Introduction: 1 Inch Axle Upgrades for Pedicabs Using Go-kart Parts

The problem is this:  The O.G. axles snap off where the step in the axle end is- right where the axle goes from inch to 3/4 inch. Plus the design uses too many bearings. The bearings don't have seals and water easily washes the grease out. The new design will use only 4 bearings and will never need lube.
Each Pedicab needs these parts:
4 one inch pillow block bearings with lock collars. part number 1-205-16-P-C from 
2 single split shaft collars part number 1-2767-100 surplus center again
4 W1B1 weld hubs part number 1-2342-I surplus
1 driven sprocket with 23 teeth and 1 inch bore for #40 chain part number 1-2123-23-E  surplus center
1 drive sprocket with 16 teeth and 3/4 inch bore for #40 chain part number 1-2123-16-C  surplus center sure is getting all my money. you only need this if the mid drive is broken
1 idler sprocket for #40 chain- part number
1-2409-17-A  surplus center
1 box of #40 chain part number
1-1163-40 surplus center- you won't use all the chain- two boxes will do three cabs.
2 axles. one inch with full length keyway.
1 disk brake rotor part number
about six inches of 1/4 inch key stock- Casa De Los Tornillos or Home Depot if you are in a pinch.
bolts 3/8 by 2 1/2 inches
grade eight .Casa De Los Tornillos or Home Depot
2 bolts 3/8 by one inch
1/2 inch by 1 1/2 carriage bolt and nut for tensioner
30 washers 3/8

14 inches of 1x2 "C" channel cut into two equal chunks. Source that from a local steel shop. You can also use 2 inch angle iron but its a bit weaker.

Step 1: Out With the Old

Strip off the body and old axle, set up the frame on some jackstands so its stable and get out your bearings.
As you can see the holes don't line up so time to drill some new ones. Get out the old bearing and mark the center line of the axle so you can drill new holes and keep the axle in the same spot. You could use one of the old holes and just drill one new hole but then the axle will move forward or rearward and won't be centered in the well when the body goes back on.

For now just drill and mount the two outer bearings using the bolts and washers you bought. Be sure the lock collar side goes in and not out. Also be sure to mount the bearing on the bottom of the frame. 
See that grease fitting? Useless. It does not lube the bearing, it is for the HOUSING that the bearing sits in. Throw it away so no one will think they have to use it. The bearing is sealed for life and good to 3000 rpm.

Step 2: Mount the Center Bearing

Slide the axle into place and mark/drill the center support bearing holes. Doing it this way ensure the bearing is in the right spot, lined up perfect.

Step 3: Build the Second Center Support Mount

Get out the 7 inch "C" channel, this will be used to build the other center support bearing mount- the cab must have a split axle or it would be impossible to turn it.  Line it up like this and weld it on. The critical part of this is that it is flush with the bottom of the frame so all the bearings are in line. Drill holes in the center of the channel using the same method as the last step  and mount the final bearing. Leave the two center bearings loose but tighten the outers so you can slide the axle out.

Step 4: Axles Assemble!

Now you just need to assemble the axles- make sure you put the lock collars toward the middle and use them, they just cam into place and the set screw keeps them in. Without the cam locks "in and tight" the axle could walk out of the bearings. 1/4 inch key cut to fit the driven gear and set screw locked, same with the disk brake rotor. Note that the cab frame is wrong side up in this shot.

Step 5: Optional Front Drive

This is the mid drive assembly. If you have a broken gear here, weld the 16 tooth solid gear in place of this bmx one-way.  The one way on the other side will do fine and the assembly can still be removed and lubed from the right side.  The #40 chain will work with the O.G. bmx gear though so you can leave it alone if it is in good shape.
To fit the 16 tooth 3/4 solid front gear to this mid drive axle involves grinding down the axle slightly, as it is metric and about 2 mm too large to fit in nicely . Here are a few photo's of what I did, just reassemble the shaft with some tape wrapped around it to keep the bearing in place and attack the shaft end with the angle grinder, carefully checking your work until it fits snug and flush. Then weld the gear onto the shaft with the gear side out and reassemble.

Step 6: Tensioner Construction

Take that other 7 inch "C" channel and  cut it like this.  Drill a hole at the top of the slot and slice out the slot with an angle grinder. The slot measures about 4 inches and is sized for the carriage bolt head to fit in it.

Step 7: Tensioner, Check Angles. Weld Into Place

Bolt up the idler gear you have to the tensioner bracket and weld it into here so the chain can be  adjusted. It is important that the bracket be spaced correctly side to side (although you can fix that with washers) and that it is straight up and down- you don't want the tensioner to move from side to side as it goes up and down. The tensioner in this photo is too far forward. it needs to be  closer to the driven gear. this changes the angle that the chain leaves the tensioner so that it won't hit the forward frame. check out pic two. Once you have a no interference fit, tack it in and then persuade it with a hammer to be straight before final welding.

Step 8: Brake Rotor

If you have the O.G. brake rotor- it is 15/16 DAMN! why did the manufacturer make an axle with THREE different steps in it?
the drive gear is on the one inch, the brake rotor is 15/16 and the axle ends are 3/4. stupid. oh well.
take a 1/4 inch shaft  grinder (mine is from Harbor Freight) to the rotor I.D. until it just slips over the shaft. If there are no rear brakes, see the instructable about adding brakes. If only the rotor is missing, just order a new one with 1 inch bore from BMI karts or the like.

Step 9: Final Axle Install

Set the toe of the whole thing with the two center bearings slide them fore and aft to align the axle. If the outer bearings are in the same place as when you first had the long shaft in place the axle will be aligned.
Toe in or out will make the thing hard to ride as the tires drag sideways. Pushing the cab across a single sheet of butcher paper will show toe in or out (tears it for out, wrinkles for in) watch the tire wear to diagnose toe problems but careful assembly will eliminate most of those problems.
Then, install the chain and  align the driven gear, lock it down with the set screw.

Now, tension the chain by sliding the idler downwards, leave a little slop in the chain to prevent drag but tight enough not to throw chains off gears.

Align the disk brake rotor, lock that down.
Then spin the axles all around and make sure it rolls smooth. 

Finally time to bolt the body back on.

Check out the other Instructables for how to make the wheels for this conversion out of W1B hubs and for adding disk brakes to the cabs without them. Also look for the one on repairing bent front forks