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Old 04-29-2009, 08:15 AM   #5236
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Originally Posted by tonyv View Post
I am not getting carried away, I am doing what any engineer would do to show that something is not linear, go to the extremes. With RC cars -4 or -5 will still in almost all situations result in less, not more grip. So stating that to get more grip you would allways need to add camber (change) is quite simply incorrect.

There is a reason the standard (rubber tyre) setups usually have -1.5 degrees of static camber. This works best in general. In general meaning that in some cases less static camber works better and in some cases more static camber works better assuming no change is made to camber change.

I am all for keeping things simple. But if a "rule of thumb" is just as likely to have the wrong result as it is to give the right result I don't consider that simple at all. It means that relative newbies get frustrated because they cannot get things to work and cannot understand why they get less grip where they think they should be getting more.

Ed and Tony are right.

If one needs an easy explanation of how these things work, get a copy of this book by Martin Crisp (Radio Control Car Chassis Setup Guide from XXX Main)
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEGG9


....
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Old 04-29-2009, 08:18 AM   #5237
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Originally Posted by tonyv View Post
I am not getting carried away, I am doing what any engineer would do to show that something is not linear, go to the extremes. With RC cars -4 or -5 will still in almost all situations result in less, not more grip. So stating that to get more grip you would allways need to add camber (change) is quite simply incorrect.

There is a reason the standard (rubber tyre) setups usually have -1.5 degrees of static camber. This works best in general. In general meaning that in some cases less static camber works better and in some cases more static camber works better assuming no change is made to camber change.

I am all for keeping things simple. But if a "rule of thumb" is just as likely to have the wrong result as it is to give the right result I don't consider that simple at all. It means that relative newbies get frustrated because they cannot get things to work and cannot understand why they get less grip where they think they should be getting more.
Whats up stranger!
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Old 04-29-2009, 09:17 AM   #5238
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Originally Posted by tonyv View Post
I am not getting carried away, I am doing what any engineer would do to show that something is not linear, go to the extremes. With RC cars -4 or -5 will still in almost all situations result in less, not more grip. So stating that to get more grip you would allways need to add camber (change) is quite simply incorrect.

There is a reason the standard (rubber tyre) setups usually have -1.5 degrees of static camber. This works best in general. In general meaning that in some cases less static camber works better and in some cases more static camber works better assuming no change is made to camber change.

I am all for keeping things simple. But if a "rule of thumb" is just as likely to have the wrong result as it is to give the right result I don't consider that simple at all. It means that relative newbies get frustrated because they cannot get things to work and cannot understand why they get less grip where they think they should be getting more.
-5 would be an extreme. 20 is just redonkulous! As far as static camber at -1.5 sure. But think of the chassis roll and it's effect on how the tire is planted. Roll the chassis and usually you lose camber. Without camber gain the car would do nothing but push harder as it transfers weight to the outside. Letting the tire roll positive will usually result in snap roll. That might be good for Joey Chitwood or a stunt pilot but wont result in good lap times at all. And as for your comment ... okay more camber doesn't generate more traction in a straight line but once you are cornering it most certainly does. Camber effect tire temperature as well.... more camber more heat! Usually more heat means more grip until you exceed the recommended tire operating range. Then they just start sliding or get gummy depending on the compound. Try this Tony, Leave your roll centers alone and try zero deg camber,,, drive it! Then try -2. you should notice faster tire warm ups and higher corner speed. If you doubt me look at the XXX Main set up crib sheet.
And maybe even the Audi tech manuals for tire and application data. Call Bridestone or Michellin and tell them their wrong.
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Old 04-29-2009, 09:27 AM   #5239
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The numbers are merely for reference. I'm sure that to someone they do mean something but for our purposes it is just a vernier for comparison.
Ours go to eleven. So they must be louder. It is one more isn't it?!
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Old 04-29-2009, 01:19 PM   #5240
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Whats up stranger!
Hiya Mark, how've you been?
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Old 04-29-2009, 01:40 PM   #5241
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Originally Posted by John St.Amant View Post
-5 would be an extreme. 20 is just redonkulous!
My point exactly. So explain why it would be "redonkulous"?

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Originally Posted by John St.Amant View Post
Without camber gain the car would do nothing but push harder as it transfers weight to the outside.
No argument there other than that this point has nothing to do with the roll center itself. If your point is that if you change the roll center you may have to adjust the static camber and/or camber gain settings, then sure. If you had optimal settings for static camber and camber gain before you changed the roll center you will most likely have to find the new optimal settings. Which may require more or less camber (change). Since the effects are not linear it is not so easy to determine which.

