Please note: The forum is now closed to new submissions. All the existing forum topics and posts are still available, however new topics cannot be created. If you need Sinclair C5 advice please use the C5 Owners Facebook Group.

Jos posted:

Hello Sinclair adapts,

Since 4 months I used my C5 (after a total refit of the wiring and an accu change). for commuting twice a week. Unfortunately my gearbox broke down and now I am looking for a replacement. Does anyone have a idea?
I am very fond of the C5 and in the near future I hope to be able to update the drivetrain by a brushless motor and a gear for pedalling as well

Met vriendelijke groeten,
Jos Ouwehand
(The Netherlands)
posted on: 02/02/2014 12:29:18

Ton C5 nl posted:

Ha Jos,
i am afraid that is your best bet.
or if you know someone who is handy with a "draaibank" (sorry guy's don't know the english word for it) you can ask them to make you a new one in metal.
it has been done.

posted on: 02/02/2014 16:08:07

Dan posted:

Hi Jos and welcome to our website

Can you say which part of your gearbox is broken.  Is it the out case with all the teeth in it? The 3 small cogs? Or the larger cog that the drive belt attaches to?

I've got an outer gearbox case I may sell you if that's what you're after?


posted on: 02/02/2014 16:21:19

Jos posted:

Hello Dan,

The three Motor gearbox cogs and the main innerpart that holds the cogs and coverts the power to the belt are ruined

Met vriendelijke groeten,


posted on: 03/02/2014 14:32:31


Hi regarding the gearbox insert and the 3 small cogs I do make and sell alloy inserts for the gearbox
Let me know if you are interested
Bye Chas
posted on: 03/02/2014 14:53:18


Hi here are some photos of the insert ....Bye Chas

5-1-METAL GEARBOX INSERT by charlessnarski, on Flickr
posted on: 03/02/2014 18:05:14

Dan posted:

I can thoroughly recommend one of Chas's  metal gear box cogs, I've got 2 and they're super reliable compared to the original plastic one especially when running on 24v
posted on: 03/02/2014 19:27:06

kamztrad posted:

As previously said, Chas metal inserts are a must if you want to run 24v, I am using one and have been running it on 36V for a fair few miles with no problems - have stripped it down regularly to check for wear and problems but so far it has proved bulletproof!!
Can't recommend it highly enough,
posted on: 03/02/2014 20:52:02

Jos posted:

Hello Chas,

Thank you for providing a solution but I rember reading somewhere on this website it is a pretty investment aswell. I am focussed on upgrading the Sinclair in the near future with a modern brushless motor and control as used in electric bikes. This will cost about 500 euro's, so I won't spend much money for this repair.

Met vriendelijke groeten,

posted on: 18/02/2014 14:26:39


Ok no problem
I would love to see some photos of the motor mod
Bye Chas
posted on: 18/02/2014 14:58:02