Friction Drive New Kepler carbon build

[Kepler]

Time for a new project. Straight up, sorry all, it's going to be another friction drive project but bear with me as i have a few new ideas.

So my motivation for this build stems from my love of not only riding ebikes, but also riding non assisted high spec carbon road bikes. I am always blown away when I get on my road bike on the weekend after riding my relatively heavy ebike commuter all week with just how easy it is to propel along.

This is my current road bike for anyone interested but not the bike I intend to convert.





Anyway, I have been thinking for a while what it would be like to have a serious carbon road bike with e-assist. What a monster it would be.

Time to set some goals.

Firstly it is going to be light. Maybe the lightest ebike ever documented on ES

Assist will be low. 250W max so batteries will be small but still must capable of an hour full time assist at max power to still call it a true ebike.

Must be ultra stealth. This means Internal wiring, no dashboard, and no visible drive activation mechanism.

Final riding weight goal will be no more that 9kg.

Frame and wheels have arrived and with the right components this bike could be kept down to 6.5kG as an unassisted road bike. Reality will be be closer to 7kg though as I cant justify the cost of ultra light componentry required to meet that weight.

20151117_072653.jpg (229.19 KiB) Viewed 17579 times

The Finished Product





Looking forward to this one.

[tomjasz]

Still inthralled by your design. Still hoping to someday do a friction on my Trek Lime. Never ridden anymore, but gathering dust for the day a Kepler drive gets mounted. Dreamer.

Looking forward to more details!

[Spanglo]

As an owner of a 6.9kg Trek Madone 5.5, I've often wondered the same. Road bikes are so fast with a strong rider... a little assist could go a very long way.

9kg is a respectable goal. Very interested in knowing the final kit weight.

Good luck on the build.

[Modbikemax]

This will be interesting. I got one down to Under 15kg but have since scrapped that bike. It goes fast ok just a bit too fast.
I found myself doing stupid things on skinny tyres and thought it's only a matter of time before I come unstuck. I have since gone to cruiser style bikes for a more relaxed ride on fatter tyres. There was a thread on lightweights.

viewtopic.php?f=6&t=61266

[Kepler]

I know what you mean. Too easy to get carried away. Plan is to keep the power low though. I just want to be able to lift my average speed a bit and maintain better pace on inclines. Give this 55 year old rider some 20 year old legs again

[tomjasz]

I'd be reveling having 55 y/o legs! <wink>

[soaresdacosta]

This going to be, an airplane on land.

[midwest mayhem]

Subbed! Looking forward to how you plan to stealthily accomplish throttle input.

[Kepler]

Managed to get the bike rolling on the weekend. Went with drop bars to start with but the riding position is a little too aggressive for me at this stage.

20151122_091017.jpg (110.96 KiB) Viewed 17171 times

So installed some mountain bike handlebars to see how the bike would go as a flat bar road bike. Was happy with the riding position but it just killed the overall look of the bike.

20151122_133425.jpg (278.17 KiB) Viewed 17171 times

So next thing is to go with some Bullhorn bars to give the bike a TT look without making the riding position too aggressive. Just waiting on the bars to arrive from Wiggle

[Modbikemax]

Ape hangers and a banana seat?

[LockH]

Subbed! Looking forward to how you plan to stealthily accomplish throttle input.

Subbed here too! "Donor" bike NOT looking very "aero"...

[cwah]

keyde motor or friction drive?

[Kepler]

Ape hangers and a banana seat?

Plan "B" I think.

[Kepler]

keyde motor or friction drive?

Friction drive. Similar to what we have already seen before but with a few new tricks in relation stealth, activation, and quick removal.

[Modbikemax]

Subbed! Looking forward to how you plan to stealthily accomplish throttle input.

How about a magnet sewn into your glove and a Hall effect under the bar tape?

[Mikebergy]

Subscribed. I enjoy the concept of "the less bike you have, the less power you need" and look forward to putting my first ebike together. This is probably a newb question, but is there any commercial way to mount a PAS system to a standard GXP or BB30 bottom bracket? I have only seen the dedicated torque sensing BBs, and they use the square tapered drive. I prefer SRAM components, and would like to continue using them if possible.

[Kepler]

Subbed! Looking forward to how you plan to stealthily accomplish throttle input.

How about a magnet sewn into your glove and a Hall effect under the bar tape?

Not a bad idea. Will keep that one in the bank.

In the case of this bike, activation is going to be though the front dérailleur infrastructure. I want this drive to have a positive activation so the motor will be drawn to the tire via the shifter mech and activation will be via micro switch down at the BB. At least that's the plan at this stage

[Kepler]

Subscribed. I enjoy the concept of "the less bike you have, the less power you need" and look forward to putting my first ebike together. This is probably a newb question, but is there any commercial way to mount a PAS system to a standard GXP or BB30 bottom bracket? I have only seen the dedicated torque sensing BBs, and they use the square tapered drive. I prefer SRAM components, and would like to continue using them if possible.

BB30 a SRAM components don't let themselves well to fitting PAS sensors. I think PAS is a good option on a bike that needs constant assist however a build like this only needs the occasional boost. I am tipping what you have in mind with a BB30 and SRAM complementary doesn't really need constant assistance either so perhaps PAS isn't the best fit.

[Mikebergy]

I think my thinking behind it is, if I regularly ride 18-19mph avg for a commute, with assistance, I could ride 24-25mph.

[Samd]

Great to see another friction build Kep!

[Kepler]

So I think I finally have the cockpit layout I am looking for. I am liking the Sram TT aero brake levers but also have some series brake levers that will work well with bar end TT style gear shifters. The riding position with the Bullhorn bars is similar to riding in the cups of my roadbike so that suit me fine. Plan is to have the bike fully rolling by the weekend and getting some non assist miles clocked up. With beautification complete, electrification will be next. Really enjoying this build.

[Teh Stork]

If a boost up hills is what you're after, why go for 250W instead of a more powerful ~500W motor? During downhill or flats, keep the motor off.

I'd skip the "ebike criteria" and build it exactly to your need. My need would be somewhere along 140Wh battery, with the abillity to climb two very long hills at a fast pace (14 km commute).

[Kepler]

I think we are on the same page and I am definitely building this to my needs. My rides are often 100 km plus so two hills worth of assist isn't going to cut it. Friction drive and road bike tires could be a risky mix so low powered friction drive reduces risk of tire damage and at the same time lifts range for a given battery size.

250W with my added input will be plenty for this bike. Still deciding on battery size. I am thinking 150Whr might be all I really need.

[danjpendleton]

im digging this. i bet it will be a lot of fun. ive hit almost 60mph downhill on my trek madone. nothing beats the feeling

[Kepler]

Managed to get the bike finished for the weekend as planned. Took the bike out for a 70km ride with my Saturday Beach Road crew. Was very pleased with the way the bike performed and had no problems staying with the peloton and taking my fair share of time at the front. Riding position is aero but comfortable and the bar end shifters easy to use without moving away from my prefered grip position.

At this stage the left hand shifter isn't doing anything however it be used to activate the friction drive and put it up onto the wheel.

I have nearly finished modeling the friction for this bike and will start building the drive next week.