• Hello ES! We could use some help to get us past the finish line on building the new knowledgebase for the forum.
    Can you donate? Please see our fundraising page. Thank you!

CYC PHOTON

IDK about whether it is better or not to service but I tend to believe "not". Unless it is leaking out the grease isn't going anywhere.
I tend to leave things alone, but there are 2 issues around grease - firstly, it does age and may thicken (which is why Spragg clutches use a specialised type of grease) and secondly, it is good to check for metal particles contaminating the grease due to normal wear, but then contributing to accelerated wear. At least the Photon is actually pretty easy to get mostly apart for servicing. It is very well designed and built and you can see a lot of work has gone in to simplifying the design.
But one thing I do know is that I need to get down there to visit and ride those beautiful trails!
Yeah, me too. The weather has been rubbish lately.
 
CYC Photon makes it to Friday Fails.

Pretty high speed OTB (35kph) not a scratch on the bike, battery didn't even move (I use hook and loop straps to hold it). Enjoy (I didn't).

Number 8: 😵


Longer version here :)

 
Photon/34T Chainring Conflict

Hi guys, I recently bought a replacement 34T chainring - the 2 piece adapter with the separate removable 34T steel chainring. This is for my Photon, which is one of the earliest that CYC produced of that model.

In use, the chainring makes a very quiet regular clicking sound - when I removed it to identify the problem, I can see the inside of the ring is conflicting with the motor casing. There are scratches in 2 locations on the inside radial face of the chainring mount and lighter scratches on the other perpendicular axial face and the inside tips of the steel chainring itself.

I can't see any feature that would cause all of these scratches, but the bulge on the front of the output gear housing is causing some of them. There just isn't really enough clearance between the protrusion and the inner faces of the redesigned chainring.

How have other owners addressed this conflict? Is it safe to remove some material from the motor protrusion - and if so, how much? I'm guessing the protrusion is the housing for the smaller gear that drives the large output gear, and doesn't actually house the bearing for that shaft itself.

20260409_173212.jpg

20260407_144422.jpg
 
I had to dig to find this old original Photon thread. Whilst I consider upgrading to the Gen 2 or maybe even the new Pro I keep riding my Gen 1 Photon.

Last week we did the 4-day Bon Ton Roulet tour up in the finger lakes region of NY. Absolutely beautiful back roads with some nice lakefront views, albeit on busier roads. I rode my Canondale F1000 hardtail with Photon, my buddy and his wife also on Photon bikes, and his brother on a factory Trek FX something e-bike. My bike performed flawlessly and I did 185 miles in 4 days, longest day was 63 miles. I probably could have done the optional century that day except I rode part of the way with my slow friends who are too social with their riding... lots of starts and stops, yakking and conferring, and just slow in general. That's OK for awhile but not if you want to do serious miles. I prefer to get into a good rhythm and flow and bang out the miles.

Her Photon bike had some issues where it would randomly turn off, as in no power at all, even to the display. I suspect some issue with the BMS or motor controller tripping but not sure how he will go about trying to diagnose that.

As far as the Trek bike with a low power Bosch motor, the Photon seems to be better in almost every way, except maybe a little noisier. My friend's brother is new to doing longer rides and ridiculous upright geometry of the Trek was not really suitable to that. I tried to coach him on some possible changes to improve his riding position but the geometry of the bike will be somewhat limiting.
 
Last edited:
Does anyone here have or know where to find the CYC Photon Gen 1 wiring schematic? My friend's wife's bike is tripping offline during rides... no power to the display or motor at all. Sometimes it comes back and starts working again later. I want to carry a multimeter along on a ride to check to see where voltage is present or not after this happens. IOW, is the battery still providing voltage to the motor controller and display and one of those is defective, or is the BMS tripping off. They have the CYC battery which apparently does not have a bluetooth interface so can't check that status easily while out on the road. For now he plans to swap batteries and see if that resolves the issue.

I have tried the CYC downloads page but that seems to be offline for some reason. 404 not found error. I hope this is not permanent.
 
Last edited:
Did you replace that bearing, or still riding it?

Further update after disassembling the motor. Generally the motor is clean inside, no sign of water ingress, with plenty of grease but I would still recommend cleaning and repacking at this mileage. CYC have used a very nice waxy white grease which is brilliant - because it shows any wear and metal contamination very clearly. I would consider there to be normal amounts of metal contamination on the gears at this stage.

However there seems to be 2 problems, one the has existed since manufacture, and the other during use.

1: The crank bearing in the centre of the chainring retaining ring is not concentric with the axis through that side of the motor. This introduces variable drag as shown in the previous videos. I don't have a dial gauge to measure this, but it is bad enough that I could probably measure it with digital calipers. :-(

See this video:


2: The large bearing that mounts the output gear is stuffed. This is a 6816-2RS bearing, and shows signs of water damage. This is a bearing that is very exposed to the environment and in a particularly dirty location. The rubber shields are not enough to protect the bearing - there is a large retaining ring (use a pin spanner to remove, is reverse threaded) that protects the outer edge of the seal, but the inner edge of the seal on the outside of the bearing is located under the clearance gap between the retaining ring and the chainring and there is no extra protection. Even a thin plastic shield may have made a difference, but surely there is a way to fit an o-ring or proper seal in there?

I cleaned out and flushed the bearing and repacked it, and it will run a little while longer, but it is irreparably damaged and needs replacement. The old bearing needs to be pressed off the gear, has anybody done this? How tight is it?

Video:

 
Back
Top