Question about BMC hub motor

B

big4x4

10 mW
Joined
Sep 23, 2007
Messages
28
I am buying what looks to a be a BMC hub motor with a 35 amp controller. I will be installing it on a full suspension MTB with an 8 speed rear cassette. I have already checked and this motor will fit the 8 speed rear cassette. The only thing that concerns me is that I know Team Hybrid is coming out with the 320 rpm version of the puma that can do 25+ mph on 36v, while this motor is rated for about 21 mph on 36v... I would like ample torque to climb hills, but would also like a decent top speed of 30+ mph. I will be running 51.8v 8000maH Lipo batteries.

So my questions: 1)Is there any way to make this motor faster (rpm/volt). 2)Does this have more torque than the 320 rpm version? 3)Do both versions have the same max rpm rating, meaning that I will just have to input a higher voltage to reach its max potential? 4)Do you think the new 320 RPM versions will fit an 8 speed rear cassete? Help would be greatly appreciated. Thanks!
 
I beleive it's a tradeoff with durability. depends on your goal. :twisted:

Consider the number of gears very closely, depending on the bike frame of choice, 135mm without disk brake.... 150mm with disk brake ( most standards ) .. the motor with 7 speeds may exceed this and require the frame to " stretch " , some ful suspension swingarms don't bend easily.

Other than that.. sound like fun ! :mrgreen:
 
I don't think we know the full answers yet.

A higher rpm/volt motor will have taller gearing, so the hill climbing torque will be less. Personally, I like lots of torque, so to make it go faster, increase voltage. I would have to assume the 320 rpm version will have porportionally less torque than the slower one.

The only way to change the rpm/volt would be to change the internal gears (very difficult) or to re-wind the stator (equally difficult). Wheel size does the same thing too, but your choices are limited there.
 
I had an email from Mark yesterday confirming that the new motor will only take a single speed.

I think Knoxie found that torque between the 250 and 320rpm motors was very similar, the 320 just faster.
 
Thanks for the replies! I have bought the new Synergy Cycles hub from Sierra Cycles. It is claimed to be a BMC brushless, geared hub motor. It came with the 25 amp controller. I confirmed with Keith that it can take an 8 speed freewheel... I plan to upgrade to a c-lyte 36-72v 35 amp controller... but in the mean time, I will compare it against my USPD 52v full suspension Li-Po Mongoose and see how it compares! Should be fun..
 
That's interesting.
How much for the motor there?

I'll be interested to see some pics too. I wonder if it's the same as Maytag's motor.
 
I bought mine off of ebay. There are some more listed for $579 buy it now with the 25 amp controller...
 
I'd like to purchase a geared rear hub motor mounted on a 26" rim with strong spokes. I intend to run it at up to 52.8 volts. I haven't purchased the controller and throttle yet but am leaning toward a modified Crystalyte from ebikes.ca. I'd like a Cycle Analyst but prefer to wait for the direct connection version that will accept a separate speedo signal (I was told that the freewheel geared hub precludes speed estimation from hub hall sensors through controller). I am looking at two geared rear hub motor options -- Team Hybrid puma and EVTECH BMC motor. There may be other geared hub motor options of which I am unaware. Advice and guidance would be greatly appreciated.

What are the real differences between the Team Hybrid puma geared rear hub motor and the EVTECH geared rear hub motor? Searching the endless-sphere forums I have picked up on three possible differences: (1) motor phase wires are 15 gauge on puma and 18 gauge on evtech motor, (2) motor shaft/housing is keyed on the puma but I don't know if it is keyed on the evtech motor, and (3) puma motor can only currently fit one sprocket gear and the evtech rear hub motor can fit 7.

I have thought about getting the EVTECH motor and doing the re-wire to 15 gauge myself, but would prefer to have it done by the seller or possibly a third party. Does EVTECH sell the motor mounted in rim separate from controller? I assume that the keyed motor shaft/housing feature is important. Have there been any reports of slippage with the EVTECH motor? I'd like to have more than one rear sprocket gear and three at the pedals in case my battery pack runs out of juice and I have to pedal home unassisted, so I am leaning toward the EVTECH. The puma is alledged to produce more speed at the same voltage, but I suspect that this is due more to the reduced gauge wire than anything else. How do the puma and the EVTECH motor really compare? Is there another option?

