Cannondale Habit & Moterra Ai Offset ***Update***

[Zaskar20]

So I wanted to change to a 36T and decided to go Hope E Chainring. Trouble is, the Cannondale uses its own Ai offset.
First, the chainring lock ring tool. I purchased this from Amazon. Did a great job, but needs a 32mm socket.

When I had removed the FSA spider (and ring) I placed it on a flat surface, against the Hope ring, to see the difference.

As can be seen the original stands a couple of mm higher.

To try to maintain this height, using the new Hope ring, I decided to use a carbon 1.25 inch aheadset spacer. However, the internal diameter had to be opened up slightly to allow it to fit over the motor’s drive spline. This was easily done using a Dremmel type grinding tool. (Plus a mask!)
This was placed over the splined drive before the new ring was fitted.

The aheadset spacer is highlighted behind the new chainring being placed.
The rubber o ring that came off with the old chainring was placed, then the lock ring was carefully threaded and tightened ANTI-CLOCKWISE.
New chain was fitted, gears checked for alignment along with new chainring and that was it.
Hope fitted to roughly the same custom Ai alignment.

 

[Zaskar20]

****UPDATE****
This modification failed today! The lock ring had come undone.
I am currently looking up the forum thread on this very issue.

 

[Zaskar20]

So, on gathering as much information as possible, I have decided to reduce the carbon spacer size from 2mm to 1mm.
Obviously using any spacer reduced the amount of thread the lock ring would have to tighten. I thought that the modification I performed would be ok, but I was proved wrong.
The plan is to halve the width of the spacer to give an extra 1mm thread. Also I am not going to use the O-ring so that potentially could give me a little more. I am still unsure as to the role of the rubber ring??
I am also going to clean all threads around the lock ring and apply blue locktite.
I am hoping this will solve the problem of coming loose.
Pictures to follow.
I purchase a new lock ring kit from these people:

Bosch CX (Gen 4) Spider Lock Ring Kit – e-bikeshop.co.uk

This is the Lock Ring and O-ring kit to hold the front chainring and/or spider onto the motor drive pinion on the Bosch Gen 4 e-bike Drive Unit (BDU4XX)

www.e-bikeshop.co.uk

 

[Zaskar20]

Pics as promised;

New lock ring with tool. The existing ring loosened during a ride. I tried to tighten but failed and crossed threads.

Spacer placed on with assembly grease behind.

Hope E chainring fitted with more assembly grease behind. The exposed threads were cleaned with disc brake cleaner before loctite blue thread lock was applied to both the drive threads and lock ring threads.

Tightened to 30Nm

Clearance still ok

Crank placed back on and torqued.
Let’s see how long this lasts

 

[Zaskar20]

******Update******
Blue loctite is the answer, it doesn’t undo. No problems since the last post

 

[Flupke]

****UPDATE****
This modification failed today! The lock ring had come undone.
I am currently looking up the forum thread on this very issue.

The locking ring came loose on my Habit as well …while still with the original FSA spider. I tried to put it back without the Bosch tool but it didn’t stay Long in place… I am planning to visit the retailer to fix it.

 

[Flupke]

So I wanted to change to a 36T and decided to go Hope E Chainring. Trouble is, the Cannondale uses its own Ai offset.
First, the chainring lock ring tool. I purchased this from Amazon. Did a great job, but needs a 32mm socket.

When I had removed the FSA spider (and ring) I placed it on a flat surface, against the Hope ring, to see the difference.
View attachment 80040

Cannondale does not document properly it’s custom offset indeed: they just document its “customity“ without any instruction on how to find a replacement part. Even retailers do not seem to know.

Hence it may be easier to avoid a direct mount rather by keeping the original FSA spider (and its custom offset!). Then replacing only the “104mm BSD 34T narrow-wide” part equipped with four screws.

 

[Flupke]

Cannondale does not document properly it’s custom offset indeed: they just document its “customity“ without any instruction on how to find a replacement part. Even retailers do not seem to know.

Hence it may be easier to avoid a direct mount rather by keeping the original FSA spider (and its custom offset!). Then replacing only the “104mm BSD 34T narrow-wide” part equipped with four screws.

…I just noticed you wanted a 36T rather than 34T but I guess keeping the spider is still possible. Moreover, easier as there is no need to unmount the locker ring and the pedal.

 

[Zaskar20]

The locking ring came loose on my Habit as well …while still with the original FSA spider. I tried to put it back without the Bosch tool but it didn’t stay Long in place… I am planning to visit the retailer to fix it.

Blue thread lock works a treat.
Hasn’t undone since I’ve used it.

 

[Flupke]

Blue thread lock works a treat.
Hasn’t undone since I’ve used it.

Thanks but I don't have the tool for the locking ring as you do have.
As I purchased the bike to a local retailer and it is still under guarantee, I will pass by.

 

[Zaskar20]

Cannondale does not document properly it’s custom offset indeed: they just document its “customity“ without any instruction on how to find a replacement part. Even retailers do not seem to know.

Hence it may be easier to avoid a direct mount rather by keeping the original FSA spider (and its custom offset!). Then replacing only the “104mm BSD 34T narrow-wide” part equipped with four screws.

Judging by the difference in height of both original chainring and spider and the new Hope E-chainring, I would say the offset is 3mm, the same as found in the wheel (drive side).

 

[Orangie]

That hope chainring sucks. Pitched mine. Super noisy under heavy load. Even tried new chain. Very disappointed

 

[Zaskar20]

That hope chainring sucks. Pitched mine. Super noisy under heavy load. Even tried new chain. Very disappointed

Weird!?
No problem with mine , noise or otherwise!

 

[Flupke]

That hope chainring sucks. Pitched mine. Super noisy under heavy load. Even tried new chain. Very disappointed

Sorry to ask but I was myself confronted with a newbie issue: are you sure you have properly inserted the wide chain links (external) on the wide teeth, and the narrow chain links (internal) on the narrow teeth.

With new chain and transmission, it should not be possible but with a used chain it happens. At least it happened to me. And it was working but very noisy.

 

[Zaskar20]

So, after the 2nd incident of the lockring coming loose I decided to ditch the spacer used in the original post. I came to the conclusion that the lockring must be coming loose because all of threads on it were not engaging the all the threads on the splined crank shaft.
I am now using the Hope chainring directly attached. No Ai offset.
Now, considering the derailleur has been set up with the front chainring with the offset, without the spacer (and offset) it still runs perfectly without adjustment.
The Hope 36T chainring just clears the chainstay (see pic)
I have tightened a new lockring with the recommended torque, now with the O-ring, but using the stronger red threadlock

.

 

[ctk371]

So it is possible to attach a 36T to the Moterra. And I just put the chainring on and nothing else?

What’s the diameter of the ring?

I guess putting on the 104 chainring won’t work cause of the offset?