I got my Microcar almost a year ago. The previous owner had given up on it, so I picked up where he'd left off. It came with 17" bernardi 3 star mag wheel in the front, sping loaded EBRs, and 17" spokes in the back.
The rear axle the last guy put in was too long so he sawed a chunk off and tried connecting the two ends with a Lovejoy coupler.
Gas tank is held together by what looks like some epoxy. I later discovered a gnarly gash in it.
Initially I planned to keep the original drive sprocket and the band brake setup. But I read bad feedback about this band brake on account of it not braking and also binding. Here's a shot of the stock sprocket with welded on brake drum.
Stopping is a top priority so I opted for the dirt bike front disc brake. Most of the braking is accomplished by the front brake anyway. The KX65 hydros replaced the flimsy EBRs and the CR85 aluminum spoke rim with rotor replaced the Bernardi mag. The caliper is off KX65. Brake line is some 60". Those are Tomos triples bored out to 33mm.
I sourced the replacement 1" diameter 30" long solid live axle from a go kart vendor. The existing axle bearings were both 1" diameter. I looked for an axle with the differential but non exist in this length. Neither is there any space for the differential because of the trunk. Differential axle would also call for two disc or other brakes on its each end.
Next I looked into a custom aluminum sprocket to cut weight. The stock drive sprockets weighs a whopping 5 lbs 7.2 oz. The custom cut sprocket with mounting hub weighs 1 lb 15.7oz.
That's pretty sweet.
I am not good with 3 wheels.
I crash
The new sprocket called for a rear disc brake. The braking surface on modern band brake drums is some 1/4" wider than that on the stock welded on drum. So I ran into clearance issues with the modern stuff and in the end chain alignment issues. The band brake had to go.
With the trunk in place there is just enough clearance for the rotor. There are a couple of calipers available: a conventional single piston in the photo below and a much heftier one with a built in parking brake. The Microcar is missing the parking brake. It remains to fabricate the caliper mounting bracket. I'll bet the parking brake on the bigger caliper is operated by some sort of a lever to lock it in place.
Rear brakes are all foot activated on go karts and obviously motorcycles because a lot more force is required. So my rear brake setup calls for a master cylinder, pedal with mounting rail, mechanical linkage to the master cylinder. All that stuff can wait because there's a disc brake in the front.
(edited)
The rear right wheel is supposed to freewheel or handling suffers
This is awesome!!! So cool to see old bikes get revamped with modern tech that didnt exist when they were made
Dave is right though, the right side wheel should spin free on an axle bushing. If you only ride it on dirt or grass the solid axle wont matter, but pavement will suck. Speaking from experience, I also own a micro car that was converted to two wheel drive lol. We later put it back to one wheel drive.
yeah this is really neato, i've been dicking around with riding lawnmowers lately, thinking about a microcar with a riding lawnmower transaxle... hmm.
Dear Dmitry,
I spent a number of days installing a solid rear axle on my trike including a new disk set up and all, only to cut it in half before starting the bike. Have you tried to push that assembled unit around your driveway or garage yet? It won't work and won't turn at all. One wheels spin will be fighting the other and you'll drive the ped right into the curb. Especially since that rear end is as wide as it is. Needs a differential.
if you have the ability to turn metal, which it looks like you do, the suggestion of a free wheel bearing in the hub of one wheel might be pretty do-able.
I get what y'all are saying and your feedback is the reason I posted this. Yes the drive wheels need to rotate at different speeds in the corners hence the need for a differential. You're saying put a bearing inside the hub so it rotates freely around the axle, get rid of they key and the set screw, and leave the rest of my setup alone? I just tried moving the bike a few feet around the garage and it does turn albeit with a huge turning radius.
Here's my wheel hub setup.
I have. Both types of trike, freewheel and differential Trust me there is no comparison in handling. The Triped wins by a mile. Stu Pivar nailed it
> JBOT Admin Wrote:
> -------------------------------------------------------
> That's pretty sweet.
>
> I am not good with 3 wheels.
>
> I crash
sounds good to me! the fun part's when you're riding a 3 wheeler on 2 wheels anyway
yeah i was thinking those one way needle bearings like this:
bore out the hub and either turn the shaft down or make a smooth sleeve that goes over it,then you'd have to put a bushing into the other part of the hub to act as a bearing when its free wheeling, which would probably be relatively little.
I rode almost the entire Boston StPaddy parade one year on two wheels on the Microcar. Crowd favorite
HELL. YES. THIS. FUCKIN. R00LZ.
Tripeds are rad AF, glad to see another one getting some love!
