??FREEWHEELING BHT?? or other powerful motors?

to freewheel or not to freewheel- that is the ?
I'm trying to find real world examples of moderate power via single reduction put to the rear wheel, preferably successfully using freewheels for motor and pedals.

I am reworking the bht on my klein mantra as the 1st iteration needed much improvement.

I initially used a cheap 2 pawl freewheel w/ adapter to the freehub cog. This fully threaded freewheel enabled an additional 1.37"24 adapter to thread a 6sp freewheel onto the wheel also.

Needless to say, the bht @5hp is not just questionable for a non mx rim, as well as my frame.
But so far the freewheel was what failed.

It appears all other middirect driven BHT's are non freewheel. Drum, evolutiongts, and skeetab's builds have been helpful, but they aren't running freewheels and in most cases are pedaless.

Am I missing a build using a freewheel on rear with 50-60t sprocket and moderate power? (perhaps a white industries- but does it hold up, and has the user acheived any tandem bike gears?)

View attachment 1

Thanks

b.bump*
There are some good threads on this subject, all older.

It seems that broaching freewheels were popular in the past, but have faded away?

What would be the point of broaching two freewheels over a freehub, when one could just use the native threads of both freewheels and thread them together? My simpe adapter I posted pix of in jackjetful's build achieves dual freewheel, but needs a fully threaded 1st freewheel in it's current state. (HD won't work)

Can a freehub even take the torque that W.I. HD FW can take? It seems obvious there is an alternative because broaching really isn't mentioned anymore.

What is the alternative? I'm finding nothing other than guys bolting the power (not freewheeling) direct to the rear!

So, has anyone sent 4k watts to a rear wheel freewheel successfully?

Is the standard or HDversion white ind. freewheel usable for this?

I don't see anyone else freewheeling a bht or similar, and don't want a 90$ lesson on whether the white industries HD will hold up.

well, since I was left to my own devices here I just ordered the hd wi freewheel. Think I have a way to use it and a freehub/6sp cassette in my 142mm d/o.

Modded left d/o and mounted caliper and disc w/ that hiddencable brake sensor thingy for ebrakes.

Next need to mod for deraileur on right and mount 'dash' and mudflaps. still waitin on some alternate chain tensioning stuff and the wi hd fw.

I found that a 5$ deraileur hanger/mount is well worth the money vs engineering/fabbing from scratch. I went with steel so I can just weld it on the extension.

Mounted the ca/keyswitch/gopro platform. Waiting for headlight integration and final ca and control/cable routing. Not sure if ca3 is worth integrating into controls for throtte/e brake. It's kindof a PITA to setup and I'm disappointed that a near- 200$ 'best option' doesn't come with ANYTHING IN PRINT???????????? only an '''unofficial manual''' on this site. WTF GRIN. I only mean to be constructive- seems slightly unprofessional.

2day got the sks-65 23$ mudgaurds/fenders- they should work good. Look good-at least when I put the front on the rear wheel lol.

I'll post some pix to add context later.

Still slightly surprised noone has helped me out with the fw question- either it's that obvious or I am really misconceived/directed? RRRRRRRRAAAAAAAAAAAAUUUUUUUUHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!

I get few replies to many of my threads (some get none), kinda depends on what it's about and what I'm asking. Sometimes people just don't know, and someitmes I think they don't wanna read the wall of text details I already know as explanation before they answer.

As for which will take more, I dunno, but a freehub has bearings along it's length in various places, while single-speed freewheels may have only one (meaning if forces are not aligned perfectly it's gonna side-load it to one degree or another, and wear it faster or break it).

for the pawls that actually transmit the torque from sprocket to drive core of each, I expect there are more pawls with wider grip on the average freehub vs the average singlespeed freewheel, but that's something you'd have to check on for each one you want to use.

What they are made of and the ratcheting surfaces they ride upon when freewheeling will also make a difference, as well as how well they are lubricated and with what.


There've been a fair number of discussions of freehubs, freewheels, and whatnot, but none of them are "conclusive" becuase they can't be: there's too many different brands and clones of them.

There was a post that did have a picture of a number of freewheels, and some data on them, but I don't remember for sure where it is or who it was by. I think it was in one of the dual-freewheel / WI threads, but I'm not sure. At least three years ago.


As for how much power successfully run thru one? That would depend on yoru definition of success.

On one version of CrazyBike2's powerchair drivetrain, I ran over 3KW successfully thru one, probably closer to 3.5KW....right before the controller blew up because my chain derailed at the mid-front chainring and tangled in the crank there, then pulled the axle loose in the dropout on the right side, then bent it, then pulled spoke nipples partway out of the steel rim, and bent it, bringing me to a screeching halt in traffic.

