Upgrading MTB Groupset - What do I do about chainline?

I’m looking to upgrade from a 10 speed Deore 4100/5100 parts to Deore 6100 or 8100 12 speed. I know nothing about MTB, just road, so seeing various cranksets with chainline settings was a bit confusing. I think I generally understand the term in regards to crosschaining but I don’t know what to do next.

Current: 10 speed 11-46, 1x
Proposed: 12 speed 10-51, 1x

I’d like to use the current 10 speed Deore crankset (I know it’s not ideal but it sounds like it should work) but I don’t know if I will have an issue with chainline. If so, how do I figure out what chainline I need if I do buy another crank?

The other option is get the same cassette range, but in 12 speed so there would be more gears in the middle.

What crank do you have? Was this spec’d on your bike?

In general, you just need to replace the Cassette, Chain, RD (I don’t think you can use your 10sp for 12sp), and Shifter. I’d take a risk on the chainring before replacing that. The chainline needs to match your rear hub spacing, so whatever you have should work - Shimano says 52 - 55mm will work for boost frames.

If you need to change the ring, you likely need a 96bcd 4-bolt chainring.

Cassette - You probably have a standard (HG) cassette; for 12, you need an Microspline freehub body.

For price, The M7100 SLX bits make more sense than the Deore ones . I’d only go Deore from used take-off parts

It might make sense to go 11sp if you don’t want/need the 10t small cog and HG+ shifting under load. Then you’d likely just need the cassette and shifter likely.

Thanks! The crankset is: Shimano Deore M5100 170mm, 30t.

I am certain I don’t have a boost frame, this is the bike.

You won’t be able to use a shimano 12 speed cassette, your free hub is HG (HyperGlide) not MS (MicroSpline), you will need a sunrace or sram SX cassette. Then 12 speed chain of your choosing, a deore rear D and I would go for an XT shifter personally, only an extra $30 there.

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Just to be clear here. … the difference between your 10sp and 12sp setups won’t be much different. You’re getting a 10% lower gear, a 10% higher gear, and you’ll be able to shift better going uphill. Going 11sp 11-51 would get you the gearing without some of the other costs.

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What’s different on the XT?

Two things, you can throw the whole cassette in 3 throws instead of 4. Multiselect lets you pull 2 gears on your up shift instead of 1, which is really nice on rolling terrain.

The downside, the shifter is much stiffer on xt vs deore.

I’ve got an SLX m7100, so I’ll have to look what’s on it. MTB cassettes are like double shifts anyway, but it’d be nice to get out of the climbing gears more aggressively.

The SLX shifter is 1 up/3 down.

I swapped to an XT shifter on mine. The upshifts are light enough that I’ve accidentally shifted 2 when I only wanted one, but that only happened on the first couple rides.

The downshifts, especially that 4th, do require more force.