You know when you see something cool, and you're like "I have to have that". Well this is how my drift trike started.
Custom designed steel frame. 5.5hp 4-stroke petrol engine. No brakes. All fun.
Below I'll go into specifics but if you have any questions or clarifications I'll try my best to answer.
The very first thing you want to do is get all the main components. These include: - Engine and clutch - Rear axle assembly (chain, sprocket, axle, bearings, hubs and wheels) - Donor BMX (or at least front forks) Once I had all these I could mock up the arrangement and over all size to get an idea of how much steel I would need for the frame.
The steel I used is 25mm square tube which has a wall thickness of 2.5mm. All the frame was cut with a cutoff wheel on an angle grinder. The frame is basically a rectangle with a triangle attached to which you'll see further down as I build it. I do not have measurements for it as it is based entirely off the size of your parts and of yourself. The first piece to do is the rectangle that holds the rear axle assembly. The long sides is determined by the length of the axle itself and where the axle bearings need to sit along it. The short sides are a little less important, I made mine a little wider than the rear wheel.
To make sure the rectangle and axle are square I cut the two short lengths to the exact same length then taped one on top of the other and drilled pilot holes for where my pillow block bearings would bolt on. This ensured they were in the exact same position at either side of the frame.
- pilot holes for the bearings
- rear axle, pillow block bearings bolted to the short sides
Once everything is doubled checked to be square and level the rear axle assembly frame can be welded up.
With this done we can now figure out where the engine needs to sit. This will be dictated by a couple of things. - location of the sprocket on your rear axle - location of the sprocket on your clutch - length of your chain - mounting location of your engine - and most importantly what looks the coolest to you. I mocked this up with bits of wood so I could take measurements to build the motor mount.
This is what I came up with. basically just a raised platform that sat over my rear axle that I could bolt the engine to.
- welded onto the frame.
The next step was to extend the frame forwards towards where the top tube would run upwards to the forks. - this bit is where your butt goes. All I did here guess how much length I would need to put a seat, ran a tube flat from the centre of the rear, forward to a 'T' piece at the top to make space to weld a lateral support tubes either side so there was no chance of going it anywhere
Now to run the top tube upward to the forks. The angle and length will be determined by the size of your forks and front wheel. So just use some clamps and mock things up to where they need to go.
Go slow here and keep everything in parallel with the centre of your frame. I spent an evening researching correct rake angles of forks and decided that it doesn't matter that much. Just don't go too crazy in either direction and you'll be fine.
I welded down tubes on either side of the top tube in a triangular layout because I didn't want to eat asphalt mid drift.
The last step of the frame is to figure out how mount your seat. In my case I made a cage around it that the seat pops into. This is great for disassembly and stops you sliding out from centrifugal forces but looking at it now seems unnecessarily complicated.
Boom. There it is. frame done. make sure you paint it so all your hard work doesn't rust. Now it's time to assemble the components onto the frame and go for a drift. I won't cover the specifics of attaching the components because that will be different for everyone depending on what parts you get. But I'm happy to try answer any questions you have about it.
TL;DR Beginner welder. made a drift trike. super fun. you should do it too.