Specialized Big Hit FSR with midmount

Thanks for sharing all the info on your project with the foum. I have been following this thread with interest and also Whiplash's mid drive with the mac. I have just recently got my first electric on the road.........an HS3540 used as a direct drive hub. Happy with it for a trouble free project which was good for a starter bike but the two disappointments with my bike are not having gears to get the motor into its happy zone for climbing and also the DD does not seem to coast that freely when used as the rear wheels hub, lots of drag. Way more draq then I was led to believe.

My next bike will be a mac mid drive and I am glad to hear you are thinking of something like this as well, I will be watching with interest should you go this route. I have been inspired for sure seeing your bike, looks awesome, quiet, smooth, light weight...............its got it all. It would be real cool to have a mac mid drive with a 20 mile range that was super light and some kind of an internal geared rear hub maybe like the Rohloff or something, this is my dream anyways.

Thanks again for showing us what can be done with a project like yours. Awesome!
 
I have made big improvements in the throttle since i built it and even improved it a little more since the vid was taken, the main issue is with the lower gears but this is only because of the torque that is transmitted from spinning the motor at 3 times the wheel speed in bottom gear (about 1-1 in top gear) Dave had mastered it within a few minutes of being on it so it is not so much a problem as just the nature of the beast and you quickly get used to it, better than it being dull and under powered! :D
 
I'm interested in the physical throttle. What type is it?
It looks like a standard half-twist hall throttle. but you have the grip going over it? did you do any physical mods to the bike or throttle?
Or is that a magura throttle with your own grip?
 
waynebergman said:
Thanks for sharing all the info on your project with the foum. I have been following this thread with interest and also Whiplash's mid drive with the mac. I have just recently got my first electric on the road.........an HS3540 used as a direct drive hub. Happy with it for a trouble free project which was good for a starter bike but the two disappointments with my bike are not having gears to get the motor into its happy zone for climbing and also the DD does not seem to coast that freely when used as the rear wheels hub, lots of drag. Way more draq then I was led to believe.

My next bike will be a mac mid drive and I am glad to hear you are thinking of something like this as well, I will be watching with interest should you go this route. I have been inspired for sure seeing your bike, looks awesome, quiet, smooth, light weight...............its got it all. It would be real cool to have a mac mid drive with a 20 mile range that was super light and some kind of an internal geared rear hub maybe like the Rohloff or something, this is my dream anyways.

Thanks again for showing us what can be done with a project like yours. Awesome!

If your main issue with DD motors was the drag and the feeling of not getting the motor in its happy zone :) then you dont need to mid drive mount it simply put it on the bike, the BMC and MACS freewheel pretty much like a normal bike and the motor doesnt bog down as its geared with a wide torque band its also light too in comparison, Simons build is just fine IMHO with what he has done with my main concern being the reliability of the BMC or MAC on an off road bike whether mid drive or rear mounted, the geared motors would certainly survive a lot longer being mid mounted.
 
velias said:
I'm interested in the physical throttle. What type is it?
It looks like a standard half-twist hall throttle. but you have the grip going over it? did you do any physical mods to the bike or throttle?
Or is that a magura throttle with your own grip?
The throttle was the one on the ebikes .ca website, i did find the tube was a little short so i cut the grip off extended it to full length and fitted a set of medium compound Renthal grips, it is a hall sensor throttle.
I also got to grips with the small issue i was having with the CA not limiting properly, it now all works properly and runs even better with more power and speed, had a quick spin upto 40mph the other day :D it is now everything i hoped it would be when i started this project.
 
waynebergman said:
Thanks for sharing all the info on your project with the foum. I have been following this thread with interest and also Whiplash's mid drive with the mac. I have just recently got my first electric on the road.........an HS3540 used as a direct drive hub. Happy with it for a trouble free project which was good for a starter bike but the two disappointments with my bike are not having gears to get the motor into its happy zone for climbing and also the DD does not seem to coast that freely when used as the rear wheels hub, lots of drag. Way more draq then I was led to believe.

My next bike will be a mac mid drive and I am glad to hear you are thinking of something like this as well, I will be watching with interest should you go this route. I have been inspired for sure seeing your bike, looks awesome, quiet, smooth, light weight...............its got it all. It would be real cool to have a mac mid drive with a 20 mile range that was super light and some kind of an internal geared rear hub maybe like the Rohloff or something, this is my dream anyways.

Thanks again for showing us what can be done with a project like yours. Awesome!



Yes, the MAC is an excellent choice!!

