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Old 04-08-2002, 12:00 PM   #1
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Default Setting Droop Techniques

Ok, there seems to multiple formulas for this setting that has so much effect on our cars. I think this adjustment should be somewhat standardized because everyone has a different way of doing it, which makes it hard to compare setups.

I am finding it to be better to actually measure downtravel and use that number as my setting, not the actual droop number. Why you ask? Well tire sizes vary from tire to tire and foams change, thus a taller tire will actually handle like it has less droop in it (more downtravel).

Now here is how I am coming to set my droop. Set droop to where you think it should be with whatever gauge you use. Now set your ride height to where you want, say 5mm all around. Now in the front, place a wrench under the bumper like you are going to lift for checking tweak. Right when the tires are floating on top of the table measure your ride height again from the same spot. Say this is 7.5mm, subtract the 5mm that you set for your ride height and you now have 2.5mm of downtravel.

This is the number I think is the most accurate to use when describing your settings. So what are your thoughts on this, instead of giving your droop settings you can give your downtravel setting or both. Maybe I am missing something, please point it out, I am trying to learn this as well.

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Last edited by David Joor; 04-08-2002 at 12:03 PM.
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Old 04-08-2002, 01:38 PM   #2
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Hi David

I ask this question on the TC3 forum but no one replied. From what I read below your saying that to set your droop by the amount of down travel, correct. For instance in your example of 5mm ride height, once lifted with a wrench it took it up to 7.5mm, subtract that from your original ride height 5mm and that equals your down travel, = 2.5mm. So do you set your droop at 2.5mm?

The question I ask on the TC3 forum was this. What should my droop height be if my ride height is the following:
Front 6mm
Rear 5.5mm
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Old 04-08-2002, 01:47 PM   #3
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that's simular to how Kinwald sets his droop, he adjusts everything else first then sets the car on two RRP spur gears glued together (10mm tall) and adjust the set screws until the wheels just touch the table, I think he usually runs 5mm ride height so his droop would be 5mm also.
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Old 04-08-2002, 02:03 PM   #4
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The # 2.5mm is actually just a reference # that could be used across cars as a better reference point. Because tire sizes change, and the different techniques make it tough to figure out what 5mm = to everyone. So 2.5mm is not your droop setting it is what I would call your "Weighted Downtravel" but I am just making that up.

Paul L. sets his droop by his spring gap on the collar, Brian uses two spur gears and I am measuring downtravel. Just so many different ways to set this. Honestly I am just looking to see how everyone else sets it.
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Old 04-08-2002, 03:02 PM   #5
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David- I'm 100% in agreement with you on the down travel issue. I too have been brainstorming on how to standardize this measurement, but never thought to begin a discussion. Since you have, here are some of my thoughts-

1) You called it "weighted downtravel". I would call it "static downtravel" since it's being measured at a stand still with no other forces acting upon it and all of the other adjustments already done. "Weighted" gives me the implication that you are altering the weight of the car- if I didn't already know what you mean...

2) Your measurement procedure is OK, but I think it can be improved. Keep in mind that tires change shape without any weight on them and that will alter your distance if say you are running a tire with a lot of airgap. Also, if you unload only one end of the suspension until the tires barely touch the ground, then the only place you can get an exact measurement on height is exactly between the axle centerlines becasue the suspension will be at an angle and therefore be lower than actual height if measured inboard from the axle centerline or higher if measured to the outside of it. I believe the best way to take this measurement would be to somehow extend all 4 shocks to their max extension leaving the car sitting on the tweak board and then take the height measurements. Again, you would have to get pretty close to the axle centerlines, but it wouldn't be that critical since the car will basically be the same height front and rear. I don't think it would be hard to engineer a small spring loaded tool that would extend the shocks to full travel and you could clip one onto each shock without altering the shock setting. This method would also put the same amount of weight on the tires as when the the car is sitting at the static ride height. It would also take out almost all variables in the measurement of actual shock downtravel. On cars that don't employ droop screws (i.e.- Yokomo, early TC3 etc) it would also take out some of the guessing game when trying to run a longer shock body or shaft.

3) It will suck if we all have to go buy an off-road ride height guage after we have all bought the Hudy droop guages or Integy or whomever. So to solve the measurement tool problem, all you have to do is stack the regular ride height tool on top of the Droop stand tool which is 10mm (I think) and then measure and add 10mm to the tool's reading. Obviously, if the car isn't high enough to do it this way, you can just use the tool without the chassis stand tool.

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Old 04-08-2002, 03:17 PM   #6
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1) I called it weighted because my initial measurement is ride height, thus it is weighted from the battery, chassis, motor, ect... I would figure static would be the full travel of the shock (down to up). I am no engineer so static could very well be the correct word, just throwing out my thougt on it.

2) I didn't think about that because I was thinking of foams I am having trouble visualizing what this tool would be but I would like to figure a way where we don't need to buy anything.

3) I was thinking your later, just placing the car with no blocks under it.

I am going to play around tonight with all these types of droop setups and see what they yield, and then cross reference it to see if one way is close to another. I just would like to see racers adopt one way of setting it, but setting it with the shocks and swaybars off it not enough info in my book.
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Last edited by David Joor; 04-08-2002 at 03:19 PM.
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Old 04-08-2002, 03:59 PM   #7
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1) David- I think in this context static usually means "not in motion" or "at a stand still" hence my mention of not having any other forces (meaning lateral g-forces) affecting the suspension.

3) I wasn't exactly clear on this one- I meant to use the stand tool and the guage stacked together while the car is fully extended with whatever method of forcing the shocks to full extension is used since most ride height guages don't go up high enough. It would sorta be like adding 10mm to the regular guage.

