Deepcherry

I am looking at replacing the tired Acera X 3x7 mech on my 90s GT Outpost, whilst retaining a similar ‘range’ of the gearing I would like to simplify things and have a single chainring.

The bike is used for transport to and around our village, via a dirt road with a gradient, and some asphalt back roads.

High speeds are not necessary, so I feel that the large chainring is mainly redundant.
I use low gearing more due to the climb back home, using lowest and second gears.

I feel that with with these two low gears plus another 6-8 higher gears I would be happy.
Does it make practical sense, or am I dreaming?

Deepcherry

I am looking at replacing the tired Acera X 3x7 mech on my 90s GT Outpost, whilst retaining a similar ‘range’ of the gearing I would like to simplify things and have a single chainring.

The bike is used for transport to and around our village, via a dirt road with a gradient, and some asphalt back roads.

High speeds are not necessary, so I feel that the large chainring is mainly redundant.
I use low gearing more due to the climb back home, using lowest and second gears.

I feel that with with these two low gears plus another 6-8 higher gears I would be happy.
Does it make practical sense, or am I dreaming?

cb400bill

Duplicate threads merged.

dsbrantjr

Well, you will be hard-pressed to have a similar range of gearing, but if all you need is the low end it may be more practical. Here is a gear calculator which will let you compare your current and proposed drivetrains and see what you can do with a 1X system, and what you will be giving up: https://www.kstoerz.com/gearcalc/compare/

Retro Grouch 

How dissatisfied are you with your bike's current gearing?. I have no doubt you would be able to achieve the gearing range you think that you need with a 1 X 10. Have you priced out the components?

Deepcherry

Thanks for the comments.

By range I mean equivalent highest and lowest gears, but reducing drastically the number of gears between. I find 21 gears are unnecessary for the use.

I would err toward 3-4 low gears for the uphill, offroad use, and then three mid range for around the village which would still leave me 3-4 higher gears for roads. This of course depends also on how many sprockets I can get between the forks without changing the wheelset.

As I am a non-professional and require a simple, strong and capable runner/shopper, I am looking to reduce the bike down to the minimum.

I can of course use the bike as it is, whilst getting a feel for which gears are more useful, but that old mech is in need of a complete overhaul, and being a lower-grade (Acera) mech it is likely more practical to replace it.

Of course if I could find an excellent XTR mech set with 24 gears I might be tempted.

presently just looking at my options!

Thanks

xroadcharlie

Its probably a major job to convert to a 1 x 10 speed. Your current drivetrain can probably be repaired for a fraction of what converting it to a 1 x 10 speed. I find leaving my low end 3 x 7 on one chainring most of the time works perfectly and we can always switch if needed when it's operating correctly.

I'm sure it can be done but you might need new wheels (if you want them to match) to start to accommodate a much wider cassette, A new rear derailleur, cassette, crankset, and perhaps even a bottom bracket as well.

If I wanted simplicity I would replace the entire derailleur drivetrain with a 3 speed Internal hub. With the right chainring it might be fine for your needs, and a SO much simpler design, But still a major repair.

70sSanO

Sure you can change it. You may need a new rear wheel if your GT has a freewheel, (or a 7 speed freehub body), and you may want to buy a wheelset. I imagine it is 26” with 135mm rear dropout.

From there you need a 10 speed rear derailleur, cassette, shifters and whatever tooth chainring to put in the middle position of your triple crankset. For just tooling around on smooth roads you don’t need a narrow-wide chainring.

You might as well replace all the cables and housings and brake pads while you are at it.

John

fietsbob

I suggest the simplicity of an Internal gear hub for that application Nexus/Alfine 7 speed perhaps? Or spluge for the 11 speed..

Deepcherry

Good stuff.

I get the feeling that it almost seems pointless to change the mech in the name of practicality,
as obviously the most practical thing is to use “don’t touch if it ain’t broke” mentality.

I’ll see how well I can tweak it- I’m taking the advice of renewing the cables and changing the plastic twist-shifts to friction levers which I prefer.
..but that is another story

dsbrantjr

I am very much of the Never Fix A Running Piece school but going to friction will go a long way towards your desired simplicity. It is surprising how much improvement new cables can make.
It is going to be a real challenge to get the kind of range from a 1X system that you get from your current 3X, as you will see with a few minutes spent with the calculator I linked to before.

