Belt drive in a full suspension bike question

[PedalUma]

Seems like your attraction to a IGH belt drive is contradictory to the fact that you just ordered a bike that is known to be hardest on chains in the ebike spectrum that has no chance of ever being a belt drive. Or have an IGH because the torque an Ultra puts out will spin a Rohloff's axle right out of the dropouts, I've seen it happen with a BBSHD that has similar power on tap. Good luck.

I had an HD for three weeks. It ate my new Eagle drivetrain. I promptly removed it and sold it at a loss and installed a very nice lighter weight motor with 85Nm. And installed a generic nine speed drivetrain on that bike. That torque sensor bike out climbs high end bikes from stores. Those (Specialized..) need to be walked up some sections of Sonoma Mountain, while I ride. I have had and enjoyed that bike for just over three years. A rear shoe is wrong now. Seems I never get to work on my own bikes. My three speed with a hefty half link chain is my go to bike. With several big rides daily, I have not washed or lubed the chain for six months. It is still fine.

 

[tomjasz]

It ate my new Eagle drivetrain.

In my experience, you.

I have seen the BBSHD eat rear suspensions. But having ridden 3 it’s all about the learning you talked about with the cancer patient. However, I prefer the lower powered mid drives. I sold all 3 and all my spare parts, one of every part available. I’ve never regretted it.

 

[PedalUma]

So many think that more is more. That was expensive tuition to get to the truth. It may be that we each need to pay it for ourselves because the lesson is just not transferable. It needs to be felt to be experienced. @m@Robertson recently talked about a dog getting its nose burnt on the stove. Over 90-100Nm is too much. That is how we learn. Getting to less is what takes extra effort and is most rewarding. Even Poutine can be overdone to the point you can't even see the cheese curds.

 

[AHicks]

So many think that more is more. That was expensive tuition to get to the truth. It may be that we each need to pay it for ourselves because the lesson is just not transferable. It needs to be felt to be experienced. @m@Robertson recently talked about a dog getting its nose burnt on the stove. Over 90-100Nm is too much. That is how we learn. Getting to less is what takes extra effort and is most rewarding.

Spoken like a flat lander. One point I need to disagree on, and not just a little bit. I would agree anything over that might be too much for some.... This 300+lb rider for example, that spends much of his time riding in a fairly hilly area, 100Nm is NOT too much......

The need for fat tires (for my riding) was the expensive lesson for me.....

 

[MrCaspan]

Seems like your attraction to a IGH belt drive is contradictory to the fact that you just ordered a bike that is known to be hardest on chains in the ebike spectrum that has no chance of ever being a belt drive. Or have an IGH because the torque an Ultra puts out will spin a Rohloff's axle right out of the dropouts, I've seen it happen with a BBSHD that has similar power on tap. Good luck.

Yeah I get that now, I'm just dreaming I guess Wish it could be belt driven like the Worthog from area 13 with a 1000 MD.. I am going to guess a lot of IGH on those will be returned as people will shift them under load and destroy them. Maybe in a couple of years tech will improve and IGH will get better or have some mech that disengages the power to shift so it does not destroy the IGH internals

 

[MrCaspan]

So many think that more is more. That was expensive tuition to get to the truth. It may be that we each need to pay it for ourselves because the lesson is just not transferable. It needs to be felt to be experienced. @m@Robertson recently talked about a dog getting its nose burnt on the stove. Over 90-100Nm is too much. That is how we learn. Getting to less is what takes extra effort and is most rewarding.

I disagree you assume everyone is just applying the full 160nm every time they bike. A properly configured controller and torque sensor and a rider that does not just jam the full throttle each time. That's like saying 500HP in a car is over kill. The majority of the motors life will be spent at ~40% of the engines top performance. I would rather run a 160nm motor at ~40% its entire life then run a 80nm motor at 100% it's entire life. I fell it will just last longer and also when you do want it, the pick up and go is there. Just my opinion though and yes you pay for that privilege!

 

[m@Robertson]

...
I would rather run a 160nm motor at ~40% its entire life then run a 80nm motor at 100% it's entire life. I fell it will just last longer and also when you do want it, the pick up and go is there.
...

I have a number of builds where I was tempted to use a lower-power BBS02, but this exact line of reasoning won out (having the same motor across many bikes is also compelling in that I have a common set of spares). I program the PAS to run highly efficiently and if I feel a need, there's always the throttle. But more than anything I want a motor thats overbuilt and under-utilized, so I never need worry about breaking things or letting the smoke out.

