The BEST and FIRST Qulbix Raptor mid-drive build!

[tikivic]

Elegant solution Mike. Mine is decidedly less elegant, I moved the axle all the way forward, and machined a spacer that goes behind the axle secured by the pinch bolt. So of course I have no adjustment for the chain tension, that is handled via the Rohloff chain tensioner. I am curious if (why) you require the adjustment (i.e. motorcycle) and if so how you get around the chain growth on the Raptor as the suspension moves?

V.

My chain tugs arrived. They are almost perfect as delivered. I had to relieve the front of the raised boss that rides in the dropout slot, and I had to widen the slot on the adjuster nut bracket to accommodate the unusually wide Qulbix dropout:

I was able to make those mods with an angle grinder and a flat file. With those two changes the tug fits like a factory part:

This should positively keep the axle from sliding forward under power.

 

[LightningRods]

Thank you V. I was stressing over this a bit and was relieved to have it resolve so nicely.

The chain required tensioning because the center to center distance with the axle all the way forward just missed being short enough for one link pair less. Once I added a link pair the chain was floppy loose. I needed to move the axle back about .316" and somehow have it not slip under power. The chain tugs were the solution.

There is zero chain growth because the motor is mounted on the swingarm. I was originally going to mount the motor on the main part of the frame but was persuaded that the lack of chain shenanigans made the unsprung weight (near the fulcrum point) a reasonable trade off.

I was just online looking at Rohloff tensioners for the pedal side. I wasn't lucky enough to get both chains properly tensioned at the same axle position.

 

[tikivic]

That makes sense now, I forgot you are doing the swingarm mount. I have a little over 800 miles now on the Rohloff tensioner (Cyclone 3000W) and no issues at all. I did have to machine down the inside of the derailleur cage to accept a wider chain though.

 

[LightningRods]

I'm settling into production on the 165mm billet hubs for the swingarm drive. My machinist has made some fixtures to speed production, all the little issues have been sorted, and I was pleased to find that my local plating shop is under new management. I got my black anodizing back in a week at a good price and the parts look great.

I've been running my own swingarm drive around for a couple of weeks and I'm very impressed with it. It's the quietest drive I've ever made since there are very few moving parts. With 84v 8O amps it runs great with one speed. The only change I have planned is a two speed geared chainwheel from PowerVelocity. The 1.7:1 overdrive will make it possible to pedal with the motor up to 4O mph or so.

 

[skeetab5780]

You still sell the 6kw hd motor? How much are they going for out of curiosity I love mine!

 

[LightningRods]

The motor you're running is completely different from mine. A lot of people are using "LR motor" or "big block" to describe any large motor they've found. That's E-S. Everything gets appropriated.

 

[skeetab5780]

Well do you sell more of the motor you sold me? not sure what the proper name is

 

[LightningRods]

Apologies. Your profile photo still shows the original BHT motor on the swingarm drive. I went through your thread and saw that you swapped that motor out for one of mine later in the build. LMX did the same thing. They started with the BHT and then switched to my motor and are still using it.

The Big Block is still $325 USD.

 

[LightningRods]

Jake P. has his Q140R up and running. Apparently he has already caused a pizza delivery boy to soil himself by coming up on him silently at 30 mph. The poor kid thought that some apex predator was about to grab him off of his bicycle.

Jake's bike gets to be in the office during the day because it's well behaved and doesn't leak oil on the carpet.

Jake has also employed the wheel tugs. After a bit of filing they work well. Jake has no right side sprocket because he is rocking footpegs. You are not going to find a simpler mid drive setup than this

 

[Luk]

An overdrive from PowerVelocity ?!

 

[LightningRods]

Jake doesn't have pedals and so can't benefit from the o.d. crankset. Ive told Vad at PowerVelovity that I want one. It's going right onto my Q76. Two speeds in front and one in back will be perfect!

 

[LightningRods]

Luk your swing arm drive is ready to ship. I need to work out the details with you.

I have two drives and hubs left. More are being made.

 

[devo1223]

I think the direct drive is my next build. Mike, what is your top speed at 84v? how's the motor temp in the tight/rocky stuff? Can you give us an idea of the power compared to the hubbie that was on there?

 

[LightningRods]

I did the math and the drive is geared for 55 mph @ 84v. 650 wheel rpm.

The bike has noticeably better acceleration now, especially from a stop. The 3000 watt hub maintained speed well up hills but was soggy and slow off of the line. I have a much better controller now than I had with the hub so it's hard to say how much that enters into it. I'm still only seeing 3100 max on the CA. I think the battery that came with the bike may be limiting the 6kw+ the Big Block and PowerVelocity 18 FET are capable of. So I may have the potential for twice the present power! Time to contact EM3EV.

The ride is noticeably smoother off road. The suspension is quicker to respond now and soaks up the high frequency stuff that came through with the hub.

