96DXCivic
96DXCivic Dork
7/9/10 5:15 p.m.

Ok so I am working on a vehicle (a NASA Great Moonbuggy Race Vehicle) and I am looking for shocks. The vehicle has 10 inches of travel and weights about 325lbs including two riders. Does anyone know of shocks which have close to 10 inches of travel that will work for a light vehicle? Car shocks seem like they would be to stiff for these vehicle. Should I get shocks custom valved for this application?

thatsnowinnebago
thatsnowinnebago GRM+ Memberand Dork
7/9/10 5:26 p.m.

Have you thought of a cantilever design using motorcycle shocks?

96DXCivic
96DXCivic Dork
7/9/10 5:49 p.m.

Like a pushrod setup or a rocker setup like the back of some mountain bikes?

thatsnowinnebago
thatsnowinnebago GRM+ Memberand Dork
7/9/10 6:02 p.m.

Either one. Just some way to convert the short stroke and high spring rate of the motorcycle shocks to the long stroke and softer rate you're looking for.

Now that I'm thinking about it, why not just mount the shocks way inboard on the suspension arms? It would be way easier and lighter. You need 10" of wheel travel, not 10" of shock travel. I'm not sure how rough the courses are but if they are very rough, working the shock that hard might result in some overheating issues. Luckily bikes often have some pretty trick shock with external reservoirs to avoid that problem. Dirtbikes have short little shocks mounted way away from the actual wheel and pretty near the swingarm's pivot for lots of travel. See below for an example:

(hotlinked because I make my own rules)

iceracer
iceracer Dork
7/9/10 6:05 p.m.

Known as motion ratio.

thatsnowinnebago
thatsnowinnebago GRM+ Memberand Dork
7/9/10 6:10 p.m.
iceracer wrote: Known as motion ratio.

So you're telling me my entire paragraph could be summed up in two words? You must be one of those smart fellers who troll here

96DXCivic
96DXCivic Dork
7/9/10 6:14 p.m.

I read that a motion ratio of 1:1 was better but I think I will just mount them someway to increase the motion ratio. I am thinking about cane creek double barrel shocks.

Capt Slow
Capt Slow HalfDork
7/9/10 7:33 p.m.

Have you thought about mountain bike shocks? They are considerably lighter than the motorcycle ones, which seem like overkill for your application. Heck even the mountain bike shocks might be overkill, I know the SJSU FSAE team was using them on their car...

I don't know much about your competition but it appears that speeds are fairly low, and crude suspension won't slow you down much...

96DXCivic
96DXCivic Dork
7/11/10 5:42 p.m.

But we have pretty much as much money as we want so I want to buy the best shocks that will work the best for our application.

RXBeetle
RXBeetle Reader
7/11/10 7:12 p.m.

Most mountain bike shocks suck real bad when you put them up against a well built race shock. I know the cane creek double barrels are pretty popular as well as Öhlins. If you have the $$ talk to the guys at Penskee/Kaz. We run them on our formula car and the support is awesome. They will dyno them and valve them to what ever you order (for a price) ;)

44Dwarf
44Dwarf HalfDork
7/11/10 7:29 p.m.

I'd sugjest you give Sany at http://www.coneindustries.com/partsgallery.php a phone call. His in to baja racing now and he knows about long travel shocks.
He make some awsume axles for dwarfs and rx7's.

44

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