26v Agattu gearing vs cadence

[Gringo]

Hi there folks
I'm sure some here have experience changing the gearing on Kalkhoff Agattu and could help point me in the right direction.
Question,

If I fitted a bigger motor sprocket, would I loose out on range & if so, by how much? Or is there another way to increase crank rpm?

Although I'm happy to ride a no powered cycle on a 40 mile ex-railway route without issue,
due to arthritis in the knees I have a problem with road work because of the many hills in my area.
That's where my 26V Agattu comes in to it element, well almost !

The problem,
My Agattu seams to have its max assistance around 50/60 rpm but my personal cadence is around 70/80 rpm, I can keep this up for most of the time, pedling slower normaly means more pressure on the knees = more pain.
So on those killer hills where I need assistance the most, I'm forced to pedle slower and press harder to get the best out of the motor.

PS : apart from the old railway line all my other potential routes are hilly, and those "killer hills" are steep enough to freewheel down reaching speeds of 30 mph.

Any advice welcomed.
Regards Carl

 

[flecc]

I'd advise you to fit the larger motor sprocket but also increase the hub gear sprocket number of teeth roughly pro rata so you don't increase the speed at which the assist cut-off operates and the road speed for the increased pedal speed. That way you won't lose any range while getting the cadence you want, also keeping the knee pressures from rising due to the pedal effort of higher road speed.

If you have the 41 tooth chainwheel, another approach is to change to the 35 tooth option leaving the motor sprocket as standard. This method if available means you won't have to change anything else.

However, in both cases you may find a new item means rough running if there's appreciable wear in the transmission. Best practice when wear is present is changing the whole sprocket and chain set, though one can sometimes get away with the same chainwheel since the larger size can mean less wear.
.

 

[Gringo]

Thanks for the advice flecc, with only 600miles on the clock, hopefully the chain set should be ok.
I'll look out for a larger motor sprocket and see how much range I loose before changeling anything else.
At the moment I cover 30 + miles on a full charge, 1/3 power most of the time & 2/3 for the hills (on 3/3 there doesn't seam any more power)

Ps I've now found & reed the posting "agattu 11 tooth sprocket". I wish I'd found this forum when I first brought the bike

 

[Gringo]

Hard work !
I like to try things myself before asking stupid questions but after much searching, I can't find a 11 tooth motor sprocket anywhere 12's & 13's yes but no 11's.
50cycles did say they would let me know when they have stock but I'd like one now
Dose anyone know who has these in stock.

 

[tillson]

There are a few on eBay

Connex Motorritzel 9 + 11 Zähne Panasonic Pedelec-Motor | eBay

 

[Gringo]

On order thanks.
Not being a German speaker I wasn't sure when I first saw these, conformation from people that know these things is always a big help