Disconnecting the shocks and swaybars- You are correct ESPECIALLY when you consider that the Yoks etc. use the shock's overall length to set the droop. On the swaybars- we both know you must disconnect the swaybars to make most settings and then disconnect the shocks to check the tweak on the swaybars, but I don't think you would have to disconnect either if you use my idea to force all four shocks to full extension and then take the droop height measurement.

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Old 04-08-2002, 10:44 PM   #8
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1) Remember that I am subtracting one from another (ride height will change the outcome) so static still in my head is not correct, but nevertheless, what works works

After playing with this tonight at the track, I came up with all sorts of different ways to measure the droop and the most accurate to me and quickest it to use a standard gauge like the AE or the Losi. I set droop with no shocks/sway attached, attach shock and sway and tires, set ride height, and then measured the "Weighted Downtravel". Which seems to be a very good judgment of what my car is going to feel like. Now I just need more time with this adjustment at different droops setting and tire size.

As far as some device that pressed all shocks down, the XXXS would have trouble because the plastic bumper that holds the tweak screws would flex if you put much pressure on it
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Old 04-09-2002, 12:39 AM   #9
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I've recently been using a different system to set droop, it's been working very well for me so far.

Here it is... First, back out the droop screws, then set the ride height and tweak of the car with the spring collars or spacers, then run the droop screws back in so that there is no slack in the spring at full extension. THen lift each end of the car with a sharp tool at the centerline to see that both wheels at that end lift at the same time.

Doing it this way typically gives more droop with softer springs, but I would normally run more droop in the same situations as softer springs (low grip) so it sort of self regulates. I've run spring combos all the way from Black (25lb) front and Purple (20lb) rears down to Pink (10.6) and Orange (8.6) with this method, and it's been working quite well so far.

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Old 04-09-2002, 04:24 AM   #10
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David, just finished reading the thread through and I'm wondering. How do you define droop? What you called down-travel in your first mail is exactly what I call droop, the amount the car can be lifted until the wheels lift off.
AE, Hudy and all other makes have made their droop-gauges that measure "droop" from wherever it is the easiest. These however don't give the correct value, but with an offset, depending of the car and gauge. True droop values should always be the ones given out, not Hudy or AE numbers. If these are used instead, it should at least be mentioned!
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Old 04-09-2002, 07:24 AM   #11
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JesseT - That is my point exactly, the gauges like Hudy, AE, blah blah blah only tell you a single number which I don't think is enough. Say I am running 62.5mm foam tires as opposed to 57.5mm tires, that is a 5mm difference and say at big races when you see all the setup sheets from say they are running 6mm droop in the rear, that honestly means I need to be somewhere close to 8.5mm droop setting to compensate for the extra tire size. Meassuring the weighted downtravel so to speak is just an added adjustment because a lot of people don't measure thier tires. If I had either the tire size or the weighted, I could equate what the droop should be set at.
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Old 04-09-2002, 09:53 AM   #12
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So you are suggesting that when people are about to tell their droop value, they first should measure it by measuring the droop...
Sounds logical! ;-)

If someone measures the distance between the ground and the tip of the lower wishbone, they will get the distance between them, AND NOTHING ELSE. These kind of measurements are for own reference only.
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Old 04-09-2002, 10:31 AM   #13
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Now this is a posting that I really have trouble understanding, and some of us out here need some serious schoolin. My problem is that I've had a Yokomo, Hpi, and Tamiya cars in the past and there is no uniform explaination on "droop", or "ride height." So my definition of "droop" or "ride height" is probably way off. I've always just "drove" the car never really thought about these adjustment till now.
First, for example, I now have a shumacher mission. It says in the manual to adjust "ride height" by whatever spring clip you need. Ok, so with no clips the car right now has about 6.5mm in the front 7mm rear using a aluminum combo guage (droop/height) so no clips are needed, it actually is too high. The manual says that 5.5mm ft, and 6mm rear is a good starting point, but in order to achieve the 5.5/6mm I must use the set screws in tha a-arms to achieve these numbers. Is this the wrong way to get the 5.5/6mm? What if I wanted to say go to 4.5, or 5mm? Or are the set screws used only for "droop"? What is droop, and why do we need it?
I'm starting to think that the way my car is set now to get the 5.5/6mm must not have any droop since the set screws are basically doing that job when they should'nt be.
Any info would be appreciated.
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Old 04-09-2002, 10:41 AM   #14
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hobbipro,

It's generally a BAD idea to set your ride height with the droop screws. Set ride height with the spring collars. If you can't get the car low enough then something's wrong, you need to find out why.

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Old 04-09-2002, 11:12 AM   #15
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Trips hit it, try and get another brand of springs, maybe the ones you have are to long. The stock mission blue springs are a tad long and cause this problem. With no clips you should at 0 to 1mm ride height. Here is how I set my car (once I have the right springs on the car )

1) remove shocks and swaybar and set the droop (on the mission do 3mm in the front and 2mm in the back).

2) Put it all back together with tires mounted and set ride height with spring collars. (5mm front 5.5mm rear)

3) Now I set tweak and off to the track.

Now what I am starting to do now is measuring my tires once I find a setup that I truly like. Now say you like the car with droop at 3mm front and 2mm rear and tires are 60mm in height, I now have a basis for setting my droop for different tire sizes. So in this example I goto a tire that is huge for some reason, it is 62mm. I go and look at what I liked before which was 60mm, subtract it, I am left with a 2mm difference. Now don't forget, you don't add 2mm to the droop because only half the tire is on the side of the axle that is being used for the measurement, so you would add 1mm of droop on step 1 all the way around. Now your car should feel almost identical (well minus the tire difference). Hope this helps you understand what I am trying to do, but droop is probably the most drastic change you can make to your car and it is so quick and easy that everyone should understand inside and out.
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