more than others for as long as my current frame remains sound.

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

Postby cycleruk » 3 Feb 2014, 7:49pm

You say that the bike may have been 8 speed originally?
Then, unless something has been changed the 9 speed cassette should fit.
If you need to use a spacer with the 7 speed cassette then yes it should also take 8/9/10 speed cassettes.
There's no such thing as a tailwind.
It's either a headwind, or you're going well.

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

Postby Brucey » 3 Feb 2014, 7:58pm

personally I'd be tempted to stick with the 50T big ring but each to his own, eh? Is the present chainset worn out? If the chainring teeth look even as worn as very worn sprockets they usually still work OK.

You do need to measure the mech clamp diameter and make sure it will fit your frame; there are several possible diameters and most shimano mechs are made in two or three different sizes, sometimes achieved using a shim but not always. You should in any event get a mech that matches your big ring size and the chainline you are running. In total there are at least ten or twelve defining parameters for a front mech.

If you presently have a 'road' triple and you convert to a MTN triple you may find that your 'Q' value increases by 10mm or more, because the cranks may have a larger offset and the chainline goes outwards several mm. This is annoying enough for me that I won't willingly use a MTN triple unless it is the only thing that will fit a frame. My favourite triple setup has a Q value that is ~40mm less than a typical MTN triple. Again this doesn't trouble everyone in the same way.

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, 8:20pm

cycleruk wrote:You say that the bike may have been 8 speed originally?
Then, unless something has been changed the 9 speed cassette should fit.
If you need to use a spacer with the 7 speed cassette then yes it should also take 8/9/10 speed cassettes.


Well the wheel and cassette have been replaced more than once, with the last time happening together.

I've just done a bit of googling, then looked at the wheel but I can't tell. The bike's going into the shop on Wednesday though to get a rounded off seat post nut removed so I'll ask them then.

Bowak
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Joined: 18 May 2013, 6:45pm

Re: 7 speed to 9 speed conversion for a Galaxy

Postby Bowak » 3 Feb 2014, 8:27pm

Brucey wrote:personally I'd be tempted to stick with the 50T big ring but each to his own, eh? Is the present chainset worn out? If the chainring teeth look even as worn as very worn sprockets they usually still work OK.
cheers


The chainset's not gone yet, but the front's starting to show some wear and it's just geared too high for me to use for loaded touring in the hills. It's about right for my current hilly commute with just that day's clothes to carry in.

What I am considering once I've turned it back into a full-on touring setup is using it to take in a week's worth of clothes on a Monday, and then buying a road bike for the other days. If I add a couple of miles to my trip I can avoid the worst of the hills that I'd struggle on and hopefully enjoy having a nippier bike.

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

Postby cycleruk » 4 Feb 2014, 9:40am

Bowak wrote:I've just done a bit of googling, then looked at the wheel but I can't tell. The bike's going into the shop on Wednesday though to get a rounded off seat post nut removed so I'll ask them then.


Can you get a hacksaw blade in the gap of the clamp to cut the bolt in half?
There's no such thing as a tailwind.
It's either a headwind, or you're going well.

Bowak
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Joined: 18 May 2013, 6:45pm

Re: 7 speed to 9 speed conversion for a Galaxy

Postby Bowak » 22 Mar 2014, 6:13pm

I did eventually use a hacksaw, but I still had to get the shop to drill half of it out.

I've completed the conversion/re-vamp of my bike to 9 speed this week, so I thought I'd post a couple of pictures of the finished work. I eventually went for 44-32-22 up front and 11-32 at the rear. It's only been a few days but I really like having a much more even range through the gears whereas as a 7 speed it had 2 big gaps for the lowest cogs. My top gear is only fractionally below my previous top one so it's effectively the same on the rare occasion I need a gear that high.

Thank you to everyone who provided advice in this thread, and also in a couple of others relating to frame rust and precisely what front wheel to get:

http://imgur.com/I0sosaA & http://imgur.com/087Evam

This bike's had an awful lot replaced in the last year and I'm treating it as a sort-of-new bike. In the last year it's had new:

front & rear wheels,
front & rear racks,
pedals,
saddle,
entire drivetrain except for the shifters - they're currently in friction mode only, but I will probably go for slightly wider handlebars in the next year so I'll keep an eye on sales and consider picking up Dura Ace 9 speed bar ends to give me the option for index shifting.

Overall I've spent about £500 on parts and work and it'll hopefully keep me from looking at brand new bikes for a few months at least :D