Yes. I had a custom axle made.

The bike is held to the dyno by the axle and A-frame assembly. The A-frame assembly (which I've dubbed "the spider"... kinda looks like a spider with legs lol) is bolted into the chassis of they dynamometer, and is also bolted thru the deck of the trialer into the steel frame of the trailer.

Yes, the straps are adjustable in 6" increments, and are to keep from looping out. I can set it so that the bike comes up only a foot, or all the way to 12 o'clock.

I also have a climbing grade bungee system that is also adjustable, and helps soften the snap a bit as you load on the safety system. I can set it so that it helps when you're 2 feet from looping, all the way to about 6" from looping... or can remove the bungee system all together.

And, yes, the shocks are there to lighten the landing and take it easy on the bikes' shocks as you land again. I can remove the lower bolt, and slide the shocks under the spring board, and double it as a ramp to load the bike on and off. =)



The axle has a 1 3/4" bearing, held in place with 2 locking collars. That assembly then slides into a 2" square, x 5" long brick with a hole in the side of it to allow the bearing assembly to just barely fit.

The quick release pins remove from the top of the a-frame, and the brick assembly slides into the vertical upright. An upper adjustable brick locks in place with the pins...

Taking the bike on and off the system takes about 2 minutes. The system is wicked solid, and very easy to change out bikes later on. The double sheer strength of each quick release pin is 20,700 lbs. So 20 tons double sheer strength per side. So basically it'd take 40 tons of vertical force to snap the pins and get the bike to come off unwanted.

Here's a picture of the vertical upright system before I had it shortened a bit to accommodate room for my exhaust, and before I had it all welded together.


My mock-up tire on the completed A-frame assembly.



Well, there ya go. A few close up shots of my design.

- Pixel -

 

That is f'n sick bro. Good work. I thought about building one a couple years ago, but abandoned the idea due to lack of monetary means for the end result. It looks as though you have done your homework and things came out well. Very well done indeed.

 

What kind of dyno did you use for that setup, if you don't mind me asking?

 

A matching pair of Sun XX portable dynos, with the computer control system, emissions testing equipment, and software.

RG 240P Model EESE 101A

Works out well in Colorado. About 10 years ago, all the auto shops here could do emissions testing, so everyone had dynos. Then the state took over emissions testing, and all the cars on the market became computer controlled.
So now an auto shop can just hook up a computer and do all the diagnostics a dyno would tell them. So basically, dynos in Colorado are worthless to auto repair shops, and just take up room on their shop floor.

Yay me!

So since I have two matching dynos, I'll get to work on the other one as soon as I work out all the bits on my prototype design.

- Pixel -

 

Going back to my machinist tomorrow to test it again.

I took the large pulley off of my spare dyno, and am having him replace the small pulley on my machine with the large one, so testing a 1:1 ratio, and seeing how close the weight of the fly wheel is. Had to wait for longer belts to come in... so haven't played on it for a week.

Hopefully this will get the sensation right. If we need to, we might add more weight to the fly wheel and re-balance it.

So tomorrow is test number 3. Wish me luck. Hopefully it will be close, or I'll be making more changes, and will have to wait on test number 4.

- Pixel -

 

Ok, here's where the project is at.

Test 1: Couldn't get traction, so did diamond knurling and increased the down pressure.

Test 2: Got traction, but the fly wheel pulleys were giving the drums a 1 to 1.3 ratio. That ratio made the fly wheel spin faster than the drum, making the wheelies feel wrong on launch, and engine braking. Also had to use way too much throttle to both launch it, and keep it at BP.

Test 3: Today. Got a new fly wheel put on the system, at a 1 to 1 ratio. So now the wheelie feels right when it's at BP. However, I now have a problem with too little rotating mass. The acceleration on the launch feels too light. But I have no problem spinning up the mass I'm moving.

Based on the weight of steel, and plugging in some numbers, The drums each weigh about 75 lbs. So a 150 lbs combined there. The fly wheel also weighs about 150 lbs. So the mass I'm currently moving is 300 lbs give or take.
The number I'm looking for, is the weight of the bike plus rider... so figure 450 + 150 on the low side... 600 lbs. I'm a little over 200 lbs... so my target number would be more like 650 or so.
So I'm now 350 lbs too shy on my rotating mass.


So my possible solutions, are

1: Add the fly wheel from my other dyno to the fly wheel on the existing one. Brings me to 450 lbs, so still 200 lbs shy. Would be fairly easy to do though, so might give this one a test.

2: See if the eddie current brake will work with only one side of the dyno plugged in. If I get lucky here, I can use the eddie current brake to resist the 300 lbs I'm moving, and make it feel like 650 or whatever.
Only reason I don't like this one, is the system starts to become computer controlled, rather than a mechanical system, which I'd prefer.

3: Plugging in the math, a 28" drum, 8.5" thick, would weigh 460 lbs. Then add the other drum at 75 lbs... and fly wheel at 135 lbs... so total about 670 lbs. Right around my target weight for the system.
If the eddie current test doesn't work, I'll probably have to go this route... only drag is steel is about a dollar a pound... and I'll need to get a 675 pound drum of steel 42" wide, and get it machined down in width to 28.5" wide.
So basically I'll have 200 bucks in metal shavings sitting on the floor if I do this one. =/

Well, anyways, got a crappy phone vid of my first test today. Sorry for junk quality. Was getting dark quick, so had to rush this test a bit. Ooh, and sorry about the first minute of on the vid... was warming up the tires, and I don't have a good editing program for video on my laptop to crop the first part out.
First couple of pulls you can tell I have too little weight I'm moving. Thing spins right up!

http://vids.myspace.com/index.cfm?fu...deoid=46370940

Will give the eddie current brake a try on Friday when I finally get some free time!

- Pixel -

 

rent that thing out at events

 

i may be totally wrong here but couldn't you make up the difference by gearing the bike super high , would be a lot cheaper and easier to do ...

go up a few teeth over stock on the front and down a few from stock on the rear

 

shift the bike into second to get an idea maybe

 

Crap. Totally forgot to try 2nd gear today! lol. Good point.

I'm already geared -1 / +13

I don't think I have an easy fix on this one.

Might give something like concrete a try... since I have an extra drum in the garage. Can load up the spare drum with that, and just see how the added weight feels before I have a new one machined.

Maybe I can find a way to add a liquid metal to the hollowness of the drum? Any ideas there? Has to be a solid when it's done... a liquid would not give any benefit. The added mass ultimately needs to spin with the drum.

- Pixel -

 

your geared exactly the wrong way to solve your problem and as far as a liquid goes you would just need to have chambers so the drum would have to move the liquid instead of it just sitting there while the drum spins but before you gt into all that try shifting because i really think your whole problem could be cured that way , you may not even have to change sprockets if it feels right in second or third

 

look at the wheels in your avatar ....lol

picture that inside of a sealed drum , that would force the drum to move the liquid

 

Man. I shoulda had a V8

 

have you rode a different wheelie machine before? all the ones I have seen are really hard to pop it up(almost always require someone lifting on the cage) and the one I rode had TONS of EB, and you had to stay in the gas the whole time

 

Pixel... you still around man?

 

edit: didn't realize this post was mad ******* old.

 

wow that thing looked well made!!

 

Without doubt I would like to have one at home....

I learned rear brake control with an Atv... it wasn´t so real but was very cheap.....

 

since its been resurected....

pixel you still got this beast....?

im from colorado and would love to check this beast out?

 

thats badass dude