Retro Grouch 

You're probably overthinking the 21 gear thing.

Most of your riding is probably on relatively flat surfaces. If that's the case, keep your chain on the middle sprocket in front. If you think your feet are spinning too fast, shift the rear onto a harder gear. If you think it's too hard to pedal, shift they rear onto an easier gear.

You mentioned a climb on rides returning home. Shift into the smallest front sprocket just before the start of the hill. That's probably the only time you need it.

The big front sprocket is for riding fast downhills or for the twice a year when you have a strong tailwind.

70sSanO

I disagree. It’s your bike. If it has a tired drivetrain replace it. I had a double road bike I converted to a triple and triple mountain bikes I converted to doubles, but that was easy.

The only issue is the rear wheel as to whether it is a freewheel or if it can accept a 10 speed cassette. If not you’ll need another wheel. Microshift has their 1x10 Advent group, and all you need is a chainring in the center position.

A lot depends on the current condition of the bike and if you want to spend the money on it. It is always worth it if you like the bike, will enjoy it more, and you spend less than a new bike you’ll enjoy more, which are impossible to find.

None of my bikes are worth what I have put into them over the years, except to me and that is all that matters.

John

Miele Man

As another poster mentioned, changing to a 10 speed system involves a lot of changes and thus is expensive. Another thing is that use all ten cogs you'll probably need a new rear wheel and you'll most likely have to get the rear triangle cod set to a wider width to accept that 10 speed wheel and then you'd have to get the dropouts aligned so that they are parallel again so they don't break.

If it were me, I'd just buy a new 7-speed compatible rear derailleur. You should be able to find 7-speed index thumb shifters online and for a reasonable price. I like index shifting when pedaling up hills when I'm tired as there's far less risk of a missed shift. Some index thumb shifters have a little lever that allows them to be switched to friction mode.

There's a shop not to far out of town here that has 7-speed index/friction shifters for iirc $5.00 Canadian including the inner cable. they also have friction only Shimano thumb shifters for about $5.00 CDN a pair including the inner cables.

Cheers

cpach

So the most significant technical question regards your rear hub. If it has a freewheel, it's probably a no go without a new wheel. If it's spaced to 130mm, it's likely to be 7 speed specific. If it's spaced at 135mm, you can throw whatever you want on there.

I'd recommend finding what gears on your current setup you really need, and find out what that range really is using https://www.sheldonbrown.com/gear-calc.html . You may be able to get away with a relatively small single ring and a not especially wide range cassette, and use your current derailleur with a friction shifter to shift more gears, requiring just a new cassette, chain, and chainring. If you do go with a somewhat hacked up setup, I strongly recommend leaving your front derailleur in place as a chainguide or using a narrow/wide chainring, or both for the purposes of chain retention.

If you do go with relatively modern 1x, I hear good things about the newer Microshift Advent groups for the cost, though I haven't had my hands on them.

rosefarts

1x10 works great and provides plenty of range.

I wouldn't do it on a 20+ year old bike that wasn't all that great to begin with. Clean the bike up and replace cables and housing. If you've already got the friction shifters, do that at the same time.

That's the best you can do on for it.

If you had a high end bare frame from the same era, 1x10 is often an economical way to get the bike rolling.

dedhed

Also take into account the current bike part supply chain issues. Might not even be able to get all the parts you need to complete a project.
If not doing the work yourself, it may be months until a shop can perform the service

squirtdad

at lesat in the united states......how is it in Spain our of curiosity.

as for simplicity. put it the front in the center and using what you have is simple, no changes needed, with the benefit of being able to go lower or higher on the occasions that you need.

Deepcherry

Just as I am digesting the pros and cons I discover quite ‘by accident’ a detailed blog titled :
“How to convert a vintage mountain bike from a 3x7 to a 1x10 drivetrain” by ‘The Cyclopath’

Deepcherry

[QUOTE=squirtdad;21633107]at lesat in the united states......how is it in Spain our of curiosity.

Here is always a little trickier, but movement of goods between euro countries seems to be fine, so there is a good supply from France, UK and Germany.

70sSanO

The other option is to buy an 8-10 speed rear wheel with 135mm spacing; need to measure your dropout width. I’ve done 7 speed freehub body swap and there is not a guarantee that any freehub body will fit.

John