Another 4 Link Thread

[Trubble]

Originally Posted by Duuuuuuuude

Could be right, could be not right. I like to hang it off of the chassis so that there is a greater angle where the two lines intersect. It makes it easier to pin point the cog.

Okay, done again, this time hung from the upper shock mounts.





Okay, that gives a much more accurate picture and puts my CoG *just* ahead of the mounting bolt for the front lower links. A quick and dirty 'balance point' check is in the general vicinity, too. Thanks!

[Charel]

Awsome thread.
Thanx to all that participated and to Duuuuuuuude for creating the platform.

[wolf_rt]

Thanks very much Duuuuuuuude for this information.

Would you be able to go into any more detail about how the Line of force (LF) affects handling, and how it interacts with squat/as?

[Duuuuuuuude]

LF essentially is how the suspension "pushes" on the chassis. A high LF angle will push up, a low angle will push forward.

It's hard to go into its relationship with S/AS without typing a few paragraphs to keep things clear. If I remember to, I will do that tonight when I am not typing on my phone.

[Duuuuuuuude]

So...how does LF (line of force) interact with S/AS (squat/antisquat)?

It doesn't. It is just a visualization of the forces at hand.

Keep in mind that squat values are just reference points. Two rigs with identical S/AS numbers can behave very differently since those same numbers can typically be found both ahead of and behind the COG.

To some degree, you can have over 100% AS and still have a rear suspension that compresses under power, so don't get hung up on chasing numbers. Sort out where your IC is, take a look at the LF and see if it is in an agreeable place, and write the S/AS number down so you know where you are at.

[Revoasian]

Phhhhhhh. College is over rated, lol....I've learned more in 20 minutes on this thread than I have in my college years. Duuuuuuude, thanks so much for sharing your knowledge and experience with us here on this forums. Definitely helps us to understand the concepts for those who are not familiar with how suspension geometry works. Much appreciated...

[mrG]

So Anti-squat question. When drawing it out do you use degrees or height for positive AS. Degree example-neutral line is at 20*, 125% AS is at 25*, 150% AS is at 30* and so on. Height example-neutral line is 4" from the ground, 125% AS is at 5", 150% AS is at 6" and so on.

[Duuuuuuuude]

Originally Posted by mrG

So Anti-squat question. When drawing it out do you use degrees or height for positive AS. Degree example-neutral line is at 20*, 125% AS is at 25*, 150% AS is at 30* and so on. Height example-neutral line is 4" from the ground, 125% AS is at 5", 150% AS is at 6" and so on.

Neither. Refer to the pic below...




Note the horizontal blue line extending forward from the COG, and the vertical blue line extending up from the axle centerline. To find the Neutral line, you draw a line from the rear contact patch up through where the first two lines converge. It will be different for every rig because it is dependent on cog, wheelbase, ride height, etc. And, if you happen to alter any of those things on your rig after you've sorted the AS values out, you will have to sort them again because some of those points may have moved.

[mrG]

I don't think you understood my question. I understand how to find AS value. The examples I gave weren't from any rig, just round numbers. In your wraith pic with all of the positive AS lines how did you determine what was 25% more of the neutral line?

[Duuuuuuuude]

Originally Posted by mrG

I don't think you understood my question. I understand how to find AS value. The examples I gave weren't from any rig, just round numbers. In your wraith pic with all of the positive AS lines how did you determine what was 25% more of the neutral line?

Yup. My bad. I've exceeded my multi-tasking limit.

Here is a more detailed diagram.



Note that the distance between 0-100% is the same as 100-200%. Just remember that you are mapping out points in an arc and not straight up and down.

[mrG]

Thanks that answers it.

[Super]

I really struggle with this stuff, but today I was watching a 4x4 xtreme and he really explained triangulation and squat/anti-squat well.

2009 episode 7

I hope this is helpful.

[Bananaclip]

Duuude, can I send you my rigs for scientific suspension adjustments?

[BigSki]

Just a "bump" for a good source of information.

[Natedog]

THanks for starting this excellent thread Duuuuuuuuude! Reading and re-reading.

[84yoda]

Originally Posted by BigSki

Just a "bump" for a good source of information.

Edit: duuuude, what about figuring out the front setup, and front/rear working together or against each other? Does front caster play a roll?

[Duuuuuuuude]

Originally Posted by 84yoda

Edit: duuuude, what about figuring out the front setup, and front/rear working together or against each other? Does front caster play a roll?

Sorry for the late reply.

The same rules apply for the front axle. I honestly don't spend a great deal of time thinking about it though. Due to space restraints, you don't always have the same options that you do in the rear. Tuning the front is still important, but not quite as critical as the rear.

I'm sure that it's a habit I should break, but I just eyeball the front and roll with it.

Caster doesn't have a direct effect on the suspension.

[GoatFarmRC]

I finally understand Torque twist! (still a newb, only 1 yr in crawling, but long time in rc). Thank you so much.

[countrytoker]

Thanks for an awesome post

Sent from my XT1650 using Tapatalk

[FjolnirG]

Could you please put back the pics in the first posts. This is absolutely the BEST post on this forum, and I come back here regularly for reference.