Best replacement MTB gear train ???

[ncutler]

I have an ancient ( 1995 ish ) hard-at-both-ends MTB and I'm thinking of using it during the winter as it might cope with the deteriorating surfaces on our local lanes better than my Hewitt Chiltern ( see: viewtopic.php?p=1796784#p1796784 ). Although I am still tempted by a gravel bike it does feel like a rather indulgent extravagance.

The MTB is generally fine except for its transmission. It's only 7-speed ( which is actually ok for me as I'm always in the wrong gear anyway so having only 7 of 'em could be seen as an asset ) but just about all of it is sloppy and worn out and needs replacing.

So I'd appreciate the collective wisdom of The Forum. Low gears for hills are more important than speed, I quite like the idea of a single chainwheel but is that stupid ?

[PT1029]

Just to set the scene, is the chain set/chain rings worn as well?
If you go over 7 speed, you will need to replace the rear wheel to fit 8 or more spockets on the wheel. If the wheels are still good wheels, I'd stick to 7 for now. In 7 speed, 11-28t cassettes easily available, 11-32 available, but not quite as widely available as the 28t variety.
If you go greater than 7, you'll need new levers, if you are on cantilever brakes, you may/may not have to go to V brakes, depending what levers you buy/are avainlable (I am assuming combined brake/gear levers).
If the gear levers are separate from the brake levers, the brake issue is a non issue.
Also check the rims for brake wear (assuming rim brakes).
While at it, check if the BB/HS are still smooth.

It is worth adding up likely costs (wheel,BB/HS etc), if you are paying a shop to do the work, costs mount up very quickly, and the gravel bike becomes a more financially justifiable option.

[djnotts]

IMO/E 3 X 7 is fine. Not all 7 speed free-hubs limited to 7 - e.g some STX hubs will take 7 or 8, according to model number.
Source a pair of 7 speed index/friction thumbies c. £50 and run whatever you want at rear.
Best way to replace worn drive train etc is a mint early '90s complete donor bike - around 120 quid mark. They do exist.
One in my garage if you're near Nottingham!

[UpWrong]

Does the rear wheel use a a freewheel or a cassette? What crankset, FD and rings does it have?

[Cadence]

Just be aware that a mid-90's 7 speed may have a screw-on freewheel rather than a freehub and cassette. You probably have a 14-28T freewheel at the moment. 7 speed freewheels are available in several combinations that would give you lower gearing for hill climbing, 14-32T and 14-34T being most popular. You might need to fit a longer cage derailleur for a 34T, but might possibly get away with the existing one for 32T - a photo would help. You will need a new, longer chain.
A single chainwheel is OK, but for hill climbing you'd be better off with a 42T rather than 46 or48T. You might already have one - again a photo would help!

[Nearholmer]

If it is only 1x7, rather than 2x or 3x, the range of gears is going to be very limited, so a lot hinges on how long/steep the hills are round your way, and how fit/strong you are.

These days, I like to have a climbing gear close to 1:1 on the road (maybe not quite that low with 26” wheels and modest tyres), and noticeably below 1:1 for off-road climbs, because although it isn’t very hilly overall round here, we have some very sharp 200ft climbs, and when I go down to Sussex there are some 600ft steeps (forty years ago I could do them in ‘top’; no longer!).

So, on 1x7, with 32 largest cog at the back, I’d probably go for a 32T chainring, which would leave a rather annoyingly low top gear (I personally reckon 4:1 is really the lowest sensible top gear).

Personally, with a 1x, I’d want more than 7 gears. I got on fine with 11, 10 would probably be alright, and 12 or 13 is luxury. But, I doubt you’ve got the width for that.

[slowster]

I think it is heavily dependent on exactly what needs replacing, and on your requirements as regards gear range and intervals etc.

- Is it a freewheel or cassette, and is the hub spacing 135mm?

