Pedalling resistance with a powerful motor

[Ebiker555]

Question please forum masters & apologies if this has been answered elsewhere.

I am currently looking into my first e-bike purchase & test rode a friends MTB this morning which has been modified with a 1500w rear hub motor with a 48w battery. It was fast to say the least.

The only major downside I experienced is that the bike was so fast you could not get any traction resistance whatsoever even when peddling in 'level 1' (the slowest/weakest) pedal assist mode. It was such a horrible feeling riding when there is no resistance at all on the pedals, I might as well have been riding a moped!

My question Is this a common issue when riding on these fast motors or do you think his bike was set up poorly? I am looking at a 500w Motor & i do want to be able to feel pedal resistance in PAS mode in order to get some exercise in!

Thanks in advance for any thoughts & responses you might have.

 

[Steve Dyson]

I find that with mine, once i am above about 12 mph i have very little resistance but then i commute daily on mine so want to arrive fresh to work so it suits me, you are probably better with a 350W motor and controller

 

[KirstinS]

Question please forum masters & apologies if this has been answered elsewhere.

I am currently looking into my first e-bike purchase & test rode a friends MTB this morning which has been modified with a 1500w rear hub motor with a 48w battery. It was fast to say the least.

The only major downside I experienced is that the bike was so fast you could not get any traction resistance whatsoever even when peddling in 'level 1' (the slowest/weakest) pedal assist mode. It was such a horrible feeling riding when there is no resistance at all on the pedals, I might as well have been riding a moped!

My question Is this a common issue when riding on these fast motors or do you think his bike was set up poorly? I am looking at a 500w Motor & i do want to be able to feel pedal resistance in PAS mode in order to get some exercise in!

Thanks in advance for any thoughts & responses you might have.

Many of these high power motors are direct drive rather than geared motors. Great for high speed but pedaling then is a pig as you are effectively driving a generator. Geared motors have a clutch type arrangement so they can be freely peddled (or vastly more freely any way )

 

[vfr400]

You have to change the gearing, but that can be complicated with those motors. If it's a narrow one, you can use a 7 speed DNP freewheel with 11 teeth on top gear, then change the large chainwheel to at least 48 teeth.

11/48 will allow you to pedal just over 30 mph and 11/53 about 35 mph. Some MTB frames won't allow a big chainwheel because of the shape of the chainstay, so have a look and see how much clearance you have. For a 52 or 53 tooth chainwheel, look for road bike cranks.

If you want to pedal without power, a direct drive motor is no good. you should look for a geared one or a mid-drive of some sort. A 500W geared motor will give a lot more usable power than those cheap 500w direct drive ones.

 

[Woosh]

every kit is a trade off. You should choose a kit according to:

- the donor bike: frame type, weight, tyres, gears, handlebars, suspension, crankset
- the person's weight
- is the area hilly?
- does the person hate changing gear?
- does the person like to spin the cranks reasonably fast? (over 60 RPM)
- maximum desired speed

 

[danielrlee]

There becomes a point at around 30mph where it is less efficient to pedal and you're better off tucking your legs in to minimise aero drag.

 

[anotherkiwi]

https://www.sheldonbrown.com/rinard/aero/formulas.html

On my way to work I peak at 42 km/h, I am not pedalling but concentrating on negotiating a -15% gradient with a corner at the bottom. I guess if I tucked in and lay down on the bars I could top 50 km/h but I'm scared my tie might get caught up in the front wheel... Not going to do an Isadora Duncan, sorry!