My humble take on E-bike design and contruction
- Thread starter wallemannen
- Start date
wallemannen
10 mW
1000w said:Just wanted to let you know that I love the look of your design and I hope to see this one come to fruition.
thanks a bunch!
wallemannen
10 mW
2moto said:
I took a walk to the workshop and checked my tubing and it was actually 1.5 mm wall thickness and not 2mm so i was wrong, but that said it looks like it's going to be a better size of tube if i understand you right?
Chalo
100 TW
wallemannen said:
Even a racing bike has the pedals located 15 to 20 degrees forward of the vertical, relative to the seat. The location you have might work for pegs, but not for pedals. Remember that one pedal will be 170mm or so behind the bottom bracket position you have placed.
I am skeptical about whether 22mm tubing is stiff enough to do a curved tube frame like you have drawn here. Curves rob stiffness from the frame's truss, and so do small diameter tubes. Small tubing would lend itself well to a Ducati-style space frame, though. Here's an example:
Chalo
Ykick
1 GW
Coming from antique motorcycle background I love nostalgic homage. Excited to see your rolling chassis and welcome to ES.
Have you seen Maars and Liberator builds on this forum? A search should find their threads. Quite different in many regards but similar layouts.
Have you seen Maars and Liberator builds on this forum? A search should find their threads. Quite different in many regards but similar layouts.
2moto
100 W
Sounds like your tube is perfect! Should make for strong, lightweight frame. 1.5 mm wall thickness is plenty.
With the motor and batteries being low in the frame, your COG will be very low. Typically, you want the COG above the wheel centres for a well balanced chassis in terms of handling. And, as you said earlier it's not a cruiser, handling may be important. So, the higher you can position the batteries and still have an aesthetically pleasing design, the better it is. If you keep the motor position as is, I would try to raise the battery box even more. Youd could then make the very bottom of the frame narrower, as opposed to flared out as it is now. Just my thoughts, not a critisism of your design.
If you have a COG below the wheel centres, you will effectively have to lift the weight up as you turn into a corner. Having COG above will help you "tip into the corner", which makes for a more pleasant bike to ride. Of course, you can also have the COG too high, but that won't likely be a problem in your design.
I should temper my comments by saying that these COG considerations become much more important as vehicle speeds go up. The extreme are MotoGP motorcycles where 1 mm increments in COG positioning, both up/down and fore/aft, are often the difference between winning and placing 3rd of 4th. At normal bicycle speeds, i.e. <25 kph, these effects are less of a concern, although can't be entirely dismissed.
However, make sure your trail figure is reasonable. Racing bicycles with very agressive handling have around 45 mm trail figures. For less nervous handling, you'd want to increse this to > 55 mm.
With the motor and batteries being low in the frame, your COG will be very low. Typically, you want the COG above the wheel centres for a well balanced chassis in terms of handling. And, as you said earlier it's not a cruiser, handling may be important. So, the higher you can position the batteries and still have an aesthetically pleasing design, the better it is. If you keep the motor position as is, I would try to raise the battery box even more. Youd could then make the very bottom of the frame narrower, as opposed to flared out as it is now. Just my thoughts, not a critisism of your design.
If you have a COG below the wheel centres, you will effectively have to lift the weight up as you turn into a corner. Having COG above will help you "tip into the corner", which makes for a more pleasant bike to ride. Of course, you can also have the COG too high, but that won't likely be a problem in your design.
I should temper my comments by saying that these COG considerations become much more important as vehicle speeds go up. The extreme are MotoGP motorcycles where 1 mm increments in COG positioning, both up/down and fore/aft, are often the difference between winning and placing 3rd of 4th. At normal bicycle speeds, i.e. <25 kph, these effects are less of a concern, although can't be entirely dismissed.
However, make sure your trail figure is reasonable. Racing bicycles with very agressive handling have around 45 mm trail figures. For less nervous handling, you'd want to increse this to > 55 mm.
wallemannen
10 mW
Chalo said:wallemannen said:
Even a racing bike has the pedals located 15 to 20 degrees forward of the vertical, relative to the seat. The location you have might work for pegs, but not for pedals. Remember that one foot will be 170mm or so behind the bottom bracket position you have placed.
I am skeptical about whether 22mm tubing is stiff enough to do a curved tube frame like you have drawn here. Curves rob stiffness from the frame's truss, and so do small diameter tubes. Small tubing would lend itself well to a Ducati-style space frame, though. Here's an example:
Chalo
On my frame the center of the pedal axle is 16 % in front of the center of the seat so i think it is going to work okej
The long curves in the design might be weak in itself but there is a panel holding the two bent tubes fixed together.
that is an awsome looking bike you got there!
wallemannen
10 mW
Ykick said:
I've having trouble to find there builds, can you post a link here?
