Smaller chainring

Stuart569

Well-known member
Jun 24, 2019
128
111
NE Scotland
Funnily enough the motor gets the speed from the SPEED sensor it doesn't care what chainring is installed. Lot's of people increase the size of the front chainring not decrease. What's your reason?
 

ichauchtt

Member
May 14, 2020
63
24
Switzerland
Funnily enough the motor gets the speed from the SPEED sensor it doesn't care what chainring is installed. Lot's of people increase the size of the front chainring not decrease. What's your reason?

How else should it get the speed if not from the sensor? If the motor itself would have to measure it, it would have to know in what gear you are and what drivetrain you are using. Maybe with the Di2 that would be working, but not with manual shifting.
 

Stuart569

Well-known member
Jun 24, 2019
128
111
NE Scotland
How else should it get the speed if not from the sensor? If the motor itself would have to measure it, it would have to know in what gear you are and what drivetrain you are using. Maybe with the Di2 that would be working, but not with manual shifting.
The system calculates the speed based on the pickup (speed) sensor which looks at your wheel or disc. The system does not care what chainring you have installed.

Yes they could use the cadence to calculate the speed but as you say the system would need to know which gear you were in at the rear and the size of your front chainring. That would also only work when you were pedalling... But it doesn't so what are you saying?
 

Camstyn

Well-known member
Jun 19, 2019
121
142
Kamloops BC
There are some steep hills around here that are difficult to pedal up even in boost mode, Chain/chainring/cassette were due for replacement so figured I’d go down a size.

By steep I mean difficult to keep the front wheel down while seated, and for extended lengths. I find my cadence was very slow in the 9 tooth cog on the E13 cassette at max assist speed also so switched to a 10-46 Sunring as well. Shifting is better as a bonus. Not as nice as the new 12spd Shimano but better than the E13 cassette at least.XT Di2shifter/derailleur.

I’m not a strong pedaller, I run a 30t on my non assist bikes even with 12spd cassettes.

CD55F282-9B00-4616-86DE-EC2436C17BE1.jpeg
 

TransAmMan

Active member
Sep 18, 2019
154
142
Canada
^^ Curious as to what chain you are running ? GOLD (blingy):unsure:

How much better do you find the Sunrace cassette ? The only benefit I find to the e13 cassette is its loud enough to scare away bears and let hikers know your coming a mile away :)
 

Camstyn

Well-known member
Jun 19, 2019
121
142
Kamloops BC
Did you get a 32t? Looking for 1 also but cannot find any.

Yes, my local shop put on a 32t OneUp ring same time as the Sunrace 10-46 cassette and KMC chain, it’s just a standard chainring your local shop should have one. I’m not sure the exact spec of the OEM one for spacing but it was nothing special.
 

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