Posvar

iTrader: (470)

Thanks Kraig!

mdowney

iTrader: (21)

I have a set of the new AKA Handle Bars (Clay) and they're pretty nice. I tried them at WCRC after a short break-in out in the street and they were a little loose but I think they just needed to be broken in. I didn't really have the time. Going to try them at TRCR where I think they will work better.

Diff adjustment is on the left side. There's a small hole at the base of the out drive. Slide a 1.5mm wrench in there and slowly turn the right wheel until it slides into the groove, then you can adjust the diff.

Cpt.America

iTrader: (52)

Caster, Bumpsteer, and Ackerman math.

I decided to break out my hudy setup station, and my 2mm hex, and do some measuring for our setup sheets. Lets start with bumpsteer and caster.

Bumpsteer - bumpsteer is what happens when you induce either more toe in, or more toe out, as the front suspension compresses. (bump-in, or bump-out). You can change how much or little bumpsteer you have by controlling the vertical angle of the steering turnbuckles. The more vertical the steering link goes as the suspension compresses, the more the turnbuckle will pull the steering block inwards, inducing bump out. So to reduce bump-out, you have to reduce the height of the ballstud on the turnblock. If you get bump-in, that means you need to raise the height of the ballstud.

What some people don't realize, is that changing caster, changes the relative height of the ballstud / turnblock, because more caster rotates the turnblock backwards, so it drops the ear/stud closer to the ground. So if you run 25 caster and set your bumpsteer to 0 (no bump in or bump out), and then decide to change your caster to 30, you actually dropped the height of the ballstud by 2mm. So I did a lot of testing and measuring just to make sure that the numbers are accurate. For ZERO bumpsteer:

• 25 caster = 0mm washer under turnblock ballstud
• 27 caster = 1mm washer under turnblock ballstud
• 30 caster = 2mm washer under turnblock ballstud

Ackerman - Ackerman affect is the difference between the turning radius of the inside wheel, and the outside wheel, in a corner. Because the inside of the car will natually track along a smaller circle, to maximize steering and minimize a slip angle, the angle of the tires need to match the steering radius. If you have too little ackerman, or too much, the slip angle means one tire is sliding instead of rolling, reducing steering.

I tested just two ackerman settings on the steering rack just for my own info, and got the following:

• 0mm under steering rack ballstud = 30deg and 23deg
• 1mm under steering rack ballstud = 30deg and 23deg

zero change in ackerman. Might have something to do with the fact that the steering turnbuckkles are right about flat, straight across /perpendicular to the chassis. I think ill test again later with my plastic steering rack to make sure it's not my alu version. More to come.

K_King

iTrader: (47)

Is your caster at the pivot or at the caster block? Im guessing 29 is a 1.5 or so?

Cpt.America

iTrader: (52)

at the front suspension hanger. For 26 or 29 degrees, you may actually have to actually unthread the ball stud a fraction of a turn in order to get 0.

My test was done with Lunsford ballstuds, which sit the tiniest bit lower... Using the khosbo ballstud, ar 25 caster, I couldn't actually get 0... I got a half degree if bump out. A lower ballstud is needed.

Just1More

iTrader: (11)

Great info Brandon, 2mm it is.

K_King

iTrader: (47)

I meant .5. Or 0 I guess

Just1More

iTrader: (11)

Are you talking about that flat shim(comes in .5mm and 1mm) that goes between the caster block and chassis? I run without it, don't really see it's purpose

Also Brandon, how do you sauce with WD40? Spraying it on a rag then wiping the tire or a direct shot to a spinning tire?

Cpt.America

iTrader: (52)

Just spray a tiny bit onto a dedicated toothbrush, and then brush into the tire. BUT... I want to see you run your car full throttle on the table, and then hit the tire with a blast of wd-40 Bring your glasses

asc6000

iTrader: (15)

Brandon have you run Panther Bobcat front tires yet ? they are very tall especially compared to a jc rib. What changes would you make to the car if any to compensate for the increased height of the tire ? This may not be the right thread to get into that whole scene but since you busted out the Hudy....

Cpt.America

iTrader: (52)

man, im not sure what i would change if the overall outer diameter of the tire was measurably larger. We don't run anything panther at our track, mainly because we really have ONE tire that works best. Im tired of being the tire guinnie pig at my track, because so far, whatever tire I am testing ends up sucking. Ill just stick with my gold barcodes

SAMCRO

iTrader: (2)

What does the .5 or 1 mm space do under front caster block? Also, is going from 25 degree to 30 as simple as flipping the block to where 30 facing forward vs 25?

Thanks!

SAMCRO

iTrader: (2)

What is wd 40 supposed to do vs plain old buggy grip or is it the samething?

eper

iTrader: (14)

those spacers are kind of like changing droop.it changes the relation between the chassis and axle. adding a .5 would give you more droop and 1mm would give you even more. this would take away on power steering
wd40 softens the rubber. some people apply it like tire sauce others apply it and bag the tires for a given period of time to soften the rubber

Cpt.America

iTrader: (52)

Raises and lowes the front roll center. Lowering the suspension block should lower the roll center.

yep!

Not the same thing at all. I clean my tires after every run, and use a light scrub of wd-40 right afterwards to keep the rubber soft, and to keep the rubber from drying out from the water. It soaks into the rubber and keeps the entire tire soft. It might provide slightly less initial traction than actual traction compound, but seems to be far more consistent throughout the run. It will certainly depend on your tracks clay, so YMMV quite a bit. some people really prefer something like sticky fingers or buggy grip, though. I find the WD-40 does far less damage to inserts, as well.