I also folded some chainrings like tacos on other versions...but I never broke a freewheel (mine were multi-sprocket ones, rather than single-speed, so they had wider-set bearings, so my experiences do not directly correlate with your question).


Printed documentation...realistically, most people throw this away with the package before they even take the plastic bags off the products. Then they fail to figure out how to install or setup the item, and call tech support (or take it back to the store, minus the packaging and documentation that would have prevented this).

So many places no longer provide anything but electronic online documentation--especially small businesses that can't really afford (without increasing hte price of items) to print stuff up like the CA documentation (there is a manual online for it at the Grin site...and though it is not as detailed as the UUG it does cover most things a new CA owner needs to know, and it is about 1/4" thick printed on 8.5x11" paper, singlesided, based on my stack of printout from a while back used to keep around).

Have you considered a sprag bearing sprocket on the motor? Lots more power handling. You could drive it to the brake disk side of the wheel and keep them separate.

Thanks AW, speedmd.

No worries, I understand the people with time/answers just aren't even aware of the question when it goes unanswered. Better than trolls though right? Just was venting a litte, I am surprised they're not easier ?'s to answer, but that's cuz the majority are either too custom or vanilla I suppose.

On the ca documentation I thought that too. alot of deluxe vehicles don't have shop manuals anymore either-theyd be too big. It's a pain to me to try to find the link and page on a screen when I could flip to it in a manual so much quicker- that and the ca is complicated- enough I can't memorize the funtions right-off, so it takes a while to memorize and then program correctly. I think it should be simpler, have a printed manual to aid learning, and an upgraded interface- but it's still the best of what it is- as is.

Thanks for the input on the drive power! If I can get my hands on a sickbike HD, I am ready to run my xt hub adapted to threaded fw body for the HD powered by bht 4.5k, then back to a cassette 6/7spd for pedals. I'll post a writeup when done and it works. made my 10t freehub cog earier- what a pita with an angle grinder.

Speed md, I originally wanted to do leftside drive because I percieved it as simpler, but I need so much more frame and bb clearance it just didn't workout. I'll check out 'sprag'- not sure if I came across one before. fw'ing @ motor is an alternative to rear fw, maybe worth considering over non-fw should the sickbikesHD not work.

Thanks guys, I appreciate the input.

speedmd said:

Have you considered a sprag bearing sprocket on the motor? Lots more power handling. You could drive it to the brake disk side of the wheel and keep them separate.

Click to expand...

Can someone explain what is a sprag bearing sprocket? It is not in my dictionary and when I try google it is mention in regards to clutches.

Is sprag bearing sprocket some special freewheel made for high powered motors running clutch and chain like on some go karts?
And where can one order a sprag bearing sprocket?

How are the sprag bearing sprockets compared to the UHD freewheels (sickbikeparts.com) in terms of longevity. Which one of those will withstand the more powerful motor the best you think?

The clutches in the common geared hubs around here use a "ramped roller" mechanism. It is cheap and strong. A sprag clutch has more contact points, so it is stronger, but it is also more expensive. I can't access the 2-speed hubmotor article about the Xiongda on electricbike.com from work, but....there is a pic comparing the two near the bottom.

The affordable freewheels found on bicycles use pawls, and that is the source of the classic clicking noise when spinning backwards. I suspect you could modify a Bafang BPM clutch to attach it to a motor shaft. Time-consuming, but possible.

Lots of different types. Some ideas.

Check out also what Crossbreak built using a shared front mounted jack shaft that drive chain went direct to rear wheel. Also what matt built using dual astros. There is enough room on most to sneak a chain by the BB shell.

Interesting thread.

Have you thought of asking Hagop Torossian via the BHT online email?

Or Adam Mercier? (bzhwindtalker)

Worth a shot...

Thanks guys, I'll check out those recommendations further.
I already widened the bb by an 1" and moved sprocket in/shortened shaft on bht.
There's 1/4" clearance side-to-side between pedal and the bike chain for the bht, so a bigger (clutched) motor gear wouldn't work.

I continued on my previous trajectory and came up with this:
View attachment 1

It goes on a wheel just like a freehub because I welded the female pawl in the backside of half of a freewheel hub, then spaced and welded a handmade (grinder) pawl to slip the bike gears cassette on.

I chose this cassette because it had a few extra threads for the retaining ring, so I should be able to easily shorten it a bit if the wheel is too tight for the 142mm d/o.
I think the freehub pawls can take enough power, so it's just down to the whiteind fw. Being serviceable should be a plus.

I am wondering if you aren't onto something. All the bikes I see with freewheels holding up somewhat better on big power (actually, torque) seem to have the freewheel very late in the drivetrain sequence.

