QS 3000 138 motor bike installation generalized

Discussions related to motors other than hub motors.
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DingusMcGee   10 kW

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QS 3000 138 motor bike installation generalized

Post by DingusMcGee » Jan 11 2021 9:25pm

Having completed such a task, some insights are worth passing on to new enthusiasts for when they begin the same task.

Here is a pic of my finished product:
QS 3000 mounted in Specialized Big Hit
IMG_0675.jpg (507.24 KiB) Viewed 373 times
Building the motorframe:

Drive train possibilities:

No more writing tonight -- tired but stay tuned.

See a little bit more of this installation that was posted on page 139 of the thread,"new Cyclone 3000w mid- drive kit?"

larsb   1 MW

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Re: QS 3000 138 motor bike installation generalized

Post by larsb » Jan 12 2021 2:41am

Thought about doing the same with my kona stinky. A bit overpowered, that front wheel will like to fly :thumb:

DingusMcGee   10 kW

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Re: QS 3000 138 motor bike installation generalized

Post by DingusMcGee » Jan 12 2021 8:38pm

HI Lars,

Thanks very much for your contributions to the thread on the Votol Em 100 & EM 150 controllers. They aided me in getting this system up and quickly.

'You say, "...that front wheel will like to fly."

Yes, the position one has using an ordinary bike seat location is too far back to keep the front from flying.

DingusMcGee   10 kW

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Re: QS 3000 138 motor bike installation generalized

Post by DingusMcGee » Jan 12 2021 8:52pm

The QS 3000 138 motor came with a type 428 14T motor sprocket 20mm outer 17mm inner with 6 splines was not available in the USA in that size as a motor cycle part. I sent a request to QS-motor.com and got a reply within 12 hrs.

The output shaft measures:
IMG_0679.PNG (679 KiB) Viewed 303 times
Here is the QS reply
IMG_0681.PNG (365.18 KiB) Viewed 303 times
So Robert Chen of QS will likely be willing to supply these sizes of motor sprockets.

I have since found this link that has the 20mm type 428 hub for the QS 3000 and others:

https://www.aliexpress.com/popular/420- ... 75ceUNeTLo
Last edited by DingusMcGee on Jan 18 2021 6:44pm, edited 1 time in total.

DingusMcGee   10 kW

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Re: QS 3000 138 motor bike installation generalized

Post by DingusMcGee » Jan 12 2021 9:58pm

We are talking a mid-drive installation for the QS 3000. The motor mounted either in front of the bottom bracket or additionally inside the bike triangle and simply a right side drive with a 2-stage chain reduction employing the BB axle as an idler shaft for a spinning connected dual sprocket.

Some early design considerations and contraints:

You do not need pedals on cranks connected to the rear wheel to subsidize this motor. You may prefer pedals to foot pegs.

Much like the electric cars, having one ratio of gearing can cover most your performance needs because of the power/torque of this motor. No derailleur needed. One gear ratio suffices.

Motor chain size and rear wheel chain size along with how you will manage the pedal/crank connection to the rear wheel determine how much and how heavy of real estate you will need between the right side of the bottom bracket and the left side of the right crank. The motor comes with a type 428 sprocket which can use #40 Chain as the cog width is 5/16". This cog could be milled/ground to 3/16" width and then a #415 chain would suffice with the 150 amp votol controller. #410 chain seems a little undersized for strength to me but should you want, try #219 go kart chain? Some are sold on it. Likely with bigger chains you have more weight but less chain adjustments, replacements, sprocket wear and a lower pitch chain running noise.

The other early needed detail is whether the cranks must be able to rotate 360 degrees and if so they then must have enough separation to clear the motor on the left and the motor's chain guard on the right.

I had a group of various ISIS axles and square taper axles at my disposal but based on the motor width (215.15 mm = 8.47" ) and pedal/crank rotation desired plus the double cog space needed this square taper looked best suited for the suspected length needed.
IMG_0640.JPG (1.23 MiB) Viewed 298 times
Using this crank part #20432 from MBRebel.com I ended up with clearance of 1/4" on the left and about 1" on the right. You cannot shift this spacing because of the built-in bearing stop(s) on the BB axle. However there may be more lengths of the square taper axle than I found. You can get cranks from MBRebel that bow out quite a bit more than the standard crank offset and with these extra bowed cranks you may come up with the motor clearance needed while using a shorter axle. With this wide motor your steep q-factor is gone.

