QS 3000 138 motor bike installation generalized

[DingusMcGee]

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

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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]

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

[DingusMcGee]

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]

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:

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Here is the QS reply

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So Robert Chen of QS will likely be willing to supply these sizes of motor sprockets.

[DingusMcGee]

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.

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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

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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.

AFN

[DingusMcGee]

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)

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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

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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.

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Here we see the triangle motors plates fastened to the BB bracket.

Identical motor plates fastened to BB

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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

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