A front suspension fork made for a hub motor

[shinyballs]

For high W, telescopic forks won't last as seals, dropouts, etc. gets damaged. It would be able to handle the same amount of power as a rear hub(mxus, cromotor, 54XX) setup. I haven't seen one that exists, so planning to make it. I have seen a while back of an ebike where the fork is made like a swingarm but have no luck finding the link.

Post is not to discuss the pros/cons of using a front hub motor.

 

[amberwolf]

I have a couple of thoughts on it here, considered for my trike. (for a different reason)
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=22720&start=100#p1020933

"springer" forks may work the way you're wanting, and would allow any dropouts you want on there. I believe ddk has something like this on one of his trikes in the Follies thread.

Telescopic forks can be altered as John in CR did to put a tube with clamping dropouts over the original.

 

[Drunkskunk]

Eliminate the seals, eliminate the problem.
2 designs come to mind The Monarch style Springer, and the girder style, Most famously made by Girvin.
Add shocks instead of springs, and some beefy dropouts, and you'll have a winner.

 

[IdleMind]

When I converted my home built recumbent to electric, I wanted to keep my Sturmey archer rear cassette drum brake so I decided to go with front wheel drive. I built a front suspension with a swing arm, the design was inspired by the system used on old BMW motorcycles.

Take a look at this thread to see how I did it.
http://endless-sphere.com/forums/viewtopic.php?f=2&t=61982

I'm only using a low powered hub motor, but this would work well with a bigger motor too. I like to build bikes, so I was prepared to take a lot of time to design and build it.

 

[Doctorbass]

I'm just wondering...

If braking force on the front wheel can make more relative G force when hard braking... than the acceleration of a hub motor can do, this mean that the force that the front fork take with the motor is less important than when braking right !?

So the only concern is about the suspended mass of the motor acting on the piston of the fork suspension...

I'm just thinking building a DUAL MXUS3000 + DUAL Max-E... from couples weeks...

I have a white Brother front fork that is in to shape.. so I think even 120 lb ft of torque would be ok for the fork...

What do you guys thing?

Doc

 

[spinningmagnets]

Just for the record, Zlatko Vidic built the "Mental Manno" e-bike from scratch, so if you can talk him into it and agree on a price, he made a heavy-duty girder fork for his 2WD bike. (ES member name "dred")

 

[Ch00paKabrA]

I know that you don't want to talk about pros and cons of front hub motors but I think you should. A front drive motor at 10, 15, and maybe even 20 miles per hour will behave much differently than a front hub motor at 30 or 40. At 40 mph if you try turn the bike without countersteering, the result will be less efficient turning and possibly even a high side if you turn the front wheel in the direction that you want to go. If you countersteer with the front wheel under power you just are asking for the front to slide resulting in a low side (better than a high side but they still hurt).

So the question is: Why do you want to build a high power, high speed bike with a front hub when even if you can build a fork that can handle it, it will be so far behind a rear wheel build in terms of stability while turning. If the answer is to just do it to see if can be done, then I say go for it. but, if you think that there will be any advantages to it in terms of performance, then I think you will be severely disappointed.

Sorry to break your rule but other people who might not know this might read this thread and think it was a good idea.

 

[spinningmagnets]

It's not that it "shouldn't" be discussed, it's just that there are already other threads for that. There is a growing interest in 2WD E-bikes, so I feel this is still relevant. I personally agree that a front-wheel-drive "only" Ebike is best limited to the US-legal 750W, but if someone wants to build a high-power FWD, this thread will highlight the possible performance and mechanical issues that might arise. I would think that dual clamping drop-outs would be a reasonable plan to embrace, along with a strengthened fork to withstand the increased forces.

The Original Poster (OP) has stated that this thread is not for discussing the pros-and-cons of FWD, so any further posting about that will be considered Off-Topic (OT), and members will be free to discuss that topic in another thread.

 

[flathill]

Girvin is awesome but looks dorky. How many inches of travel do you need?

How about this Pi Cycle fork. Note how it hides the wires

 

[Doctorbass]

The 2WD idea is only for drag racing and test.. I want to be able to swap the front wheel is few minutes to go back to normal rear 1wd drive...

Some suggested to use a more powerful motor on the rear wheel.. but to get the same power i wold need to get a heavy hub motor with very large axel like the scooter hub motor and i would just hate it for all the regular run i make...

With the idea of two medium size motor ( 3000W rated) i can keep one on teh rear wheel all the time with low weight.. and swap the front wheel to a front hub motor wheel in few minutes...

Drag racing.. various high acceleration test for the eyes of E-S etc that would be max 24kW on two 24 x 3 tires. The bike would weight just 25 more pounds for the 2WD swap.

The actual Farasis cells based battery i have can take 400A according to Luke so both controller with 160A batt current and 400A phase woudl be just perfect.. 320A batt =)))

As well the grip of the front wheel hub motor would be lower for the first km/h but then once the torque reduce a bit at a given speed i would still get the peak power of both motor =)

Doc