thoughts on shock angle

[fuzzhead]

well here it is.

i have seen many, many crawlers running their shocks at some pretty good angles. i know that this setup works. and works well. i have been coming up with ideas for my tlt and this includes having the shocks at an angle.

the problem being is that my dad totally disagrees with that setup. he says that the shocks and the whole suspension setup would work better with the shocks straighter up and down.

im looking for all of you guys opinions and views on this debate.

thank you
fuzzhead

[WR450F]

with the shocks straight up and down you only get wheel travel thats the length of the shock.

With it at more of an angle you get.... more travel... lol i know what i see, not how to explain it. And the angle of the shock also messes with its effectivness the more extreme the angle the squishier it gets. I think this also goes for moving the shocks up and down the links....

I dunno maybe i shouldnt be giving out info right after a nap.... lol im not exatly all here...

[ILoveRCRockCrawlin]

well for anyother offroad vehicle its fine to put the shocks straight up and down, but for crawlers its not the best setup. The more the shocks are angleed the more travel. fir crawling you need like at least 80degrees to run against the big dogs.the travel allows you to go over rocks without the truck flipping over. it also allows all the wheels to stay on the ground. yea the more angled the shocks are the more squishier it will get so dont expect the shocks to bush the truck up all the way. plus its kinda good to have a lil down travel.

[fuzzhead]

Originally Posted by ILoveRCRockCrawlin

plus its kinda good to have a lil down travel.

dont they call that droop travel?

[EeePee]

Well, different angles have different rates. Falling, straight, rising.

There's also a few factors to consider, including spring rate, and oil weight.

But generally, falling rate is not good. A suspension should at least remain constant, or ideally raise in rate, even if ever so slightly, but that's a tough feat to accomplish.

If you can visualize the arc that the axle follows, you should be able to visualize shock placement, and at least start there. A rising rate will have the shock end up at a 90 degree angle to the arc-it won't get more rising than that. Anything other than 90 degrees is considered falling.

An example: Bulus are seriously falling rate set-ups. Bender's TXT looks to be real close to straight rate, though still falling. The Xtreme (the stick) is a raising rate, as the shock ends up perpendicular to the axle (little different set up, but if you had one in front of you, you'd see ;) ).

The deal with the falling rates is the shock shaft slows down in velocity, and allows more travel because of that. And that's why you see it often.

Then there's the whole progressive spring thing...

[EeePee]

Originally Posted by ILoveRCRockCrawlin

fir crawling you need like at least 80degrees to run against the big dogs.

Not.

[fuzzhead]

well im siding with eeepee for the moment.

but he said that falling rate is bad. however the bulu rigs who he mentioned run it. seem to do very very well. so do you mean that it is bad in most situations and that for r/c an exception can be made? i want to learn as much as possible

[EeePee]

I'd really like to see others add some input on this one but...

I do believe in the little RC crawler world, 8 times out of 10 it's a matter of convenience.
Where can I put the shocks? Especially with the smaller scale trucks.

I cannot speak for RCRockGear, and I may be way wrong. I don't have one either.

I notice they have some torque twist. The shock location and it's falling rate design have a large part in this.
If it were a rising rate, the shock would become stiffer as it goes through it's motion, and it would fight the torque twist to a degree.
So would a progressive spring, though.

I imagine since they are so light, that the falling rate doesn't hurt at all really.
And because they lay the shock down, they can get a lot of travel out of a short shock.
A shorter shock is much easier to package than a longer shock.

And there's no denying they can perform!

I suppose since we aren't jumping these things, ultimately, it doesn't matter as much as I think. :?

[EeePee]

Originally Posted by EeePee

A rising rate will have the shock end up at a 90 degree angle to the arc

I don't think arc is the correct word. The line that is the radius would be correct.



If A is the inner link pivot point, and AC is the link, C is the link axle mounting point, and BC is the arc the axle travels, a rising rate set up will have the shock perpendicular to AC at full compression.

Rough, but you should be able to visualize it.

Anything greater, or lesser than 90 degrees is falling rate. The more the angle, the more the rate falls.

Anyways...

[toyofast]

Yes, the Bulu chassis shock setup isn't the most ideal way to run shocks but hey, it seems to work for most users. Although many of the hardcore Bulu chassis rigs have some sort of shouck mounts coming off the chassis to get a short shock more vertial and keep the axle movement more constant.

There is no denying the Bulu's while in action, as long as they have been setup correctly.