Suspension Theory

[Charlie don't surf]

Ok here we go, this may have to be broken into two posts--

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[Charlie don't surf]

Part 2 Bump in used with (1) changed ballstud location

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This is with 30 deg castor blocks, the effect with this setup is lessened with a decrease in castor-
if using 20deg blocks you might have to change both outer ballstuds to get the same effect.

Also when using this set-up you will change your toe out accordingly via steering rods as normal, but you will take the changes in toe throughout the suspension articulation into consideration.

And as a rule, your car will jump with a little more front end altitude and a little further due to the front end not "digging" into the jump face during compression, or running a large amount of constant toe out

[PBR Allstar]

Good Tech Reg. I'm sure this will help some people. Have you done any work relocating your camber links? I've been playing with that a little bit lately to change the camber gain, which also makes the bumpsteer a bit more managaable.

[markt311]

I'm taking notes!

Good night at the track, my car ran much better and I finished right behind Brandon. CDS I handed out the parts you sent me to 2 other RC10 guys and we all ran faster in the main.

[Charlie don't surf]

Good Tech Reg. I'm sure this will help some people. Have you done any work relocating your camber links? I've been playing with that a little bit lately to change the camber gain, which also makes the bumpsteer a bit more managaable.

Absolutley, makes a very big difference in DO for sure, you can actually cause "reactive castor" by using the two combined, getting different contact patches on the RF & LF. This is a tool I mostly use with foams though, don't recall if I stumbled upon this when we were running rubber tires or not-But I did this to a Nitro Sprint running CW street tracks (with "special" traction compound) and
the difference was very noticable.

* just went to grab the camera, wife took it this morning-I'll pop some pics later today*

Mark, glad to hear it had some difference on the track- in a few more races we'll have you passing Brandon Sorry Brandon--you've become the bar that has been set

[losiXXXman]

I'm definately liking the way this thread is going, let's keep it up.

Charlie, I'd love to hear more from you about camber gain through the entire travel of the suspension, how it effects handling and a general description of how the location of the mounting points, affect the camber change. Specifically, it's common knowledge that a camber link shorter than the arm results in a net camber increase as suspension compresses. However, if the camber length is held constant but moved central to the chassis as opposed outward, does this result in more camber change toward the bottom of stroke, or initially in the compression.

Also, did I see someone changing the location of the ballstud to the bottom of the steering block on one side of the car only? I know that there was some dirt oval talk in there, but it wasn't specifically mentioned in those pics. Was that a LTO setup, or just done on one side for demonstration purposes?

Here's somethign else to think about. I don't have a place to race right now, but was thinking of building some jumps, hauling them to a softball field, and setting up. Being that I'm looking at a FLAT track, would a setup with increasing camber through the travel help cornering? And, should the shocks be leaned in as much as possible to combat chassis roll? I'm putting my XX$ back together, and trying to determine what locations to use. Those inner camber ones are soooo hard to change once the cars are together.

Enough for now.

[Charlie don't surf]

I'm definately liking the way this thread is going, let's keep it up.

Charlie, I'd love to hear more from you about camber gain through the entire travel of the suspension, how it effects handling and a general description of how the location of the mounting points, affect the camber change. Specifically, it's common knowledge that a camber link shorter than the arm results in a net camber increase as suspension compresses. However, if the camber length is held constant but moved central to the chassis as opposed outward, does this result in more camber change toward the bottom of stroke, or initially in the compression. I'm not sure I follow, just because you can't centralize w/o changing the length-unless you were to physical move the link inboard, which in turn would move outer link further away from the hinge point (castor block). But one way to change the rate of camber gain is by changing the angle of the camberlink in relation to the suspension arm. For example, if both arm and link are
parallel, and equal length, there should be little or no effect of camber gain, if the inside of that same camber link was moved down so that it was lower than the outer portion of the link, then you will have camber gain due to the "pulling" of the camber link because on the non matching arc's of motion. This is a nice trick, because you change the "speed" of the gain via rod length
shorter/faster-longer/slower

Also, did I see someone changing the location of the ballstud to the bottom of the steering block on one side of the car only? I know that there was some dirt oval talk in there, but it wasn't specifically mentioned in those pics. Was that a LTO setup, or just done on one side for demonstration purposes? It was both--with the current front end that we use in DO it's one of
8 things that you do in relation to the other 7 that make a hole in reality, and allows you to visit
an alternate dimension know as the A Main. That being said, weather it is done on the left or the right ( on that front end anyway ) it has the same effect on both steering directions because when the steering rods are connected the push/pull effect all acts as one unit, regardless of the geometry change. You could do both sides, and with a 15-20 deg block you would have to do both.

