02 Jamis Dakar Comp mid drive choice

Slozukimc

10 W
Joined
Nov 28, 2016
Messages
73
Location
Montour Falls,NY USA
Like the title says, I need to choose a mid drive for my Jamis Dakar. I want it to be as much like an electric trials bike as I can get without sacrificing reliability. I have a Montague Paratrooper BBS02 running 14s lipo and it is fun but pretty boring on the trails. I want to pull hills full throttle without burning it up. I want low enough gears to crawl slower than you would walk and a top speed no more than 30mph.
I think it will be between the GNG or Cyclone. I have been looking at the BBSHD with an external controller but if I am going to go that route I might as well go big or stay home. Lol. I don’t want a hub motor because of weight and not low enough crawl speed without overheating.

So what is the best mid drive for slow speed, wheelie popping, climbing over shit, trail riding and general being a hooligan?

Thanks, Mike
 
What do you folks think about the reliability of the aluminum frame Dakar with anything more than a bbshd? I don’t want to build a bike that is going to destroy itself in a short time.

Thanks, Mike
 
Also I have been spending a lot of time on the Paratrooper and for the most part it has enough power and more than enough speed. I am thinking I will go with one of the bigger drives just for the fact that I feel like I have to be careful of breaking the bbs02.

Mike
 
So after doing a lot of reading I have decided to put a BBS02 on the Dakar to see how much flex I get in the rear suspension. If it holds up well to that I may put a BBSHD on it.
I also think that unless the Jamis really impresses me I will keep my Montague Paratrooper as my primary ebike.

Mike
 
Slozukimc said:
That looks sweet but I think out of my budget.

I couldn't find a price anywhere on the website. I guess its a case of "If you have to ask how much; you cannot afford it!".

I hate that marketing ploy. Why make me contact you -- wasting my time and yours -- just to find out I cannot afford it. D'ya really think that you can sell me something I can't afford? (And if you could, do you consider that ethical?)
 
Been working on the bike here and there. The bbs02 fits quite well. It required a 2mm spacer to keep the chain ring side of the drive from hitting the rear suspension mounting bolt. Now it just touches. The 42 tooth Lekkie bling ring is pretty close to the chain stay. Will have to keep an eye on it to make sure it doesn’t hit when the bike flexes. The bbs02 is all installed, except brake sensors for the hydraulic brakes.
Currently regreasing all of the bearings and rearranging the cogs on the cassette so I have a better chain line for the 3 gears I will use most. Going to use the 3 biggest I have as I don’t need to go fast. I want to try to put the biggest one in the middle and one on each side of that for the other two. I know it will make shifting odd but I will be using the lowest gear the most off road and on big hills so I want that to have the best chain line. So rather than putting the next two smaller on the outboard side I thought it might be better to split the difference by having the big one in the middle. Any thoughts?

Mike
 
Hi Mike,
I see what you are trying to achieve, but my choice would be to keep the progression from one sprocket to the next "standard".. biggest sprocket nearest the wheel, then next smaller etc.. and set the middle one of the three you expect to use for the "perfect" chain line. I think one sprocket spacing either side would be ok for chainline, and the derailleur is set up to move further away from the axle line the further it goes in towards the wheel, so the standard arrangement of sprockets makes most sense in that regard.

It will be interesting to see if the derailleur can handle having the biggest 3 sprockets in the middle of its range instead of at the inward end. I will watch comments here, as there are others with much more experience than me who might have already tried the arrangement you propose.

Good luck with it,
Dave
 
I put the cassette together with the biggest (32) spaced out so the chain line is almost perfect. I have the derailleur adjusted so it won’t shift into the smallest of the cogs but have yet to be able to get it to stop before going past the big one without paying attention. I did end up just leaving the gears I want to use in order as the frame of the derailleur would hit otherwise.
I did notice my back wheel is a bit bent and the bearing races in the hubs are a bit rough so if I like how this bike rides I will build a wheel with a IGH.
Still have to get batteries all set up in my backpack and wire up a tether of some sort. I am going to run the wire up the front of the seat and up to my waist so it is away from the wheel and any other moving parts. Should be safe there and allow plenty of slack.

Can’t wait to take it for a spin. This thing should be great for a trail bike and still plenty fast enough for me on a bicycle.

Mike
 
Got the backpack all set up. I have my Kilowatt frame bag inside the backpack. Only using one side of the Kilowatt bag allows me to use the straps and another to make it very compact and provide excellent protection for the batteries.
Didn’t get a chance to ride much but I did notice a few things. The Hutchinson Scorpion tires SUCK in the slippery mud. At least the front has to go. The gearing is pretty good. The motor spins plenty fast even in the higher gears. With the 42 front and 32 rear it seems to have quite a bit of power, enough to lift the front wheel easily if you want. Going to pick up a Luna Mini 30 tooth for the front for crazy slow climbing. But, before I can do any technical trail riding I need to figure out how to reprogram the throttle to be more progressive. It will work to go slow if you are very precise with the throttle but in real world riding that can’t happen and it just comes on way too strong.
Is there anyone close to Ithaca, NY that would be willing to program the BBS02 for me? I will buy the cable and learn to do it eventually but would like to get it fixed before I hurt myself with it.
Getting used to the full suspension is going to take a bit. Feels loose to me but that is probably just tuning and better tires to keep it planted.

Thanks again All, Mike
 
Brakes are dragging. I think the calipers are sticking a bit. Figure that has a lot to do with the squirrelly handling in the mud. The front is the worst. I will service the brakes and try again when the weather is better.
 
Put a 30 tooth front sprocket on. Holy shit! It climbs anything as long as you can stay on it, keep traction and the front wheel down. Slow speed throttle control is much better and pedal assist in 1 and 2 are now useful instead of being way too fast. Now let’s hope the Jamis holds up or its back to the Montague Paratrooper.
 
I hate the throttle on the bbs02! The range of control sucks and the programming sucks worse! Using pedal assist, wanted a bit more power so tried the throttle, no response, more throttle, no response, stop pedaling saying what the heck, full throttle, bike loops out, I go on my back and lay there going what in the hell just happened?
If the throttle had responded when pressed it would have been fine. I know to expect that behavior now but man that was one hell of a surprise!

Mike
 
Hi Mike,
Re the throttle behavior on the BBS02.. it seems lots of people are having similar issues, especially on motors with recent controller firmware, and several people are working on solutions.
Check out the thread called "Throttle Behavior" on ES, E-Bike Non-hub Motor Drives.
Other than the throttle issue, it sounds as though you have got the bike working well.
Dave
 
Thanks Dave. I have been reading through those posts. I know now to use the + button if I need more power in PAS mode. It’s still a very dangerous setup.

The bike is like a 40 pound 2 stroke dirt bike with a sticky clutch cable. It’s on or off and you don’t always know exactly when. Lol

I am thinking about selling this bike or trading it for a Tangent Ascent kit for my Paratrooper.

Mike
 
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