From 35T to 41T chainwheel on my Kalkhoff Agattu

danfoto

Esteemed Pedelecer
Dec 2, 2010
395
33
Sarfeast England
Following on from my "How long should my chainwheel last?" saga, I've now done getting on for 10 miles with the 41T chainwheel and the 12T motor sprocket.

In case it's of any interest to somebody considering the change because they reckon their Agattu's under-geared, the verdict is

(a) I can't tell any difference now the motor sprocket's one tooth bigger (but didn't actually expect to)

(b) But to my surprise, the 9% or so change from 35T to 41T chainwheel is too big an increase for me considering the hills round here and the loads I sometimes carry or pull. First now seems to be very close to what second was, and top gear's too high unless we move to East Anglia, which I really don't want to do.

So FWIW I'd just caution anybody considering the change to consider how much they use their existing first and second, and be prepared for that 9% having more effect than you expected
 

tillson

Esteemed Pedelecer
May 29, 2008
5,249
3,197
Following on from my "How long should my chainwheel last?" saga, I've now done getting on for 10 miles with the 41T chainwheel and the 12T motor sprocket.

In case it's of any interest to somebody considering the change because they reckon their Agattu's under-geared, the verdict is

(a) I can't tell any difference now the motor sprocket's one tooth bigger (but didn't actually expect to)

(b) But to my surprise, the 9% or so change from 35T to 41T chainwheel is too big an increase for me considering the hills round here and the loads I sometimes carry or pull. First now seems to be very close to what second was, and top gear's too high unless we move to East Anglia, which I really don't want to do.

So FWIW I'd just caution anybody considering the change to consider how much they use their existing first and second, and be prepared for that 9% having more effect than you expected

Put a larger sprocket on the rear wheel to lower the overall gearing.
 

danfoto

Esteemed Pedelecer
Dec 2, 2010
395
33
Sarfeast England
Could do, but simpler to revert to 35T front. At least then the bike's standard when I come to flog it.
 

flecc

Member
Oct 25, 2006
52,763
30,349
I'm not very surprised, I think Panasonic largely have it right they way they've set up this limited power system for most territories. When I did the original Agattu review I remarked on the disadvantages that changing the gearing can bring. OK for some in moderate territories, but if like both of us there's real hills to climb and trailers to pull, it's often best left alone.
 

JamesC

Esteemed Pedelecer
Sep 1, 2007
435
5
Peterborough, UK
I think that the Agattu remains a worthwhile consideration for hard work with trailers etc in hilly areas, but going back to your earlier question as to the expected life of the chainwheel, it may well be that wide teeth and 1/8" chain are significant for this type of work.

If you go back to a narrow 35T chainwheel, would you consider testing a narrower chain to see if it changes the unusual wear pattern that occurred ? I would be interested to know the answer.

James
 

danfoto

Esteemed Pedelecer
Dec 2, 2010
395
33
Sarfeast England
James, the 35T and the 41T chainwheels are both 2mm thick, for which the Shimano HG40 supplied by 50 Cycles is the correct chain.

AFAIK ...
 

JamesC

Esteemed Pedelecer
Sep 1, 2007
435
5
Peterborough, UK
James, the 35T and the 41T chainwheels are both 2mm thick, for which the Shimano HG40 supplied by 50 Cycles is the correct chain.

AFAIK ...
Apologies - I had missed the fact that you had changed from 1/8" to 3/32" already.
 

danfoto

Esteemed Pedelecer
Dec 2, 2010
395
33
Sarfeast England
Apologies - I had missed the fact that you had changed from 1/8" to 3/32" already.
I hadn't, James - either Panasonic or Kalkhoff changed the spec before we bought the bikes, and AFAIC it's a real shame that they did.
 

103Alex1

Esteemed Pedelecer
Sep 29, 2012
2,228
67
Following on from my "How long should my chainwheel last?" saga, I've now done getting on for 10 miles with the 41T chainwheel and the 12T motor sprocket.

In case it's of any interest to somebody considering the change because they reckon their Agattu's under-geared, the verdict is

(a) I can't tell any difference now the motor sprocket's one tooth bigger (but didn't actually expect to)

(b) But to my surprise, the 9% or so change from 35T to 41T chainwheel is too big an increase for me considering the hills round here and the loads I sometimes carry or pull. First now seems to be very close to what second was, and top gear's too high unless we move to East Anglia, which I really don't want to do.

So FWIW I'd just caution anybody considering the change to consider how much they use their existing first and second, and be prepared for that 9% having more effect than you expected
Presumably this is an old Agattu if it's Panasonic ? If you reckon they're undergeared then just plump for an 11sp one. They definitely aren't and no mods needed.
 

JamesC

Esteemed Pedelecer
Sep 1, 2007
435
5
Peterborough, UK
I hadn't, James - either Panasonic or Kalkhoff changed the spec before we bought the bikes, and AFAIC it's a real shame that they did.
In one of your posts in the "Chainwheel" thread, you had said BTW, don't forget this is a single chainwheel and a 1/8" chain.

You have just fitted the HG40 3/32" new chain, which is a better match for the narrow, 2mm, teeth of your chainwheels.

Has the bike always been fitted with 3/32" chain from new ?
 

danfoto

Esteemed Pedelecer
Dec 2, 2010
395
33
Sarfeast England
Sorry for the brainfart, James. The original was 3/32".