Shimano XT 12 Spd M8100 Transmission

Let me start by saying I've always been a Shimano guy, but I've been running SRAM drivetrains since 2016. The Shimano stuff always seemed to shift a little easier, a little quieter and a little more precisely.

However, I spec'd my short-lived Pivot Firebird 29er with SRAM GX Eagle, and I was really impressed. Shifting was tons lighter and more precise than the XO 11 spd stuff on my Tracer. A world of difference.

Then I decided to trade the Firebird for a Megatower, and I spec'd it with the new Shimano transmission, based partly on my prior preferences, partly on reviews but mostly on gear ratios. The SRAM has a 50t climbing gear bolted to the same old 10-42 cassette that was on my Tracer. Shimano decided to devote a little more attention to the steep side of the trail by going 51-45-39-33 on its top four cogs, theoretically giving me better choices for climbing the steep stuff I climb.

Turns out it's true. I find myself using the 45 a lot. I can climb most anything in that gear, but it's nice to have a bailout above it if need be. Quite often, I am toggling between 3rd (39) and 4th (33). By comparison, my 10-42 cassette on my 27.5" wheeled Tracer just doesn't give me the climbing options I need. Oh - I ran a 30 t Race Face Turbine chainring and KMC chain on my 11 spd Tracer and I am running a Wolftooth Hyperglide specific 30 t chainring and Hyperglide chain on my Megatower. That matters.

As for shifting precision and quality, as I said above, the Eagle stuff is really good. I think this new Shimano is a bit more accurate and smooth in some situations (shifting to bigger cogs under moderate load). I don't think it shifts any better down the cassette than the Eagle. I do like the trigger pull option on Shimano, provided you can position the levers right. They don't play nice with the new 8120 brake levers and need to be mounted outboard of the brake lever clamp for me. The clutch on the Shimano is better than it was on my last Shimano in 2015, but I worry about how long it will remain strong.

So there you have it. The gear ratios alone are well worth the move to Shimano for me. I have far more useable options and I can run tougher gears because they aren't too tough. I like looking down while climbing and seeing 2-3 more gears above where I am spinning. The shifting is great, and I am guessing the durability will be par for the course for Shimano drivetrains.

I know it would be prettier if it were clean:



Levers:

 

The really nice thing is Shimano made the clutch replaceable!

 

Really like my Shimano 12sp...so smooth and accurate...

 

Competition is great. I really like both systems and find both shift super well. I also agree with the better gear spacing with the new Shimano. One place it seems SRAM still leads is in cassette and chain life.

On another note, what led to the switch from the Pivot to the SC?

 

@herzalot, thanks for the skinny between Shimano and Sram 12 speed cassettes. Perhaps the 12 speed Shimano cassette would be a better choice for the steep climbers who are running an Eagle 12 speed drivetrain.

 

They are on-line for a little over $10.

I didn't have to replace it, but I did have to take it apart for cleaning and regreasing after only a few months when it completely stopped its clutch duties. It seems to be holding and clutching now...

 

How big of a task is it to switch to a Shimano coming casette if running a sram one?

It's not just as easy as swapping one for another right?

 

If you have a SRAM cassette on a XD Driver, you’d need to swap out to a new Microspline Driver for Shimano 12 spd. Depending on your rear hub, this may be an issue.

even if your SRAM cassette is low end and on a regular Shimano HG freehub body, you’d still need to swap to Microspline.

 

Yep, it would require a small investment and some labor but it might just be worth it.

 

Oh good lord. I've probably written 30 posts about the process of switching. Here's the shortest version I can come up with:

I bought the Firebird 29 on impulse. Rode it a dozen times over the month of November, working on dialing it in, upgrading parts (most notably, brakes), etc. At the end of the month, I rode the Firebird on a collection of local faves, then rode my Intense Tracer on the same trails the following day. The Tracer was clearly superior. A big brawler, slack 29er like the Firebird, with a 170 mm fork and 162 mm rear should mow down everything in its path and beg for more. Instead, it was the Tracer that was more composed, more plush, more precise and more agile.

I went back to The Path and said "This is not the bike for me. Is there anything you can do to help, or should I just sell it?" They said "You're welcome to demo anything we carry, and if you like something, we can talk numbers to make it happen." Amazing offer. I demo'd a few bikes and decided the new Hightower was the awesome, do-everything bike that I was looking for that could match and maybe surpass my Tracer. I ordered the Hightower frame, but after two months, it was nowhere to be seen. They had the Megatower frame hanging from the rafters, so I had them build that up. And here I sit, very satisfied with a new Megatower for $400.

With a Shimano drivetrain.

 

...and he railed happily ever after!

