Downhill with motor switched off

JoeBlow

Active member
Jul 7, 2019
729
448
South West, UK
Does anyone do this? Met a couple today on hire bikes. The guy fell off and blamed it on getting an unexpected surge of power as he hit a bend because he had forgotten to turn the motor off. Personally I think he simply hit some loose gravel on the berm. Met them later and they were struggling with tight uphill turns and once again blaming the bike. I managed the turn OK and I'm by no means an accomplished rider, just average if that. They were not impressed with E bikes.

I tend to just stay in EMTB mode with the Bosch motor unless I'm a) trying to conserve battery or b)needing some extra assist in Turbo on really steep, gnarly stuff.

Al
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,999
20,749
Brittany, France
I wonder if he had it in turbo/boost and then pedalled as he went into a bend. If you were inexperienced it would throw you off balance.

The motors generally respond to your input. You don't need to Turn it off to avoid assistance catching you out. Some hub motored bikes have very long over runs if they don't have a proper torque sensor.

Poor Chap, though I suppose like many things, people judge something based on not using it properly or having taken the time to learn how it works.

Ask me again in 50 years time though ... :)
 

Stihldog

Handheld Power Tool
Subscriber
Jun 10, 2020
3,492
4,869
Coquitlam, BC
I can’t remember turning off the assist during downhills. I leave it in EMTB mode 90% of the time. Any unexpected surge is usually from Turbo mode, but that is used only for very very steep climbs.
The savings of power, while going downhill, must be minimal or barely noticeable.
Ask me again in 51 years time…?
 

Jeffrey

Active member
Jul 29, 2020
97
461
Switzerland
On downhills with technical parts I often switch off the assistance to avoid getting an unwanted push in case of a pedal strike (bosch gen4 motor react extremely quickly to suddent torque inputs!).
 

steve_sordy

Wedding Crasher
Nov 5, 2018
8,930
9,269
Lincolnshire, UK
My money would be on that they were in Boost mode (Turbo, whatever).

I have never turned off the power when going downhill. If I needed some power part way down, it would be too long in coming!
 

Gyre

Well-known member
Jan 25, 2021
630
422
Pasadena, CA
Does anyone do this? Met a couple today on hire bikes. The guy fell off and blamed it on getting an unexpected surge of power as he hit a bend because he had forgotten to turn the motor off. Personally I think he simply hit some loose gravel on the berm. Met them later and they were struggling with tight uphill turns and once again blaming the bike. I managed the turn OK and I'm by no means an accomplished rider, just average if that. They were not impressed with E bikes.

What's that thing about bad carpenters and tools? ;)

Definitely sounds like they are riding above their skill level because of the motor, especially considering the UK 25kph limit.
 

Gyre

Well-known member
Jan 25, 2021
630
422
Pasadena, CA
They were experienced but not with EMTB's.
Did you happen to notice the assist mode? It's hard to imagine this occurred in one of the tamer modes.

Anyhow, to answer the question, generally I leave the assist on. Around here downhill is almost always above the speed limiter anyway. One of the use cases I can think of where you may want to turn it off if you're on a trail where pedaling puts you right up against the limiter speed just as you hit the lip of a jump or drop. If I'm going downhill on a tight singletrack, I'll generally leave it on Eco or Tour, and if there's still any doubt I'll feather the rear brake around sharp turns.
 

JoeBlow

Active member
Jul 7, 2019
729
448
South West, UK
I'm not judging them and have no intention of doing so I simply wondered if they had a point with regard to switching off. I ride mostly on my own mid week so I don't get many opportunities to compare notes. It's never caused me a problem and there are times when an extra burst of power can help so I will continue to keep the motor on until someone persuades me otherwise.
 

lightning

Well-known member
Apr 5, 2021
715
410
UK
l always descend in eco mode, but l also change to a higher gear so l can get motor power if l need it, at the higher speeds l am travelling.
Being in a higher gear also reduces any power surge if you do start pedalling.

Only thing is, you need to change down at the bottom of the hill in preparation for climbing.
Which is what l forgot to do tonight, stalled crossing a river at the bottom of the descent, found l was in too high a gear to get any power, and fell in the river.
 

RustyMTB

E*POWAH Elite World Champion
Jul 22, 2020
2,830
6,838
UK
All the gear no idea. :eek:
I literally have that on one of my bikes. Know thyself & all that.

ZywA88Tw.jpg large.jpg
 

04fuxake

Active member
Feb 12, 2018
321
205
Porirua, NZ
The only times I pedal going downhill is because I've over-braked and need to pedal it out. For that I want assistance. So if I'm not pedaling the rest of the time, lowering the power level doesn't make any difference.
 

