Rotor Aldhu 24 cranks - advice needed

Equipment
1

On the advice my bike fitter, I am moving to 155 mm cranks on my triathlon bike.

I have settled on a Power2Max spider, but unfortunately these don’t come in a complete 155mm crankset, so I am having to get the pieces separately.

I have no experience with Rotor Aldhu cranks, so if anyone can give me some advice on the parts required, I would be appreciative. The chainrings I will transfer from my existing (Ultegra) crankset, the spider is from Power2Max, I assume I will need:

  • 155mm crank arms
  • 24mm axle (I will be retaining the existing BB72).

Advice on the small parts (eg. spacers, pre-load caps) required to make it work is especially appreciated.

2

You will also need a BB, unless you already have one. Rotor’s BBs have (to my knowledge) a very good reputation (they were also mentioned as good options for BBs on the last episode of Geek Warning).

3

109

According to this your current BB if shimano should come out the same as BB86 - 41mm OD, 86.5mm width.

You need the PF4124 Bottom bracket (likely same as shimano)

And 0mm spacer on NDS, and 0.5mm spacers on the drive side.

4

I think it would be beneficial to reach out to Power2max for clarification.

I have an Aldhu 24 crankset on my TT bike (non-power) and bought it in piece parts similar to you.

I know I only ordered BB, axle, spider, arms and chainring and that gave me everything I needed.

I received 4x 0.5mm spacers and there was instructions provided on how many I needed to use based on my BB - but i cannot remember with which item the spacers (or any other small item such as chainring bolts) were bundled with.

1 Like
5

I’ve ordered complete set for Shimano from Power2Max including 165 mm cranks and then switched for 155 mm cranks while I was experimenting. The set included 4 0.5 mm spacers as mentioned above. However I’ve removed them completely after consulting with Rotor as my cranks couldn’t do a one free revolution. You can buy an axle and cranks separately if you don’t need the 165 mm cranks, obviously. I don’t think you need anything else as the Shimano BB is compatible with 3d24 aldhu. If you want to make sure, contact them. I had to contact both and they respond (although not right away).