experimental front suspension

[sicivicdude]

I've got a couple questions. If you plan to use the full amount of travel those shocks offer, how are you going to do it so that the shock bottoms out before the frame hits the ground?

Also, I like the idea of a zero bump steer bike, but I also have my doubts about building one while using a stock blaster chassis.
Third, is this going to be a setup for a straight line desert bike?

I'm planning on using a lower ball joint (RS3003) but heim uppers and tie rod ends because of the amount of articulation needed. At +5, the RS3003's will offer approximately 11.34" of travel bind to bind which is WAY more than enough to soak up those soft works shocks.

The lower mount on the works is going to be out near the very outside of the lower control arm for two reasons. #1 weight carrying capacity. I'm heavy so my suspension needs to be able to carry my fat ass

#2 better valving control. These shocks are designed for a slightly different application so mounting farther out should put the valving at more of an advantage for my application.

Lastly, I have never wanted nor would ever want to venture out into the middle of nowhere with just a blaster and myself to survive on...... there are no super long straight line desert runs in my future but I'd like to think this would be the setup that it could be done on.....

 

[ddq]

This project fascinates me. Im guessing the shock valving and spring rates will be trial and error? I run 19.25" eye to eye shocks on my banshee. Nobody makes shocks that long for a banshee so I got them off a walsh race craft 250R. Even though they weren't setup for my weight, skill level or bike weight, they were very close to how I like my front shocks. My suspension guy tells me this is because of the different operating angle of the shocks on the banshee (much wider frame) and the 250R.

Do those works shocks have adjustable preload? Have you thought about re-constructing the front of the blaster chassis? It would be a lot of work, but it seems like a narrower nose and a arm mounts closer together would help A LOT.

 

[sicivicdude]

This project fascinates me. Im guessing the shock valving and spring rates will be trial and error? I run 19.25" eye to eye shocks on my banshee. Nobody makes shocks that long for a banshee so I got them off a walsh race craft 250R. Even though they weren't setup for my weight, skill level or bike weight, they were very close to how I like my front shocks. My suspension guy tells me this is because of the different operating angle of the shocks on the banshee (much wider frame) and the 250R.

Do those works shocks have adjustable preload? Have you thought about re-constructing the front of the blaster chassis? It would be a lot of work, but it seems like a narrower nose and a arm mounts closer together would help A LOT.

I'm one of these types that likes to "optimize" what I have available. I can build my dream suspension around a completely custom frame and get some unbelievable amounts of travel and control. Or I can build my dream suspension around the blaster frame and get some unbelievable amounts of travel and control..... there will be a limiting factor somewhere so why not let it be the stock frame?

Plus, isn't cooler when you can do what they do, even better? I'm going to get a foot of travel and zero bumpsteer without hacking up the frame....

 

[ddq]

Since there isnt a devils advocate in this thread, Im going to be him, for the sake of argument.

I dont think you can get 12" of travel (suspension travel not wheel travel) from a stock blaster frame and not have the frame hit the ground before the shocks bottom out. Unless this blaster is going to look like its riding on stilts.

 

[Triple_B]

Since there isnt a devils advocate in this thread, Im going to be him, for the sake of argument.

I dont think you can get 12" of travel (suspension travel not wheel travel) from a stock blaster frame and not have the frame hit the ground before the shocks bottom out. Unless this blaster is going to look like its riding on stilts.

Good point DDQ. I think with at least +5 +1 Long Travel A-Arms with extremely long shock absorbers, it could be done. phragle's Blaster had 18" of suspension travel and it looked like his blaster was seriously on stilts.

 

[sicivicdude]

My blaster already sits higher than a stock blaster but not a LOT higher.

I've already done the math for them based on the known angles, lengths, and sizes and I'm figuring 11 3/4" (so NEARLY a foot, not exactly a foot) if it all works out like it's supposed to.

Before running it, I'm going to design it the same as I did my current setup. Sit the frame 1" off the ground. Remove the springs and bumpstops from the shocks. Fab the arms with the angles at the lowest point and then temporarily "pin" the shock in place. I run it through cycle after cycle using a jack to lift and lower while turning the handlebars lock to lock..

This will confirm the amount of travel, ability of the shock to make its full travel, ball joint bind, and any interferences before the frame ever leaves the workbench.

You have to figure 12" of travel with 2" sag while on the quad is only 10" of wheel travel. If, at the bottom of that travel, the frame is 1" off the ground the frame only sits 11" off the ground with rider weight on it. The stock height is like 8" so I'm only "jacking it up" a few inches.

 

[ddq]

So you arent going to go with the industry standard of 33% suspension sag on the bike? 2" of sag for 12" of suspension travel is going to be TALL.

Triple B, in that pic those front tires look like 21's or 22", if not taller. There is a reason for that I bet, so the frame doesnt hit the ground as hard. If that bike had 19 or 20" mx front tires that thing would plow the ground like a ditch witch.

