Im thinking of coverting to a 1 x 12?

[AlanW]

First off, l'm wouldnt really class myself as a MTB rider anymore, l do the odd towpath ride every now again, or maybe a ride when it snows.
My current MTB is a Scott Scale 10, which l've had for donkeys years and in that time it's served me very well. Its a hard tail with Fox air forks and a carbon frame, all up weight less than 22lbs.
Back then l would have considered myself a MTB rider, albeit part time 😆
It's has full XTR group set and has a triple chainring and a nine speed cassette. Being a roadie, l never really warmed to the big gaps with a standard MTB cassette, so within days l had replaced the MTB cassette with road one, 12/25 to be precise. That cassette has remained on it for years, and l've never wanted anything lower. I ridden 10 x Hell of the North Cotswolds events over the years and found that gear combo just perfect.
So....fast forward to today.
I used my MTB last week on a 50 mile tow path ride, it was the first time in over two years since l'd ridden it!
While everything still functions exactly as it should, l did find the triple set up clunky and rather old fashioned. Which made me wonder that maybe upgrading to a 1 x 12 might encourage me to use it more often or am l just looking for excuses?
1 x 12 MTB group sets are pretty inexpensive really, and the chances are that selling the XTR groupset would go a long way to funding the exchange.
But in truth l don't know how l'd cope with the big jumps on the cassette. I think the norm for a 1 x 12 cassette is 10-51, so that's some mighty jumps as you go down the cassette!!
Just wondering, has anyone made that change and how did you get on?
I appreciate that everyone is different and everyone has there own riding style, just curious to understand others views really.

 

[AlanW]

 

[figbat]

Chances are you have an HG freehub so will only be able to get an 11 tooth minimum. I recently bought a SRAM 11-50T which will have slightly less of a gap than you’d envisioned (although still big jumps compared to a 3x9 with 12-25).

Your 3x9 will likely have a lot of overlap between the gears so the number of unique gears will be somewhat less than 27.

I have 1x gearing on 4 bikes; 3 MTBs and one gravel. In fact the gravel I converted from 3x7 to 1x10 (11-42) and one MTB I converted from 3x10 to 1x10 (11-46). The other two MTBs came as 1x12 as standard (one is 11-50, the other 10-50). I’m a big convert to 1x drivetrains and very rarely find myself looking for an ‘in-between’ gear.

 

[AlanW]

Useful info thanks. I did wonder as soon as l posted this about what size cassette l could put on the freehub. How well does the SRAM cassette work with the Simano groupset?
That said, from what l gather a 12 speed cassette probably won't fit on my freehub anyway.
Which means either going 1 x 11 or in truth l haven't ruled out going 2 x 11, the latter has to be better than 3 x 9 at least and would be more in line with road bike gearing.

 

[figbat]

I believe the SRAM NX Eagle 12-speed cassette may go on a regular HG freehub (please verify). Since you’re changing groupset then you can get the appropriate derailleur and shifters to go with.

 

[chriswoody]

Rear spacing is going to potentially be an issue, I expect you'll have the old 135mm spacing and wether 12 speed will fit on there I really don't know.

As for cassettes, as figbat mentions, 11 tooth cogs will be the smallest that a standard HG hub can take. That said, SRAM NX Eagle 12 speed cassettes, which are 11 - 50 tooth, capacity, also work on HG freehubs. I know that for a fact because my MTB runs NX Eagle.

If you want to go to 10 tooth cogs, then you'll either need a micro-spline hub (Shimano) or XD driver (SRAM)

With regard the jumps in teeth, it really is a non issue. The SRAM NX Eagle cassette for example has 11, 13, 15, 17, 19, 22, 25, 28, 32, 36, 42, 50 teeth. You'll notice at the smaller end of the cassette that the teeth only go up by 2 each time, then they start spacing out more as you reach the middle of the cassette. So for flat/road/canal path riding, there really will be no appreciable gaps. I often find that at the larger end of the cassette I'm changing up several gears at a time because of the steepness of the terrain or the roughness of the trail, so negating the jumps in teeth size.

I'm currently running SRAM NX Eagle 1x12 on my mountain bike and 1 x 11 SRAM Rival 1 on my gravel bike. I do find that the 1 x 11 is lacking in overall range, especially for the bikepacking trips I like to do. So I'll be converting the gravel to run 1 x 12 GX Eagle drivetrain in the spring.

 

[AlanW]

It would be great if it did, that's a fact!!

 

[AlanW]

Rear spacing is going to potentially be an issue, I expect you'll have the old 135mm spacing and wether 12 speed will fit on there I really don't know.