 

[madin88]

The ride is noticeably smoother off road. The suspension is quicker to respond now and soaks up the high frequency stuff that came through with the hub.

This is so true!

 

[LightningRods]

The Enduro Electric Bike version of the swingarm drive is now available. It's very similar to the Qulbix drive except that the brackets are revised to fit the Enduro swingarm and there are added horizontal dropout extensions so that the drive chain can be tensioned.

 

[Bbeforeart]

Hi there

I really like this fixed spocket type of setup, without pedals to keep it clean! I am wondering what this motor setup would cost including chainwheels and chain (tensioner)?

Regards, Bart

 

[LightningRods]

Hi Bart,

The pedals really expand the usefulness of the bike but I know that Qulbix does offer a foot peg package. It’s an off road toy only with foot pegs.

Customer totals are coming up right around $1k for the drive, rear hub, sprockets, chain, brake mount and chain tugs. The EEB version needs dropout extensions for $50. That’s the only cost difference.

Thanks,
Mike

 

[Bbeforeart]

Dear Mike,

Thanks for your reply. That sounds very interesting to me!

I really see this as an advantage opposed to my Crystalyte HS3540 with a 72v25Ah battery setup providing 3000w peak. It does not provide sufficient torque at lower speeds, that's why this took my attention.

Furthermore, I am wondering if it is feasible to have a Qulbix Q76R with that mid drive kit without a chain tensioner?

Lastly, how much will the shipping be to the Netherlands?

Regards,

Bart

 

[LightningRods]

Hi Bart,

I ran my Q76 with a 3000 watt hub motor and then with my swingarm drive at the same power level (battery limited). The swingarm drive has much better low end due to the 8:1 reduction. The hub motor was actually better overall than I thought it would be except that it was super soggy at take off.

I’m not sure that I’m completely following your question about the mid drive. Are you referring to the chainwheel drive where the motor is mounted on the front of the bike? Yes it works great on the Q76. The Q130’s battery box is a bit wide for the front mount motor. What do you mean by “without chain tensioner”? The secondary chain drive from the jackshaft to the chainwheel does need a roller tensioner.

If you want to go single speed with a chainwheel drive you could also mount my single stage drive on a Q76 just like I did on the FUTR Beta. You can get much lower gearing with that system than the 8:1 of the swingarm drive.

Shipping to the Netherlands should be in the range of $120 USD.

Thanks,
Mike

 

[efMX Trials Electric Freeride]

if you mount a mid drive motor to the bike main frame then you will need a chain tensioner at the rear dropout to allow for rear suspension movement.. but if you mount a mid drive motor on the swingarm then you will not need a chain tensioner because the motor drive will be moving with the swingarm and will not effect chain tension..

Dear Mike,

Thanks for your reply. That sounds very interesting to me!

I really see this as an advantage opposed to my Crystalyte HS3540 with a 72v25Ah battery setup providing 3000w peak. It does not provide sufficient torque at lower speeds, that's why this took my attention.

Furthermore, I am wondering if it is feasible to have a Qulbix Q76R with that mid drive kit without a chain tensioner?

Lastly, how much will the shipping be to the Netherlands?

Regards,

Bart

 

[LightningRods]

You don’t need a spring loaded tensioner. You do need some way to get the chain properly tensioned to start with. You are correct that chain tension doesn’t vary with suspension movement on a swingarm drive.

 

[Bbeforeart]

Thank you very much for the verification of this part, I'll consider soon to buy it,

Regards,

Bart

 

[Bbeforeart]

By the way, I was wondering: have you guys considered a belt transmission from the motor to the hub? This would save a lot of maintenace in comparison to a chain. Will there be any belt sprockets available which will fit onto the custom hub and the motor shaft?

Tell me what you guys think about this idea, I'm curious about your opinion.

Regards,

Bart

 

[LightningRods]

I'm a big fan of belt drives. I mostly like how quiet they are. What little noise they do make is far less annoying than the high pitched metalllc clatter of link chains. Unfortunately drive belts do have some shortcomings. In order to have the torque capacity necessary for a powerful electric motor we need a fairly coarse tooth pitch on the pulleys. At least 8mm for a final drive like this. In order to get the same 8:1 reduction that the 219 chain provides the rear sprocket would have to be huge. An 18t driver pulley is as small as we can go and still have enough pulley teeth engaged in the belt. 18 x 8 = 144 teeth on the rear pulley. With an 8mm pitch thats 144 x 8 for a circumference of 1,152mm and a diameter of 367mm or 14.5 inches. The present 219 rear sprocket is 241mm or 9.5 inches. So around 50% larger. In this particular application there is just barely enough room to make the driveline run from the motor to the present sprocket without hitting the swingarm with the belt or chain.

I think 219 chain is the optimal simple, single stage solution. I have been playing around on the computer designing a two stage drive with belt primary and then 219 chain secondary. It might be possible to make the secondary run belt instead of chain. I will take a look at that.