- Exactly which items are worn out and must be replaced? The chain, cassette and cables are presumably a given, but what about:

rear derailleur
chainring(s)
shifters
bottom bracket
front derailleur

- What are the current chainring teeth sizes and what is the cassette/freewheel range?

[Norman H]

Not what you asked for I know, but thinking outside the box, how about an Alfine 8/11? IHGs are generally low maintenance and work well on a winter bike.
If you want more gear range you might also consider a Sturmey Archer RF3?

[rareposter]

Depends a lot on how much the bike is worth and what needs changing, what you want to change, how much you're willing to spend and what gears you currently use/want/need.

Also how much of the rest of the bike is in need of new parts. Some bikes, especially ones of that vintage, start to require other new bits if you change one thing.

New chainset for example will 99.9% require a new BB.
If you go for more than 7 sp cassette, that'll need new shifters and (probably) mechs...

Etc.

It can get costly and if the bike isn't worth a lot, there are questions of economics...

[peetee]

It’s still possible to buy a 44/32/22 crankset and 11-32 cassette in 3x7 gearing. Any rear Shimano mech up to 9 speed ( currently Altus/Alivio/Tourney) will work along with a Tourney front mech.
If you are prepared to consider used parts then the choice is much wider.

[Jupestar]

Change as little as possible to get it moving and if it works as a winter hack, upgrade and amend as required.

7x3 drive trains (which I assume it is, are cheap enough to replace)

[freiston]

I have a 3x6 hybrid of a similar vintage (so probably quite similar to your mountain bike). The freewheel on mine has a silly jump between 1st and 2nd (24 to 34T - Shimano Mega Range - stupid idea) and I find this so much of a cadence killer that I just don't use it and limit myself to 5 speed and spend more time towards the top end of the block when on the little chain ring rather than run out of gears and accidentally go into 1st on the middle chainring.

So I started looking for 6 or 7 speed freewheels with 34T but without a big jump between 1st and 2nd. I didn't have much look at all. Smallest jump that I found was 28 to 34 (cheap Sunrace 7 speed that gets bad reviews for having excess play as far as I could tell).

I don't have any hill that I can't manage when I use that bike (It's for commuting/utility use) and so I've decided to keep things as they are and keep the expenditure down but if anything gets to the stage of needing replacing, I will try to keep it simple and replace the freewheel otherwise I reckon it'll be a new wheel (frame/wheel is 135mm OLD) and a conversion to 9 speed cassette, keeping the 28/38/48 chainset if possible and getting the ratios that I want (but knowing my luck, the BB will go first and the chainset be well and truly bonded on). My reckoning is that if I do end up having to do it all, I can do it on a budget and will still spend less than on replacing the bike - but until/if then, I will carry on with a cheap but functional bike.

[gregoryoftours]

Please post photos of the bike and parts in question

[Manc33]

I found 9-Speed to be the sweet spot, with a specific cassette (CS-HG200-9 in the 11-32t variant). Look at the jumps on that cassette and you'll see why (11-13-15-17-19-21-24-28-32t). It's unique in that regard and as far as I know is the only 11-32t Shimano cassette still available new, in 9-Speed, without a gear jump from either 18-21t or 17-20t. The exact spot you don't want a big jump.

Nothing's cheap anymore. Everything's doubled or tripled in price compared to 5 years ago. If you buy it all used you can probably get something like Deore shifters for £20, XT M772 rear mech at auction for around £20, that cassette I mentioned is £20, a new KMC 9.93 chain the same, £20. By the time you add it all up it's probably more than the bike is worth (no offence).

[Greystoke]

I have a similar age MTB converted to drop bar tourer.
It's a 15 speed so only 5 on the back.
I have 14-28 on the back and 44-40-24 chainrings.
Top 2 chainrings almost split the ratios in half leaving 24 chainring for serious hill duty.
From memory I now have 13 gear ratios.
It's super robust, everything's easily serviced and cheap to replace