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Old 02-19-2003, 10:11 PM   #46
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Quote:
Originally posted by johnbull
Hi guys. Greetings from Malta.

I once saw a set of corner weight scales advertised in an American RC magazine, just like the ones we use on real race cars.

I e-mailed the company advertising them as I was interested in buying a set, and still am, however they never replied.

Does anybody know who manufactures them and what sort of price they go for.

I'm still interested.

Regards

Joe from sunny Malta.

I think, this is what you are looking for....

http://www.teamirsrc.com/tweak.html


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Old 02-20-2003, 01:50 AM   #47
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Thanks ELNITRO.

Thanks BIG4343.

I've just E mailed Irgang today.

Regards

Joe from sunny Malta.
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Old 02-20-2003, 10:46 AM   #48
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Default DEM SCALES!!

HEY DUDES!,
GREAT WORK ELNITRO...HOLESHOT MAKES A SET AS WELL BUT I DONT KNOW IF THEY ARE CHEAPER OR NOT.WHAT CLASSES DO YOU GUYS RUN?
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Old 02-20-2003, 11:40 AM   #49
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Postal scales with 2.2 kilogram (5 pound) capacity and sensitivity to 1 gram run about $ 30 each at a big office supply. You can make a couple of pedestals about the same height as the scales by stacking any kind of precision objects. Just measure both stacks with the dial caliper and make sure the stacks are the same. Suitable material are keyway stock brass strips metal shim Rectangular plastic stock metal or plastic shim stock, Associated practice transponder modules, etc. This reduces the number of scales you need to two.
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Old 02-20-2003, 12:52 PM   #50
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Quote:
Originally posted by johnbull
Hi guys. Greetings from Malta.

SEEBALL.

I can't see how your droop can vary by preloading the shocks,
Because, droop depends on ride height. Once you change your ride height you will change droop.

--> The ride height is set using the preload shock collars.

--> Tweak is set using the preload shock collars.

So when you set tweak, you'll change your ride height at that corner of the car, which will also change your droop at that corner. Unless setting tweak doesn't change your ride height... but I don't see how it won't since you're moving shock collars (which is how you set the ride height to begin with).
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Old 02-20-2003, 12:59 PM   #51
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Yeah okie dokie!

You need to check your math on that one good buddy.

Ya see the droop is very independant from the ride height or tweak, as long as the droop is properly measured for each corner.
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Old 02-21-2003, 09:29 AM   #52
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Spdyrc- I'm sorry to have to correct you on this, but I don't want someone to be misinformed. ISO Octane is correct on the part about droop being relative to ride height. He is exactly correct. Any time you change the ride height whether it's to change ride height or compensate for tire diameter, the droop changes. The reason for this is that droop is the amount of downtravel of the hub from static ride height to full extension given the chassis stays stationary. It doesn't matter what limits the suspension; droop screws, shock length, suspension bind, etc. Another way to explain droop is the actual uptravel of the chassis to full extension of the arms/hubs given the axle stays stationary.

The part that Iso has wrong is the part about droop changing with tweak setting (assuming you aren't changing the ride height when you adjust the shock collars to set tweak). The reason for this is that ride height is relative to shock collar preload with the car static at full race weight, but droop is relative to the suspension's travel with no weight because that's the only time the suspension will reach full travel.

If I haven't explained this clearly enough please let me know. I never claimed to be a communications specialitst...
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Old 02-21-2003, 10:07 AM   #53
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Default One more clarification

Changing the Ride Height will change the Droop MEASUREMENT in relation to RH, but will NOT change the actual chassis extention.

So if you raise your Ride Height you come closer to the limit of full chassis extension, less Droop.
If you lower your Ride Height, the opposite occurs, more Droop,

You would then need to adjust chassis extension with Shock length or limiter screws to correct. This really should only be nesessary in extreme examples.
Minor adjustments in Tweak will have a very small effect on ride height, which can be corrected by spliting the tweak adjustment between both shocks at the same end of the car.
Cars that use Shock clips/spacers to adjust ride height become a problem because you are limited by the thickness of the spacers and fine adjustment are just not possible.

Last edited by popsracer; 02-21-2003 at 10:11 AM.
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Old 02-21-2003, 10:31 AM   #54
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Default Big Dog you are absolutely right!

Pardon me Octane,

Droop and ride height will be the measurements for arm travel, but this would be relative to the tire diameter or the axle height.