 

Great info here @herzalot

I've only used Shimano, on all of my one bikes so far...
But my new one is coming with sx eagle. Will try it for a while but upgrade as it wears out...

Like the sound of the gearing for the steeps...
Good for weekend warrior legs

 

SX Eagle is going to be a Shimano Driver, but not Microspline.

 

I rode @pperrelle s Ripley today on a demo and he had the new 12 speed XTR. I have SRAM Eagle X01 (10-50) on my bikes. I'll say this about the XTR, it was very precise for sure as I could literally feel every shift but I don't know how anybody could say that is smooth. While not complaining, I think it's the opposite of smooth since I literally feel every shift. As I told Paul, both systems are great. I think Shimano is like a German sports car transmission while SRAM Eagle actually is smooth and elegant like a Lexus. All depends on what you're after. I've been using SRAM ever since they invented 2x10 for the masses and I've never needed to replace a derailleur clutch so that's not an issue....but I do love the way SRAM derailleurs lock back when you're working on the back end of your bike. I was told Shimano doesn't do that?

 

I'm bummed that Shimano went with the Microspline instead of XD. Creating a new standard just to divide brand loyalties. I'd consider trying the cassette if it wasn't for that, but I'm not going to buy a new driver (that doesn't exist for my hub anyway) when I know how great the XO1 and XX1 cassettes are.

I haven't worn out a clutch yet, even with the abuse I put my bikes through. But, if they do wear out, it is nice that you can swap them out.

I don't understand why Shimano didn't put a lock on like Sram has. Not a deal breaker either way I don't think (I say that now), but seems like an oversight on such a simple and useful function.

SX/NX are junk. If you buy a bike with those, just plan to trash them nearly new and go with your preferred Shimano or Sram system. Just a super cheap system for improving profits.

I keep hoping ODI will make some nice lock on grips some day to match Sram gripshift, then I can have what I really want (use GS for XC with cut foam grips).

 

Anyone try a box 12 speed?

 

No way in hell Shimano was gonna admit that SRAM has a better interface without reinventing the wheel.

 

Interesting discovery yesterday and today.

But first a little background.
The new Hightower and the Megatower are universally reviewed as amazingly quiet bikes. That was my experience while demo-ing them as well. Zero chain noise and barely any hub buzz. So quiet.

Yesterday I noticed a little bit of chain slap while descending The Luge - not much, but not silent. Now granted I was in one of the smallest cogs in back, and I coast with my right foot back, which introduces the likelihood of chainslap on the crank arm.

Then I remembered that the Shimano derailleurs have an adjustable clutch! You can tighten the tension! Yay! So I looked up how to do it and gave that puppy about two and a half full rotations. Woo Hoo! That outta lock it down better.

So off I go for my ill-fated ride this morning and my derailleur and chain were making weird noises as I pedaled toward Willow. As I headed up the trail, it was popping out of gear. Well, the only thing I've changed is the clutch tension, so I backed it off 1/2 turn. Stayed in gear up Willow, but was still noisy and shifting horribly. I got to the top and let out the tensioner another 3/4 turn and I physically saw the derailleur relax. The shifting was just fine after that, and the noise went away.

Buuuuut, the slight chainslap was still there on some of the downs. Better than any other bike I've ridden (without a chain tensioner), but not silent like the demo rides.

Bottom line - SRAM's clutch/chain tensioning system works better - (until it fails).

 

Guys, I'm soo far behind, what's a clutch on a RD?

 

Wizardry built into derailers that helps maintain chain tension when not shifting. It may or may not be user-serviceable.

 

Around 2011, Shimano invented a mechanism that keeps the rear derailleur cage tight so that the chain doesn't flop around while coasting down bumpy terrain. It was a game changer. It allowed me to remove the mechanical roller style chain tensioner I had mounted on my 2 x 10 transmission. It was a switch you could turn on for riding and turn off for working on your bike.

SRAM quickly followed with their version which is not a switch like Shimano, but was simply built into the derailleur. I think it works better.

Here's a picture of the clutch lever when it was first introduced. Only available on XTR at the time:

 

Helps keep chain tension so your chain does not derail off the front chainring. Also slows down and often prevents chain slap on your chainstays by keeping tension via the clutch in the Rear Derailleur. But they wear out like most everything does. Shimano built them to be serviceable.
SRAM currently has chosen not to.

 

Which is funny n, since so much of Shimano’s products are considered disposable with no service parts.

where as SRAM makes everything serviceable with parts available.

 

I still have yet to have a derailleur failure. I mostly use Sram, but even Shimano. None have failed.

About 4000 miles on my GX Eagle (been on three bikes now).
3500 on the XO1 11s

 

Box does not make a 12 speed drivetrain. 7,8,9 and 11 only.