See axle at: https://mbrebel.com/?s=20432
IMG_0682.PNG (1.99 MiB) Viewed 297 times
Note this square taper axle has a key-way slot and is a standard round diameter = 0.6250" = 5/8 " giving more common bearing options than an Isis axle does.


DingusMcGee   10 kW

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Re: QS 3000 138 motor bike installation generalized

Post by DingusMcGee » Jan 15 2021 8:45am

This dual sprocket BB hub (DSBBH) occupies about 1.4" on the BB axle when using #40 chain and #415 chain.
Dual sprocket bottom bracket hub (DSBBH)
IMG_0639.JPG (946.04 KiB) Viewed 234 times
There are 4 bearing units within this hub and the chain loadings are on the axle not the crank arm.

Knowing the DSBBH width and the motor length facilitates deciding motor frame dimensions. Here is the DSBBH on the chosen axle.
The QS 3000 motor kit and the BB axle. On the left is the Cyclone 3K
IMG_0649.JPG (1.14 MiB) Viewed 234 times
We will proceed to the motor fame making and come back to making the DSBBH later.

Having had both the Cyclone 3K and Cyclone 6K I had various motor frame plates from old & new kits. To just copy the Cyclone motor frame would push the somewhat bigger QS 3000 motor closer to the ground which is not what one can have with an edirtbike. A longer motor frame is needed to get down tube clearance to raise the motor. The Cyclone motor frames length ends up with about 12" of motor clearance to ground whereas with just a little more frame length my QS motor has 14" of ground clearance. Simply more motor frame length would make for a more wobbly frame.

Most of the ebike motors of power 3K and above have shapes of cylinders and have mounting thread holes on the ends. The Cyclone 3K, Cyclone 6k, QS 3000 and QS 4000 ( possibly the QS 2000 also) have cylinder-like rims on the ends that have a diameter of about 130mm. It turns out that the right side Cyclone motor plate curve fits the QS motor ends also.

For this QS motor frame the Cyclone motor plate was converted to a triangle with a round top.
Make 2 identical motor plates from 6" wide 3/16" thick A36 steel plate.
IMG_0695.JPG (1.01 MiB) Viewed 229 times
Here we see the triangle motors plates fastened to the BB bracket.
Identical motor plates fastened to BB
IMG_0651.JPG (920.96 KiB) Viewed 229 times
I claim here identical, becasue, even though the motor plates were jig sawed from the same width flat steel plate, they were then clamped together with factory edges matching and the jig saw cuts were then ground to make for a straight/flat surface. The 1 3/8" holes in the triangle plates for the BB hardware were "sawed" on a drill press using a new 1 3/8" hole saw while the two plates were clamped together.
DSBBH and cranks are added to check fitting
IMG_0653.JPG (1.04 MiB) Viewed 218 times

DingusMcGee   10 kW

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Re: QS 3000 138 motor bike installation generalized

Post by DingusMcGee » Jan 16 2021 8:45pm

Motor side Plates

The motor side plates bolt on the ends of the motor and they are curved to match the end cap's short cylindrical rise. The QS 3000 has 6 - 8mm x 1 threaded holes suited for a plate mount similar to the Cyclone motors. The motor comes with a single pintle hook mount plate
The Pintle Hook reversed and a gear clamp holds (keeps) the motor from falling (rotating) downward.
IMG_0490.JPG (769 KiB) Viewed 157 times
fastened on the central shell of the motor with 4 bolts. Likely to match the down tube angle you will want to rotate this central anchor 180 degrees so that it's transverse bolt is at the top of the motor when mounted in frame. Just down the down tube from the bolt are slots that accept a gear clamp or large cable tie which like Cyclone such is used to keep the motor frame from rotating down.

A pattern for the motor side plates can be copied from the right side Cyclone Motor plate. Your motor likely will run cooler if you make the motor sides plates long enough to leave a space for circular ventilation , say 1/2", between the motor and the motor face plate which is the retangular steel plate that connects the 2 side motor plates.
From Cyclone side plate is copied QS 3000 motor side plate
IMG_0714.JPG (891.56 KiB) Viewed 169 times
If jig saw cut out, clamp these motor plates together and grind them so they are the same size to 1mm. Drill 2 holes in these to fit 2 of the threaded holes with the motor side plate centered between the 2 bolt holes. My center line of the motor side plate is 120 degrees from the top. Fasten these plates to the motor.