-- Joey
 
you can add an external speedo sensor to the direct plug in version of the cycle analyst by splicing it between GND and pin#5 on the Cycle analyst connector.

rick
 
I can confirm that you cant really tell the difference in torque between 260 and 320RPM motors, and in any case a the motor you were quoted (36v 21mph) wont be a 260rpm (more like 17mph@36v). The 260rpm motor will take 60v to reach 30mph..

The Puma has had many "upgrades" over the evtech motor, and is currently the best motor I've tried (i've got some 10 odd BMC/earlypuma/latepuma's here to try).
Justins modified controller is about the best one for the job at the moment, beware that the new digital x'lyte controllers may have problems with BMC/Puma motors.
 
Hello

Yes the keying of the motor shaft is something I got Mark to get the factory to change as the old stock BMC motor rotors can slip on the axle unless they are welded, you can do this to an old BMC motor if it slips simply by removing the planetary gear mech and blob welding the edge of the rotor to the shaft. The other issue that you may come across on the Pumas is the Nylon gears wear harder when used at power levels over 700W, I have stripped a set on one old motor, again Team Hybrid are getting metal versions of the gears as an option for power users and again you could modify the old school BMC motors to take these gears, in all motors the main ring gear inside the hub is metal and does not need to be changed.

The stock BMC wires are fine if the lead is clipped as near to the axle as possible, the wire upgrade on the TH motors was something that was undertaken because it was possible and certainly helps reduce heating, I would certainly recommend power Puma users fit a break on rise stat to the windings on the motor and break the return on the halls to kill the motor control on over temp.

The 320 and 250 RPM motors are close on torque but the 320 motor is much faster, I dont know about their relative efficiency but I would go with the 320 motor every time.

I have been running Pumas for 18 months now and these are the few glitches that I have found, in general though they are IMH O the very best hub motor all rounder that you can get and will perform well on relatively low voltages unlike other gearless motors, the weight of these little pumas is so negligible as well when compared to most of its rivals.

Keep an eye on Deecannios thread for details of how a BMC puma runs on 80V with a clipped motor lead, twin lipo modified BMS and controller, come on DC pull your finger out :)

Cheers

Knoxie
 
I already have an eZee front hub 36 volt kit installed and running on my old Chrome-Moly frame Nishiki Pueblo. There are before and after pictures in the pics and video forum topic. I really like the torque the geared hub provides, even at this low voltage. It is also pretty light in weight. I find the pannier mounted Li-Mn battery pack configuration a bit awkward but plan to upgrade to 12s LifeBatt anyway and will mount it differently.

I'm planning to assemble a second e-ride from hand-picked motor and electrical components. I would like to stick with a geared hub but want to try a rear hub configuration. The eZee is a front hub kit. Justin at ebikes.ca told me that eZee may come out with a rear hub kit later but there isn't one available now. This is why I am looking at the Team Hybrid puma and the EVTECH BMC motors. I'd also like my second e-ride to 48 volt so I will need to use a different controller, e.g. Crystalyte.

-- Joey

eZee front hub with 36V Li-Mn on Nishiki Pueblo.
second e-ride in planning stages.
 
Hello, just joined, this is my first post, would like to share with you that i have bought a BMC motor recently from EVTech. They laced it up nicely with stainless spokes on a 26" rim. I had read before buying that a weak point was the 18 gauge phase wires. I wanted to do the largest upgrade possible, but the inside diameter of the axle is not very big. In researching wire diameters I found mil-spec, silver coated, teflon insulated wire on ebay- very pricey stuff. The jacket is very thin and strong, so I was able to go to a 14 gauge wire. For the hall wires I used 24 gauge teflon-kapton wire. The three phase wires and five hall wires all fit inside some expandable sleeving (the chinese finger trap type). Just barely fed through the axle. Paid $600usd for the laced up rim and motor, less controller. I bought a clyte 7240 pre-modded controller with direct plug in cycle analyst from ebikes.ca- very good guys, IMHO. I am waiting on a 16 cell lifebatt pack from Goodrum, hoping it will be ready soon. I will get some pics of the motor mod tonight, will post soon. I hope to make some good friends here- :D
 
The EVTech motor that I just got has flats on both ends of the axle. Two 180 degree opposing flats with an axle thickness of .395"(10 mm) between them. Axle diameter at threads is .550" (14 mm).There is a small woodruff key that indexes into the planetary gear drive on the inside. Wires exit through the left side axle. comes supplied with a nice stainless torque arm that goes on the flats, can be used on either side. Not sure of the rpm's, I haven't powered it up yet to get a tach reading, nothing was specified when purchased.
 
