What kind of shocks would you use for a small off-road vehicle? The vehicle will weight around 400lbs without driver and have 10" of travel. I was thinking ATV shocks. Any other suggestions?
What kind of shocks would you use for a small off-road vehicle? The vehicle will weight around 400lbs without driver and have 10" of travel. I was thinking ATV shocks. Any other suggestions?
Mountain bike shocks, but you would need custom springs or dirt bike shocks...
like this?
http://cgi.ebay.com/ebaymotors/Honda-Dirt-Bike-CR-125-Rear-KYB-Shock-CR125R_W0QQitemZ310106288537QQcmdZViewItemQQptZMotorcycles_Parts_Accessories?hash=item4833c67199
Get yourself a set of older mountain bike shocks, the little coilovers. Our local scrap metal yard has a giant crate of unused Eibach mountain bike springs in just about every rate and length you might want, and they're selling 'em for about 25 cents each. I'd be happy to help out. I remember seeing a rate as high as 400 lb/in.
Depending on your motion ratio, you may need to stack a few...
Damn, what kind of fat ass needs a 400lb/in spring on his mountain bike?
Yeah, MTB shocks are the way to go. You see them on FSAE cars all the time. The big travel will be a little tough, but you can use a rising rate arm to get there.
Oh and the 440lb is because they might have a 2:1 lever arm actuating the shock... so 220lb/in
Appleseed wrote: Damn, what kind of fat ass needs a 400lb/in spring on his mountain bike?
There is a reason I replaced my full suspension bike with a fixed frame
Chris Griphen said: If I hadn't learned to laugh at my self I would be dead by now
Appleseed wrote: Damn, what kind of fat ass needs a 400lb/in spring on his mountain bike?
Ever heard of motion ratio?
Mountain bike shocks under that kind of ratio will overheat real quick unless they have an external cooler and even at that they'll be borderline (have to take into consideration the shaft speed). I'd go with dirt bike shocks.
Nashco wrote:Appleseed wrote: Damn, what kind of fat ass needs a 400lb/in spring on his mountain bike?Ever heard of motion ratio?
Yeah, just occurred to me that they're probably not 1:1. D'oh.
Is this the pedal powered moon buggy thing?
Keith wrote: Is this the pedal powered moon buggy thing?
I'd guess an SAE competition buggy. Remember, in another post, he was asking about FSAE engine stuff.
I wonder if you guys are trying to make one car be able to compete in both events. You know it's been done before, right?
Anyway, I have nothing else to add, but a very hearty good luck!!!! Great projects to work on!
E-
Look up Fastace pit bike shocks. They have about a dozen offerings, with different styles and lengths, single and double adjustable etc.
Very simple to service and revalve if required.
You'll notice a lot of the fancier brand names have the same basic look of the Fastace. Many are made in the same factory.
Chris H.
Jensenman wrote: ..... ........ overheat real quick unless ................. the shaft speed......
Sorry, been a long day.....couldn't help it
rjones33 wrote: Yeah, MTB shocks are the way to go. You see them on FSAE cars all the time. The big travel will be a little tough, but you can use a rising rate arm to get there. Oh and the 440lb is because they might have a 2:1 lever arm actuating the shock... so 220lb/in
Quick correction (since it's an important suspension fact, and a mild pet peeve of mine).
2:1 motion ratio affects both Force AND displacement of the spring relative to the wheel. SO: 2:1 motion ratio, 440lb/in spring = 110lb/in wheel rate. (MR^2).
Nathan
Look at the original Honda Odyssey or Pilot for guidance. Both are about what you are describing. for more travel, go for truck shocks with a light spring
If this is moon buggy, then mountain bike shocks are the winner.
A human powered moon buggy better not weigh 400 pounds without driver.
At the low speeds of a moon buggy, MTB shocks would be the shizznit. The higher speeds and extra weight (total of around 575 pounds from what I read) of a dinosaur powered creation operated on rough ground would rapidly overheat a tiny mountain bike shock. A ~250 pound dirt bike with a ~180 pound rider will get the rear shock hot pretty quick, on real rough ground at higher speeds hot enough to raise a blister (he remarked, wincing at a painful memory).
I'd make the motion ratio somewhere around 2.5:1, then find a street bike shock with around 4" of travel, shoot for a ~150 pound wheel spring rate (as a starting point) and have fun. ATV shocks will certainly work, but they tend to be pretty long (harder to package) and most of them I have seen don't have easily adjustable damping. Also, off road shocks demand a premium on eBay etc where street bike shocks can be had dirt cheap.
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