Drivetrain renewal

Equipment
1

Currently running m8000 xt 2x 165mm cranks in 1x (so chainline might be funky but seems ok?), mech, cassette and shifter with a Deckas eBay 1x 32t ring, a Hope Pro4 hub. Shifting has completely gone to pot which after 3 chains in the mud points towards cassette, shifter also has odd clicking/physical clunk from 1st to 2nd.

So it’s time for either a refresh/rebuild. Ignoring money (but not totally irrelevant so no full XTR or XX1) I’m looking a AXS GX or XT setup.

Trying to work out the pros/cons for either, or whether I should have just find an 11 speed cassette and hope shifter isn’t fubar.

An opinions either way, or even left field options like Box or Microshift? This is assuming 1x chainrings work with both 11 or 12 speed chains. If I’ve got to spend a bunch I’d rather not spend lots on 11speed since it’s a generation or 2 back.

2

I’ve heard very good things about AXS GX but haven’t used it. I can say that Shimano XT 12 speed is the best shifting system I’ve used yet & would recommend it for sure if you’re going to go mechanical. You could also go AXS GX shifter & derailleur with an XT cassette for best of both worlds.

1 Like
3

Have you tried the easiest fix – new cable and housing?

2 Likes
4

This!!!

Cables can fray in the shifter and cause increased friction in the system, which is a primary cause of poor shifting.

5

Given the age of the drivetrain (4ish years?), it should be fixable by normal maintenance. It is hard to tell what is wrong, with older, well-used drivetrains the answer is often that everything is worn out. Especially if your cassette and/or chainrings are worn out, once you replace a well-worn chain, it is very common that your shifting will go haywire. To be honest, I’d just replace everything — cassette, chainring, inner and outer cables — and use original Shimano parts.

That happened to me when I got a new-to-me used hardtail with an XTR 9000 drivetrain. I was stupid and only ordered a new chain, and then once I replaced it, my chainring and chain sounded super unhappy. That was fixed by getting a new XTR chainring. Like others have said, you should also be looking at inner and outer cables, etc. And that is assuming that your rear mech is in good condition.

However, That’s less sexy than getting a brand new drivetrain, but unless some parts are damaged or you haven’t kept up with maintenance at all and parts have worn prematurely, you should get it to working order.

Going 12-speed is also an idea. Just keep in mind that you’ll at least need an XD driver-compatible or Microspline-compatible hub, but perhaps a new rear wheel. So things might cascade. I think the previous owner of my bike also boxed himself into a corner like that. The bike had a complete XTR drive train, XTR hubs on nice Stans wheels, etc. You’d be tempted to keep the wheels, but I don’t think the XTR M9000-series hubs are neither Microspline-compatible nor XD Driver-compatible. So either you buy a Rotor 12-speed cassette or get a new wheel.

I don’t think you can go wrong with either Shimano or SRAM. If you like to have a good power meter, I’d go SRAM, no question. They also have two GX cranksets, one made of aluminum and a more fancy carbon version. If you want electronic shifting, go SRAM because you got no choice. Otherwise, it is quite even. With mountain bikes, you can replace brakes and drivetrain separately, so your brake preference does not play a role here, fortunately.

1 Like
6

I’ll add this:

I faced a similar situation with my hardtail in 2020. I decided to stay with 11-speed XT. I haven’t had parts availability issues, the components are generally less expensive, and I’ve bought high-end wheelsets and just switched the freehub body to HG.

The big thing I changed when I replaced the drivetrain was maintenance. Now I lube the chain (wax-based Squirt) every four hours of riding. No problems so far.

1 Like
7

I was in a similar boat. My almost 10-year-old fully was ripe for replacement. Got a great deal on a well-used; but well-loved hard tail. The carbon frame is from 2014, but in 2018 the previous owner put top-of-the-line components on it, an XTR 11-speed drivetrain, a World Cup-level fork, the works. Comes out at 9.9 kg with pedals.

I was a bit skeptical how I’d like 11 speeds, and for me it works so far. Yes, I’d like one or two more gears, but I top out at 38-40 km/h with the 30-tooth chain ring. That should be fast enough. And I really like having a bailout gear. I don’t understand Shimano’s logic with their 12-speed cassettes: I want larger steps between gears, not smaller ones.

8

Order of attack with shifting issues:

  1. clean (properly)
  2. check mech hanger alignment - you need a special tool for this but without doing this everything else is guesswork.
  3. check indexing
  4. new cables and outers
  5. check wear on chain, go with manufacturer’s recommendations, if at upper limit replace chain, cassette and possibly chainring.

