I recently came across a track SRM with square taper cranks arms - I already have Octalink cranks and BB's so I removed the square taper arms to fit the Octalinks. I have only ever made Octalink/Octalink swaps before and noticed that the spider needs an additional piece to work with a Octalink crank. A piece that fits into the centre of the spider and provides the BB Taper with support - the splines are part of the crank arm. This colar is integral to the sqaure taper crank but is a small part for Octalink cranks.

I have made 3 attempts to get SRM to understand what I meant but they simply don't understand what I mean - are the cranks I'm trying to fit incompatible with this crank or is it something else that I'm missing?

Can anyone tell me what this part is called or fin a picture of it?

Many thanks
Gavin

I have never seen a set of two-piece SRM crankarms before. It is possible that the SRM crankarms that you have are from a different generation of PowerMeter chassis than the PowerMeter that you own. The best way to do it (short of just sending your PowerMeter) is to give Uli your PowerMeter serial number and ask.

The crank on the right is a square taper crank removed from the spider at the top. The crank on the left is a Octalink crank and does not have the protrusion of the square taper crank. The spider on the bottom had a Octalink crank previously and has a collar (red arrow) that is an interference fit with the spider. I need that piece to run the crank on the left in the spider at the top.

Anyone know what this piece is called please?

To confirm, we are looking at two SRM Track PowerMeter chassis, one wired and one wireless and you are looking to transfer the Octalink arms from the wired PowerMeter to the wireless PowerMeter? I suspect that the newer PowerMeter probably uses different arms and that Uli should be able to tell you that from the serial number on the chassis. Sorry I can't be of more help on this one .

No worries, I appreciate the time you've taken to reply.

The square taper crank / spider is a track crank, wired. The Octalink spider is an old Amateur wired model, and the Octalink crank is from another Pro model.

I also have another Adjustable Octalink crank that is the same as the one from the Pro. So either there is a piece that enables the Octalink crank to be fitted into a spider that had previously been fitted with a square taper crank, or this Track Spider I have needs a special type of Octalink crank?

There is a bush that is required with the octalink cranks that fits in the powermeter hub, this is what you need to fit prior to bolting the octalink arm. The sq taper arms have this intergral with the arm.

Check if the track bolt pattern PM is compatible, Pro arms are 3 bolt however some track PM's are 4 bolt and some are 5 bolt, the 5 bolt ones can be used with 3 bolt arms, although not recommended for powerful sprinters etc.

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Not sure what it is called. As an interim measure, this should pop out of your Amateur spider easily?



If you need more pictures just say...

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I have tried to remove the Amateur 'bush' but it is very happy where it is!

SRM have a third package out to me do we'll see if its right this time - the picture may really help though so thanks for digging that up

sorry for the gravedig on this one...

GZA: did you ever get anywhere with this? i have exactly the same problem as you are - i removed a set of campy cranks and tried to replace them with a set of octalink cranks but unfortunately i needed an extra spacer to do it properly. it did all bolt together without it and i did manage to use it like this but my offset was wandering around a fair bit and the torq bolts backed themselves off within ~25km. i think all the spacer does is give the spider a bit more meat to bite on so it may run ok without it but i certainly won't be risking it again.

the campy cranks i removed had the "spacer" as part of the crankarm so maybe the solution is just to pick up a set of campy cranks and change bottom brackets as well but i'm not 100% sure that all campy crank arms will be the same. i haven't been able to find the spacer only for sale online (SRM don't have it on their webstore).

the part we're both after is shown on pg 28 of the following manual: http://kinetic.com.au/images/stories/ki ... H3oceQdRV3

oh yeah, and further to that, i have a set of 4 bolt 165 octalink crank arms (nfi what they're for - track maybe) and they have the "spacer" as an integral part of the drive side crank arm. weird.

Hiya - the picture Dalai posted is what you need. Are the 165mm cranks you mention surplus to your requirements? If so PM me!

yes, the 165s are surplus to requirements, however they are located with me in australia. happy to post if you're still interested.

did you end up getting a part number or finding a source from where you could order that spacer?

PM me a price! I ordered it direct from Bettina at SRM Germany

The four bolt (bolted from the front of the crank) SRM crank arms are for an older SRM Track model. this Octalink crank arm is one piece including spacer...

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^^ this is correct.

I managed to source the required spacer from SRM in New Zealand. Dallas was very helpful, quick to answer my emails and had 1 in stock ready to go.