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Originally Posted by John St.Amant View Post
Letting the tire roll positive will usually result in snap roll. That might be good for Joey Chitwood or a stunt pilot but wont result in good lap times at all.
Again no argument there and exactly what I already indicated. Not only do you have less grip with positive camber settings, you will most likely roll the car because you are running on the outside edge of the tyre. But then if you run too much camber you will not have enough grip also albeit normally without rolling the car.

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Originally Posted by John St.Amant View Post
And as for your comment ... okay more camber doesn't generate more traction in a straight line but once you are cornering it most certainly does.
As said before, it may or it may not. Critical here is the contact patch of the tyre. If you have too much camber the contact patch is smaller than if you have the exact right amount of camber. This is true for any arc you want to make during cornering. From a grip perspective ideally the tyre is almost at a 90 degree angle all the time. Slightly less actually to compensate for the deformation of the tyre which explains why some negative camber is allways needed.

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Originally Posted by John St.Amant View Post
Camber effect tire temperature as well.... more camber more heat!
Again with the linear thinking. More camber does NOT necessarily equate to more heat. It all depends on the starting point and how much you increase the camber angle. I can guarantee that you will not get heat into the tyre if you run -20 degrees camber.

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Originally Posted by John St.Amant View Post
Try this Tony, Leave your roll centers alone and try zero deg camber,,, drive it!
As explained above zero will indeed work less well. However I have run on tracks and tyres where -0.5 rear and -1 front worked best as well as other settings, even with little or no camber gain.

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Originally Posted by John St.Amant View Post
Call Bridestone or Michellin and tell them their wrong.
Even Bridgestone and Michelin know they will have no grip at all if you go to the utlimate ridiculous camber angle: -90 degrees. No contact patch at all and therefore no grip. Then again also no forward traction so it doesn't matter.

Ah well, I think I have proved the point more than sufficiently supported by examples everyone can understand and if they want test for themselves. The net result is, like most settings, camber and camber gain settings do not result in linear changes and they have nothing to do with the static roll center settings as Ed already mentioned before. These settings do however work together which is why setting up a car is not just a science but an art as well.
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Old 04-29-2009, 04:47 PM   #5242
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Tony, I recommend using rctech's ignore list feature, like I did.
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Old 04-29-2009, 05:35 PM   #5243
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I agree.

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Tony, I recommend using rctech's ignore list feature, like I did.
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Old 04-29-2009, 06:10 PM   #5244
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What was the reason for the motor mount change between versions of the 416? Did they feel the original one had too much movement?

The more I drive this car with a spool (13.5 rub), the more I wonder how I ever completed a lap with a one-way.
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Old 04-29-2009, 09:39 PM   #5245
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WTF!? No one would ever use 20 or 90 degrees camber. And Where ever you learned about roll center that does not effect camber well... That would be zero camber gain or loss would be more likely in an off-road situation. I told a few guys about this little spat we are having here and as far as I'm concerned you can all kiss the fattest part of my a$$. Not one of you seems to follow the logic and using an over extreme like four times the maximum camber mechanically acceptable to say I'm incorrect is beyond reason. Never exceed the limits of REASON. What I said is right on the money and roll center is a MAJOR tuning factor because of its effect of the wheel angle in relation to the chassis. i.e. camber!!! Believe it or not. The tire doesn't care what the chassis is doing. The chassis does however mind wheel angle .. slip angle .. and most of all camber. More is more... but saying you can run -20 isn't even an option. So how can you justify that as a plausible situation. Your logic is flawed. Please also remember that no one under any circumstances would run positive camber so like caster the number is absolute. If I say I'm running 2 degrees camber thats a NEGATIVE 2.. and more would be 3, NOT 20. Not like a number line where -2 comes after -3. In this case 3 IS more and will generate more heat and more traction than 2. Do not use any thing unreachable or mechanically impossible to say "Your wrong John" because I'm not. So go ahead and ignore me. Thats your choice. Pressing down on the suspension does NOT show what your car is doing in a hi "G" turn nor would it show how the chassis rolls under those circumstances. I will be the one passing you on the inside and you will be out in the clag!
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Old 04-29-2009, 09:44 PM   #5246
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Originally Posted by syndr0me View Post
What was the reason for the motor mount change between versions of the 416? Did they feel the original one had too much movement?

