Kepler Bottom Bracket Friction Drive For Sale (Finally)

[Kepler]

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I am pleased to announce that my latest friction drive is finally ready for sale to the general public. This has been a long time coming and is the culmination of many hundreds of hours testing and countless miles.

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The drive has been designed to be as simple as possible but at the same time highly refined in its operation. Durability has also been a major factor with the entire drive being made from 304 Stainless Steel and all fasteners also being Stainless Steel.

The drive is designed to be fitted to bikes with 68mm English Bottom brackets but suits most bikes with screw in bottom bracket bearing cups.
The drive is offered as a mechanic's set only with the purchaser needing to separately purchase the motor, speed controller, and battery. This cuts out the middle man an keeps overall cost to an absolute minimum.

When paired up with the latest Vesc speed controller and 63mm outrunner motor, friction drives have gone to whole new level of smoothness and sophistication. Used a 250W assist on a lightweight bike, the riding experience is nothing short of revolutionary. Check out this video and decide for yourself.



And for all details on the drive development, please check out my build thread. viewtopic.php?f=28&p=1267698#p1267698

Keeping the parts count down and the quality up means I can bring the drive to market for $100 USD. Standard postage is $20.00 USD to most countries in the world however I reserve the right the check postage costs to make sure I at least break even.

I have also put together a full installation manual detailing the drive setup, various configurations, and some finer details on how to get the most out of what is arguably the most developed friction drive system on the planet.

Great response with the first batch of drives nearly sold out. Thanks to all who have been supporting this project and patiently waiting for the drive to be finally released.

[Kepler]

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[Kepler]

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[charlie33]

I came across your build thread on the weekend, looks to be just what I'm after to get a bit of boost and keep bike light and rideable! PM sent.

[cwah]

thanks that looks good I'm interested with the bigger 500W motor. Few questions:
- With the spring, does it mean it doesn't need a brake cable to compress it the motor to the wheel?
- I'm having trouble to understand the electronic part with the on off switch. Can I use a normal throttle?
- I think 500W is enough to use it as a normal motor with throttle as sitting only without doing anything else. Can it be used that way?

Thank you

[Kepler]

That is correct, it doesn't need a brake cable or any active engagement system to activate the drive. The gravity spring is tensioned to neutralise the weight of the motor. When the motor is started, there is torque kick that makes the motor contact the tire. Once it contacts the tire, the motor will climb the tire under load and subsequently press firmly into the tire to eliminate any slip. As soon as you drop power to the motor, the motor will drop away from the tire so there is no drag on the bike.

Yes you can use a normal throttle if you prefer.

The drive is designed as an assist but if you use a Vesc controller at 500W, you could let the drive do all the work if that's what you prefer. You would still preferably need to pedal to get the bike started though and then use the drive once the bike is moving.

[cwah]

Thanks Kepler. I may keep the simple push button to keep the weight down and have things simple.

Is there any chance I could someday have it as kit? I'm really newbie at electronic

[Kepler]

Now wheres the fun in that if you dont build it yourself . Seriously, it is really straight forward to make, just takes a bit of time. Time is the problem for me so at this stage I will only be selling drive mechanics. Sorry.

[cwah]

Yes too bad time is so scarce.

I'm hoping one of the buyer of your kit could maybe build a spare one for me lol

[mechhead]

my design for a regen device addon for your kitis progressing and i havnt got your kit yet, i have two ideas for this and intend to try both; one is a simple cable splitter from the rear brake lever that lifts the motor onto the tyre and then works the rear friction brake as well one after the other so you get regen first then regen and friction brakes. ill work out a program for the vesc later but im sure with a brake switch input it could be done or maby a linear variable pot in with the cable splitter to give proportional regen and friction

Idea two, a second articulation on the end of the first that flops the motor can down onto the wheel with the rear brake from the retracted drive arm position allowing increasing tyre bite as more regen is applied, it would then spring retract away from the tyre into the break disengaged position ready for drive engagement. that would increase it to 3 moving parts with two sets of stops for both motion ranges both requiring adjustment to achieve proper function.

a diagram may be in order

[cal3thousand]

I've been waiting for this kit for quite a while now. Very glad to see that it is ready and quite affordable. I understand why it took so long though: quality. Good job on the constant revisions and being able to keep it so simple.

[Kepler]

Thanks for that. I am very pleased with the finished product and look forward to feedback once people have installed their units.

