Rotor ALDHU for Sram eTAP Force AXS & BB86

[wijmaar]

Good morning!

I hope I can tap in to all the available knowledge in this great forum! I am going to build up a Velobuild frame and am currently trying to gather all the parts to do so. I'm really happy with my ovals on my MTB, therefore considering to install on my roadbike as well. After doing a second masters degree on Rotor Road Cranks and bottom brackets I am a still a bit puzzled

Some facts:

Frame: Velobuild VB-R-168 - BB86
Groupset: SRAM Force eTap AXS 2x12 Disc
Wheels: Farsports Kaze (DT Swiss 350 Centerlock) 142 x 12 & 100 x 12 thru axle

The dilemma 30 vs. 24mm:

When combining a Rotor crank with the SRAM Force eTap AXS Disc group, it seems to be the logical choice to opt for a setup like:

Crank arm: Rotor ALDHU 3D+ Crankarms black-matte/172.5 mm
Crank as: Rotor ALDHU 3D+ / VEGAST Crank Axle Offset
Spider: Rotor ALDHU 3D+ / VEGAST Spider, 4-Arm, 110 mm BCD black-matte/universal
Inner ring: Rotor SRAM AXS 2X, 4-arm, Q-Ring, 110 mm BCD, Spider Mount Chainring
black/35 tooth
Outer ring: Rotor SRAM AXS 2X, 4-arm, Q-Ring, 110 mm BCD, Spider Mount Chainring
black/48 tooth
Spacers: 4 x Rotor Bottom Bracket Spacer for 30 mm Cranks transparent/0.5 mm
2 x Rotor Bottom Bracket Spacer for 30 mm Cranks black/2.5 mm
Bottom bracket: Hope Stainless Steel Pressfit Bottom Brackets, 41 x 30 mm

However I do read a lot of issues when combinig a 30mm axle with a BB86 bottom bracket, the Hope bearings seem to be the best (or least worst) option. The alternative route would be to go for a Rotor ALDHU24 crank with a 24mm axle, which would enable me to use a bottom bracket like the Dura Ace BB92 and seems to be a more reliable solution.

The ALDHU24 does however not come in an offset version, and therefore does not seem suitable for a Disc Brake setup. The original SRAM Force eTap AXS 2x12 crank has a chainline of 45mm, the ALDHU offset 46mm and the ALDHU24 43.5mm. I am a bit torn between the different options... I am currently leaning towards the ALDHU24 but am a bit afraid I will run into issues because of the chainline that not matches the SRAM group, especially als the setup of the front derailleur seems to be a tricky thing even with the correct chain line.

Any suggestions on what to choose? Thanks!

[Wildstyle5000]

Hi,
Was running a Rotor Aldhu 24mm axle with a sram force, chainrings 35/48 and a 10/28 cassette. No problems, all good.
Now I run a rotor 30mm axle with no offset combined with 50/36 and a 10/33. All good. As far as I understood the offset axle is for 1x.
Hope that helps, by the way: I like the 50/36 vs 10/33 more since it provides a significantly larger range...

[wijmaar]

Hi,
Was running a Rotor Aldhu 24mm axle with a sram force, chainrings 35/48 and a 10/28 cassette. No problems, all good.
Now I run a rotor 30mm axle with no offset combined with 50/36 and a 10/33. All good. As far as I understood the offset axle is for 1x.
Hope that helps, by the way: I like the 50/36 vs 10/33 more since it provides a significantly larger range...

Thanks for the quick reply! As far as I know there are no rotor 50/36 chainrings specifically for SRAM AXS (which there are for 48/35). So are you successfully using the non-AXS rings with an AXS group and flat top chain?

I do live in The Netherlands, so in general I don't really need a 36x33 unless it's really steep, uhhh windy .

[DaveS]

I use the shimano 43.5mm chainline on my force axs disc brake bikes with no problem. I do this with a shimano grx 48/31 or 46/30 crank with spacing washers added to eliminate the +2.5mm chainline. Tried shimano DA bb86 bottom brackets but wasn't impressed. I've changed to wheels manufacturing thread together BB with angular contact bearings.

[rawjunk]

I didn't know Power2max pm will work even with 2x12. It seems it works pretty much anything? Grx/regular 2x11 depending on spacing, 1x 104 bcd etc.

[Wildstyle5000]

Hi,
Was running a Rotor Aldhu 24mm axle with a sram force, chainrings 35/48 and a 10/28 cassette. No problems, all good.
Now I run a rotor 30mm axle with no offset combined with 50/36 and a 10/33. All good. As far as I understood the offset axle is for 1x.
Hope that helps, by the way: I like the 50/36 vs 10/33 more since it provides a significantly larger range...

Thanks for the quick reply! As far as I know there are no rotor 50/36 chainrings specifically for SRAM AXS (which there are for 48/35). So are you successfully using the non-AXS rings with an AXS group and flat top chain?

I do live in The Netherlands, so in general I don't really need a 36x33 unless it's really steep, uhhh windy .

Yes I run Rotor 50/36 (for shimano/sram 11 speed) with sram axs and a sram flat top chain.

[jch3n]

I recently agonized over some of this as well. I ended up going 30mm in BB86 mostly because I wanted to re-use Vegast arms from another bike. I've had good experiences with Token bottom brackets so I'm using a Token BB86R386 bottom bracket and pressed in the bearings with a little Loctite 641. So far it's working fine, but only time will tell I guess....

In an ideal world, there would be thread-together bottom brackets for BB86 and 30mm axles, but no such thing exists it seems. And I sure as hell am not shelling out $200+ for the BBInfinite one-piece.