Bummer about the gas tank. I would recommend an aluminum tank from Sandstorm. They have a huge selection, choice of finish, and can include many of the necessary accessories (petcock, cap, cap with gauge, reserve tank partition, clamps, etc.). You have a first gen, second revision body/frame style so the tank won't be quite the same as the one that I used as it will need to fit within that frame clearance. Link if you want to go that route.
The hydro front end made a huge difference, and you have taken it to another level with disk brakes; nice work!
I am having issues with the drive chain on mine, and need to add a secondary tension point with a roller guide or something to keep the chain from throwing itself off. Such a long run on these things. I have also found that a 415 HD chain doesn't match the rear sprocket so I need to source a chain that matches the pitch as the stock chain is in need of replacement, but it looks like you have alleviated that issue.
I look forward to seeing the progress. Keep up the solid work!
A metal gas tank from an older lawn tractor would work well and look similar to the original which may very well have been from a supplier of same
Maybe convert a mini keg to a gas tank .
Your microcar is right there on their website. Smallest horizontal aluminum spun tank is 6" diameter in 16" or so length for a 1.6 gal tank which is plenty big. My stock tank is 5.5" x 15". I have 17" clearance. $150 though luckily my budget isn't clearly defined.
1/4" thread in those aluminum spun tanks for the petcock?
Yeah, a 1/4” barbed hose with 1/4” NPT thread. No reserve option on that assembly...but they had a gas gauge option on some of those tanks.
Today I did a mock up with the Peerless Gear differential, yet another 60T sprocket mounted on the LH side, and another 8" steel rotor on the RH side; a little mechanical caliper can mount right under it on currently non existent mounting bracket. This drive train revision leaves no clearance for the stock trunk. I haven't decided whether to go with a foot or hand activated rear brake.
Differential sits all the way on the left because of the drive sprocket and chain position. LH axle half will be stubby after I cut it to size. Unforfunately, the RH half isn't long enough to mount my wheel & hub.
damn.
cool you went with a differential. this is gonna be awesome. I love it a whole lot
Made some some more progress. Had to exchange the existing differential to the supplier for a different model. Problem I ran into was the offset V1 placement on the frame. Being a pedal version the motor naturally sits right underneath the driver yada yada yada. So the motor and the drive sprocket are offset. Existing differential RH axle half wasn't long enough as a result. Here's the different model differential on the bike now. The only issue now is the axles need cutting to size and threading on the ends.
Here's the end result.
Both axle halves cut to size, ends threaded, various spacers made. Next step is the pedal activated rear mechanical disk brake.
if the tank is plastic you can do Labs repair on it with a backup grid. Liquid ABS + mek and backup grid will be as strong as original although you might have to paint tank later with uv resitant paint. I have some grid I could send you. If it is metal maybe you can solder it with a pencil torch and 50/50 solder. (edited)
i just bought this cobbled together homade water wagon off craigslist and it uses that same differential
i think the source is a lower-end rear engine riding lawnmower. there is a guy by me with a few of them in the weeds i was gonna go scope out
just FYI if anyone is looking to replicate this project on the cheaps or fix a bent rear axle on a tri-ped.
I would be cautious about that scheme of yours.
That's a Peerless Gear model 100 differential. These can be had for as low as $170 plus ship from places like this. There are several variations of the same model and I'm sure none are plug and play in moped application. Axle halves are not interchangeable as I found out trying to source a longer RH axle half. Spline ends are different, etc. Some are built to withstand greater loads than others, built tougher. Luckily I was able to return all the stuff that didn't work.
Mine came is what is called Peerless Differential Kit and came with blank axle halve ends albeit sufficient length to work with offset motor, completely disassembled, included a giant tube of differential grease, gasket material, oil seals, all hardware, and was more money.
Here I tried ordering a longer axle half from a different model which wasn't compatible.
Here's another example of a one wheel drive on my 2yo daughter's trike. That's about the only suitable application of a one wheel drive because on a large vehicle such as the microcar a single force of the driving wheel is acting off-center to the center of mass of the microcar making it always turn as it accelerates. I'm sure Stu Pivar's chose his one wheel drive design because it was low end mechanically simple like that trike of mine and cheap.
I am going to try this one more time and then give up. I have owned 40 trikes. I have owned many with the Peerless differential axle (mostly Pryers and also Tri-Rads) and many more with the standard American Tri-ped freewheel solid axle. There is NO COMPARISON on speed, on accelearation, on handling, on everthing. The freewheel is the cheapest, fastest, most reliable, lightest, best turning ...yada yada yada. Please do not waste your time and money on al;l this expensive stuff that only diminishes the enjoyment of the trike.
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