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PostPosted: Sun Aug 02, 2020 10:27 pm 
Newbie

Joined: Sun Aug 02, 2020 9:45 pm
Posts: 5
Hi All,

Completely new here so really hope I'm in the right place.

I have a bespoke muddy fox mountain bike purchased 2nd hand from the MF bike designer at the time (1996 ish). He designed the light aluminium frame for his girlfriend at the time, they were upgrading so I bought it with all Shimano Deore XT parts and purple trim detailing, bespoke. I love this bike soooo much! So Its now over 20 years old and even though I love it, I haven't taken care of it properly. It got heavy use in the first 3 years, then not much, and for the past 10 its been pulling my kids about in trailers and what not, so not really heavy doing the school run. I have replaced virtually nothing. It has always had a problem with the gears as the rear derailleur has a short cage and I do not think compatible with my chain set. The crank/bottom bracket also creaks. Over the last couple of years my chain has snapped a couple of times and because I've had slack I simply rejoined but this meant I couldn't get into a few gears, damaging my rear derailleur further.

Anyway lock downs here and I really would like to sort out my bike but really do not know where to start. The original chain died (HG-78) so I did buy a new one (HG-40) but now that's constantly slipping so I know I have a few issues, and its now dangerous to ride. Before the chain died the gears did change nicely but now I have a new chain I feel more components need to be changed. I'd just like to get it to a reasonable state, all gears working, no chain slip. Please help with what I can/need to get compatibility etc

Here is what I've got, let me know if I need to tell you other bits I have?

Parts as original all Deore XT throughout,
Deore XT chainset - triple SG C-46, C-36, C-24 - This middle chain ring is very shark like, others ok. On the small ring the chain has little tension, do I even need this ring as its rare I use it? should I just replace the middle chain ring? (110BCD 5 hole btw)
Bottom bracket - tried to get this off but very ceased on and does creak. I can accept this just staying put and me working around the creak by closing my ears.
Deore XT FC M730 - crank arms 270 long
7 speed HG 12-28T rear sprockets (can't see an actually model number) - middle gears probably sharkie, should this be replaced...with what? (Shimano HG41 7 Speed Cassette or something better or could a larger # speed fit in there?)
Deore XT RD M735 - Cage a bit battered but does work.
Gripshifters - I know people hate them but they still work ok to.

Is it worth trying to get a long cage rear derailleur to go with my chain set, what would work that is silver finish? Or change the chain set to a double and keep my rear derailleur? Or both?

I love my retro look its all chrome/silver finish and would like new purchases to be like this finish too. Any suggestions would be greatly appreciated.

Carski


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 Post subject: Re:
PostPosted: Mon Aug 03, 2020 10:38 am 
Dirt Disciple

Joined: Sun Aug 29, 2010 6:33 pm
Posts: 28
Hi, From what you have said above the reason for you gearing issues is a new chain on, by the sounds on it, a very worn cassette and chainrings. Two options really fit a new cassette and chainring(s) or put the old chain back on. As for running it 2x should be no problem with a 28 cassette and short cage rear mech. When I was fit, a long time ago now, I removed the smallest chainring on my Fat Chance as I didnt need it. Just use the front derailleur limit screws to stop the derailleur swinging all the way back. The same theory will work for the big ring as well. On my trials bike the outer ring was replaced with a bash guard and just ran the small and middle rings.


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 Post subject: Re:
PostPosted: Mon Aug 03, 2020 4:25 pm 
Newbie

Joined: Sun Aug 02, 2020 9:45 pm
Posts: 5
original chain is dead. I'm sure I need a new cassette and chain rings as the minimum...but its where you go with it.

I know the whole thing could be upgraded and changed but I'd quite like to keep it original as possible..., keep costs down and while functionally working well. I really need help with compatibility.

If someone can suggest a 7 speed cassette and middle and outer chain rings as a minimum, that would be great.

Second, can I go to a double at the front (I have a square tapered bottom bracket which I doubt I'll be able to get off) and something larger at the back...I really don't know about compatibility with what I have existing. (rear wheel I think is freehub system), any pointers/suggestions would be great.