[Kepler]

my design for a regen device addon for your kitis progressing and i havnt got your kit yet, i have two ideas for this and intend to try both; one is a simple cable splitter from the rear brake lever that lifts the motor onto the tyre and then works the rear friction brake as well one after the other so you get regen first then regen and friction brakes. ill work out a program for the vesc later but im sure with a brake switch input it could be done or maby a linear variable pot in with the cable splitter to give proportional regen and friction

Idea two, a second articulation on the end of the first that flops the motor can down onto the wheel with the rear brake from the retracted drive arm position allowing increasing tyre bite as more regen is applied, it would then spring retract away from the tyre into the break disengaged position ready for drive engagement. that would increase it to 3 moving parts with two sets of stops for both motion ranges both requiring adjustment to achieve proper function.

a diagram may be in order

Sounds like you have some interesting ideas their. I think Regen could definitely work if using a Vesc controller. I would suggest that you keep it simple though for starters. I might have a bit of a play with regen myself now the main drive development is complete.

[jonescg]

Looks great, and perfect for "little e" e-bikers like myself

[schosser]

Mr. Kepler;
I have been lurking on this thread for a while, following your process and gaining knowledge as I go.
I salute you for a well executed development plan!

There are a couple of issues which I still find puzzling .

First, as far as power goes. How would your set up compare to an equivelent hub or mid motor of the same wattage. My current Catrike is powered by a 36v 250 watt 20 inch hub motor. Would the preformance of your setup with an RC motor of 250 watts be similar? If not what , what would be the (approx) delta?

Given the unique configuration of a tadpole trike it would be really cool to fab up a mount which allowed your setup to pivot on a mount attached to the trike frame just in front of the rear wheels . Any way you could sell a unit without the BB cutout so us trikers could fab up our own pivot mount?

Keep up the fantastic work! I'll probably purchase one of your standard setups for a folding bike I own as I believe the weight savings would be fantastic.
Bill

[The fingers]

That's awesome, it would be great for my daughter's new cruiser.

[Kepler]

Mr. Kepler;
I have been lurking on this thread for a while, following your process and gaining knowledge as I go.
I salute you for a well executed development plan!

There are a couple of issues which I still find puzzling .

First, as far as power goes. How would your set up compare to an equivelent hub or mid motor of the same wattage. My current Catrike is powered by a 36v 250 watt 20 inch hub motor. Would the preformance of your setup with an RC motor of 250 watts be similar? If not what , what would be the (approx) delta?

Given the unique configuration of a tadpole trike it would be really cool to fab up a mount which allowed your setup to pivot on a mount attached to the trike frame just in front of the rear wheels . Any way you could sell a unit without the BB cutout so us trikers could fab up our own pivot mount?

Keep up the fantastic work! I'll probably purchase one of your standard setups for a folding bike I own as I believe the weight savings would be fantastic.
Bill

Thanks Bill,

In relation to a performance comparison with a 250W hub or mid motor, there really isn't much difference. On 250W, the bike will do do around 30kph on flat road with this friction drive without any input from the rider. I think acceleration and low speed performance will be a little less then a hub and certainly a mid drive with the advantage of gears is going to have better climbing performance. However if you want the lightest weight and a system that completely decouples form the bike when not activated, this friction drive is going to be hard to beat.

[Slopes]

Hi. I'm a long-time lurker on this great thread

Kepler - I PM'ed you a few days ago... do you have any of these units still for sale? Thanks.

[Kepler]

Sorry, travelling OS at the moment. No problems with a drive. I have placed you on the list.

[Slopes]

Sorry, travelling OS at the moment. No problems with a drive. I have placed you on the list.

Thanks Kepler, much appreciated. Any idea when they will be available?

BTW, I wonder if etching/sandblasting stripes onto the can's metal surface would help with wet surface conditions?

[Nordle]

I'm interrested too, pls pm when when they would be available and final costs included shipping to EU.

[Jestronix]

Any details around wh/km, this sucker on light road bike should be under 10wh/km ?

[Tezca]

I plan on using RC lipo batteries in my set up eventually. Anyone have some recommendations for battery packs? I intend on using a 68mm motor for mine.

[Kepler]

Sorry, travelling OS at the moment. No problems with a drive. I have placed you on the list.

Thanks Kepler, much appreciated. Any idea when they will be available?

BTW, I wonder if etching/sandblasting stripes onto the can's metal surface would help with wet surface conditions?

Should have them all shipped by the end of the month. Still away overseas on holidays but will have time off my my day job to get stuck into assembly and sending them off.

In relation to etching or sandblasting the can, it might help in wet weather but the easiest solution is gluing grip tape around the motor. 120 grit belt sander material works really well and can be glued on with contact adhesive. Of course you can expect some accelerated tire wear so choose a robust commuting tyre if you plan to go down that path.

[Kepler]

Any details around wh/km, this sucker on light road bike should be under 10wh/km ?

I average around 6wh/km on my carbon road bike. That is at a decent pace of around 35kph to 40kph.