Link placement help

[BeerMonkeY]

i put together a tube buggy and just made my own links, when it flexes i get some horrible rear steer, i know that link length and placement affect that but not sure how. its a triangulated 4 link front and back. any tips or push in the direction of somethig i can read up on

[Duuuuuuuude]

Pics would help a ton...

[BeerMonkeY]

Trucks at work right now. Yes we get to tinker on r/c's at work, therrs prob more stuff than some hobby shops have in stock in our office

[supermoturd]

Originally Posted by BeerMonkeY

Trucks at work right now. Yes we get to tinker on r/c's at work, therrs prob more stuff than some hobby shops have in stock in our office

Where do I send my resume?

[mark32]

Where do I send my resume? xxx's 2

[BeerMonkeY]

applications will be accepted only when sent with a RC part/accessory.
uploading pics now so you can see how the links are setup. i dont have much to adjust prob cause its a cheap chassis

[BeerMonkeY]

so also i noticed when i whack the throttle the left front lifts , but that could be from the motor size and 3c

[doublej]

Are you sure your getting rear steer or are the lower links flexing and causing it?

Looks like your front uppers need to come down at the axle. Make them parallel to the lowers.
And your tire lifting sounds like torque twist - can you mount the lowers on the inside of the chassis?

[BeerMonkeY]

i dont think there bending but i had though of that. i can make some metal ones to be on the safe side. i can move lowers to inside but need to mill tranny mount, or make a new one.

[Master Basher]

Lower links need some degree of triangulation. They are the source of your displeasure.

[BeerMonkeY]

so i raised the tranny/motor so i could put links on the inside and it helped a little. if i need to get more triangulation out of the lowers i can make a tube to move them off the chassis all together and mount them close to each other (kinda like a losi night cralwer) also seemed my shocks were limiting travel so i moved them to the lower arms but whe i went to test it i snapped a axle shaft on the first obstacle and 3 wheel drive sucks

[crawl-o-matic]

If you can, mount the upper links to the outside of the chassis and the lower links to the inside. Also, I think torque twist is part of your problem here.

[Whiplashdjs]

I found this online, it's from a circle track racer so keep that in mind. But it may help.

More uphill angle of both left rear and right rear lower links creates more roll over steer.

4-link suspension link angles Excessive left rear upper link uphill angle creates under steer Increasing downhill angle of lower links reduces roll over steer and increases indexing Reducing uphill angle of right rear upper link reduces roll over steer and decreases indexing Increasing uphill angle of right rear upper link increases roll over steer and indexing. The adjustment range is 14 to 18 degrees. Stiffer rate makes car tend toward over steer Softer rate makes car tend toward under steer

[Whiplashdjs]

Going on that info and your pics, looks like you want to essentially want to have a shorter ride height in the rear to get the link angles flatter. Or lengthen the rear links.

I'm playing around with a homemade chassis as well. My secret agent ridgecrest lol. I set it up at static ride height lower links are almost level and shocks mostly compressed, yes it shows torque twist but that's not my num 1 concern. I'm trying shorter shocks more upright with stiffer springs to try to find a happy middle ground for crawling. With the secret agent geo my uppers are much longer than most shafty's have, I don't know why they don't use longer uppers on shafty's?

[crawl-o-matic]

major problems I see:

#1 plastic links

#2 the front link geo is all wrong

#3 rear shocks are way too long

[BeerMonkeY]

plastic links i had laying around and i wanted to see what wheelbase i liked, will make metal ones
what do i need to do on front links? i moved the front uppers down a little and the frame side of front uppers to the outside of frame.
shocks were also leftovers, i do need shorter ones to get the ride height down. i did move them to the links instead of axle which wont lower ride height but did help compress them with the leverage

[crawl-o-matic]

Your front geo may look off because the rear shocks are too long and they're pushing the back of the truck up, also the front uppers look super short...everything is coming together to make for an odd look.

[Master Basher]

Originally Posted by crawl-o-matic

major problems I see:

#1 plastic links

#2 the front link geo is all wrong

#3 rear shocks are way too long

I missed that the first time around, but yeah, they bend really easy. Must be replaced.

[Whiplashdjs]

It looks like a little rock racer with a brushless motor in there, speedy 2.2 rig?

If that's the case I would extend the front wheelbase 1/4-5/8 inch if you want to keep those shocks, top links lengthened 3-5 mm more than the lowers. Use the driveline angle as a reference for the lengthening.
Rear: extend 1/2inch or so with the links and then internally limit the rear shocks as needed to bring the ride height down until rear links are levelish.

I like the way my 60/40 ridgecrest handles, except its a bit tippy. So I'll be doing basically the same thing to it soon. Except I have a delrin chassis and can drill new shock mount holes, your bound by the single shock mounts on the chassis to either use adjust the shocks & links to fit the chassis.
Looks like a fun rig.

[BeerMonkeY]

Well i got some gmade internal spring shocks for cheap so i threw them on and it made a big difference, its doest flex as much but i took it out on its first trail day yesterday and it did great, went everywhere a wraith did and made it some places a wraith couldnt. and it is brushless so on a 3c its pretty fast. think ill make some metal lowers and call it done on this one.