Suggestions Need for "Real Mountain" Biking Rig Build

I wanted to start a new build. I want to build a full suspension 29'er with a rear hub. My BMC Rear hub is on it's way out and will need to get something with a bit more umph to get my fat ass (250lbs) up those nasty hills. Any suggestions i'm more interested in torque that speed as this will be a purpose built heavy duty mountain bike. I would like to do most of the work my self so looking for suggestions.

Lynn 72 A Controller
MXUS 60V 29" 3000w Are there better options for rear hub kits? Any issues on a 29" wheel? Are there better options? Looking for rear hub sealed hub ONLY.

Battery pack's not sure was thinking 1650's custom made pack need to know what size pack would I need? Trail is about 10 miles but lots of climbing. What size pack would you recommend 10ah 15ah 20ah??? I'm thinking 15Ah pack.

My current rig is a
26" Full Suspension Giant Anthem bike with a BMC Rear hub motor, 72A Lynn controller, upgraded torque arms and 10Ah Zippy lipo pack consisting of 4 5000mah 25c 6S packs. I put 2 in series and those two in parallel to make a 10ah 12s pack. Unfortunately I believe I burned my hall sensor so looking for a new replacement. This setup has plenty of torque and speed for the type of riding I do but I dont think the BMC was setup to withstand 1800w for any extended period. Need something designed for the higher load's.

if its for off-road then why not mid drive such as BBSHD, or Tangent motors ?? heavy direct drive hub motor won't be that great for aggressive off-road riding due to the heavy un-sprung weight in the rear wheel..

What amps were you pushing through that motor in order to melt the solder or otherwise damage the Halls ?

As you probably already know a smaller wheel on the back is best when wanting to go up hills, and the slowest speed motor as well. You can put on a 26 inch wheel/hub motor combo on the rear of a 29er, all you are doing is giving the bike more of a slack head angle, which is what most of the newer down hill bikes are doing nowdays anyway .

What I do with my rear hub motors , riding on roads with small inclines is to use a 12s pack like you , but when staying on the flats or for a faster ride on the road bike I use a 14s pack . If I went up steeper hills I would use a 10s pack instead and up the amp draw a little through the C.A. .

My current rig is a
26" Full Suspension Giant Anthem bike with a BMC Rear hub motor, 72A Lynn controller, upgraded torque arms and 10Ah Zippy lipo pack consisting of 4 5000mah 25c 6S packs. I put 2 in series and those two in parallel to make a 10ah 12s pack..... .......This setup has plenty of torque and speed for the type of riding I do but I dont think the BMC was setup to withstand 1800w for any extended period. Need something designed for the higher load's.

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Your statement is sort of conflicting, but I think you are saying that you are close w/ your current set-up. Given the amount of time and money you have invested, it seems a shame to ditch everything and start over.
Why not add a sm. geared mini-motor to the frt. for a 2WD? Then you could;
1)Install new Halls(avail. @ Ebike CA, BTW), leave the wires alone and use a more reasonable controller in the 35 to 40 Amps range.
2)Stay w/ the LiPoly and use another 2S/1P or 2P pack for the frt. motor, giving you a total capacity of 15 Ah or 20 Ah.
3)Take some of the money you are planning to spend and put it into better whl.s and tires.
Now I know the experts will come on here and say that a frt. motor will ruin the handling and is not needed, but I will say it depends on what kind of trail rider you are.
If you rail the berms, do drop-offs, loft the frt. end alot and generally haul ass, yes, I would say go w/ the mid-drive or a huge hubbie and deal w/ the problems that will arise from using those set-ups.
But if you are like me, have slowed down a little, pick the trails that are not the most difficult and don't try to climb hills that you couldn't walk up w/out to resorting to all fours, 2WD works very well.
More or less, the same rational applies to the donor bike. Your Giant is fine for 'less than all out" trail riding and if the above mentioned whl. and tire up-grades are performed, that could be taken up a notch and flats could be a thing of the past. My experience w/ trail riding here in the desert is, flat tires have been the biggest challenge to overcome.
I've worked out the throttle set-up and the best way to bulk charge LiPoly over the years and could supply some links should this might be an option for you.

I also have a Niner full suspension bike that I'm planning on using. So I already have the bike. This would be for off road and like the simplicity of a rear hub setup. Don't want to do mid gear drive. Dont want to do front hub although that's very interesting. The setup I have now is great in terms of torque and speed just want to get a gear hub setup with high torque. The 29er provides great coasting power and the larger wheel alows me to go over most anything. So really just looking for a robost rear hub setup. Any recommendations? What would the recommendation be in terms of amps I would need to put through the system?