My BBSHD on this bike, finished just a few days ago, set to PAS9 - the highest level - Reports a yield of 470w of assist. Thats it. If I start spinning the cranks it will pull up to 60% of that output and drop me to as low as 190w. This is a motor whose 52v battery could yield 1500w/30a sustained if it was told to via the throttle. I'm using the Version 2 settings detailed here:

BBSHD Performance Settings (slightly refined)

In BBSHD Programming for the Pedaling Cyclist, I laid out what my preferred settings were for my ebikes. I have settled upon them after a fair bit of tinkering over time. Since that was published, …

talesontwowheels.com

Its the same with my 2wd hub bikes. Running one hub, the thing gets HOT. Running two, they barely even get warm (There's actually specific electrical principles involved that explain this and confirmed I'm not imagining it).

 

[MrCaspan]

that's a nice looking bike!!

Question for everyone is an electric motor the same thing as a gas motor where is more efficient at a certain threshold? Or do all electric motors have the same efficiency from 10% to 90%? Does anyone know?

 

[scrambler]

You need to differentiate Overall efficiency to efficiency across rpm and Torque delivery over rpm.

Internal combustion engine are roughly around 20/30% efficient when electric motors are over 85% efficient, so in terms of overall efficiency, there is a huge difference. In an internal combustion engine, most of the energy is lost as dissipated heat.

Internal combustion engine have a narrow rpm Torque delivery curve, which is why they need to be paired with a gearbox so they can deliver their torque over a large speed range.
Electric motor have a much wider torque curve, so they usually can deliver almost their full torque across the whole rpm range, which allows them to work without any gearbox (most electric cars or electric motorcycle only have one gear ratio).
Now on e-bikes with a low power/torque motor, using the gearing (mostly required for the pedaling cadence) can still provide some optimization of the motor power delivery.

Now the efficiency across the rpm range for electric motors will depend on the exact motor type, but it is also fairly flat for electric motors

https://core.ac.uk/download/pdf/19158668.pdf

 

[AHicks]

that's a nice looking bike!!

Question for everyone is an electric motor the same thing as a gas motor where is more efficient at a certain threshold? Or do all electric motors have the same efficiency from 10% to 90%? Does anyone know?

Agree with @scrambler, especially the piece about IC engines needing transmissions to allow them to stay in their power bands. Electrics not nearly as fussy here, especially at very low rpms.

Additionally, when it comes to electric motors, they can be tuned to be more efficient within certain rpm bands by the number of windings on the armature. Here's an awesome tool available for use by anyone wanting to, where you can do a little playing around with a lot of the variables, then check the results of your change. This "tool" is incredibly accurate, and well respected by the industry.

To make the point regarding the effect with different number of windings, here's this tool set up with 2 identical motors, with one having 12 turns (12t) and the other 8 turns (8t).

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

Check out the different amounts of starting torque on the far left, speeds where each is most efficient, top speeds, and also the info/differences in the boxes across the bottom - especially motor amps and range.

The bottom line here is to demonstrate there is a LOT to this. It's not something you are going to pick up overnight. Keep up with the questions! -Al

 

[PedalUma]

I did a BBS02 throttle bike this week for 325 prouder. And just finished a fat throttle 90Nm fat bike for a 300 pounder. I live in a seismic area with big hills and 350W at 85Nm suits me just fine for big climbs where $9,400 dollar bikes need to walk. Costal Northern California is hilly.

 

[MrCaspan]

I'm assuming these are all mid Drive correct? and don't get me wrong I'm not saying a compact car doesn't get the job done just as well as Mustang GT. it's just about having the get up and go when you want it, the over-the-top power. it's not that you have to have it, it's just nice to accelerate going up a hill as opposed to just going up a hill. and I know everybody's different that's just my opinion some people are perfectly fine with pedaling a little bit while going up the hill. And you do pay for that privilege. that's my thoughts behind my 1000 watt apose to getting the 750 or the 500.

And believe me I drive a Mazda CX-5 worth 20K brand new in 2013 that has no horsepower at all and I look at all these people driving Porsches that are worth $120,000 and I laugh at them cuz I say to myself you don't need that kind of power you're just paying to drive a fancy car and I know that's exactly what I'm doing with my bike. I guess it's to each their own what they prefer what they think is worth it. but I'm definitely not buying my bike as a status symbol LOL

 

[MrCaspan]

Now with that said this is the Porsche in my opinion from Biktrix..

