BBSHD Montague Paratrooper Pro build

[CPG]

I just pulled the trigger on another BBSHD with a 42T Luna chain ring for my new Montague Paratrooper Pro, which I should have by this Thursday. This will be my third Bafang mid drive build, as such I expect to pretty much knock it out in a few hours, we'll see!

I am waffling about going with a Rohloff drive hub, but I really wanted to get the build going in the mean time, so I compromised with myself by figuring to set it up initially with the stock rear cassette. I'll have a good chain line if it's like my older Montague, and I want to see what it weighs as it's for the plane so weight is a big concern. For now I'll be using the same frame hung padded quick disconnect battery bag and battery (11.5 AH) I'm currently using on my old Montague. Pictures when it's done.

I have a huge fly in to attend in 2 weekends, mostly Super Cub types and other planes designed for getting out in the boonies, and I want to take the new ride there. I have appointed myself the official ambassador to the back country/ off airport airplane world and e bikes, and feel a evangelical zeal to spread the good word, by leading by example. Plus they'll have a lot of beer there, should be fun.

[JPLabs]

Sweet. I bet the bike will be coveted by the other pilots once they see it in action or ride it. Such a great way to amplify the utility of a backcountry plane.

[CPG]

I'm really struggling trying to decipher what model Rohloff I need for the Montague. I've already stripped off the front and rear derailleurs, and have the BB pulled. I got on their site and tried to use their "finding the right hub for your bike" feature, but couldn't get it to translate from German, that didn't help much. Cycle Monkey is the US authority on the Rohloff, but it appears like I'd take about a $300.00 hit by buying from them, compared to other (legit) sources. I don't mind paying a bit extra for anyone's expertise, but that seems a bit much, just to make sure I order the correct model.

It pretty much comes down, I believe, to the correct torque arm, or lack thereof. I have managed to determine I want the external gear mech, as opposed to the internal, and that I need to buy a new 4 hole disc rotor so it bolts up to the hub correctly, and that I need a QR axle model. And, I'll need a chain tensioner, or maybe use part of my derailleur system to serve as one, since I don't have adjustable horizontal dropouts. Also, that the shifter cables are (I think) plain old cables and housing like we're used to using, nothing special there. So I know a lot more then a few days ago, Monday I will call a Kansas bike shop (extremebikeandsport) as they have a great EBAY price, and see if they can get me lined out.

They all seem to come with a 16 tooth standard in the rear, and I am going with a 42 T chain ring up front, so that will be my initial gearing selection, then I'll see if I need to go with one of the larger ones in back for better hill climbing, they are supposed to be easy to change out and not much money. I've read all of Sheldon Brown's articles on the subject, and then decided to just try it out and see what it feels like. None of my local bike shops know anything about them, somewhat to my surprise, though it seems they do know wheel building so I plan to have the hub built into my existing new wheel, local. Cycle Monkey can do it all, sell me the hub, already laced into a high quality wheel, but again, a lot more dough.

[CPG]

The Rohloff is on it's way, should be here early next week, it will arrive already laced to a new rear wheel, I ended up deciding Cycle Monkey's expertise in all things Rohloff (and wheel building also) was the way to go, literally. Tyler helped me through the selection process of the rear sprocket, after I told him I had a 42T chain ring. 19T I believe is what we specced out, and it will be using the newer attachment method that allows for quick and easy change outs if required. Somewhere along the line it slipped out this was going to be a e bike unit, I had not gone out of my way to mention it earlier, and he was totally cool with that. He just said something like "lots of ebikes going with Rohloffs." I guess I was thinking he might say "no way, you're on your own," or something like that, I don't know if he was wearing spandex or not but he had zero issues with the subject.

I have the BBSHD mounted, and a straightedge and a measurement from Tyler from the Rohloff shows that my chain line will be almost exactly perfect, maybe 1/8" out, which he scoffed at, as in "that's WAY close enough, and better then many." I'm also getting the purpose built Rohloff chain tensioner as part of the deal.