Beautiful build Tench!

http://endless-sphere.com/forums/viewtopic.php?f=28&t=34158
 
I have not modded it to work better in any way than any other CA, this one just had a continuity problem with one of the wires between it and the controller which was causing me a problem with the programing of the throttle overide functions, now it is all working correctly i have been able to fine tune the throttle output voltage with a potentiometer and get the voltage settings right in the CA to work best with it, which has unleashed the true potential of the build.


Whip, been watching your build too, same idea slightly different execution, great minds think alike!! :D I too think it is the best way to build an off road bike if you want all the benefits, quietness and efficiency of a hub motor with the verstility of a mid mount, gears, weight distribution etc. I am thinking of doing another with a MAC, lighter, slightly smaller dia i think aswell?
I keep getting thoughts about doing one with a Cro, but to a different design, i am either going to have to do it or get therapy! :evil: but one of Matt's 4" motors would be an exciting prospect too!!
 
Yikes a Cromotor? That would be INSANE as a midmount! More like a dirtbike!
 
Accountant said:
Whiplash said:
Yikes a Cromotor? That would be INSANE as a midmount! More like a dirtbike!



correction : IT WILL BE INSANE.


:shock: :shock: :twisted: :twisted: :mrgreen: :mrgreen: 8) 8)
 
Tench said:
Accountant said:
Whiplash said:
Yikes a Cromotor? That would be INSANE as a midmount! More like a dirtbike!



correction : IT WILL BE INSANE.


:shock: :shock: :twisted: :twisted: :mrgreen: :mrgreen: 8) 8)

yep, it would be a bit insane, cos there are lighter, higher efficiency, more powerful and compact motors to chose from once you are no longer putting it in the wheel, where the cromotor is designed to go..
 
They are also noisy and hard to control unless there is something I have not seen yet? The trails I ride would be deadly with a violent RC motor, you would almost certainly end up dead...One slip of the throttle and.... oops!

No offence, but for now RC drives are for high speed street and maybe some easy singletrack otherwise you could easily get hurt. My little 63/74 was still pretty violent and it had halls! They just tend to be too touchy for my kind of riding at least...
 
I agree, i have lightened the HS in my build a little, i may even add some flywheel weight in future to calm down the pickup and smooth the delivery even more, a little well placed weight might be worth a small increase in the gross weight. The RC motors are much noisier and snappy, more suited to high speed setups, thats not what a capable trail bike needs, i want torque from low revs with accurate control. I wonder if anyone has ever done an RC drive that included a flywheel for this purpose?
 
Tench said:
I agree, i have lightened the HS in my build a little, i may even add some flywheel weight in future to calm down the pickup and smooth the delivery even more, a little well placed weight might be worth a small increase in the gross weight. The RC motors are much noisier and snappy, more suited to high speed setups, thats not what a capable trail bike needs, i want torque from low revs with accurate control. I wonder if anyone has ever done an RC drive that included a flywheel for this purpose?

Its not nessersary to have a flywheel on the rc setups as long as the throttle and gearing is setup well , running the rc motors on 48v do tend to make them noisy but if running through the bike gears the voltage can come down to 24v ( this make the ride comparable to the noise that a hub motor makes ) I am currently thinking remaking my hub road bike to run with a rc motor running on 24v with a current limit of around 120A should be more than enough to play with the other traffic :lol:
 
Tench said:
I agree, i have lightened the HS in my build a little, i may even add some flywheel weight in future to calm down the pickup and smooth the delivery even more, a little well placed weight might be worth a small increase in the gross weight. The RC motors are much noisier and snappy, more suited to high speed setups, thats not what a capable trail bike needs, i want torque from low revs with accurate control. I wonder if anyone has ever done an RC drive that included a flywheel for this purpose?

i think i know what you both mean here ( ive added flywheel weight to a moto for tight single track) but for any electric machines that have a heap of torque like these ive found the problem to be our speed based throttle, i did end up getting fetchers torque based throttle working ok after a fair bit of grief (and kellys have the option also) and it really is heaps better more controlled and easier to ride, might even save your life whiplash. :lol:
im thinking once that is sorted, then you just want the quickest response, and lowest motor inertia possible? -and yes good torque from low revs with accurate control is doable for all these motors.
 
