SRAM 12sp Road cassette compatible with 12sp MTB derailleur?

[erider1]

I am trying to use SRAM Road cassette XG-1270 or XG-1290 on e-mtb with T-type transmission AXS derailleur (for more gears in low range)
The plan is to swap XD for XDR. That will allow fitting road cassette. Now I just need the RD work with the cassette.

Anyone has done it and is it working?
Biggest concern is gap in between gears and perhaps chain type.
I can go with road AXS Flat chain.
Will this work with any a) T-type AXS transmission RD or b) mechanical 12 speed Eagle RD?

Thanks

 

[nowayfra]

You are right the gap between the upper derailleur cog and the larger cassette cogs would be substancial so you wouldn't have a crisp shifting experience if it shifts at all. Best to swap the derailleur too, you usually can use SRAMs UDH adapters to put a road derailleur onto your bike. Riding this setup too for maintaining cadence. Overall if you don't do heavy uphill battles a rear cassette with 10 to 36 ahould be sufficient with a full power ebike. My setup is front 38T and back 10-33T. Even with the 33T I didn't come across a upward slope my bike couldn't handle so far.

 

[erider1]

You are right the gap between the upper derailleur cog and the larger cassette cogs would be substancial so you wouldn't have a crisp shifting experience if it shifts at all. Best to swap the derailleur too, you usually can use SRAMs UDH adapters to put a road derailleur onto your bike. Riding this setup too for maintaining cadence. Overall if you don't do heavy uphill battles a rear cassette with 10 to 36 ahould be sufficient with a full power ebike. My setup is front 38T and back 10-33T. Even with the 33T I didn't come across a upward slope my bike couldn't handle so far.

View attachment 182194

Awesome, thanks for your response! Similar thinking... I also intend to use 10-36t, and yes to UDH adapter... 36t chainring is on (unfortunately my e-bike will not fit 38t. )
So using Rival AXS RD was my plan #2; and since both MTB AXS shifters and AXS RD, both belong to AXS ecosystem, it just works.

But more for mechanical Eagle:
I understand that Eagle is for higher gearing up to 52T, so converting it to run on 10-36 or 10-44 xplr cassette might not be ideal, due to cage riding too high above sprockets, but it appears that Ratio company makes the proper adapter to do just that. Anyone tried that one...?

 

[Suns_PSD]

I know the Amflows are hella powerful, but I'd be afraid that you'd damage parts applying that much torque through them on steep hills, unless you don't have any hills to speak of.

I'd also be curious what this set up weighs?

 

[erider1]

I know the Amflows are hella powerful, but I'd be afraid that you'd damage parts applying that much torque through them on steep hills, unless you don't have any hills to speak of.

I'd also be curious what this set up weighs?

My assistance even on short steep hills is set to ECO level- and capped at 145 Watt ~ 15 Nm. 90% of time... Hardly anything for the motor... That + 400w of my own on 36T on short hills, will get me anywhere.... Last time I checked my 10-52 cassette, the top two chainrings did not get a chance to say hello to the chain... see below.
Setup is at 49lb mostly due to large battery but I am still WW and will remove weight where possible.

 

[nowayfra]

I know the Amflows are hella powerful, but I'd be afraid that you'd damage parts applying that much torque through them on steep hills, unless you don't have any hills to speak of.

I'd also be curious what this set up weighs?

Good point about torque and component wear and i thought quite a bit before making the decision about what parts to slap on the bike. On my primary meatbike I ride a 3x9 drive train and over the years I settled with a cassette of 11-23T while having 22-42T on the front. With that i can climb all the hills i stumbled upon over the years while having very good cadence for the flat parts of touring. My meatbike chain usually lasts for years so i thought for the amflow with considerably more combined power a 33T on the back should be sufficient for the steepest of my hills without f**cking up the chain. The lever is 47mm on a 23T cog while 67mm on a 33T cog. This reduces the strain on the amflow chain by ~30% while climbing the same slope by using the largest cog on the rear compared to the meatbike. The only moment where the amflow could be nibbling on this margin is during accellerating on the climb up.

For the weight savings using the road components. The original XS-1270 cassette was 555g, the GX Eagle derailleur 411g. The road cassette is 207g, the road derailleur 260g. Which makes a weight saving of 499g. Add to that ~10 links you can strip off the chain.

 

[Suns_PSD]

I appreciate the way you've thought outside the box and the detailed explanation you provided. I'm really impressed with how light that road derailleur is. I'm not following what you mean when you're talking about levers and percents. What are you referring to there?
Here's the setup I have going on and I'm pretty darn happy with it.
It's a sram XO1 11 speed cassette (10-42) and it weighs 272 g. For the record I have a Bosch Wild with a CXR motor and I definitely need that first gear 42 tooth. The bike came with the 34 front chainring and I'll keep it. I combined this with a Wheeltop electronic derailleur system. If you're not familiar with it, it's like a generic Alibaba electronic shifting system. It's big advantage is that it's completely programmable to any cassette that you want. It works very well and I actually prefer it over my AXS. It's not hardwired however and the derailleur hanger is still in place which I have not decided if that's a pro or a con yet.
The mechanical shifting system that I included in the photos is an XO1 11 speed, so pretty much as light as it gets.

 

[erider1]

For the weight savings using the road components. The original XS-1270 cassette was 555g, the GX Eagle derailleur 411g. The road cassette is 207g, the road derailleur 260g. Which makes a weight saving of 499g. Add to that ~10 links you can strip off the chain.

You forgot about the 2 extra chainrings, 2 sets of bolts and heavier spider and likely heavier cranks (as all all modern cranks are 1x), for the weight calculation

 

[erider1]

I appreciate the way you've thought outside the box and the detailed explanation you provided.
Here's the setup I have going on and I'm pretty darn happy with it.
It's a sram XO1 11 speed cassette (10-42) and it weighed 272 g. For the record I have a Bosch Wild with a CXR motor and I definitely need that first gear 42 tooth. The bike came with the 34 front chainring and I'll keep it. I combined this with a Wheeltop electronic derailleur system. If you're not familiar with it, it's like a generic Alibaba electronic shifting system. It's big advantage is that it's completely programmable to any cassette that you want. It works very well and I actually prefer it over my AXS. It's not hardwired however and the derailleur hanger is still in place which I have not decided if that's a pro or a con yet.
The mechanical shifting system that I included in the photos is an XO1 11 speed, so pretty much as light as it gets.

Nice !!
I forgot about that alibaba RD... yes for sure that programmability a adjustability for each gear is very nice. I had a look at them some time ago.. and decided against it, as it seemed a bit pricey... almost 70-80% or SRAM AXS at that time.. will check as I might like it now....
Currently my top choice was going with Force or Rival Road AXS RD... which is about 312 or 228 g and 10-36 12sp road cassette. at 303g and will keep my axs shift pod.