Peerless 100 Differential Axle for my peditruck

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So I got one of these Peerless 100 Differential go-kart axles for my pedal truck build. Definitely not the cheapest (or lightest) option but it seems extremely robust, and is used on commercial pedicabs. I thought I'd make a thread on it to share my experience and seek the advice of some others...

I bought it from here: https://www.geminikarts.co.uk/product/peerless-100-series-differential/

I am going to mount it to my chassis using four 1" oval bearings from Simply Bearings. I have already bought these, or I might have gone for these much lighter weight ones: https://simplybearings.co.uk/shop/p22814/SBPFL205-16-Oval-2-Bolt-Pressed-Steel-Bearing-Housing-with-1-inch-insert/product_info.html. Heck, I've not built the chassis yet, so I might still change my mind.

For the wheel hubs, I have asked a machine shop to machine them out of aluminium. They will fit over the 1" bore of the axle and fasten with a simple shaft collar on the end (https://simplybearings.co.uk/shop/p152339/CABUI100Z-Zinc-Plated-En8-Steel-Shaft-Collar-1x1-5/8x3/4-inch-with-Set-Screw/product_info.html). I will have to take the axle to another machine shop to have the 1/4" keyway milled onto it. I have also asked them to make an axle adapter, which will accept a 3/8" bearing pressed into it and clamp over the ends of the hubs so I can true the wheel in a truing stand.


It has taken me weeks of research even to get to this point - shaft collars were a recent revelation as I didn't even know they existed! I'm completely new to this, so hopefully this info can help someone else get off to a faster start than me.

I've still to figure out the drive sprocket. I will use a fairly typical mid-drive hub with a freewheel on one side and a fixed gear on the other, but mounting the sprocket on the differential is proving difficult. Gemini karts sells a platewheel to fit the differential, but it is a different pitch from typical bike/trike parts and I'd like to use a standard 3/32" or 1/8" chain if I can.

I haven't been able to find any 3/32" or 1/8" platewheels - does anyone know where I could get one? My plan was to buy one and drill it to mount onto the diff, but I can only find sprockets for much wider chains. Alternatively, I could have another part machined/lasered/plasma cut to adapt it to a standard front chainring, but that would add to the cost. I'd really appreciate some input on this - so that seems like a good place to leave this thread for today. I'll post more updates as I progress towards a completed drivetrain and wheels.
 
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Oh, and here's a picture of the differential itself:



Is there any way I can upload a pdf to my builder's gallery? I'm happy to share the drawings for anyone else, if I can figure out how to upload them.
 
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Wow! That's a monster Diff & Axle. Is the stated 10# weight the diff alone, or the diff + the axles?
 
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So not much progress yet... Wheel rims are on back order, machinist was sick with COVID but is getting back to work on my hubs today. I did speak to a rickshaw driver yesterday, he let me have a go on his rickshaw and even tipped up the undercarriage to let me have a look!

It was very enlightening. His axle had a chainring spider adapter to the diff and used a standard bike chain, so I'm going to send off for something like this to be laser cut in 4mm carbon steel:


Unsure about the brake rotor still. Staton Inc. over in the USA sells these which seems to be the way to go: http://www.staton-inc.com/store/index.php?p=product&id=2239 but they need special bolts with a longer shoulder to fit the diff, supposedly. Maybe since I'm using a thinner platewheel I could get away without. I'll probably have these laser cut with the spider to save on importing something from the USA.

Would anyone be able to tell me what grade steel/thickness I should get that done in? And will this be fine in a normal bike hydraulic brake caliper? I understand that they are suposed to be slightly concave, which this wouldn't be.
 
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Std bike rotors are 2.0mm. Pit bike rotors are typically 3.0mm. Motorcycle rotors are 4-5mm. I've never seen a concave rotor - they're always flat. Cheap bike rotors are stainless. No idea of grade. Motorcycle ones must be some form of carbon steel as they rust to a degree when not used. Most calipers will have a limit on what they'll take. The best way to tell is to push the pads back as far as they'll go and measure the gap. You may get fatter rotors in with worn pads.
 