Thanks again


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 Post subject: Re:
PostPosted: Mon Aug 03, 2020 4:40 pm 
Newbie

Joined: Sun Aug 02, 2020 9:45 pm
Posts: 5
also would really like anything new going on to be chrome/silver colour. As whole bike is this colour, pic attached.


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 Post subject: Re:
PostPosted: Mon Aug 03, 2020 5:40 pm 
Old School Hero
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Joined: Thu Apr 02, 2015 9:18 am
Posts: 175
Location: Sheffield
Just a thought about the chain slipping - is it too narrow? I'm afraid I don't know what all the shimano chains are, but as freewheel blocks got more cogs on them they got narrower. A later chain may be designed for narrower cogs, which could be why it isn't engaging properly.
Really nice bike, though.


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 Post subject: Re:
PostPosted: Mon Aug 03, 2020 6:01 pm 
Newbie

Joined: Sun Aug 02, 2020 9:45 pm
Posts: 5
umm that could be one of the issues...I asked my husband to get a new chain and he got a HG-40 but I looked yesterday and I had a HG-71 on there :facepalm: . Website that I can buy from says the HG71 is 'Hyperglide (HG) series 7- or 8-speed compatible chain, recommended for 1995 and earlier Deore LX / STX-RC and 1999 and earlier 105 drivetrains'. So that could be what I really need!

Who knew chains can be so different! But this then leads me to another question...if this chain works, I will then have an issue with my rear derailleur having a short cage. So is there a long cage 7-speed rear derailleur with a chrome finish out there? Ebay, seconds is fine I just need to know the model number. Plastic rubbish, I'm not interested.


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 Post subject: Re:
PostPosted: Mon Aug 03, 2020 6:13 pm 
Old School Hero
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Joined: Thu Apr 02, 2015 9:18 am
Posts: 175
Location: Sheffield
Deore XT mechs came in long and short cage versions. It sounds like you need the long cage version


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PostPosted: Fri Aug 07, 2020 10:32 pm 
Dirt Disciple

Joined: Sun Aug 29, 2010 6:33 pm
Posts: 28
7 speed cassette then Decathlon is a good bet if you are not worried about it being exactly the same looks wise as the original.

https://www.decathlon.co.uk/12x28-7-spe ... 29145.html


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PostPosted: Fri Aug 07, 2020 11:45 pm 
Old School GrandMaster | Rider
Old School GrandMaster | Rider
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Joined: Thu Nov 26, 2015 7:29 pm
Posts: 7365
Location: peak district
Hi, and welcome to the site :)

Just a few things to hopefully help out, im sure others will be along to help out too.

The chain you bought is a Hyper glide, that's the HG bit. There are a few reasons a new chain can slip, some new chains have stiff links so worth checking that, also if the rear cassette or the front chainrings are worn, which it sounds like they may be, then that is a good candidate for a slipping chain. You can still buy HG cassettes new from around £15 upwards. If you are wanting larger gears at the back then you will need a longer caged mech. You could sell the short cage rear and buy a longer one. You can always put a wanted ad up on here, or ask if anyone has one they would like to swap for a short cage even. There are altenatives to shimano as well but personally i feel you have a good setup already so its just a case of swapping some of the worn parts.

The other thing i would sort is the creaking bb, could be just the cranks need tightneing up slightly but worth sorting out.


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 Post subject: Re:
PostPosted: Sat Aug 08, 2020 9:33 am 
Newbie

Joined: Sun Aug 02, 2020 9:45 pm
Posts: 5
Thanks for replying, I decided that I really like how this bike has functioned over 20years so I thought I'd reply with nearly new parts of the time after extensive searching on mainly ebay. I've bought the chainset, cassette and long cage rear derailleur. Most is in very good condition so pretty expensive but figured I'd sell my parts.
As for the BB, I originally just wanted to get it out and clean the item but there is no give in there at all to tighten or loosen, any ideas anyone?


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