So you were partly correct,

but the tweak adjustment is only related to the spring tension to compensate for the ballast of the chassis.
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Old 02-21-2003, 10:34 AM   #55
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Quote:
Originally posted by BigDogRacing
the part about droop changing with tweak setting (assuming you aren't changing the ride height when you adjust the shock collars to set tweak).
Well, you can't really just assume away that you aren't changing the ride height since it's such a critical factor here in whether or not droop will be affected but:

Quote:
Originally posted by popsracer
Minor adjustments in Tweak will have a very small effect on ride height
So you see, you are changing droop (via a ride height change), but in such a miniscule amount that it can be ignored. So the original thing about what to do first, tweak or droop, setting the droop after tweak might eliminate that tenth of a millimetre change to droop that was made during tweaking. Provided that droop can even be measured to such accuracy.

Last edited by Iso Octane; 02-21-2003 at 10:37 AM.
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Old 02-21-2003, 10:40 AM   #56
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Okay, I'm going to jump into this one again. . .only because I want clarification and NOT (as many suppose) merely to argue (although I like the occassional good argument. . .)


Is not droop the measurement of maximum arm down-travel measured from the plane created by the bottom of the chassis to an established point on the arm (usually the hub)?

Like this:



So it's a static measurement of the maximum amount of down-travel. Am I correct in saying that?

And bump is the measurement of maximum arm up-travel measured from the plane created by the bottom of the chassis to an established point on the arm (usually the hub)? I realize we don't use this in on-road. . .

Like this:



But isn't ride height a relative measurement, based on weight, spring ratios, etc. that sits somewhere between max up-travel (bump - limited by shocks) and max down-travel (droop - limited by shock or screw-adjuster) and adjusted by preload on the shocks. . .? And it's measured from the bottom of the chassis to the ground. . .

Are my three definitions correct?

RH - measurement from bottom of chassis to ground, adjusted by weight and pre-load.

Bump (max up travel) - measurement from bottom of chassis to max up travel on the hub.

Droop (max down travel) - measurement from bottom of chassis to max down travel on the hub.

If they are correct, then RH is not related to either droop or bump, and droop is not related to tire size although RH is.

If I'm wrong (and there is a distinct and constant possibilty of that. . . ) please show me where.
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Last edited by Boomer; 02-21-2003 at 10:42 AM.
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Old 02-21-2003, 10:58 AM   #57
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Sorry Boomer, but you are wrong. If you had read my prior post, you would have saved yourself a lot of typing.

Droop is NOT the measurement of the full extension of the suspension in relation to the plane of the chassis. It is the DISTANCE the suspension travels from static ride height TO full extension. Therefore ride height DOES afftect droop. You are simply referring to one method of measuring droop which is to measure it relative to the chassis. The better way to measure droop is to take a ride height reading with the car in race-ready trim, then extend the suspension to full travel and take another ride height reading. This will give you ACTUAL ride height and droop measurements, not RELATIVE.

ISO- again, I stressed that we were NOT changing the ride height by adjusting the tweak. When you measure full extension you are eliminating the variable of weight so the position of the shock collar is irrelevant.

Droop= chassis height at full extension - actual ride height
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Old 02-21-2003, 11:16 AM   #58
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I love pictures.

Here's the view of the rear of a car at static ride height, travelling at a constant speed, neglicting track surface imperfections (bumps):


Now the car is going to brake, in a perfectly straight line:


Okay, so notice the change in ride height. It went from static 5mm to 8mm under braking. The droop screws on the suspension arms are up against the chassis plate, thereby limiting the downtravel of the suspension. The droop is 8mm - 5mm = 3mm.

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Old 02-21-2003, 11:21 AM   #59
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Hmm, my explanation is different than yours, BigDogRacing.

Ach, there was a whole thread on droop way back when....
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Old 02-21-2003, 11:55 AM   #60
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Hi Guys. Greetings from Malta.

ISO OCTANE.

Your last contribution, with diagrams probably explains it best.

I think we all knew what droop was, just that we couldn't quite communicate it so easily. Figures work wonders, don't they.

Now I think you will find we are all in agreement.

Now here's a question not really related, but perhaps you can all help.

I decided yesterday to have a bash with my son's TC3. I prepare it for him but I rarely get to drive it. I drive a Yoke SP which I think handles very well. Now son Josh has been doing alot of winning with his TC3 and tells me he thinks it handles well.

Well having now driven it myself, and comparing it to my Yoke, I think it's aweful. I recently replaced the front tower with a rear one, thus changing shock angles, but nothing else. What i find most disturbing is the fact that it doesn't keep a straight line down the straight. the slightest transmitter (steering) movement and it darts left or right. The Yoke is so steady - granted I have more caster (2 degree bulkhead and 7 degree blocks). The TC3 has the 2 degree front arm mount and the 4 degree blocks.

It really feels as though it needs more caster to run straighter with less effort. Turn in is good, and corner exit is good too, but it's such a handful on the straight.

Any ideas anyone?

Regards

Joe from sunny Malta.......where it's been pissing down all day!
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