Monte Capro Ultra 2 Fat Tire

Experience the thrill of extreme off-road performance with our Carbon Fiber Full Suspension Electric Mountain Bike. Engineered with a stiff carbon fiber frame and powered by the formidable Bafang Ultra motor, this bike is designed to conquer any trail effortlessly. Features: Powerful Motor...

www.biktrix.ca

I wanted it for flashyness only but it looks so nice but that was a little over kill and I could not get partner approval for this one LOL

 

[AHicks]

Now with that said this is the Porsche in my opinion from Biktrix..

Monte Capro Ultra 2 Fat Tire

Experience the thrill of extreme off-road performance with our Carbon Fiber Full Suspension Electric Mountain Bike. Engineered with a stiff carbon fiber frame and powered by the formidable Bafang Ultra motor, this bike is designed to conquer any trail effortlessly. Features: Powerful Motor...

www.biktrix.ca

I wanted it for flashyness only but it looks so nice but that was a little over kill and I could not get partner approval for this one LOL

First, no they are not all mid drives. The examples shown in that link I posted are actually both geared hub motors. There are both types, along with direct drive motors, all mixed up together within that database of sample motors. The biggest difference geared hub vs. mid, is the gear ratio the motor is run through. Geared hubs are fixed at 5:1 (or so) and there's nothing you are going to do to change that. The mid runs through the same gears you are using when pedaling, giving you potential for a granny gear able to climb walls for instance.

And that link for the Porshe from Biktrix? With the fat tires, I would consider it more of a large SUV. Graceful/light handling is generally not mentioned much by folks that prefer the fatty's.... -Al

 

[AHicks]

I did a BBS02 throttle bike this week for 325 prouder. And just finished a fat throttle 90Nm fat bike for a 300 pounder. I live in a seismic area with big hills and 350W at 85Nm suits me just fine for big climbs where $9,400 dollar bikes need to walk. Costal Northern California is hilly.
View attachment 119787

I get what you are saying. My wife/riding partner weighs less than half of what I weigh, and she can go anywhere I can on her 500w bikes which are half the power (or less) compared to my preference. I was responding to your comment "Over 90-100Nm is too much". It most certainly is not too much. Some will want even more, to the point things start getting ridiculous - just cuz. Others, myself included, like riding with a large reserve available for when/if we need it. There is no "too much", as long as you aren't behaving like a jerk.....

Another question might be do you NEED more than 90-100nm? I believe that question is going to depend on your weight and the weight of the bike, coupled with your need to ride hills for instance, and the drive type being considered. -Al

 

[m@Robertson]

that's a nice looking bike!!

Question for everyone is an electric motor the same thing as a gas motor where is more efficient at a certain threshold? Or do all electric motors have the same efficiency from 10% to 90%? Does anyone know?

Thx! It is early and I am still working on tidying it up. Have already made changes in that regard.

Efficiency: In short - Keep it spinning fast. When you pump in power to an electric motor, that power is used to either a) spin the motor or b) generate heat. So if for example you lug a mid drive, not only does it do hateful things to the chain and gears, it cooks the motor.

I am greatly oversimplifying here, but the above is pretty much the golden rule. Shift under low load so the motor rpms stay high.

How To Ride a Mid Drive Ebike Without Breaking It

If you can ride a bicycle you already know how to ride a hub drive ebike. Not so a mid drive. Particularly a powerful one that can tear your chain apart. Fear not. The rules are simple.

talesontwowheels.com

 

[m@Robertson]

Another question might be do you NEED more than 90-100nm? I believe that question is going to depend on your weight and the weight of the bike, coupled with your need to ride hills for instance, and the drive type being considered. -Al

Don't forget the load being carried on that list!

 

[MrCaspan]

Don't forget the load being carried on that list!

View attachment 119835

Good god is this one of those tiny homes lol, Where is the bed!

 

[MrCaspan]

What is the rule (if any) on dumping gears with a mid drive. Is it bad to dump 3-4 gears at a time under light load compared to one gear at a time?

 

[PedalUma]

I did a BBS02 chopper recently with a throttle. Not my cup of tea but I am not the customer and he weighs 350. Today I made this one. It is an amazing climber. The bike has a 750W 90Nm torque sensor with a throttle. The throttle is limited to 20. Although the gearing is low for climbs, under pedal power I took it to 25 on a rainy flat. @m@Robertson is correct about keeping up cadence. Less is more, is more of a philosophical approach that I have been applying. It seems to be helping me improve my builds. I was in high tech. We would sell 'solutions' that were additive. Those always created more problems which then required more solutions. By dumping gears, I will take that to shifting to higher gears. That is no problem. Shifting to lower gears takes care.