I suspect the violent backlash of high powered midrrives is smoothed a little by the chain and upstream components. It doesn't alter the load on the system, but it does reduce the rate at which the freewheel is loaded up on takeoff. Maybe enough, maybe not.

Well, the whiteind hd held up to 5ah of all the abuse I could give it. The motor got fairly warm, as did the 5.8ah of batteries discharging 60amps. But to be fair, I was beating the sht out of it. I really like the setup!
The adapter allowed pedals and motor to both fw independantly on rear- It works!
I dropped to a 50t sprocket (ratio from 1:5.45 to 1:4.45). Need a speedo, but I think it went from 30 up to 35mph, and the torque doesn't feel as dangerous, even though it still can wheelie if you aren't careful. I really did like the hold-on-for-dear-life-gearing though. I wonder what the lower gearing would do with more volts? Might have to try that.

was running 11,16,21,26,32 bike gears in the back, will prob drop the 21 or 16 to compact more and improve chainline (which is tight because of the klein frame underneath the extended 142mm d/o.
4 gears is an acceptable sacrifice for this build if they allow enough range. The groundwork is laid for a custom frame that would allow a 10spd and maybe 2/3sp front also.

I would love lower gears on this, the 48/32 is higher than I expected. I'm guessing 1:1 is ideal for sub 5mph, which just isn't gonna happen, I want to be able to pedal at speed. Will hunt a reasonably priced cassette for the 34t (or the largest I can find) gear.

Tried a gopro knockoff, but the results were horrible- will try some other mounting methods. Unsure if there is some deficiency assoc with it being a knockoff? I tried handlebar and chest mount, and it was even worse on the chest. (even on the road it's jumpy/dropping frames)

Heres some pix at least for now.






I still have to order the other half of the battery. Ran 18s/60amps. 6,6,6.
Might try 6,6,4,4 20s 2P 11.6ah.

Is everybody buying the alloy chargers for bulkcharge now? How much voltage adjustment do they have? What about em3's chargers?

Fitment is going to be a big challenge on this little build. topframe pannier style is what I'm leaning for. Sewing/textiles would be really handy to incorporate with hard plastic shells rather than metal boxes.

Edit, ps, why does only the one pic load?.. . .Oh, I had the camera turned on that one, so I assume the width of the others is too much. Wish there werent 7actions to upload each file, or I'd do it again with corrected sizes.

Hi, Only just found this thread because I spend most of my limited time on the "Non Hub Motor" page.. maybe your thread would have had a few more replies if it was over there.

Good to see that you are getting some success with dual freewheel. For my bike with no pedals, I think direct drive / regen is the way to go, but if I had pedals I would certainly want a freewheel in the motor drive side.
When deciding whether to put a freewheel on the motor or on the wheel hub, remember that the speed reduction ratio in the chain drive also multiplies the torque, so your rear hub freewheel sees 4.5 times the torque that the motor sprocket sees.
A much smaller sprag clutch could be used at the motor end than would be needed at the wheel end of the drive.

However, we are using minimal size sprockets on the motor to keep the size of the rear wheel sprocket reasonable, so fitting in even a small sprag clutch would increase the size of sprockets we would have to use.
Also, a freewheel at the wheel means that the motor chain will not be turning while pedaling with the motor stopped, which is a significant advantage. So keep up the good work, I will be interested to see how well the freewheel lasts with your setup, especially as if I build another e-bike, I am sure it will have pedals, and equally sure that I will want a reasonably powerful motor on it!

Re the gearing on the pedaling side of the drive.. did you know that you can now buy extra large sprockets to add to your cassette to lower the gearing. They appeared after 1 x 10 gearing became popular on mountainbikes, to allow a "Granny Gear" for steep hills without needing 2 or 3 speed at the cranks. From memory they are around 42 teeth, and you can buy them to work with Shimano or Sram cassettes. You decide which of your existing sprockets to remove, and add the large sprocket inside the cassette.
I hear good reports about them, but they are not exactly cheap. (Cheaper than the new crankset / derailleur / shifter / cables etc I am just putting on my 1 x 10 Giant Trance though! Somehow the hills seem to be getting steeper in approximate proportion to the number of grandchildren I have!! So I am going to 2 x 10).

Regards,
Dave

Thanks Drum, well put. I found a 36t cassette I'll dissect to redo the gears. Thanks for mentioning those huge cogs, I didn't know about them b4, and they are pretty cool. You'd have to find a way to mount them to another cog unless you go all out and buy the special hubbody, and prob shifters and deraileur too. So far I'm having enough of a challenge and cost.

Good point with the driveline torque, it's proportional to rpm (motor shaft vs axle). It would be interesting to try that, but It was tight enough doing pedals too. And if you drop the pedals theres more con than pro for fw at all. I would like to try a build like yours, but for now this is just what I wanted.

