Help with friction drive bracket

see pic, the surface is pretty flat
I want a bracket for one of those skateboard motors like a 6354
I'm thinking I can get away with a metal U shaped bracket going onto the chain stays (with cable ties around those bits)
then a right angled piece to attach the motor to
I might even drill another small hole in the carbon, try and feed a piece of metal through that existing hole, then bolt the 2 pieces together
what do the endless sphere gurus think?
thanks!

searching through my collection of acquired rubbish over the years and found this....the head happens to fit through the hole
maybe I could acquire something similar with a shorter thread BUT do I risk cracking the carbon?

Carbon frames are like eggshells. They'll do the job, until the least little thing goes wrong. And they only do what they're designed to do.

It looks like you don't have a threaded bottom bracket shell. If you did, I'd suggest using that to mount motor brackets. As it is, I don't see a good option for you. If your seat tube is round, you may be able to clamp a motor bracket to it somewhere above the curve of the tire.

The best kind of frame for a friction motor drive like that is one with a kickstand mounting plate.

Ah now I see!
Firstly what crankset are you running. It looks like Shimano? If it is, and you can afford to, switch out the pressfit and go for Kepler's BB mount.
DON'T drill the frameset.
What is the threaded nut on the non driveside chainstay for? It maybe useful as it will be reinforced.
Lastly, your running way too big a tyre in the rear Be careful, because if the tyre picks up mud etc it will go through the carbon before you realize it. I'm speaking from personal experience unfortunately
:thumb:

it's a standard Shimano 50/34 crank, looks like the frame is 85mm wide down there
Could you send a link to a suitable BB please? I did a search and found some weird FSA thing
re the threaded nut, there are two, must be an attachment for a cadence sensor thing, I should try one of them, keep forgetting :lol:
Good point re the tyres, I'll have to stick to the smooth French roads
here'a another angle...the tyre has a bit of space in front but yes the sides are a bit close

Look at Rotor,Praxis and Wheels manufacturing. They all do a threaded option for your BB setup. It's got to be threaded in order to clamp Kepler's BB bracket. As long as your spindle is 30mm(mine was) you won't have to alter the bracket. It's a simple fit if you are going with the cable activativation. A little more fettling required if you are intending using the tyre climb method.
Your sensor mount might be ideal for mounting an asymmetric bracket to carry the motor with a stablizer fixing in the centre via your cable guide mounting hole. If it were me I would go with trying to use Kepler's bracket as it's a very neat looking setup.
You will always have plenty of clearance at the forks,it's the chainstays that determine max tyre width. You could run a wider tyre up front and slightly smaller at the rear to maximise comfort. Smooth tyres are best but if you are intending doing any offroad the Specialized pathfinders are great. Also try the 3" inner tube sheath attche to the motor can with 3M tape.Works great and again very quiet without sanding away you expensive tyres :wink:
The Orbea is a good bike for this project. You should end up with a very light e bike.

my motor arrived but it's a bit big :lol:

Impressed with aliexpress though, only 11 days delivery....
Got a smaller motor on order....

:lol: it is rather large! For a lightweight road bike,I found the Turnigy SK3 5055 280KV a great motor. Obviously you need to factor in your intended battery setup to get the right rpm/torque for your proposed level of assist.
As a rough guide a 50mm motor @ 280Kv would be 'best' at around a 6s/7s setup.
So for say,a 6s and a 280Kv motor (50x3.14x25.2x280x0.7x60/1000000)= possible road speed@full charge of approx 46km/h. Although even with the 0.7 factored in(70% of Kv when under load) there are other factors to consider. I've found it to be helpful and fairly accurate in deciding what Kv motor/battery setup to go for.
Regards
David

urga said:

So for say,a 6s and a 280Kv motor (50x3.14x25.2x280x0.7x60/1000000)= possible road speed@full charge of approx 46km/h.

Click to expand...

Great thanks, so what formula is that? I can see pi in there...

Homemade formulae I'm afraid Based on what I've gleamed from the forum.
motor circumference x pi x voltage of cell x Kv of motor x efficiency factor x 60/100000( to convert from mm/min to kn/h) should give you max speed acheivable at full charge(4.2)

The offset at which you'd have to mount that motor would create a notable weight imbalance. Unless you mount it significantly behind the chainring. But if you did that, the twisting torque of the motor is much further out versus where it's mounted. The amount of lever you have exaggerates the effect of the twisting force on the frame.

I don't think that any of the pre-existing drilled holes would be strong enough to handle the twisting forces of that motor. Even if you used all 3.

The bottom bracket mount idea is the most sane way to go.

I personally would not motorize a carbon fiber bike at all.. they have the lowest structural integrity of all bicycles. You'd be better off converting a walmart bike.