A geared hub is not the most reliable in mountain trails. If you want torque and reliability, don’t be afraid building with a 25 lbs DD hub with 50mm magnets, a slow winding for a 29er.

Assemble 5Ah lipo bricks 18s 2p, even 8Ah bricks if you can. With a slow motor and 29 wheels, you should do 30 Mph. Feed it 80 to 100A battery current, 160+ A phase current to start with, to make it a good climber.

That is the way to build reliable motor bike feel for mountain trails, while driving the chain is the way to build the best bicycle feel for technical and jumping.

Here are a couple of pics of my current rig. I may try and fix the hall sensors first. Thanks for all the suggestions.

halls are easy to fix
lyen has them as well

You make it sound difficult to install new Halls, it's not, especially since I can tell you how. I've done two of 'em.
Remove the cover screws w/. a hand-held impact driver so you don't strip them.
If your motors are like my EZee's, the Halls didn't fail, but the wire-to-PCB solder joints did. It really doesn't matter because the parts are cheap. Get all three Halls from Grin and while you are at it, get the up-dated V2 PCB. The V1 had ridiculously sm. holes and the one on there now will have epoxy in the solder holes making it difficult to get a good solder joint.
When you carefully pry off the old PCB, there will be an out-line where the epoxy was and you will use it as an guide to where you will JB Weld on the new one. The position is not critical, but you want it close to where it was.
Leave the old PCB intact and hanging to the side.
After you mount and solder the new Halls on the new PCB, epoxy it on the Coils.
After it has cured, solder in the Hall wires using the old PCB wire location as a guide.
I had to lengthen my Hall rewires because they were too short, a common prob. w/ the early Ezee's.
That's it.

I appreciate the response. Do you happen to have any pics of the pcb board so I have a visual to compare. I reached out to Lyen havent heard back yet. Also do I need any special tools?

I'm going to keep the rig as is for now and if I can get the hall sensors fixed I may not butcher up my 29er and just enjoy what I have. It's a lot of fun on the trails.

I"m opening up another thread on BMC rebuild so I can keep this on topic. But here is a pic of the inside.

motomech said:

...
As far as the 29's are concerned, I've never rode them, but I'm not sure they are "better" for a hub motor wheel. At any rate, motor cycle-like full-on HD knobbies is something a serious trail rider must have. I use Kenda Nevegals ona Alex rim.

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Larger wheels are speeding much better on the rough, but you are right in that they are not best for hub motors. Unless the winding is a perfect match for the wheel size AND the motor is heavy enough to shed the heat, a 29er wheel can make climbing very hard on a motor. Even a 26 can be, but a 24 is definitely making a bucking pony on any but the nicest trails. I use 26, Kenda Nevegals too, on Sun Double Track rims.

The hub (rear only) is a 33 lbs X5404 fed 20kw bursts. The bike is 88 lbs with 8 bricks of 6s 8Ah rc lipo. I find it a tad heavy but it is my best so far, best time and best reliability. It’s been a killer for any ebike trying to keep up in mountain trails. I can’t count those that broke or crashed trying to compete.

motomech said:

You make it sound difficult to install new Halls, it's not, especially since I can tell you how. I've done two of 'em.
Remove the cover screws w/. a hand-held impact driver so you don't strip them.
If your motors are like my EZee's, the Halls didn't fail, but the wire-to-PCB solder joints did. It really doesn't matter because the parts are cheap. Get all three Halls from Grin and while you are at it, get the up-dated V2 PCB. The V1 had ridiculously sm. holes and the one on there now will have epoxy in the solder holes making it difficult to get a good solder joint.
When you carefully pry off the old PCB, there will be an out-line where the epoxy was and you will use it as an guide to where you will JB Weld on the new one. The position is not critical, but you want it close to where it was.
Leave the old PCB intact and hanging to the side.
After you mount and solder the new Halls on the new PCB, epoxy it on the Coils.
After it has cured, solder in the Hall wires using the old PCB wire location as a guide.
I had to lengthen my Hall rewires because they were too short, a common prob. w/ the early Ezee's.
That's it.

Click to expand...

I'm kneed deep in this now. I'm at the point where I can see the controller board and see the epoxy covering the wires. My plan was to replace the hall sensors and gear's with the composite gears. However it appears that the under the controller board the hall sensors are JB'welded inplace. Can you elaborate a little on how I remove the old hall' sensors with out damaging anything? Do I have to desolder every wire on the controller board?

I try to heat the epoxy stuff to about 100C, then use a small pointy screwdriver to dig it out. It gets sort of rubber-like when it's hot. Once you get the epoxy away from the legs on the hall sensors, they can be unsoldered and replaced.