 

[sicivicdude]

So you arent going to go with the industry standard of 33% suspension sag on the bike? 2" of sag for 12" of suspension travel is going to be TALL.

Triple B, in that pic those front tires look like 21's or 22", if not taller. There is a reason for that I bet, so the frame doesnt hit the ground as hard. If that bike had 19 or 20" mx front tires that thing would plow the ground like a ditch witch.

I'm heavy...... 33% would be sitting too low and the ever increasing angles on the shocks versus the lower control arm pivot would put me at a disadvantage when I do need the spring... I'm going to start higher...

Also, Phragle ran cross desert runs. Taller tires means less blowouts from hitting things.

 

[ddq]

Yes, you will have more resistance for uptravel but for rough terrain down travel is just as important. Your weight should have no affect on the sag. If those spring rates are set up for your weight, your weight will have no affect on the bottoming resistance whether you are at 33% or 7%.

 

[sicivicdude]

Yes, you will have more resistance for uptravel but for rough terrain down travel is just as important. Your weight should have no affect on the sag. If those spring rates are set up for your weight, your weight will have no affect on the bottoming resistance whether you are at 33% or 7%.

These springs are already on there and most certainly no optimized for my weight (what suspension company do you know of that specifically designs shocks for people 325+lbs?) so I'm working within that constraint.

Trouble is, the shock mount will already have to be set before I can test the springs ability to hold my weight.... so I'm going to have to pick my poison before I ever get the chance to "taste test" it.

I wish I had $1,000 to buy shocks that are specifically setup for my weight on my arms.... but it just isn't there.

 

[Triple_B]

Triple B, in that pic those front tires look like 21's or 22", if not taller. There is a reason for that I bet, so the frame doesnt hit the ground as hard. If that bike had 19 or 20" mx front tires that thing would plow the ground like a ditch witch.

Didn't even think about that....

 

[Brute71]

I think if you... *stares at tripleB's avatar* What was I say again?

Staying tuned to see how this turns out!

 

[98blaster+4]

So you arent going to go with the industry standard of 33% suspension sag on the bike? 2" of sag for 12" of suspension travel is going to be TALL.

Triple B, in that pic those front tires look like 21's or 22", if not taller. There is a reason for that I bet, so the frame doesnt hit the ground as hard. If that bike had 19 or 20" mx front tires that thing would plow the ground like a ditch witch.

as far as the tall tires go, a taller tire on the front, such as a 22" like i run, is to keepthe front end steadier at speeds over rough terrain. the bigger tires dont fall victim to smaller holes and divets and such, allowing a smoother ride over the rough stuff. plus it does offer more ground clearance.

 

[YZ Otis]

it seems like a narrower nose and a arm mounts closer together would help A LOT.

Been doin a bit of simple cuttin & welding on this idea so we'll have some comparison info on down the road

 

[ddq]

as far as the tall tires go, a taller tire on the front, such as a 22" like i run, is to keepthe front end steadier at speeds over rough terrain. the bigger tires dont fall victim to smaller holes and divets and such, allowing a smoother ride over the rough stuff. plus it does offer more ground clearance.

You are trying to tell me the reason he is runnning heavy ass 6 ply 23 or 24" front utility quad tires is because it rides better? C'mon dude....


From that pic his rear scorpions look like 20's. Ive never seen tires that big and heavy on the front of a sport quad before, and I know damn well they dont handle like some 21" XC tires for a sport quad.

 

[sicivicdude]

You are trying to tell me the reason he is runnning heavy ass 6 ply 23 or 24" front utility quad tires is because it rides better? C'mon dude....


From that pic his rear scorpions look like 20's. Ive never seen tires that big and heavy on the front of a sport quad before, and I know damn well they dont handle like some 21" XC tires for a sport quad.

The reason he'd be running those tires would be for impact resilience. He's running across the desert floor and doesn't want (or can afford) a flat in the middle of the race. Rear suspension pulls up and away from an impact, front suspension can only articulate outwards (no movement away from an obstacle). Add to that he needs STRONG sidewalls to handle hard turns at high speed and you've got a funky setup need.

I'm not convinced that even a 22" tire up front would be needed for his front suspension not to bottom. That's a completely one off frame and suspension setup and I doubt it was an afterthought to put those tires on.

 

[ddq]

I spent the last 6 hours running the numbers on the geometry in this diagram. If you follow it exactly, it should work flawlessly. This was done using my specialty suspension model software.

 

[Quadrider10]

I spent the last 6 hours running the numbers on the geometry in this diagram. If you follow it exactly, it should work flawlessly. This was done using my specialty suspension model software.

ive been looking for thsat program everywhere! but its listed on ebay for 75$ where u get it?

 

[ddq]

I got a pirated copy from a guy on craigslist.

 

[sicivicdude]

Oooookkkkkkkk ?