Hey folks.
I've got a strange problem with my new Heckler SL: an intermittent clunking noise coming from somewhere in the drive train, fly wheel, or motor. I'm really not sure.
See the video here: https://youtu.be/qBb7nsIH-Lk
Symptoms:
– A slight 'slip' in the drive motion (perhaps 2 degrees of slippage).
– With a clunking noise.
– only upon light-to-medium leg power.
– intermittent, but reliably reproducible.
– Reproduced only in "rocket" mode (purple power level), at least so far.
– The chain is NOT jumping or slipping on the rear cassette, the chain remains in place.
It feels like an intermittent 'skip' in the pawls or ratchet on the rear hub, but it's hard to be certain — and it's strange that I can only reproduce this when the motor is powered on.
Any ideas on what is happening here? (my local bike shop is suggesting to rip out the motor for ~$250, simply to help diagnose the problem!)
Drive: Fazua Ride60
Casette: SRAM GX Eagle Transmission AXS, XS-1275
Rear hub: DT Swiss 370, XD, 6-Bolt, 36t, 28h.
Miles: < 100 miles.
Warranty: purchased brand new about 6 months ago (from Backcountry[.]com Competitive Cyclist).
!()
by Aa-Wuuhaan
1 Comment
Oh… my… god… OP, thank you for providing such a detailed write up about your issue and providing very valuable information and insight in regards to helping you narrow down any potential fixes. 🥹ðŸ˜
Guys, if you ever post stuff that requires the community to troubleshoot stuff, especially anything noise related this should be THE benchmark standard all posts should be based on.
Ok, sorry, I’ll get of your lap…
ANYWAYS, yeah if you’re very certain this isn’t the chain jumping; the noise and the sudden jolt when the drivetrain is underload is a pretty tell tale sign that the freehub mechanism is slipping or starting to fail.
The DT Swiss 370 is pretty robust, usually comes now with a 18t star ratchet (older models were 3 pawl) and super easy to open up and inspect the insides to see if it’s the culprit to your problem.
My guess is that when you have the motor on, that added torque is just enough load on the drivetrain to cause it to skip vs just with your legs.
Here some provided resources from DT Swiss to help you to see if the freehub is the problem:
[DT Swiss 370 Manual](https://d2a13k6araex7u.cloudfront.net/pmt/00/00/00/00/00/00/00/10/00/00/01/34/2/MAN_HXD10000001342S_WEB_ZZ_001.pdf)
[DT Swiss Star Ratchet LN Manual](https://d2a13k6araex7u.cloudfront.net/pmt/00/00/00/00/00/00/00/10/00/00/03/77/4/MAN_HXD10000003774S_WEB_EN_001.pdf)
[DT Swiss Three Pawl Manual](https://d2a13k6araex7u.cloudfront.net/pmt/00/00/00/00/00/00/00/10/00/00/00/89/7/MAN_WXD10000000897S_WEB_EN_001.pdf) (older versions)
[DT Swiss Videos](https://www.dtswiss.com/en/support/how-to-videos)
Good luck and I hope you find your answer quick 🫡