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Old 04-14-2013, 10:26 PM
  #18751  
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Which only proves my point. The amount of droop is difficult to measure precisely or quantify. I just can't imagine myself trying to measure the chassis height while holding the car up in the air at the precise height that the tires come off the ground. What if your chassis is "tweaked" and one tire comes off the ground before the other. I know of very few racers that adjust for "tweak" or weight balance their cars.
Yes, yes, this is right, but itīs in 90% precise enough.
And this gives always a quick impression, without thinking of some droop gauges values someone gave you from his touring car. There can be differences on the real drop you measure outside the wishbone end, even when you have the same value on the gauge. (e.g. by shiming the inner toe blocks). A very successful team driver I know said it this way to me: "The truth is always at the car, and the most simple way is to lift the chassis up above ride height, and see how far the axles come down."


Also, it isn't particularly important as to the measurement, but whether you're increasing or decreasing droop. I don't know of anyone that measures droop, but most of us do measure shock length.
In Mini racing youīre right, but if youīre measuring shock length, itīs just another way, because Mini chassis are not too flat and most cannot place it precisely on the 10mm blocks etc.. In touring cars nowadays, 90% of my racer collegues do measure it with the gauges, at least in Germany. And if you know all other facts your collegue built in his axles, then itīs very precise.


Dear Sir, since you quoted part of my response and misinterpreted what I posted, it seems only fair that you go back and actually read what I posted. In order to help you out, let me explain. I said that in a longer shock it would have more droop than a shorter shock. The example I used was a comparison between a 56 and a 57mm shock. Since the Mini or at least mine doesn't have a droop limiting or droop adjustment screw, etc, the amount of droop is pretty much determined by the length of the shock. There are limits to this of course, and I don't believe that shock lengths of over 58mm or so have any effect for an onroad Mini.
Dear granpa, sorry for quoting not too exact, and you donīt have to call me sir.
A longer shock has for sure more droop than another, if the axle can move down, youīre right. Didnīt want to mislead anyone.

No where in my post did I say shock length is droop. Also, what in blazes is the shock to axle ratio. It's something I've never come across. Explain, I'm interested. I'm guessing, you're talking about a ratio how much the shock lengthens and shortens to the amount the wheel axle moves. If it is, who gives a crap. Anyone with more than one neuron knows that that ratio would not be one just from the attachment points of the shock and the shock angles.
Yes, you didnīt say shock length is droop, but you also did not explain the relation. That is maybe hard to understand for new Mini Rookies.
The ratio you should know, in easy word itīs the travel the shock makes divided by the travel of the wheel. Itīs no crap. If you lay down your shock completely inside, you have still the same shock length, but a different droop of the wheel, but hey, you know that.
You just wanted to test me out, but yes, I have more than one neutron.

I didnīt want to offend you in any way,
just trying to get the best informative discussions for everyone in this awesome thread.

Matthias
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Old 04-14-2013, 11:37 PM
  #18752  
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Just curious: Does Bertrand still make appearances around here? I've had him blocked for quite a while now. I'm almost missing him a little. What can I say? I'm a sucker for punishment.
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Old 04-15-2013, 01:25 AM
  #18753  
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Joel and Matthias, I perhaps ungraciously pointed out that droop measurements in a Mini are for the most part irrelevant. There isn't anyone that I know who actually measures or attempts to quantify droop. We do have an interest in shock length, only because it tells us how much we are increasing or decreasing droop. Also we're probably only talking of, at max, a range of 2mm or less. If you check out Matthias's shock to axle ratio, you'll see that 1mm at the shock is much more at the wheel. No, I made no attempt to measure it.

