Single Seat SolidWorks Design Review

[jersdunz]

Originally Posted by standfast

Rear lower shock mounts need to be moved in to get good control over the rear travel. Valving will be a PITA to try to make it work like that. Would be better to be about 75% of the arm length out from the inner pivot. It would be much of an issue if the shock wasn't as layed over as it is but being layed over like that and mounted all the way out near the tire will make the shock get real soft when you want it to be getting stiff.

The current rear a-arm width is going to be hard on the bushings, the rear section of frame, and the arms. Spread out those mounting points, especially on the lower arm.

If you have very little axle plunge requirements due to your use of rear a-arms, (less than an inch or so) you may be able to get away with UJ axles.

Cutting brakes aren't gonna do much of anything without a differential and based on your ATV rear carrier description, it sounds like you will have a a locked axle.

I sure can appreciate the time you put into the design. It is a lot of work and you are doing the right thing getting input on the design. It will save you a lot of headaches in the end and leave you more time to enjoy instead of fix. Lets see a pic of your rear drive setup.

Take him seriously on this one he is absolutely right my rear shock get all kinds of to soft because of the angle there mounted on.

[standfast]

Originally Posted by jersdunz

Take him seriously on this one he is absolutely right my rear shock get all kinds of to soft because of the angle there mounted on.

The idea is to try and make your shock end up 90 degrees to your arm or as close to as possible. With his current design it appears that he is going the opposite way. If left that way, you either valve the car so stiff that that suspension will not cycle well, or you will bottom out the rear quite often. There really won't be much of a medium between those.

[yoshi]

Originally Posted by standfast

The idea is to try and make your shock end up 90 degrees to your arm or as close to as possible. With his current design it appears that he is going the opposite way. If left that way, you either valve the car so stiff that that suspension will not cycle well, or you will bottom out the rear quite often. There really won't be much of a medium between those.

Just want to clarify that you mean 90 degrees at full bump, not ride height....

[NorCalBuggy]

Thank You,

I really appriciate the input I'm getting from you guys.

Because the shocks are Emulsion type, I knew that I was going to have to get them more vertical. I will probably run a single rectangular tube for the upper rear a-arm so to give me clearance for the shock to mount to the lower a-arm (Similar to what Polaris does with its RZR S. Not sure how much torquing it will withstand though, but Cosmos should give me some decent data on that. As for the width of the rear lower a-arms.....looks like I would have to completely redesign the rear chassis, as the current configuration limits the amount of width I can seperate the mount tabs. Because the section just before the a-arms are bolted in (To allow for the engine to be mounted into the frame), I was unable to put any mount tabs along any of that section there. I may try to do a mount point up near the main roll hoop, similar to a trail arm, giving me an extra leveraging point for the rear a-arm.

I was planning on using the cut brake to lock up the rear (similar to how performance atvs lock up the rear to allow me to initiate a power slide by pulling back on the handle. If I push, the cut brake will lock up the front tires, allowing me to stage and do burnouts if needed. At least that was the original thought on using the brake. I also have available a Subaru LSD rear diff that I can use if it looks like a rear diff would work better.

As for the radiator, I have been playing with the idea of putting it on the rear frame spars, but the airbox for the GSXR (not drawn yet) may limit this option. I really do not want to take a "HOT" water and glycol shower if a failure occurs on the radiator. Also I would have to use an aftermarket radiator, as the stock one is not shaped well to collect enough air to effectively cool if mounted at such a steep angle. Also I really want to protect as much of the working and cooling parts of the engine of the vehicle for the eventual rollover, when and if it occurs. I would rather design the car to handle a moderate rollover, then oppose to the thinking that if it rolls I'll fix it then......not sound engineering I'm afraid.

I'm glad that most of what you guys are suggesting, I've been thinking about it for a while too. It means that my reasoning is not too far off from those who know what they are talking about, and have been there already. All of your insight and expertise has greatly reduced the guess work I may make when going through this design process. True it's easier to go out and have someone build you a car, but I feel the most satisfaction comes when I can say that I built myself a offroad vehicle from conseption to completion. Nothing feels better.

I'm looking forward to it all. I'll post some more angle shots so you guys can critique other areas that I might need rethinking. I really appricate everyones inputs.

Cheers

Edward

[chuckorlando]

Quik question for you guy's. Whats the reason needed for making the arms wider? Is there an equation for figuring arm width for body width, length, weight? I just want to avoid this in the future.

Thanks
Chuck

[standfast]

Originally Posted by chuckorlando

Quik question for you guy's. Whats the reason needed for making the arms wider? Is there an equation for figuring arm width for body width, length, weight? I just want to avoid this in the future.

Thanks
Chuck

The idea is to spread the load out over the frame as much as possible. Locating it all in one small area is not a good idea.

[Gene]

There probably is some science to the spread but most of us are not engineers so we use our best judgement based on what we've seen and then formulate opinions.

[chuckorlando]

Thank you guy's. So next question... When you say widen do you mean top to bottom or the actual width of the arm? Since were on the topic I figured I should ask now. Also is there something you need to keep in mind inregards to the spindle. IE.no more than twice the width of the spindle.

[Mopar]

Originally Posted by chuckorlando

Thank you guy's. So next question... When you say widen do you mean top to bottom or the actual width of the arm? Since were on the topic I figured I should ask now. Also is there something you need to keep in mind inregards to the spindle. IE.no more than twice the width of the spindle.

I believe there refering to the width of the mounting points on the frame. Spread em out to distribute the load on the frame....

[Bullnerd]

Again my opinion.

Its not just the width at the frame but also a triangular shape that makes them stronger.Right know you have a parralellegram.(i might be able to spell that!)