My original plan for the motor frame was just 5 steel pieces -- 2 BB triangle plates, 2 motor plates and a common face plate. The 2 pairs of side plates would be welded to the face plate Collin Furze style -- adjusted on the spot and bang with the welds.
The 5 piece motor frame--unwelded. The piece of metal in the upper right corner will be welded in horizontal position between the 2 triangle plates covering up the red color on the down tube.
IMG_0666.JPG (1.12 MiB) Viewed 169 times

The plate mentioned in the above photo was the first piece of plate welded with a 3/4" piece of wood giving it some rise from the down tube. The motor frame then became a 6 piece frame, instead of 5 pieces. This sixth piece of plate makes for a shear wall plate which both stabilizes the triangle plates for the rest of the welds, sets up alignment/reference points for measuring and stiffens the frame laterally for torque loading.

The motor plates were next welded to a centered rectangular plate that was 2 thicknesses 2 X 3/16" = 3/8" longer than the end to end distance of the motor plate separation. With 3/16" projecting beyond each end of the motor plate one can fillet weld it to the motor side plates rather than doing a mere lap weld.
The face plate has been welded to the motor side plates.
IMG_0671.JPG (1.08 MiB) Viewed 169 times
Trade Offs

The 5 piece frame is quick to make but has very little adjustment. By adding another face plate to triangle frames (now 7 pieces of plate steel) the motor fame system can be made adjustable for chain stretch by bolting the two face plates together. Also, if you did not get the motor axle colinear to the BB axle, a new adjustment would be possible by getting a rematch lineup and drilling new bolt holes. If down the road you get some other cylindrical motor to mount, you would only need the 2 motor side plates and a face plate.
A face plate has been welded to the BB triangle plates.
IMG_0669.JPG (1.24 MiB) Viewed 169 times
To facilitate motor alignment an adjustable webbing strap clamp was useful when ran around the motor and the interior shear wall plate that is welded between the two BB triangular plates.
Attaching a webbing clamp
IMG_0700.PNG (5.06 MiB) Viewed 169 times
These screw C clamps were used to hold the two face plates ( the motor face plate and the BB triangle face plate tightly together after proper alignment for drilling 2 securing holes. There are now 5 holes in the face plates threaded for 8 mm bolts on the motor face plate. I made my first loose chain adjustment using 2 pairs of plastic ez-shim shims running counter incline wise to each other. Pushing these shim wedges in this alignment insures parallel transport of the motor frame outwards with a mechanical advantage from shim wedges. The system moves easier when the the down tube clamp is loosened.

Final alignment before drilling attachment holes. Note the colinear plates that are clamped.
IMG_0715.jpg (798 KiB) Viewed 167 times
Next I will cover how the double sprocket BB hub (DSBBH) was made.

DingusMcGee   10 kW

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Re: QS 3000 138 motor bike installation generalized

Post by DingusMcGee » Jan 21 2021 11:34am

The double sprocket bottom bracket hub (DSBBH) consists of 5 major pieces along with washers and shims. The QS 3000 motor position left to right is determined by where the right most of the sprockets is from the BB shell. You may have some leftover axel space on the right as depending from which companies freewheel you get these components as they are merely similar, not identical. The DSBBH used for Cyclone kit builds has only one bearing. Using their set up with bigger chains would push the rear wheel chain's sprocket loading somewhat beyond centered over the bearing in the BB freewheel hub. Here is a look at the chain size at the BB axle.
#40 chain and #415H chain with adequate separation.
IMG_0493.JPG (679 KiB) Viewed 94 times
I decided not to attempt the wide chain and load balancing act employing a Cyclone BB configuration which has only one bearing. I wanted pedals as opposed to foot pegs but did not need any form of pedal assistance. This choice meant the DSBBH could simply rotate on the right side of the BB axle. The ISIS axle is less suited as its diameter in the right free space is not as standard as square-taper axle which is 0.6250" accurately.

