Big Upgrade To The Red Rocket

[toystory_4wd]

Hey, folks!

I've been toying with the idea of adding suspension to my kart. Off road thrashing without suspension- well- hurts! I beat on it, it beats on me. I figured I'd start with the front, as I already had most of what I'd need.

Given the current design of the frontend, I ended up settling on a trailing arm design. A-arms would have required me to cut the front of the kart off, and throw it out. I wasn't willing to go that far...yet...

All the steel stock used was recycled. Most of the black stuff was from an exercise machine I molested years ago. There were some bits with pivot tubes welded in, so I took advantage of that. The (rusted) curvy framing was cut off from another kart frame I had bought used and am slowly redesigning. The coilovers are from a 1988 Yamaha Virago 250 motorcycle. I think the lower shock brackets came from an old lawn tractor, but it's been so long I don't remember. The only "new" parts came from a trailer suspension hardware kit. The arm pivot brackets (welded to the new bumper tube) fit the exercise machine pivots smashingly. However, the ID was 1/2" and I needed 9/16" for the trailer bolts. Into the drill press they went! The trailer kit included 9/16" gr5 bolts and lock nuts that are just lovely for the job. The upper shock mounts are fabbed from scrap steel and the leaf spring shackle straps that came with the trailer kit.

To keep the frontend geometry from getting mangled in the process, I cheated. Instead of cutting the spindle brackets off the frame and working from there, I made the trailing arms first. I then mounted them in their pivot brackets, tacked the brackets to the frame, and tacked the arms to my existing spindle brackets. Only after everything was in place, I sawzalled the spindle brackets off the kart's frame.

I spent a retarded amount of time mocking up shock mount locations to try and get the leverage appropriate. Anyways, after I was happy with the way things felt, I burnt most of it in and went for a ride. As you can see, it's pretty muddy 'round here!!!

I still have to grind off tack spots, old connection points from when the tubing was something else, cap the open ends, clean up and paint, but I ran out of steam and it looks like it's going to rain, so I stopped. For now.

I'm happy to report that it worked out very well. My test ride was better than I expected, given the stiff springs and lack of rear suspension. Bump steer is hardly noticeable on all but the worst hits. It raises a wee bit when I hit the gas, and drops a bit when I brake hard. Soaks up irregular terrain pretty respectably, too. All in all, I'm thrilled!

The kart before the tools came out (and before last weekend's mud runs, too.) Old pic.

[toystory_4wd]

Some "during" shots...

[toystory_4wd]

Here's a few "finished" shots, taken after my test runs. I had to quickly rework my pedals for clearance, I will fully sort them out later.

It just became more fun to drive! I'm sure it'll be a riot after I do the rearend!

[anderkart]

Nice, that looks strong enough to mount a cherry picker and yank the engine out of a peterbilt

[toystory_4wd]

Thank you, I think? Of all the things I'm guilty of, underengineering is not usually one of them...

[T-man]

looks good. now with those shock towers you could put lights on them.

[bighead]

Very cool. Lets see a vid of some big air?

[toystory_4wd]

For the sake of my spine, that will have to hold until the rearend gets done!!!

I may have my wife shoot a short clip of me going over some rough stuff at lower speed to illustrate the suspension action in a few days. We've got some pretty nifty frost heaves and sink holes in the driveway this year.

[bighead]

Ok I will let you just slide this time.

[Bluethunder3320]

Jump it over your house!

[bighead]

Take it Daves Farm and fly off sky hill.

[B man]

poor dave.= [

[DCProductions]

I dig! Definitely need a video. I am disappointed that there is no actual rocket in this project, though I do see some redness.

[anderkart]

Originally Posted by toystory_4wd

Thank you, I think? Of all the things I'm guilty of, underengineering is not usually one of them...

Lol, I was complementing you, but your right it does seem to be EXTREEMLY strong and well designed/built and I was just kinda making a little joke there. I thought my comment was funny and hope you did too man

[B.M.800]

Looks cool man!

[devino246]

Originally Posted by anderkart

thought my comment was funny and hope you did too man

I did. Perhaps certain joking tones dont cross international borders

[toystory_4wd]

Anderkart- I laughed!!! Took it as a compliment, too! I'd rather that than a comment like, "Jeezus, there's no bloody way I'd trust my arse to that beer can!" Sorry if my response threw you. It was supposed to be funnier than it appeared. OOPS.

It took me a while to screw up the courage to hack into it. What's the saying? Don't mess with what works? Anyways, I took on the attitude that I'd be danged if I was going to go through all the trouble only to have the whole schmeer collapse in the washboards, or worse- fail at high speed. He//, the pig's overweight anyway. I'm going to repower it sometime in the future. For now, it's still pretty good.

I took some measurements last night. With my weight in the kart, the front sags ~1". I then have 4" of effective travel before the kart bottoms. This gives me a total of 5" of effective travel, up and down. Now- it's worth mentioning that each side individually can travel almost 8" from full droop to full bump. Last night, I stuck a 1 gallon paint can under one tire, and sat in the kart. The opposing tire did touch the ground, with both rears planted. A gallon can measures about 7 1/2". I'm pretty pleased, I got more than I expected out of it.

DCProductions- Rocket? I may well be a self-proclaimed Northern Redneck, but I'm no Darwin Award winner!!!
Tman- Lights? Oh, yeah!

[anderkart]

Dude I toataly cracked up when I read your reply, heck I just started laughing again now just thinking about it.

[anderkart]

Hey, any chance your karts name was lifted from an episode of southpark?

[toystory_4wd]

South Park- I don't remember an episode with a "Red Rocket". I must've missed it. I used to watch it religiously.