As for cassettes, as figbat mentions, 11 tooth cogs will be the smallest that a standard HG hub can take. That said, SRAM NX Eagle 12 speed cassettes, which are 11 - 50 tooth, capacity, also work on HG freehubs. I know that for a fact because my MTB runs NX Eagle.

If you want to go to 10 tooth cogs, then you'll either need a micro-spline hub (Shimano) or XD driver (SRAM)

With regard the jumps in teeth, it really is a non issue. The SRAM NX Eagle cassette for example has 11, 13, 15, 17, 19, 22, 25, 28, 32, 36, 42, 50 teeth. You'll notice at the smaller end of the cassette that the teeth only go up by 2 each time, then they start spacing out more as you reach the middle of the cassette. So for flat/road/canal path riding, there really will be no appreciable gaps. I often find t

hat at the larger end of the cassette I'm changing up several gears at a time because of the steepness of the terrain or the roughness of the trail, so negating the jumps in teeth size.

I'm currently running SRAM NX Eagle 1x12 on my mountain bike and 1 x 11 SRAM Rival 1 on my gravel bike. I do find that the 1 x 11 is lacking in overall range, especially for the bikepacking trips I like to do. So I'll be converting the gravel to run 1 x 12 GX Eagle drivetrain in the spring.

Brilliant info, many thanks! Yes my wheels are 135mm with QR axles but if the SRAM NX cassette fits then that's solved the immediate problem!

 

[chriswoody]

OK, threads like this always make me curious and eager to learn new things, so I went downstairs and whipped out the wheel of the Gravel bike. Turns out the rear spacing of my gravel bike is 135mm, I really thought it was wider, my wheel is quick release with disk brakes.

As I mentioned above I'm currently running 11 speed and will be upgrading to 12 speed in a couple of months, so yes, it appears you can run 12 speed in 135mm width dropouts.

 

[Ming the Merciless]

How about going 1 x 9? All the benefits you want with no upgrade issues.

 

[AlanW]

OK, threads like this always make me curious and eager to learn new things, so I went downstairs and whipped out the wheel of the Gravel bike. Turns out the rear spacing of my gravel bike is 135mm, I really thought it was wider, my wheel is quick release with disk brakes.

As I mentioned above I'm currently running 11 speed and will be upgrading to 12 speed in a couple of months, so yes, it appears you can run 12 speed in 135mm width dropouts.

Thanks again for you efforts in checking. Merlin Cycles while they don't have stock at the moment, the SRAM NX cassette is a lot cheaper than l expected it to be!

 

[AlanW]

How about going 1 x 9? All the benefits you want with no upgrade issues.

Even though lm more of a slogger than a spinner, l think a 1 x 9 would be a tough old ratio to cover all options.

 

[chriswoody]

How well does the SRAM cassette work with the Simano groupset?

Thinking a bit more about this, I'm pretty sure at 12 speed, apart from NX cassettes using the HG freehub, there is no cross compatibility between Shimano and SRAM. So if you want to use an NX cassette, you'll need to look to SRAM for the rest as well. As long as you don't currently have integrated brake/shifters, then you can happily go SRAM transmision and still keep your existing Shimano brake set up.

With 1x you will need the complete package if you want to have it all function properly and without the chain continually derailing.

So for the full conversion, if you decided to go with SRAM, you'd need an NX Eagle rear Derailleur and either NX or GX Eagle thumb shifters. With the front crankset you can go for NX Eagle Crankset, but then you'll need a SRAM DUB bottom bracket. (DUB bottom brackets will fit 73mm BSA bottom bracket shells, which I'm assuming you have). You could also go for another third party crankset, but then you'll need to make sure it has narrow/wide chainrings and is compatible with 12 speed. Third party cranksets do play nicely with SRAM Eagle parts, my gravel bike has a Race Face Aefect crankset for example.

You will need to think about chainlines as well, I don't know off of the top of my head what the chainline is for Eagle 12 speed, but you'll need to space out your BB to get the correct chainline for it all to work.

NX Eagle is a nice groupset though, I have it on my Mountain bike and find it gives good crisp gear changes. I've ridden that bike for a few thousand kilometers now as well as several big bikepacking trips, including the Scottish highlands and the Swiss Alps. In all that time I've been really happy with the gear ratios and never found myself wanting or needing more.

 

[AlanW]

Outstanding information 👏

That's tomorrow's task sorted. 🤣

On the plus side, l don't have integrated brake/shifters.....phew!

 

[All uphill]

My view?

It depends on how much you want something fashionable and how happy you are to spend.

I have a bike with 2 x 9 ( 44/28 and 11/34) and find it perfect for riding round lumpy West Somerset and Devon. 90% of my riding is done in the big ring, but I'm very glad of the little ring when things get tough.

You could convert your triple to something like this for the cost of a couple of chainrings and a cassette. But maybe you want something new - I get that.