Assuming you changed your chains at the first limit then the cassette is a likely candidate but you’ll need a new chain as well. Depending on conditions I’ll get two or three chains per cassette, two or three cassettes per chainring. If you consistently ride in muddy conditions then an annual replacement of cable and outer keeps things running in good order.

Hope hubs can take different freehubs so no need for a new rear wheel, just get an SD version if you go that route. They also do microspline now so that option’s also available.

1 Like
9

I run microshift on the commuter and its a bit more bang, bang of a shift. Its starting to get a bit erratic after 6,000+ miles but that is a sign of my lack of maintenance for that bike, the cables probably need replacing (I don’t think I have ever done so). Your existing setup probably just needs a bit of maintenance too.

10

The drivetrain is regularly maintained, cleaned (was very clean until I decided a pine forest was a good idea and brought most of the forest home with me!) and new chains on at just going on for 0.5.

I’ve got spare cables so will try that short term but it was less what to check more a discussion if we assume after 6 years there are parts like shifters worn, as is the cassette where would you spend the money:

  • Mid-range electronic
  • Top range cable (SRAM or Shimano is fine)
  • Leftfield manufacturer
  • Previous generation XT
11

Ive only been gravel biking a year but bringing the whole forest back with me is definitely a familiar situation :joy:

Cables would be my first bet, then the cassette if you have never replaced it. Shifters should last for years, although I did have a 4year old 2nd hand Dura ace one fail (the rachet unside according to the mechanic) after circa 25000 miles (16,000 with me).

I would love to go electronic having done the top of the range mechanical stuff (at least 2nd hand). I have no idea about its robustness off road though :slightly_smiling_face:

12

Not sure whether it is really about robustness in itself, more about the cost of replacing a mech versus electronic RD if anything were to happen.

1 Like
13

Ugh, cables suck.

Just get the GX AXS. You won’t regret it.

I have X01 AXS on my MTB and Rival AXS on my road bike. Ain’t goin back.

1 Like
14

Yes, although I’d characterize electronic shifting as a veeery nice to have, but not mandatory. I have mechanical XTR on my mountain bike and Force eTap AXS on my road bike. Being able to shift with my pinky and not having to worry about having to “overshift” get get into a stubborn gear is great. And I love trimming my rear mech on the fly. However, high-quality mechanical shifting works very well, too.

So if I had the disposable income, I’d go for electronic shifting — but I’d prioritize some other parts over electronic shifting such as good wheels.

15

In this case I’ve realised it’s a moot point chatting about SRAM or Shimano or Box. I’ve got a x-12 direct mount mech hanger and only Shimano use that standard! And not even for 12 speed!

Although good points raised for the future and if I could have used it I think AXS would have been best.

16

I’ve tried em all and came back home to Shimano. Hard to find fault with a 12 speed Shimano set up. AXS is good, but after watching a buddy forget a battery for his shifter on a ride it’s a tough sell for me. Obviously wireless is the future though. I’ve seen a Box derailleur blow up rather unexpectedly recently too, only Problem with Shimano is finding the parts.

17

The Di2 battery in my buddy’s road bike discharged over night, and he noticed it only at the race venue. (Yes, he had charged it the day before.) He fortunately found someone with the charging cable, but it was a bit of a hassle.

IMHO these are rare occurrences, but are much easier to mitigate with SRAM. I always keep a coin cell or two in my saddle bag (my power meters have always taken coin cells, as does my heart rate strap and now my two shifters, too). And you can take a spare eTap battery with you, too, they weigh next to nothing and likewise fit into the aforementioned saddle bag.

Personally, I ran out of battery once, because I’m frugal and wanted to use the coin cell battery for a few hours longer. But I had a spare with me, so no biggie. Now I just replace them after seeing the first warning on my Wahoo.

Failures also happen with mechanical drive trains, somehow rust (from sweat) in my Shimano STI levers almost ruined a race for me, because I almost couldn’t shift anymore.

1 Like
18

Fair response. I should have said that I just prefer Shimano. :+1:

1 Like
19

Riding a lot in UK mud, I expect to replace the whole drivetrain at least once a year. Thats chainring, cassette, chain and jockey wheels. Will probably need to do one or two cable swaps in that time too.
I choose Shimano slx 11sp as it has all the great shifting qualities as the more expensive offerings at the cost of just a few grams.
If I can’t get up a climb in 30t front/42 rear then genuinely its better to get off and push.
20220228_080516
UK mud is special though :laughing:

1 Like
20

I’m going to be really geeky/freaky but at a guess that looks like the bridleway on the top part of Moor Lane above Hetton in the Yorkshire Dales.