JoeBlow

Active member
Jul 7, 2019
729
448
South West, UK
EMTB mode seems to work in most situations for me but perhaps that's because I'm a fairly average rider and even that may be stretching things a little :). In the early days I did note a few situations when an unexpected burst of power caught me out but I haven't experienced that in some time. I suspect it's just a matter of getting used to and "knowing" the bike.
 

volksman

New Member
Jul 14, 2020
33
16
Ottawa, ON, Canada
I actually found this to be a problem with the Brose motor when I tried it. I found that it provided power after I stopped pedalling so you'd get this extra little bit of juice that if you weren't expecting could throw off your balance. I'm sure you get used to it eventually but I was riding that bike for a couple days and never did. I was constantly getting this extra little bit of power when I wasn't expecting it and ended up on my ass a couple times. Haven't noticed the same with the Bosch motor that I now own, it has it's own little quirks that you just get used to. Like you though I use EMTB mode 90% of the time and Turbo when I'm just gased or on a really boring trail.
 

Gary

Old Tartan Bollocks
Author
Subscriber
Mar 29, 2018
10,496
10,702
the internet
So even though you know that motor overrun is a characteristic of the motor, you refuse to actually take it into account while riding?

That really is quite a fascinating approach.
 

volksman

New Member
Jul 14, 2020
33
16
Ottawa, ON, Canada
Huh? I said I wasn’t on the bike for longer than a day or two. Also said you’d likely get used to it. And said that the motor that I ended up with doesn’t seem to have that issue so either I have taken it into account or it doesn’t exist on that motor.

Did I miss something or do you need a stool to get off that horse?
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
13,999
20,749
Brittany, France
So even though you know that motor overrun is a characteristic of the motor, you refuse to actually take it into account while riding?

That really is quite a fascinating approach.
It's for people who can't afford or don't want to change all their parts to Hope components. So they ride with Hope instead.

I hope it won't overrun this time, so I'll keep pedalling until the very last second.

I hope that tree I'm about to hit is a lot softer than all the trees I hit last week.

I hope that gravity is different today on that drop I keep OTBing on.

It's not worked for me yet, but I'd like to think that perseverance and determination trump common sense and logic any day of the week.
 

lightning

Well-known member
Apr 5, 2021
715
410
UK
Well, l have a Shimano motor on my Ebike and while it's quite noisy it doesn't over run.

lt does tend to engage with a bit of a clunk though.

Every motor has its own little differences. To be honest the best motor l've tried is the old Bosch Gen 3 in my 2016 Cube.

That motor just did the job, no rattling, over running, excessive noise, surging or other issues at all.

lt had four assist modes, all of which worked really well without any need to tweak them with an app.

The only thing wrong with it was, when you had to ride with the motor off you were turning a gearbox (very small front chain ring) so it wasn't much fun at all if the battery died before you got home.
 

Mini si

Member
Dec 31, 2020
82
50
Derbyshire
I actually found this to be a problem with the Brose motor when I tried it. I found that it provided power after I stopped pedalling so you'd get this extra little bit of juice that if you weren't expecting could throw off your balance. I'm sure you get used to it eventually but I was riding that bike for a couple days and never did.


Took me longer than a few days to get used to mine when I bought it last year so I know what you mean! I still don’t get it right every time I go out now and I’ve done about a thousand miles on it. I’ll keep hoping though ? and maybe I’ll get there.
 

kendo

Member
Sep 2, 2019
123
81
Scotland
Does anyone do this? Met a couple today on hire bikes. The guy fell off and blamed it on getting an unexpected surge of power as he hit a bend because he had forgotten to turn the motor off. Personally I think he simply hit some loose gravel on the berm. Met them later and they were struggling with tight uphill turns and once again blaming the bike. I managed the turn OK and I'm by no means an accomplished rider, just average if that. They were not impressed with E bikes.

I tend to just stay in EMTB mode with the Bosch motor unless I'm a) trying to conserve battery or b)needing some extra assist in Turbo on really steep, gnarly stuff.

Al
Yeah...I turn off assist quite a lot when I go to hit very steep downhill sections, don't need any assist at all, but the savings if truth be old are very slender indeed. Shimano EP8.
 

CjP

PRIME TIME
Subscriber
Jan 1, 2019
1,671
2,394
Everywhere
I hope some of these people never ever drive turbo cars, or really anything with power.
It’s as simple as learning the characteristics of the bike/motor and adjusting to suit. All have their pros and cons.
 

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