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Old 11-05-2014, 07:25 PM   #526
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The shorter the link, the more camber gain. Also, the shorter the link, the lower the roll center(if shims the same as longer link)
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Old 11-08-2014, 05:15 PM   #527
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Martin, how do you go about checking chassis tweak on a touring car?

My method: Set droop screws to be identical side to side using droop blocks and droop gauge. Do this front and back. Set the ride height all around. Then, using setup wheels, set the car on a setup board. Lift the rear of the car by the center of the chassis (using a hex driver under the rear edge for example) and observe the rear wheels. Adjust the front shock spring preload collars (more on one and less on the other) until the rear wheels lift at the same time. Do the same to the other end of the car.

This works but... you end up with more preload on one of the front and one of the rear shocks. This results in not entirely even ride height side to side. I think part of the problem is that the chassis twists as you lift the car at one end and the components you have taped to it affect that twist, resulting in a "tweaked" car that you have to adjust.

The other method I've seen (used by guys much better than me) is to hold the car against the edge of the setup board and lower the end "on top" towards the setup board. You let the wheels touch the board, which they should at the same time if the droop is set equally. You then adjust the shock preload collars on that end of the car until the car seems to compress both arms equally as you lower it fully onto the board (eyeball).

I thought my method was more reproduceable and more representative of a car actually shifting weight on a track, but today I started questioning that thinking. Can you comment?

Thanks!
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Old 12-02-2014, 12:49 PM   #528
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Is anybody having problems loging in to the learn setup web site
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Old 12-02-2014, 01:07 PM   #529
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Originally Posted by hanulec View Post
soft chassis and high grip just don't work. low spring rate is key when grip comes up.

soft chassis + hard springs is great in low bite.

my car almost drives like it is broken until grip comes up. dialing yourself in under low grip basically never works (unless it is a low grip event -- like 1/12th worlds). don't be afraid to try things --- and ask (more) people for help...
Martin care to comment on hanulec's comments above and why that works?
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Old 12-14-2014, 06:45 PM   #530
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Does anyone having problem logging into rc car set up workbench apps recently?

Help needed here.
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Old 12-14-2014, 07:04 PM   #531
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Does anyone having problem logging into rc car set up workbench apps recently?

Help needed here.
Just logged in, works fine.
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Old 12-20-2014, 09:46 AM   #532
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Originally Posted by bigcracing View Post
Is anybody having problems loging in to the learn setup web site

Contact me at mcrisp@learnsetup.com and I will make sure you can login.

Cheers
Martin.
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Old 12-20-2014, 09:54 AM   #533
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Originally Posted by hanulec View Post
soft chassis and high grip just don't work. low spring rate is key when grip comes up.

soft chassis + hard springs is great in low bite.

my car almost drives like it is broken until grip comes up. dialing yourself in under low grip basically never works (unless it is a low grip event -- like 1/12th worlds). don't be afraid to try things --- and ask (more) people for help...

Quote:
Originally Posted by John Wallace2 View Post
Martin care to comment on hanulec's comments above and why that works?
Hanulec and I agree re: high grip. Always a stiffer chassis and software springs will help prevent traction rolling. The softer springs will allow the car to roll into the carpet more keeping the cg lower which helps prevent traction rolling. Also it is likely your chassis will rub against the carpet, which will take away lateral grip...also helping prevent traction rolling.

As for low grip, my point of view is different than Hanulec. I would run a softer spring to enable more weight transfer forward and back so that I can control the balance with throttle and break when I need to. Also I would run a high roll center to prevent maximize lateral grip by minimizing the loss of downward force on the inside tires while cornering.

As for medium grip tracks, this is when I might start to either go up in the spring rate slightly if the chassis is rubbing, or lower the roll center if i start to traction roll.

Cheers and merry xmas

Martin.
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Old 12-20-2014, 10:04 AM   #534
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Quote:
Originally Posted by metalnut View Post
Martin, how do you go about checking chassis tweak on a touring car?

My method: Set droop screws to be identical side to side using droop blocks and droop gauge. Do this front and back. Set the ride height all around. Then, using setup wheels, set the car on a setup board. Lift the rear of the car by the center of the chassis (using a hex driver under the rear edge for example) and observe the rear wheels. Adjust the front shock spring preload collars (more on one and less on the other) until the rear wheels lift at the same time. Do the same to the other end of the car.

This works but... you end up with more preload on one of the front and one of the rear shocks. This results in not entirely even ride height side to side. I think part of the problem is that the chassis twists as you lift the car at one end and the components you have taped to it affect that twist, resulting in a "tweaked" car that you have to adjust.

The other method I've seen (used by guys much better than me) is to hold the car against the edge of the setup board and lower the end "on top" towards the setup board. You let the wheels touch the board, which they should at the same time if the droop is set equally. You then adjust the shock preload collars on that end of the car until the car seems to compress both arms equally as you lower it fully onto the board (eyeball).