I suppose it depends on your needs and preferences, a quick pick up is not near the top of my list, doing a full lock turn feet up to negotiate a tree and then followed by a bit of a climb, smoothness and control along with strong torque is what matters, i like riding the rocky technical trails where the bike needs the ability of a trials bike but with a decent turn of speed too, so a slow action throttle, low gearing with a controlled pickup suits me better. You want to try riding a hub motor when it is geared down 3-1, believe me it picks up plenty quick enough without looking for a lighter snappier motor! But then we are back at personal preferences, we each build a bike to suit our own likes and needs, there are so many variables there wont be one bike thats suits all uses for all people, so each one of us will have our own idea of what the perfect bike will be. This one i have built here is pretty good for the purpose i intended, but being only my second ebike build i am sure i can learn from this one to make the next one even more capable of meeting my perception of a usefull ebike and hopefully even more versatile too.
 
I tell you what guys...

DON'T STAND UP!

the reason you can't use a fast pickup motor for mountainbiking at the moment, is the power is so instant, you can't stand up while riding it.

I tried it on my 3220 RC setup (dialled down to 160 amps) and it threw all my weight to the back, which then made me turn the throttle more (think : the angle of your hand on the grip!). It's a real struggle NOT to flip over. Brakes VS motor are pretty well matched, so you need real control to keep it on track.

The only way I found to do this, was to sit down on the saddle - and who does this when riding a MTB on a downhill course?

I have a speed throttle which is rediculously twitchy. The RC CA setup may help
 
Yes Tench the RC setups are notoriously twitchy as my buddy Deec found out on the now infamous video we shot around my house, see below :) also RC controllers dont like low RPMS either, this is why I think what you have made is pretty much ideal, I think a geared down BMC might even be a bit too strong, I like the RC rigs a lot though and for fast trail riding and street riding they are great :mrgreen:, what you need is a throttle response switch where you can quickly dial in say on 3 positions the response, but then I guess the newer Lyen controllers already do this to a fashion.

Spoke with Dave last night, what a top chap, we were all going to meet at the weekend but its been called off last minute sadly, ahh well give me some time to get a better off road solution sorted out.

[youtube]dU8Mmqfmiqk[/youtube]

Oh and this amazing video from Luke just showing what electric power can do to gas bikes, this will make you laugh!!

[youtube]PHKXP_YA40s[/youtube]
 
Those two videos... I've never been so entertained! Thx for sharing lol
 
all points agreed in relation to RC.
Hub mid is a great solution, im not sure about putting in a cro though, i was under the impression that using a standard mtb deraileur and sprockets would have a limit as to how much power you could use, for arguments sake lets say its 4kw, i would think that the best hub to drop in to such a solution would be one that hits 4kw with the lightest weight penalty no? - still i'm of the opinion that hubs are most known about so so using them as a mid gives a wealth of known setups and would improve things no end having the hub mid frame, allowing you to bounce it around a bit ;) - certainly going for a hub mid next.


Knoxie, what happened to the meet mate :( ???
Also, yes wiring almost finished, going to test ride v soon ;)

D
 
Hi Deec yes that was in 2010!! cant believe it was that long ago :? its had a few hits that video :) That Zero really rocks doesnt it, I think a Mid drive is a very good option if implemented correctly, there are a lot of big DH bikes with loads of space under the frame due to the design where you can mount a mid drive, you of course have to watch the drive if you ride really hard off road.

Yes shame the meet is off however It is going to be rescheduled soon so maybe you can make it then? there are a few more UK riders that have expressed an interest in meeting up as well.

Looking forward to seeing your ride on the tracks, get that Gopro charged up!
 
Well if the new meet is not arranged for the last weekend in any month i should be able to make it. I am shooting in the first round of the UK championship series this weekend, then next month i am doing the world championships then the last weekend of every month untill October is the remaining rounds of the UK series, i cant knacker myself out on the bike and shoot in the same weekend!! i,m not 21 anymore! Just won the Midlands winter series aswell :D http://midlandshftleague.weebly.com/index.html
click hall of fame, first pic :D bodes well for the rest of the year to be on good form at the begining, scored 391.47% out of a possible 400 8) Chap who won the .22 class (3rd pic down was also using one of my guns)

Back to bikes, if i did go for a mid mounted cro i would not be putting it through cycle gears and a derailier, i have an unconventional alternative in mind :idea: 8) i wouldnt want to build something that was unreliable or even unrideable, whats the point it that! it would have to be more capable than this or why bother :D Just waiting on motor specs and dimensions to come through so i cant see if it is, was going to say possible but thats the wrong word, i believe anything is possible, to see,, no to work it all out 8)

So lets get a ride organised, where is it going to be, i could plan a route in derbyshire if i knew what sort of mileage we should be planning and type of terain you want to ride?
 
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