Hi all,

I’m planning to swap out a SRAM 1×11 for a GX Eagle 1×12 (10-50), replacing a very worn out transmission. The bike’s obviously already XD, so I don’t expect it to be more complicated than a straight bolt-on replacement of chainset, mech, cassette, chain and shifter, but it will be the first Eagle install I’ve done. It’s my FiL’s bike and he’s been complaining about the lack of low range on the old transmission since he got the bike, so moving to the 10-50 is a bit of a no-brainer for him, assuming that it all works OK.

Any advice or recommendations specific to this groupset in advance of getting the spanners out? Any considerations about chain line? (the packaged groupsets don’t seem to offer any options for this – just different crank lengths).

(I had a crack at searching for threads on this topic, but stuff seems to have changed since I was last here and, unless I’m blind, the forum search seems to be missing / broken!)

Thanks!

SRAM have a how-to on youtube. There’s nothing unusual to catch you out.

Here: https://youtu.be/6wCt9BJRNew

Yep, you can keep the crank and freehub but the rest will need swapping.  Make sure you get the red plastic gauge for setting the b screw on the Eagle mech up.  You could possibly keep the chain, but the Eagle chain is redesigned plus old chain on new expensive cassette is silly.

SRAM say deviation from their intended chainline will kill your cassette overly fast.  For practical purposes, so long as you have a Boost/non Boost chainring to suit the rear triangle and don’t fiddle with spacers trying to ‘improve’ things you’ll be fine.

Great, thanks all. <span style=”font-size: 12.8px;”>Thanks also for the video – I’ll watch later,</span>

You could possibly keep the chain

Nah, the whole transmission is horribly worn out. It would need a chainring, chain, cassette and jockey wheels as a minimum just to keep it going, hence the “two birds with one stone” of swapping to Eagle to get him a bit more low range for climbing.

11sp & 12sp chains are different

I’ve just watched the video and it’s absolutely excellent – covers the key points with no fluff or unnecessary waffle. Very useful indeed.

I did chuckle a bit at how you remove play from the crank axle – I’ve done a fair few SRAM installs and it never ceases to amaze me that a wavey washer and “tighten it a bit more, or stick a bit more grease on the splines” is the best that all of their engineering skills have managed to come up with for configuring the bottom bracket bearing pre-load… glorious 🙂

To be fair, I think most/all B.B. preload methods involve tightening something till it feels right, just different things for different manufacturers.

I did say the chains are different. A good/new 11sp chain would work but the 12sp is very much preferable especially if there’s an Eagle cassette at risk!

To be fair, I think most/all B.B. preload methods involve tightening something till it feels right, just different things for different manufacturers.

Yeah, I guess I come from a Shimano world, where it’s all quite precise, with gentle hand torque through the preload tool to set the preload accurately (albeit by feel) and then pinch bolts on the crank arms to secure it. SRAM’s “tighten it up bloody hard” method always feels one step away from a square taper.

That said, the Shimano stuff isn’t without its fault – their stock crankarm pinch bolts are made from an alloy of chewing gum and window putty and round off incredibly easily if you’re not taking great care. I’ve taken to replacing them with stainless steel bolts straight out of the box to avoid this during the life of a crankset. You just have to watch the torque carefully as they are more than capable of stripping the crankarm, which is a much more expensive cock-up 🙂

You sure it’s an XD hub? My SRAM 11spd cassette runs on a standard Shimano freehub

Yeah, it’s currently running a 10-42, which wouldn’t fit on a Shimano freehub.

Quick update: was a simple swapout and probably took a couple of hours, including a bit of a bearing spring clean and a good pile of swearing at the stupid internal cable routing on the rear stays on this Whyte, which fought every step of the way against getting the new cable through!

Bike was ridden over the weekend and no issues reported. Another winner 🙂

Did you have to buy a new crank or reuse your existing one?

Also does anyone know if you can use any chainring or does it have to be an eagle one?

What is a “swapout”

Also does anyone know if you can use any chainring or does it have to be an eagle one?

The new eagle chanring is a different tooth profile, find them a far bit quieter than the original profile narrow wide rings.

Did you have to buy a new crank or reuse your existing one?

The groupset came with cranks. I could have reused the old ones, but the groupset was pretty good value and I wouldn’t have saved a lot if I had and they were battered to hell anyway.

Also does anyone know if you can use any chainring or does it have to be an eagle one?

As it happens, I swapped the stock (6mm 32t) ring from the GX Eagle groupset for a 34t boost chainline (3mm) version from Superstar. 12 speed compatible and seems nice and quiet to my ears:

https://www.superstarcomponents.com/en/raptor-chainring-sram-boost-direct-mount-narrow-wide.htm

It’s very odd that SRAM don’t offer a boost chainline version of the groupset, choosing instead to offer two fractionally different crank lengths instead, especially considering that the official SRAM chainrings aren’t very cheap and, in boost line at least, are quite hard to source.

What is a “swapout”

A straightforward “one groupset off, one groupset on” with as few other bits changed as possible (e.g. BB, hubs etc.). In my case, I replaced the shift cable too because, well, why wouldn’t you? 🙂

It’s very odd that SRAM don’t offer a boost chainline version of the groupset

They do, I’ve got one on the shelf!

They do, I’ve got one on the shelf!

Aw bugger, why didn’t I find that last week? 🙂 As it happens, it wasn’t the end of the world as he wanted to swap for a slightly bigger chainring so it turned out OK anyway.

(Side question: why can Superstar sell UK made, CNC machined chainrings for £23, yet SRAM’s mass-produced efforts cost three times the price!? Someone is making a few quid here, I reckon…)

(Side question: why can Superstar sell UK made, CNC machined chainrings for £23, yet SRAM’s mass-produced efforts cost three times the price!? Someone is making a few quid here, I reckon…)

Yeah. Wish it was me!