Triger

[Wildcat]

I wanted to do some cutting with my grinder on a build off bike, the Wright Special, but there is laundry hanging in my multi-purpose shop. No smoke or smelly stuff today so I got to looking around and came up with another wild idea. I have a set of fat bike wheels and think they will work well on Bamboozle, another build off bike from earlier. It's good, but there's too much flop in the steering for me. So the idea is for a three wheeler, but not symmetrical like a regular trike. And not a sidecar configuration either, an in between thing. It won't be as wide as a bike with sidecar or a normal trike and not have an axle in the rear like a trike. The rise in height of the frame rear will alleviate the steering flop making the trail much better. The fat bike tire should be about 29" tall.
It will be six speed and geared low. A band brake will be on each rear wheel. Later, if all works well, a front wheel with an electric motor might happen.

Here's the plan so far:
1. Mount the rear wheel so the drive chain is on the left side. This will allow the extra wheel to be attached off the right side. The extra wheel will be slightly toed in and be mounted ahead of the drive wheel. I've studied sidecars and this will provide a more stable ride. Whether the supports are welded or bolt on is undecided.
2. The chain wheel goes on the left side and the derailleur mounts to the inside of the drive wheel. It should shift as normal. The wheel may have to be dished to clear the chain and tire.
3. Get tires and tubes. 26 x 4.0.
4. Paint tiger stripes on the frame. Hence the name, a trike with tiger stripes, Triger.
5. Make up a bench seat for an extra rider.
6. Make some kind of box or rack for the rear.

 

[Wildcat]

Already found a set of 26 x 4.0 tires for 22 bucks each.

 

[Wildcat]

I checked to see how much dish would be needed to allow chain clearance on the largest cog. The axle is 135mm and the tire is 4" wide. The hub needs to come over about an inch and a half. I wonder if that's too much dish and I should just get a fat bike rear hub and lace it in.

 

[Wildcat]

I didn't see any narrow trikes before, but I just found a photo.

It's also using a left hand drive like I thought of. But I can't tell if it has a rear axle or is just one wheel drive like mine will be. But it shows just about the width I had in mind, about 16". The wheels look evenly spaced left and right.
My crude diagram shows the position of each wheel. Since the right rear will be farther out from the center, it will act like a sidecar and pull to the right, so that's why it is toed in and is slightly ahead of the drive wheel. usually one wheel drive would have a pull left or right, but being so close to center should keep that effect to a minimum.

 

[Wildcat]

The tires arrived already! With shipping, the pair was $41. Now to take the wheel to the shop for dishing.

 

[rgrrbt]

Looking forward to seeing how this plays out.

 

[Wildcat]

Me too. It's mostly theory, so it will be bolt on adjustable things until it rides decently.

 

[Wildcat]

I explained the idea a couple times to the guys at the shop. I needed the cluster as far to the right as possible.

It's as far over as safely possible, the spokes on the left are straight vertical to the hub. I might not be able to get the lowest two gears but with a 36 chain wheel may not be needed.
The inner tubes haven't been shipped yet, so I may have to reorder. I mocked it up to get an idea of pedal clearance and seat height. I'm not going for a long wheelbase, so the seating will be higher than before.

 

[Wildcat]

Inner tubes showed up, and have presta valves. I've never used them but my pump has an adapter. About ten bucks shipped for 2 tubes. So that makes tires and tubes a little over 50 bucks. That's a lot of bike budget but it's the holidays!
They are tough to get seated just right but don't need much air.
I set the wheels in the dropouts to get a look. There they are 14" wide and have the frame too low, there's a lot of flop in the steering. If I mount them a foot or so ahead of the dropouts it should be just about right. I think 20" might be a better width.

 

[Wildcat]

The dishing wasn't enough, so I'll get a 170mm hub for my threaded cluster. They all have mounts for disc brakes, so that's what I'll try. I could make a home made caliper side pull brake, but the disc brake has the best stopping power from what I've seen. I'll need it with the weight of this thing. They make the adapters that bolt up to the frame.

Anyone used one of those adapters?

 

[Starnger]

I didn't honestly use one myself. But it looks way too unstable, i won't trust my health to such a sketchy solution. I'd rather go for roller brakes then.

 

[Wildcat]

I just realized those adapters won't work for this build. There's no frame tubing to attach to because the dropouts for the rear axles will be below the frame. 6-8". I could have a bracket for disc brakes welded to the dropouts I'll make up for the rear wheels. It'll take some engineering that I was hoping to avoid. I may go with rim brakes of some kind. It's up in the air right now. Getting the wheels on and working has to happen first.

 

[Ulu]

I rode a big motorcycle once, 2000cc, and we put a wider radial car tire on the rear. It almost didn’t need a kickstand. It was funny to ride but had enormous traction.

As I was riding it, it just stayed up and I had to tip it up, on one corner or the other of the tire, to make it turn.

I’m thinking that a trike with closely spaced rear wheels would be much the same in handling. In a turn it will out-track way late and quite suddenly.

That’s almost how the lengthy insanity handles as well. As it has a 25 cm wide front tire and a 100 cm rear tire. It wants to lay over a bit before it starts to out-track. Then it will turn in hard.

 

[Wildcat]

I rethought the thing again. I'm keeping the setup but changed to 26 x 3 tires with a Sturmey Archer kickback hub with a coaster brake. That solves the chain clearance and gear issues along with the braking problem.

The gearing will be low and super low with a 32/22 setup. That's a 41 and 55 GI on the 2 speed. I can swap out to an 18 cog if that's too low and then have 50 and 68 GI.
Having a coaster brake also frees up a brake lever so another band brake can go on the front. 3 wheel brakes.
The level it is sitting at is close to where it will wind up. I plan to sit above the rear wheels and have a bird's eye view. The pedals are already 5 inches off the ground.

 

[Wildcat]

The second rear wheel had a front hub, no threads for a band brake. So I unlaced a donor wheel and added the rear hub to the 57mm rim. That calls for a road trip to town tomorrow to have it trued up.

I've been researching tiger paint jobs. It looks pretty simple, yellow-orange with black stripes and a little white trim.

 

[Ulu]

It’s Grrreat!

 

[Wildcat]

I recently went on the Zoofari ride here in Subic. They take a jeepney with everything covered with steel mesh and drive you through a compound with a couple of big tigers. That's where I got the idea to paint a bike with tiger stripes. I was sitting right where the tigers were fed the raw chicken parts. Slobber and bits of chicken were flying everywhere as they tried to eat as much as possible through the window mesh.

The wheels are ready to go.

 

[Wildcat]

Those wheels went back on Riff Ratt. This build ain't gonna happen. Too costly for an uncertain outcome. And I have 3 to get ready by the 15th.
But it was a good learning experience. Fat tires require the wide hubs and a wide BB, no way around it.
I need to get some wide hubs and re-lace both wheels so they will be set for the next build idea. Maybe for this year's annual build off I'll make some kind of fat bike thing. Has there been a swing fat bike?