The more I drive this car with a spool (13.5 rub), the more I wonder how I ever completed a lap with a one-way.
I'd love to give my 2 cents but some people wouldn't understand my dyslexic left handed polish logic.
My spool pushed like a truck loaded with dirt.
Good for the outdoor stuff but not so good on twisty carpet stuff.
Oh crap, I gave my $0.02 and now I'm gonna pay for it. AGAIN
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Old 04-29-2009, 10:15 PM   #5247
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Do any of you guys know if a (front/rear)sway bar kits exists for the 416WE? If so, do you guys know the part numbers?

Thanks Chris,

P.S. Has anybody had any luck finding any 416WE spool cups in the USA yet?
Unfortunately, Tamiya's USA website says their "still" out of stock.
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Old 04-30-2009, 12:02 AM   #5248
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Originally Posted by John St.Amant View Post
WTF!? No one would ever use 20 or 90 degrees camber. And Where ever you learned about roll center that does not effect camber well... That would be zero camber gain or loss would be more likely in an off-road situation. I told a few guys about this little spat we are having here and as far as I'm concerned you can all kiss the fattest part of my a$$. Not one of you seems to follow the logic and using an over extreme like four times the maximum camber mechanically acceptable to say I'm incorrect is beyond reason. Never exceed the limits of REASON. What I said is right on the money and roll center is a MAJOR tuning factor because of its effect of the wheel angle in relation to the chassis. i.e. camber!!! Believe it or not. The tire doesn't care what the chassis is doing. The chassis does however mind wheel angle .. slip angle .. and most of all camber. More is more... but saying you can run -20 isn't even an option. So how can you justify that as a plausible situation. Your logic is flawed. Please also remember that no one under any circumstances would run positive camber so like caster the number is absolute. If I say I'm running 2 degrees camber thats a NEGATIVE 2.. and more would be 3, NOT 20. Not like a number line where -2 comes after -3. In this case 3 IS more and will generate more heat and more traction than 2. Do not use any thing unreachable or mechanically impossible to say "Your wrong John" because I'm not. So go ahead and ignore me. Thats your choice. Pressing down on the suspension does NOT show what your car is doing in a hi "G" turn nor would it show how the chassis rolls under those circumstances. I will be the one passing you on the inside and you will be out in the clag!
John,
You really should read and understand the posts better...Tony nowhere actually said that running -20 camber would actually be feasable, we could't actually achieve such a setting on the car for starters! What he's doing is very simplying using engineering principles to demonstrate the point, by taking an extreme example and showing what would happen with that. Being an engineer myself, it's very easy to spot that.

Your really trying to discuss three things;
Roll centre
Static camber
Camber gain

Now static roll centre position does have an influence on camber gain, as the link posiitions are used to calculate it. Changing your camber gain settings WILL alter your roll centre position. There are no two ways about it, as they both rely on the link angles. Static camber will not however influence roll centre, so the two can be considered mutually exclusive.
Now I mentioned before, the calculator is a guide, nothing more. Its there to give a comparison on settings, mainly as it only calculates the STATIC position only. There's no way I have the time to make one up to calculate the dynamic roll centre.

Your doing the same thing you did before with the flex topic... Trying to compare the real world with the small world, and completely forgetting about scale effects. You mention about audi's and subaru's in a previous post, but I very much doubt any of them would be able to top out at over 300mph, let alone corner at that speed.... Something else to bear in mind is that link positions are a lot easier to change on our cars, as we don't have to redisgning mounting points etc.
Instead of bagging the change as pointless, think of it as another weapon in the arsenal. I guarantee you'll feel a huge difference to the car.

Ed
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Old 04-30-2009, 12:27 AM   #5249
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Originally Posted by CHRIS CHAVEZ View Post
Do any of you guys know if a (front/rear)sway bar kits exists for the 416WE? If so, do you guys know the part numbers?

Thanks Chris,

P.S. Has anybody had any luck finding any 416WE spool cups in the USA yet?
Unfortunately, Tamiya's USA website says their "still" out of stock.
Chris... TA05 milky white or all black sway bars work fine.

Speedtech has it in stock...
Milky white version:
http://www.speedtechrc.com/store/ebp...id=461&id=7556

Black version:
http://www.speedtechrc.com/store/ebp...id=459&id=5842 (not in stock though)

- Chris
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Old 04-30-2009, 06:37 AM   #5250
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Hi all

I am looking to buy a 416 WE kit, but having trouble locating anywhere with them in stock.

If anyone knows of any shops with them in stock, please could you let me know!

Any leads greatly appreciated!

Thanks
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