Now, this next is going to get me into trouble with some. I generally run 56.5mm shocks in front, only cause at that length the spring retainer slides easily between the shock body and the lower coupler. The rears are no longer than 57.5mm and are usually 56.5 or 57mm. I've never found that changing shock lengths and consequently adjusting droop in the front ever made a damn bit of difference. Occasionally, changing to a slightly longer or shorter shock did have an effect for the rear. Please note the above may only be true for the smooth tracks in my experience and may not be true for bumpy tracks.
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Old 04-15-2013, 01:56 AM
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Originally Posted by monkeyracing
Just curious: Does Bertrand still make appearances around here? I've had him blocked for quite a while now. I'm almost missing him a little. What can I say? I'm a sucker for punishment.
Sorry Jim, if I've been the one inflicting the punishment. Not my intention at all, but I'm fascinated by chassis tuning. My driving sucks, the painting skills are highly suspect, sort of a irascible curmudgeon, but usually have one of the best handling Minis on the track.

The subject of droop in a Mini was, I realize, a topic for a heated discussion a few months ago. Much misinformation and a lot plain BS made it's way onto this thread. As I recall much time was spent how droop affected handling, but this one was about the value of actually having a numerical value for droop. I don't think so and will probably never bother to actually measure it. Would if i were still racing TC.
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Old 04-15-2013, 02:56 AM
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Hi Granpa, nice to see the thread lively!

My thoughts on droop are my own and not in reference to others (nor meant to contradict). Many opinions on droop.

The way I measure is by feel, holding by the shock towers then lifting. No rulers, gauges or stuffs. It's a mini.

Slop on the shock eyelets alone can be 1mm or so of droop. I put plumbers teflon tape to remove that slop.

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Old 04-15-2013, 08:26 AM
  #18756  
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Hey,
keep Bertrand out of this discussion, Monkey!
And I hope I wasnīt a punisher here!


In fact I never measured droop on my Minis like on a touring car for myself. I keep it like Joel and note the shock length as Granpa, just for my notes in case the car was fine.
Also my touring car sees the setup-board not that often, and I do not detweak it every 5 minutes like some do.
And as Granpa said, differences are often small and do not mean that much.
Itīs for me as for Granpa, I like to know the effects and theory of chassis tuning, as it brought me to my real job in the end. Itīs a hobby, no religion for me.
I just like to keep the theory precise.
Iīll stop now to keep this thread lively.

Back to fun,
Matthias
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Old 04-15-2013, 11:37 AM
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Originally Posted by Granpa
Sorry Jim...
No need to apologize, Bob. I actually hold you in high regard. I've really just been skimming over anything with the word "droop" in it. As far as I'm concerned, that crosses into TC territory. (Although, I now own an ABC Genetic, so I should learn about this stuff.)

My question about Bert was honestly coincidental. I almost miss his input - always a little ways left!

Jim
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Old 04-16-2013, 03:36 PM
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Entries close for the Aus Mini Nationals in 2 days.
At the moment we're sitting on 45 entries for the main Mini class, so very, very close to the magic 50 number.
Will we finally make it this year?.... Fingers crossed!
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Old 04-16-2013, 07:40 PM
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Originally Posted by tony gray
Entries close for the Aus Mini Nationals in 2 days.
At the moment we're sitting on 45 entries for the main Mini class, so very, very close to the magic 50 number.
Will we finally make it this year?.... Fingers crossed!
That's going to be awesome. Please post a link to results, pictures videos etc. Good luck.
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Old 04-17-2013, 06:13 PM
  #18760  
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Guys
Sorry have a quick question regarding the Ball Diffs
I just finished building it
After waiting a week for my major screw up, I dropped the long
screw that holds it together at my job and couldn't find the damn thing
I was going to buy one from Tamiya but after emailing them inquiring
about it they sent me one free of charge!
THANK YOU TAMIYA! GREAT CUSTOMER SERVICE!!!