I'm seeing why alot of the bht's don't bother with pedals lol. They just are an afterthought mostly. This thing is like a little dirtbike. If I twist the throttle and am not ready, it's game over- It seems way more powerful off the line than the sx125 and rm125 I've had.
I read your build so far but it's been awhile and forget what ratio and power you plan, but I think you'll be very happy with the motor for your build. Can't wait to see it in action!

I guess I got everything I wanted haha. Now to see how it holds up over time.
I did get a little footage today and will work on more to make a build page. The camera needs an extremely firm mount to seem acceptable.
It's gonna be so great to get on the trails again.

Ps, you're right about the category, I didn't think of that because I am aways in 'view active topics'. I'll assume more people are reading by category though, and follow suit next thread.

Yes, power = torque x rpm (x a constant depending on what units you are using), so in a given drive the slower end will see more torque than the faster end in the same ratio as the speed is reduced.

I have made a bit more progress with the battery cases and their mounting, and hope to get a bit more done over the next few weeks.
I will be running 20S Lipo 10Ah in two parallel packs. I will have a CA3 and can program that and the Kelly controller for max amps etc, so will be able to run as much power as I can hang on to (with both battery packs connected, 20C gives me 200 Amps!!!!) .. probably I will start at really low power and work up until it is too crazy then back off a bit or raise the gearing to calm it down.
I want to be able to play trials at really low speeds and ride technically demanding trails as well as general trail riding, so top speed is not really an issue.
Dave

That's the sort of riding I like too! I just wanted to be a legal bike for the current town I'm in, and also to see what I could do with my 16 yo klein. I don't even want to think about it geared down more even at 60a. I think my total weight is around 225-240 and will confirm that. What are you planning on?

I gave up on ca3 for the time being- still hopeful, but to set it up for throttle is so complex when the infineon has some programability and the 3 spd switch. I find the bike very manageable in the woods on spd2, (75% I think)and I can barely pedal along at it's top speed of 25-ish mph.

spd3 is 37ish topspeed on flat, motor only, and it is the wickedest to control from a stop or for very fine control. Spd2 seems to be able to tackle anything just at lower speed, more managable torque.
I'm not sure if the ca will really do much better anyway.

fyi I've been testing at 18s 60a max. The batteries get warm (5.8turnigy 25c) if I am really hard on it, (0-30mph as many times as possible lol)
but the motor is actually warmer than the batteries (18fet is ambient, isn't seeming to warm at all)
I was actually hoping to back off the amps with more volts, I don't have a thermistor and don't want to overheat the motor when I can play twice as long.

I ordered the rest of my pack, will be running 20s also, about 11ah.

btw, ca says I got 15mi on 6ah at the current settings, with negligible pedaling. It was mostly mostly flat, but I was burning up the amps with acceleration, so I'm surprised. It will be fun to see how it does on a long pedalling road ride with the full battery.

Best regards, Jay

I should update: it turns out I was running 67motor/200phase amps lol.
I'll have to check on which way to adjust each as I mess with different voltages. (thinking of a 16s 5.8ah 'in town' battery good for slightly less amps and almost 10mi no pedals, and that pack would be part of a 20s 11.6 for the power/distance pack.)
Just playin with ideas. If it isn't convenient to switch between the two and charge both ways, I'm dropping the idea, and will stay with the 20s and restrict as desired.

Ca says the max draw is about 5kw and 70ish amps. If I run @50% thru the current whole 5.8pack the batt seem happy (bursts of 100% are fine but will eventually heat the pack to warm).
I also weighed me and the bike 2day: 157/67= 225lbs. No wonder 5000w geared for ~35mph is so crazy. I'll be adding another 5/6lbs of battery for 11.6ah. Can't wait to see how it does as there will also be another 8v too.
Also playing with suspension geometry because the longer rear shock made the pedals 8" off ground and made fork angle a little high when rear is fully extended, and also playin with pedal gearing as 48/36 is my new low gear to try of the 5 available.

anyone lemme know any particular tests I should run! Or any correction to my wayward path is also appreciated lol.
This is my first attempt and am 'not'special and an oxymoron as a little bit of a specialnut.

I seem to draw 2000ish watts at full tilt 35mph on flat. .75ah per mi.
Using setting 2 (75%) is a vast difference: 700w max for 30mph and 550 avg with pedaling. .3ah per mile.

I think I will easily be able to make a 30 mile trip w/pedaling, including hills, averaging 25-30mph using 10ah. Seems like a freewheeling bht middirectdrive is the most efficient over dd, geared, and even middrive? and that's while it probably has the most pickup too?

I think the only contender is middrive. A similar 230lb weight bike/rider should do as good or better with efficiency? While I know it can't compete with pickup because it has to go thru the gears and can't use 5kw.