# Carrera subway e bike



## sean19 (17 Dec 2021)

Just purchased carrera subway e bike first ride was great just 2 mile to work then going home the assist wasn’t very good it was intermittent assist if you understand 
Any help as this is my first e bike 
Thanks


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## KnittyNorah (17 Dec 2021)

sean19 said:


> Just purchased carrera subway e bike first ride was great just 2 mile to work then going home the assist wasn’t very good it was intermittent assist if you understand
> Any help as this is my first e bike
> Thanks


As it's brand new, if there's not an easy, clear solution in its manual, I'd be taking it back to the shop to swap for one that works as it should - or my money back.


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## cyberknight (17 Dec 2021)

daft question 1st
was it fully charged?


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## CXRAndy (17 Dec 2021)

Downhill?

You were exceeding the 15.5mph assist cut-off


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## Pale Rider (18 Dec 2021)

What is the exact model?

The assist on the hub drive bikes operates a little different to the assist on the crank drive ones.


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## ebikeerwidnes (18 Dec 2021)

Without more details I'm not sure
But it does sound very similar to what happens when the battery is at minimum charge
The battery management system sees the charge at a minimum level and cuts off the assist to prevent it getting damaged. Then the batteries recover a small amount and hence the system sees it being above the minimum again - hence it allows assist again

Only happens on cheaper systems like our Carrera Crosscity - the Bosch system doesn;t do that


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## gbb (19 Dec 2021)

To start with real basics, do you understand how e bikes work Sean (apologies if im stating the obvious)
In any assist mode, the battery will supply power to the motor...up to 15.5 mph... and not beyond. Thats a legal requirement.
So you pedal, accelerate up to 15.5 then it cuts out and you pedal under your own steam. As (and if) you lose momentum and slip below 
15.5, the motor will kick back in....and so on and so on.

If thats not the reason, something might be wrong but certainly my Crossfire, my wifes Motus....and i suspect most if not all ebikes come with a nearly fully charged battery so id be surprised if its a flat battery. I assume it is a new bike Sean ?


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## CXRAndy (19 Dec 2021)

I dont know the bike, but if its torque sensing, power can fade in and out dependant on pressure applied to pedals. The OP has faded away


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## mpemburn (19 Dec 2021)

Surprised to learn that the cut-off speed is 15.5 mph. In the UK or elsewhere? They allow up to 20 mph in the U.S., afaik. Cuz we’s all cowboys here. Yeehaw.


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## CXRAndy (19 Dec 2021)

mpemburn said:


> Surprised to learn that the cut-off speed is 15.5 mph. In the UK or elsewhere? They allow up to 20 mph in the U.S., afaik. Cuz we’s all cowboys here. Yeehaw.


Having ridden several model of Ebikes. 20mph is the right level to cut assistance.


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## jay clock (19 Dec 2021)

CXRAndy said:


> Having ridden several model of Ebikes. 20mph is the right level to cut assistance.


But the law is 15.5mph


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## fossyant (19 Dec 2021)

CXRAndy said:


> Having ridden several model of Ebikes. 20mph is the right level to cut assistance.



Nah, I can burn off the e-bikers on my big full suspension on flat tracks and trails easily. Not so easy if it's 20 mph - I'd need my road bike. Can't be mixing with you lot !


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## ebikeerwidnes (20 Dec 2021)

If the bike has been in storage - or on the shop floor - for a while the battery might be 'not working'.
When we were trying to find an ebike for my wife we tried a couple in Halfords andsome of them had a battery that hadn't been charged for ages and would not charge anymore.
They were fine about it as it is a known problem - if the bike is new then take it back and explain the problem.


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## cyberknight (20 Dec 2021)

fossyant said:


> Nah, I can burn off the e-bikers on my big full suspension on flat tracks and trails easily. Not so easy if it's 20 mph - I'd need my road bike. Can't be mixing with you lot !


if they want to go more than current legal speed then they need to get orf there ashes and put some effort in  ..... exit leg pulling mode


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