Joey,
Just wanted to say that if you should choose to get the evtech motor I can send to you some of the nice mil-spec wire that I got for the re-wire. The overall build quality looks great, I can see some improvements (based on photos of older models) in the casting and gears. All sealed bearings and nice machining. Can't wait to get it going, should be able to fit it to the bike this weekend, then I will just need the battery pack.
 
Hey elecstumpy, welcome to the forum.

E-biking is also a new hobby for me. I started with the 36 volt eZee kit from ebikes.ca so I could be e-riding from day one. It arrived on a Friday evening and I was e-riding the next morning. I am going to switch to a 12s (39.6v) LifeBatt pack with integral BMC/CMS as soon as it becomes available. I'm also planning to assemble a second e-bike soon using higher-performance components throughout, and running that one at 52.8 volts (16s LifeBatt).

It looks like we're on the same wavelength when it comes to my next hub kit, controller, and battery selections. I agree that Justin at ebikes.ca is wonderful. I believe you said that you got a direct plug-in Cycle Analyst with your controller. If so, you may need to bypass the controller supplied speedometer signal with a separate speedometer sensor and cable since your hub motor is geared and free-wheels. I spoke to Justin about it and he said he would probably come out with a direct plug-in CA variant usable for free-wheeling hub motors that accommodates a separate speedometer sensor signal. I don't think it is available yet so your speedo function may not work. There is a post earlier in this topic about how to tap into the existing direct plug-in CA connector and supply a separate speedo signal. You might want to check with Justin about this.

I have narrowed my rear hub motor choices to the Team Hybrid puma and the EVTECH BMC but can't decide between the two. I'm still gathering information. If I do choose the EVTECH model, I may want to buy the same wire and sleeve material you used. Where is it on the web? Do you have any left?

regards,
--Joey in Albuquerque
 
Joey,
Thanks for the info on the speedo, I did not realize this. Yes, I have plenty of the wire and sleeving left. I have green, red and black in 14 ga and red,yellow,green,blue,blue/blackstripe in 24 ga. The wire is very nice, silver plated, 19 strand but is a little stiffer than normal stranded wire, perhaps due to the teflon jacket. Unfortunately, it costs about 60 cents a foot,(and that was the surplus price- new is about 2.00/ft) and was only available in 50 and 100 foot increments. I only used about 1.5 ft of each, so much left over. If you like, I can send some lengths of each for cost, just let me know how long. Have sleeving also, it was cheap. There was a post about the wire color matchup between the BMC and a clyte controller. Hall wires are a color for color match. Phase wires are:
motor - controller
------------------------------------
yellow - blue
green - yellow
blue - green


using the wires colors that i was able to get, this is how mine is wired now:
motor - controller
----------------------------------------
black - blue
red - yellow
green - green
 
Hi all
Just a quick word on the CA speedo alteration read what you had written then sent justin an email .
the yellow wire (pin 5,hall) should be cut from going to the controller, then as was you have written connect 1 wire of a speedo sensor to the CA where the yellow wire was and the other wire to GND,then set poles to 1.
hope this helps.
 
Hi!

I also have a couple of questions.

I read that there was a 320rpm/V version of this motor, but I do not find it anywhere, including this website:
http://www.teamhybrid.co.uk/

I read that it does around 25mph on 36V. This is a little more than what the Crystalyte 406 makes, and I would like the bigger efficiency, bigger torque and freewheeling ability of the BMC.
Front or rear mount is both ok.

Is it possible to purchase this version of the motor, but without any acessories (no controller, no rim, no nothing), preferrably in Europe?

I read, that the nylon cogwheels are a little prone to wear. Does anyone know the dimensions of them? Being a machinist, I could check the feasibility of machining standardized steel cogwheels to the appropriate dimensions.

I would also consider offers of defective motors, replacing hall sensors or the windings should not be a big problem.
I've rewound a couple of RC motors before.

Thank you,

Julian
 
I would check with Mark at Team Hybrid.

I know he has steel gears for them as well. I think one steel and two nylon will work out OK.
 
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