John in CR
100 TW
2moto said:
??? I'm sure he's not putting lead on that beauty, so how can 10-15kg make any difference? It's not a motorcycle, so the CG will always be up at the rider and plenty high.
2moto
100 W
John in CR said:
Since the rider and the bicycle are not a rigid structure the combined COG is not the key parameter. The COG of the bicycle has much more of on affect on handling. Since it has two wheels, bicycle behave exactly the same as a motorcycle. It's just lighter and slower. Well, most of them are anyways.
The battery and motor are by far the heaviest components that you can move around during the design, so the location of a 10-14 kg mass make a huge difference.
MitchJi
10 MW
Hi,
http://endless-sphere.com/forums/viewtopic.php?f=31&t=40859
If he raises the motor could he eliminate the jackshaft or idler pulleys and improve handling?2moto said:
This motor might (its a little heavy for a midhub) be a good choice:wallemannen said:
http://endless-sphere.com/forums/viewtopic.php?f=31&t=40859
John in CR said:
wallemannen
10 mW
2moto said:
played around for a while in my 3d software and made some changes to the bike, redesigned the fork yokes so the trail is now 53 mm, and moved the battery box upp 60 mm so now is the major part of the batterypack above wheel center.
and when i was at it i redesigned the motor mount to a more pleasing look. and I all so tapered the lower part of the frame in the front
Attachments
wallemannen
10 mW
2moto
100 W
At the risk of repeating the sentiments of others, I do think that your handlebar-seat-bottom bracket triangle is "non-traditional". Compare yours to the typical all around bicycle or road race bicycle:
Yours seem to have the bottom bracket located more less directly under the seat. In other words, your seat tube angle is 90 degrees. Even time trial bicycles, which are about the most extreme geometry, don't have a seat tube angle anywhere near 90 degrees.
Please ignore any of this if you've already considered all this. Don't mean to "teach you how to suck eggs", as the saying goes (in English). Not sure how that translates into Swedish! LOL.
Yours seem to have the bottom bracket located more less directly under the seat. In other words, your seat tube angle is 90 degrees. Even time trial bicycles, which are about the most extreme geometry, don't have a seat tube angle anywhere near 90 degrees.
Please ignore any of this if you've already considered all this. Don't mean to "teach you how to suck eggs", as the saying goes (in English). Not sure how that translates into Swedish! LOL.
2moto
100 W
Love that last pic. Definitely cafe racer look.
wallemannen
10 mW
2moto said:At the risk of repeating the sentiments of others, I do think that your handlebar-seat-bottom bracket triangle is "non-traditional". Compare yours to the typical all around bicycle or road race bicycle:
Yours seem to have the bottom bracket located more less directly under the seat. In other words, your seat tube angle is 90 degrees. Even time trial bicycles, which are about the most extreme geometry, don't have a seat tube angle anywhere near 90 degrees.
Please ignore any of this if you've already considered all this. Don't mean to "teach you how to suck eggs", as the saying goes (in English). Not sure how that translates into Swedish! LOL.
the center of my seat is actually 16% behind de center of the pedal axel, but it does not really matter much for me, the only reason that i have pedals and not fotpegs are swedish laws. without pedals it can't de called a E-bike, but a electric motorbike. And the rules laws for an amature built motorbike is hard and expensive!
wallemannen
10 mW
not 16% ...but 16 degrees 
or more correct 72 mm "SB" on the chart posted here
or more correct 72 mm "SB" on the chart posted here
Lebowski
10 MW
As far as the handlers go have a look at http://www.sportsmanflyer.com
2moto
100 W
wallemannen said:
Looking forward to seeing it come to life. How long do you expect it to take before you get to go for your first ride?
bzhwindtalker
100 kW
Looks cool man, I love seeing more and more mid driven hubs, I think people have been neglecting this solution for way too long!
hjns
100 kW
Very nice!
Just one thought; how fast do you intend to go? If you plan for a "racer" style, does that mean you will go faster than 40kmh? If so, consider rear suspension. Otherwise you are in for a tough ride....
Just one thought; how fast do you intend to go? If you plan for a "racer" style, does that mean you will go faster than 40kmh? If so, consider rear suspension. Otherwise you are in for a tough ride....
wallemannen
10 mW
hjns said:
Ah! you just got to have a hard ass!
I've been riding boardtrack bikes in 130 km/h with no suspension at all and yes it's rough but it has it's charm!
and I'm planning to have some seat suspension ass you can see
jimincolorado
1 µW
- Joined
- May 22, 2012
- Messages
- 3
Check out this guy's similar take:
http://www.recumbents.com/wisil/chopper/default.htm
He's built other ebikes with recumbent layouts.
http://www.recumbents.com/wisil/chopper/default.htm
He's built other ebikes with recumbent layouts.
Lebowski
10 MW
Looks like AussieJester, a long time member herejimincolorado said:
