Bosch gen 4 friction

[phutureproof]

I have a thread running in the Whyte forum, but I thought I'd put it here too as perhaps my experience with the Bosch gen 4 motor is not bike brand specific.

Basically, I have a new Whyte e150 RS. Lovely bike. It's my first eMTB. I have no prior experience!

I was aware of the 16mph limit of the motor assistance before I decided to purchase. I understood that there may be a certain amount of friction when you hit that speed. However, I am very surprised at the amount of friction I am experiencing - almost like having the brakes applied. So much so that it is a bit of a struggle to pedal through that speed on a flatish road. Now, I consider myself to be reasonably strong (maybe about average) in my legs. I'm certainly not feeble. So this amount of friction has come as a bit of a surprise.

I know that when I go with mates on their acoustic bikes, they will leave me for dust on flat or very slight gradients. I'll catch up on the climbs and maybe the descents, but it will be a bit of a struggle on many of the basic cross country bits that we do together.

When I am on my normal MTB (or even my Brompton), I go faster than 16mph on flatish roads. I'd guess around 18-20mph.

I'm interested to hear other people's experiences. Basically, is it something that you just learn to live with (probably), or could there be something wrong with my bike/motor (hopefully not)?

 

[j_s]

I get the feeling when it hits the limiter that it's harder to pedal from the fact that the motor is not assisting any longer so it feels different but it's not harder due to an issue with the bike if that makes sense. It's like riding in a higher mode and then dropping down a mode, less assist so you were used to the higher assist before so it feels worse than it is for a few moments until you adjust.

 

[phutureproof]

A quick search revealed this page (Bosch E-bike Systems 2020 – The Gen 4 Motor is no longer a rumour!) that suggests as part of a review of the motor:-

"The motor has almost no internal resistance, which should eliminate the draggy feel of the previous model when pedalling above the 25km/h cut-off."

 

[Jackware]

If I've read the bike specs correctly you've got an Assegia tyre on the front and some people report that they find it draggy - what tyre pressures do you use?

Maxxis assegia ??

https://www.bikemag.com/gear/components/tires-components-gear/tested-maxxis-assegai-three-ways/ Just read this review and mostly agree. I've run the assegai on front of three bikes and recently tried it on the back of my trance. The tire has really good grip off-camber, and at slight lean...

www.emtbforums.com

 

[phutureproof]

It's like riding in a higher mode and then dropping down a mode, less assist so you were used to the higher assist before so it feels worse than it is for a few moments until you adjust.

I suppose this could explain it, but I'm just a bit shocked as to how much of an effect. I'll try an concentrate more on it next time I am out. It feels more than just friction/weight to me. More like active, intentional drag.

 

[phutureproof]

If I've read the bike specs correctly you've got an Assegia tyre on the front and some people report that they find it draggy - what tyre pressures do you use?

Maxxis assegia ??

https://www.bikemag.com/gear/components/tires-components-gear/tested-maxxis-assegai-three-ways/ Just read this review and mostly agree. I've run the assegai on front of three bikes and recently tried it on the back of my trance. The tire has really good grip off-camber, and at slight lean...

www.emtbforums.com

At the moment I'm on 25 PSI ish in both the front and the rear (I'm around 80KG or so). Perhaps I could over inflate to 40 PSI and try some simple tests on the road to see how that affects things.

 

[j_s]

I still find it quite pronounced initially and I ride the bike a lot with the motor off so used to the weight and no motor assist.

 

[Zimmerframe]

Try taking your chain off and turning the pedals to satisfy yourself that there is no drag.

It can come as a surprise. You're being assisted on a 25kg bike with draggy tyres and then the help stops when you're going faster - so more drag and you're on your own.

Just ride in eco so the effect isn't as large whilst you get used to it. Or better still turn off the assistance so you get a feel of what it's like with no help at lower speeds and then go faster, so you can feel it's just tyre drag/weight.

 

[phutureproof]

Good ideas about trying with motor off to see how it feels. I'll try that too.

 

[Mteam]

When I first got my ebike I found myself in too high a gear for any given speed, but it didn't matter because the motor was assisting, right up to the point when the motor stopped assisting, and at that point it became really obvious I was in too high a gear, the bike felt terribly draggy.



I now ride in the correct gear for the speed of the bike regardless of whether the motor is assisting or not, and now the feeling when the motor switches off is much less noticeable.

Essentially you need to force yourself to be in a lower gear than you think you need, and then the effect of pedalling a 25kg bike with no assistance is much reduced.

You can spot most ebikers from miles away because they're travelling at 15mph,but their legs are turning as if they're going 5 mph - ie too high a gear.

 

[OldBean]

Recently tested an R & M Delight with B0sch Gen4 / Rollhof hub and Belt drive ...was amazed how little drag there was and was able to exceed the limiter without problem......as others have said maybe it feels draggy because you arrive at the limiter in a higher gear than expected.