I thought my method was more reproduceable and more representative of a car actually shifting weight on a track, but today I started questioning that thinking. Can you comment?

Thanks!
The techniques you outline are good for trying to get the left and right suspensions matched, but not for getting rid of chassis tweak. Chassis tweak mainly happens when the chassis is physically twisted and no longer will lay flat on the setup board with the tires taken off the car. To resolve this issue you need to loosen the chassis screws (about a 1/4 to 1/2 turn) on the bottom, upper deck and shock towers so that the chassis lays flat on the setup board again. Then pickup the chassis and tighten only the bottom screws first. Now put the chassis back on the setup board holding down both ends of the car while you first tighten the screws on the upper deck. Now for each shock tower while pushing the shock tower up away from the setup board tighten the shock tower screws. The reason for this last step is because as the car runs those shock towers may get pushed up by the shocks anyway, so it is better to push them up ahead of time to keep things more consistent.

Now once you have done the above, now is the time to set the droop evenly from left to right...then use the techniques you mentioned above to balance the car left to right in terms of shocks.

Cheers
Martin.
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Old 12-20-2014, 10:05 AM   #535
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Originally Posted by goin2drt View Post
Martin,

How much stock do you put in a really high end servo for on road touring car? I mean the difference between a $169 KO 30205 vs say like a Savox 1251 $69? Just curious.
The speed and accuracy of the servo is very very important. You want a very fast servo and one that remains consistent. For me it is worth the investment.
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Old 12-20-2014, 10:09 AM   #536
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Mr. Crisp, I have a situation I need help with. I am too the point that I despise large races. This weekend was the Halloween Classic. Friday practice, my car was really good. Saturday morning, and round 1 still good. By round 2, it seemed like I had Velcro on my tires, the car was stuck into the carpet. So bad, motor temps went up 50 degrees. Not sure if I did the correct things, but this is what I tried (serpent eryx 3.0 w/aluminum chassis); Removed most camber gain in front, reduced rear a lot also, 1deg camber all around, 3k rear diff oil, 2mm droop over ride height, yoke blue springs front and rear, chassis stiffener with front and rear stiffener in top deck, 2mm top deck(not split), 2.5 mill front gear diff, and 1.4 front/rear sway bar.

I really need help with this. On club race days, my cars are good, but when grip comes up at this big events I am at a loss. There must be changes people make to adjust for grip raising between rounds, or a set up that starts very loose and allows the track to come to the car.

What could I have done, or how should I have started off this event with my set up?

Thanks for your time.
Sorry for taking so long to get back onto this forum...been very busy with work. In a post just above, I talk about what hanulec and I agree upon in terms of what to do with a high grip carpet track.


Quote:
Originally Posted by TheEarlyWorm View Post
Hi martin i have a question regarding 2s2p and 2s1p lipo batteries
Whats their diffrence and if they have the same specs(mAh and C) which is better? Ty
sorry I don't really know.
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Old 12-20-2014, 10:18 AM   #537
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Originally Posted by Pokey72 View Post
Very confused...do long camber links give more traction or just makes the car more predictable and stable? Please explain long Vs short , front and rear, and do to always make front and rear both long or short?

looking to gain more corner traction on power so the back end doesn't come around at the end of the straight turn.
There may be many reasons why your back end is loose on power,...camber link length is just one aspect. You will want to also look at adding more rear toe-in, increasing the amount of front droop, and softening your rear swaybar. Your rear springs could also be too stiff or too soft,

No onto your question about upper link length. The shorter the link the more camber gain you will get when the car is compressed into the driving surface. This can translate into more grip as long as you are not getting too much camber gain where you end up decreasing the contact patch of the tire.

The length of the link also affects the roll center. A shorter upper link will raise the roll center slightly.

Here is some text from my learnsetup.com app talking about the affect the upper link has on the roll center as the car is rolling...
Quote:
The longer the upper link the more deeply the car rolls or leans, because the RC stays low throughout the roll and move further away from the center line of the car

The shorter the upper link the less the car rolls or leans, because the RC starts a little higher than using longer upper links, but more importantly the roll center stays much higher as the car rolls.
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Old 12-20-2014, 12:47 PM   #538
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Hi Martin, Great Thread and I love the Website!!! I have what is hopefully a simple question:

On XRAY's Setup website, most, if not all setups of the drivers posted are for Mod racing. I live very close to Kissimmee where the electric Touring Worlds were held. I only run 17.5 class, so what difference in setup could I expect so I can translate the mod setups into a 17.5 setup? I have a T4 '15. Hope that makes sense.

Thanks again!
Mike
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Old 12-20-2014, 12:49 PM   #539
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Martin what else would you do to take traction out of the car besides a stiff chassis and springs? Any specific tuning advice?
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Old 12-20-2014, 03:01 PM   #540
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most setup talk seems about the amount of weight transfer but little mention of the speed the weight transfers i find this has a great impact on how the car handels(weight+speed= momenterm) could we have your thoughts on this please
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