So, I'm in the position of the pain of the high cost well on it's way to being forgotten, (well, I still have next months credit card statement to deal with) while the enjoyment of the quality product will result in long term satisfaction. That's how it's supposed to work right? Also, an "internal geared hub" sounds like some urgently needed item of a crane's running gear, a business related write offable item maybe, we'll see next April 15 th.

As on my earlier Montague build, the frame design allows a very high mounting of the motor, and minimal shimming to clear the chain stay, a very good match between the Bafang and the bike.

[CPG]

I got my first test ride in tonight, no shifter hooked up yet but it's easy enough to shift once stopped using a wrench. With the battery at 51.4 volts, top speed on a gravel road seems to be about 34.5 mph in high/14 th. In first,-- top speed is 7.5 mph. This is exactly what I had hoped for! Now I'll have the rock climbing low speed torque I have in my fat bike, (which also has a top speed in the lowest gear of around 7.5 mph, and only runs out of torque about the same time a trail gets so steep I can't ride it anyway) in a folder that fits in the plane, plus a fast cruiser when the need occurs. The chain line is perfect, and of course will stay that way in any gear thanks to the IGH Rohloff. I have read many discussions on cassette, chain, and chain ring wear, or lack thereof, with different chain lines. What I have not seen is any reference to any efficiency loses due to a wacked chain line. My fattie drive line, at a bit less then 500 miles, seems to be wearing surprisingly well considering the chain line when I'm in the higher gears, but I have to think it's not as efficient/uses more power per mile then a straight line. I'll post a few pictures of The Black Beauty (what I'm calling it) when I get it presentable.

[WebEsquire]

I love reading your posts. Can I be as awesome as you one day?

[CPG]

Ha!

I got the Rubiks Cube of a shifter mechanism finally installed. What threw me off was the manual showing, in typical Teutonic thoroughness, in great detail a procedure for a shifter that I didn't have. So, thinking mine was a new type not covered by the manual, I tried to puzzle out how to insert the shift cables in the grip, the final solution was so simple I could have done it in a few minutes but it killed the morning. Then, after lunch, I for the first time turned to the back of the manual and saw what seemed to be an printing insertion concerning my type of shifter, clearly and simply showing how to insert the cables! The rest of the install was pretty simple, especially once completed, doing another would be a breeze. The usual complications of allowing for the folding process of the bike was not as bad as feared. I then stuffed it in the plane for the first time, and instantly noticed I will need to relocate my display as the handlebar mount gets in the way of the airframe, just like my old Montague, I'll probably have to jury rig up a mount for it.


More test riding, still just on the gravel road by my place. It's using considerably more power then my other rides, or at least seems to. Part of this is no doubt the hub being new and still not worn in, (the cure for that will be ride the hell out of it) low pressure on the tires last night also, too low, since fixed. The fat bike skews my ideas of "low pressure", but it sure has plenty of power. I need to calibrate my speedo, against my other Montague as I know it's speedo is spot on, I mean dead nuts. I MAY end up going with a smaller sprocket on the Rohloff (easily swapped out), as of right now I can easily use 6 or 8 gear for take off without undue lugging, I may have over done the low gearing thing but then again I haven't done any trail riding yet which was the reasoning for favoring that low gearing. I can easily envision 40+ top end with a smaller gear back there, not that I would go that fast often, but right now I run out of pedal assist, I can't pedal fast enough to help out I mean, at below 30. Wheelies are a major concern on takeoff! I'm using the stock chain for now, and with the straight chain line it may hold up fine, eventually I'll get a better one.

I may also swap out the handlebar stem, my old Montague has a much shorter one then the new one has, in fact I may be able to use the old one on the new ride. The fit is very snug in the plane, and the bars are better located with a shorter stem, riding considerations are secondary.

[xNateX]

> Pictures when it's done.

Pictures please? In particular the batteries/connections/thoughts. Closeups of the rohloff would be nice too. Why did you want and go with a rohloff?

I'm new to all this stuff but I have a couple of new folders, the Montague Urban for myself and the Paratrooper for my younger brother, and a couple of bbshd kits on the way.