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Std bike rotors are 2.0mm. Pit bike rotors are typically 3.0mm. Motorcycle rotors are 4-5mm. I've never seen a concave rotor - they're always flat. Cheap bike rotors are stainless. No idea of grade. Motorcycle ones must be some form of carbon steel as they rust to a degree when not used. Most calipers will have a limit on what they'll take. The best way to tell is to push the pads back as far as they'll go and measure the gap. You may get fatter rotors in with worn pads.
Thank you! That info is really helpful. I'll send off for a rotor to be laser cut at the same time as my spider
 
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Std bike rotors are 2.0mm. Pit bike rotors are typically 3.0mm. Motorcycle rotors are 4-5mm. I've never seen a concave rotor - they're always flat. Cheap bike rotors are stainless. No idea of grade. Motorcycle ones must be some form of carbon steel as they rust to a degree when not used. Most calipers will have a limit on what they'll take. The best way to tell is to push the pads back as far as they'll go and measure the gap. You may get fatter rotors in with worn pads.
What about the cutouts rotors usually have? Do they offer any advantage or is it just a weight reduction thing? Since I'm having it laser cut with the right bolt pattern I can do them if I want.
 
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Did some research, asked around, the cutouts are important to cool down the rotor and prevent concentrations of heat which could cause the rotor to warp, so I'm going with this design:


I'm sending it off to be laser cut in 410 stainless steel with the chainring adapter. This will mount on the right-hand side of the diff
 
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Just placed an order for all the steel!! I'm building the undercarriage out of 60x30x1.5 rectangular mild steel tubing. Bottom bracket and seat tube are off a junk bike I got for free, head tubes I had lathed a while back for my swing bike and have a spare.

I did these mockups in CAD. I know they probably don't mean much to anyone else but they helped me figure out the geometry and how much steel to order:




This is the approx of dropouts I will cut out of a bit of flat bar and weld to the end of the tubes, to hold the pressed steel oval bearing housings:



For the drive hub I decided to use a shimano freehub with 6-bolt disc mount, and I ordered one of the adapters from Maxpro mobility that they use on their trikes: http://pedicabshop.com/store/#!/~/product/id=65595&prid=23&ctid=6&tp=pv


It takes a standard 64mm BCD chainring.

I'm getting really excited about this now!!!! I'm going to start welding the undercarriage as soon as that steel arrives at the end of this week or next week. Will post some real life pics soon!
 
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Huge milestone reached! I picked up the laser cutting today and it's beautiful! Fits onto the diff perfectly (although a little tapping required on the thicker mild steel part due to melted laser edges)


The steel should be delivered from the warehouse either Friday or Monday, and then I hope to have the undercarriage built and a demonstrable working drivetrain by the end of next week!

I can't express enough how excited reaching this milestone makes me :D
 
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I just found this guy selling the mid-drive disc adapters - among other really cool sh!t! Wish I had seen this before ordering one for twice the price from maxpro that isn't even that well made, tbh.

 
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I managed to get a moment (just a moment) to go out the back and work today. Drilled some holes




This is a nifty trick to make 4 identical parts. I welded them all together at the corners and will cut/drill them all as one part. I used spray glue to attach the printed template to the steel.

I picked up a cheap second hand drill press for this, and wow! This thing just drills straight through. I must've snapped about 20 drill bits trying to get through 1.5mm steel in my cordless drill but this thing just plunges right into 24mm of steel like nothing. Unfortunately it runs too fast or isn't powerful enough for the 60mm hole saw so I'll probably go with the drill lots of holes, cut and file method.
 
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I like your wheel hubs. I had a similar idea at one point but I was trying to gen it up with standard size tubing/pipe. You mentioned threading the end or using a shaft collar; I'm curious if you're putting anything on the inside to prevent lateral movement or relying just on the keying?
 
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