Here's somethign else to think about. I don't have a place to race right now, but was thinking of building some jumps, hauling them to a softball field, and setting up. Being that I'm looking at a FLAT track, would a setup with increasing camber through the travel help cornering? And, should the shocks be leaned in as much as possible to combat chassis roll? I'm putting my XX$ back together, and trying to determine what locations to use. Those inner camber ones are soooo hard to change once the cars are together. If every thing else on your car is right, you will see increased inital cornering by leaning the tops of your shocks inboard ( mostly in the rear), I would set a car up as neutral as possible for starters, everything equal lengths ( or as close as possible) standard toe in, no camber, "middle" upper and lower shock locations, just kit stock-then make changes one at a time (pardon me for anyones car I have picked up at the track and changed 15 things at once, even if it did work) that way you should get a feel for what each change does, then once you get a feel for what does what, you can start blending all these adjustments with each other to get a very fine tune. But I will say this--not everyone
is apt to this, and that's ok--

Enough for now. Why? we are still on the front end, we have rear toe, camber positions, anti-quat, anti-dive, toe-in at the arm and/or at the hub

Sorry about the green, seemed like the easiest way to answer

[jsrracing]

will i tried the 20 degree much when you first get on power.

best way i can describe is on entry to turn no mater Tp it will float to apex then turn . un able to hold bottom at race speed



good run mark and thanks for the blocks

how will making the chasiss longer and mid motor affect on oval . would really like the car to finish rotating just before apex . now it starts rotating after apex

changes im looking at before the my first do sprint race.
may be able to loosen diff on oval vs offroad

motor change to the spec 13.5 brushless
longer chassis with mid motor . Im going to pull all the weight forward .

and i may be fighting the tires . m3 hole shots may be to much .
im going to try some other types of tires .


charile thanks for your time and typing . charlie do you know the vulcan mind trick it might make it easier(im watching star trek)

i will try to get some track measurements

[Charlie don't surf]

There are way too many variables here to use the power of the force- there are also a ton of other things that could be causing your issues with steering, including your throttle finger! If you run too hard into any corner your car will not turn until it settles down. Also you may have your diff or slipper too loose now, binding in ball cups, hingepins, incorrect shock oil/piston/springs, tires, tire inserts, servo speed, servo strength, servo saver, and so on......but to answer your other question, you don't need to stretch a chassis to mid motor is, the longer it is, the less reactive it will be to steering input.

[jsrracing]

[markt311]

He's got quite a heavy throttle finger, I drove his car and it was good. But he finished a lap down to me

http://results.rc50.com/Thunder_RC_Nashville/11-07-2009/

JSR, I put a 10.5 in my car today... See you at the track

[Charlie don't surf]

Smooth is fast when it comes to throttle--on and off Too much of either upsets the chassis
by throwing the weight around quickly, same applies to steering input, and the type of servo's and the number of "steps" it has in it's motion--Futaba's new digital brushless move less than 1/2 of the thickness of a hair per step--now if I could move my hand that slightly

[jsrracing]

mark you did outstanding with only one qual.

the buggy was faster than i could drive but it was fun

[MOmo]

Another factor in all of this is the track material and design. I was watching some clips on YouTube highlighting the older tracks. They seems like faster tracks w/ fewer jumps and that seems to play a role in racing as well.. Over the years, tracks have shifted from a loose loamy material to harder more blue groove clay. The bigger pins have made way for lower profile bars and taper pins. I've been presently surprised with how well my 10+ year old car works when newer components have been added, but the platform remains the same.

At our local track, we were running a vintage class and several people had switched over to losi pink Tapers to keep with the traction. That night of racing, I took a literally box stock RC10 6gear with the stock knobby pin tires and the tiny 3 rib fronts, and i managed to do okay. it did require some finesse driving, but I noticed a TON of push going into corners. The car jumped pretty well and overall i finished fairly well (top 3 i think) and I had the oldest car there. I'm also a pretty good driver, so that helped alot.

I've slowly been working on other cars in my collection to make into a more moderized racer. I'll have to re-visit my car again when i have time. The steering has been updated with some B4 parts, and eventually i want to try and get some Worlds parts and try a worlds setup.

I think the longer arms definitely help. I wish RPM still offered the Worlds arms, because I think it would make a lot of difference. The Klein arms are a bit pricey, but I will likely get some when more $$ is available. I'm also thinking i may try and restore one of my RPM chassis cars and make it race worthy.

It is cool to see the progress made, and the even today, with companies like Xfactory bringing back the cross chassis battery fit much like the Tekin chassis in the old days. I really want to see how that chassis performs.


MOmo