The DSBBH would have to have the sprockets connnected by bolts, thread shaft or welded. Flanges as opposed to actual chain rings would permit changing bolt-on sprocket sizes. There is sort of an ideal piece for the to rear wheel sprocket when using #415 chain and seeking a small cog.
RHD ACS 16T freewheel sprocket 3/16"
IMG_0727.PNG (965.99 KiB) Viewed 94 times
The other sprocket/flange choosen was the White Industries BB freehub also RHD.
RHD White Ind BB freewheel Hub
IMG_0500.JPG (226.97 KiB) Viewed 94 times
After I figured out a way to add a bearing to each of these, additionally as they have ratchet bearings, I first considered welding them together, then considered bolting them together but after finding a strong enough coupler rod threaded 13/8" x 24 and having a 5/8" hole through it, I settled on using a threaded coupling.
Here we see 2 flange type BB freewheel hubs bolted together
IMG_0461.JPG (545.09 KiB) Viewed 94 times
Note the left side in the photo above has a square tape bearing holder end cap screwed into the flange hub. A free spinning DSBBH could be made this way but it would end up wider than ideal and bolting the flange hubs together is not the best way for long lasting stable alignment of these hubs on a shaft.

There are several coupler like items for connecting these two hubs that have the correct threads and a bore large enough so that 5/8" shaft can pass through it.

So what we seek is a compact form of 2 sprocket/flange assemblies well aligned and bearings for each. The item looks like this:
The compact DSBBH
IMG_0639.JPG (946.04 KiB) Viewed 92 times

DingusMcGee   10 kW

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Re: QS 3000 138 motor bike installation generalized

Post by DingusMcGee » Jan 22 2021 9:21pm


There are at least three pieces of threaded stock (RHT 1.375 x 24TPI) on the bike market that could be used for a coupler of the two freewheel hubs used in making a DSBBH.

1. Included in the Cyclone BB kit for widths of 110mm & 120mm BB shells are some THIN threaded couplers for use in the kit for extension of the BB shell on the left side which is RHT. You would saw off the length you need as these are 1.375" long. SickBikeParts sells this piece in a kit for Cyclone mount wide axle.
1.375 x 24 TPI extension BB couplers
IMG_0789.jpg (2.09 MiB) Viewed 37 times
2. Staton Inc sells a long threaded (RHT 1.375 x 24 TPI)tube with a 5/8" hub & hole. Again the threaded section is much longer than you need. The coupler has a full annular section and could take a lot of torque.
Staton part suitable for coupler
IMG_0677.PNG (1.06 MiB) Viewed 37 times
Threaded part of Staton coupler
IMG_0501.JPG (228.39 KiB) Viewed 37 times

3. The earlier versions of the English BB assembly had ball bearings in a retainer that had RHT end nuts on the left suitable for the coupler we need. They are not all the same. Some are more compact and suited for use here.
The low profile for tool insertion takes up very little space and may be the ideal coupler.
IMG_0572.JPG (1009.64 KiB) Viewed 37 times

Kits for repair of this type of BB bearings have versions of this coupler included if you cannot find one of these couplers on the old bikes in the basement of the bike shop.
The coupler is fourth from the left
IMG_0688.PNG (779.16 KiB) Viewed 37 times
I did some engineering calculations for torque and shear on the first 2 mentioned couplers and found the Cyclone coupler likely low and the old English coupler at 544 ft-lbs in pure shear. The Staton coupler is obviously strong enough for this motor and controller but lacks the convenience of being "just right" in length. Do note that in this assembly the coupler will tighten the two hubs together making for tension in the coupler but compressing the two sprocket hubs tight together on their faces. Some of the torque will then be transferred accross the bearing faces by these normal forces compressing the bearing faces together and generate an associated friction sheer. Making use of both tension/compression and shear in a material results in a stronger design.

A bearing assembly that fits (sung) inside the two sprockets looks like this or shorter in overall length if you get the lower profile coupler mentioned in the photo above. Space is a premium.
This bearing assembly measures 1.4" and note one end of one bearing is pressed into the coupler. These are square taper bearings.
IMG_0793.jpg (2.56 MiB) Viewed 37 times
These bearings are either slightly too big to fit the hub or a little bit small to carry the loads depending on which freewheel hub you employ. If you use a White Industry flange type freewheeel hub on the right you will need to mill out about some approx 0.010" diameter to get a press fit for the bearing insertion.
The White Industry Hub milled to fit the square taper bearing on its outside end. The bearing has a black seal ring.
IMG_0489.JPG (812.47 KiB) Viewed 37 times

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