Anyway onto my question
excatly how tight should the diff be?
I have it at the point where it is extremely hard to turn
Is this where I want it or is this too tight?
Mike
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Old 04-17-2013, 06:20 PM
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Originally Posted by KA2AEV
excatly how tight should the diff be?
I have it at the point where it is extremely hard to turn
Is this where I want it or is this too tight?
Mike
If its that tight its WAY too tight. If you want a locked or close to it diff then you are where you want to be. But if you want a smooth diff back it off to where there is a bit of stiffness but moves without a gritty feeling. Remember that the diff will break in a bit and loosen up and need to be tightened a bit to get it back to where it was.

Jason
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Old 04-17-2013, 11:11 PM
  #18762  
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Originally Posted by KA2AEV
Guys
Sorry have a quick question regarding the Ball Diffs
I just finished building it
After waiting a week for my major screw up, I dropped the long
screw that holds it together at my job and couldn't find the damn thing
I was going to buy one from Tamiya but after emailing them inquiring
about it they sent me one free of charge!
THANK YOU TAMIYA! GREAT CUSTOMER SERVICE!!!

Anyway onto my question
excatly how tight should the diff be?
I have it at the point where it is extremely hard to turn
Is this where I want it or is this too tight?
Mike
I assume you have the M-05 diff?

That style of diff doesn't like being run very tight. It will be notchy and the screw will probably break.

Basically, make sure you get the lubrication right (the silicone grease on the balls and the black grease on the thrust - I would recommend an alternative brand of grease such as Much-More rather than the Tamiya grease in this case), then assemble and tighten the screw hand-tight, then back off just a tiny bit, less than 1/8th of a turn. The aim is to get a diff that doesn't slip and operates smoothly, yet with as tight an action as you can manage without having the screw fully tight.

It's more of an experience thing than anything else. At least the M-05 diff can be adjusted externally as you learn.

PS The M-05 diff is the kind used in the rear of 4wd touring cars. The TA03 diff is much better suited to the FWD M-chassis, if you have the budget you will probably save yourself a lot of hassle by getting one of them instead.
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Old 04-17-2013, 11:29 PM
  #18763  
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Does the PN 50746 CVA Super Mini Shock Unit kit contain parts to make only two shocks or four shocks?
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Old 04-17-2013, 11:43 PM
  #18764  
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One pair only per pack
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Old 04-18-2013, 03:46 AM
  #18765  
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Originally Posted by sosidge
I assume you have the M-05 diff?

That style of diff doesn't like being run very tight. It will be notchy and the screw will probably break.

Basically, make sure you get the lubrication right (the silicone grease on the balls and the black grease on the thrust - I would recommend an alternative brand of grease such as Much-More rather than the Tamiya grease in this case), then assemble and tighten the screw hand-tight, then back off just a tiny bit, less than 1/8th of a turn. The aim is to get a diff that doesn't slip and operates smoothly, yet with as tight an action as you can manage without having the screw fully tight.

It's more of an experience thing than anything else. At least the M-05 diff can be adjusted externally as you learn.

PS The M-05 diff is the kind used in the rear of 4wd touring cars. The TA03 diff is much better suited to the FWD M-chassis, if you have the budget you will probably save yourself a lot of hassle by getting one of them instead.
Generally speaking I agree with you, but I would say (perhaps biased by my TC experience) that the M05 ball diff is superior. It takes a bit of tuning, but that is where its superiority resides. It can cover a lot more ground than the TA03 style diff.

Personally I would use liberal amounts of Tamiya antiwear grease (this is for a FWD mini, not a TC) on the balls as well (not only the thrust bearing). This will tighten the diff action and make it last longer. Wear is more progressive creating in the end a smooth groove in the plates that is beneficial rather than counterproductive (balls don't "grind" in this groove but run smoothly), so in the end you have something resembling a thrust (axial) bearing (which is what the ball diff is in principle).

My tightness test is to find the point where by holding a wheel and turning the other one, I can spin the motor.

And yes, I use a ball diff in my M05.

Last edited by niznai; 04-18-2013 at 03:58 AM.
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