View Full Version : avoiding hidden tweak

Ibrake Ifry
2009.01.07, 12:35 PM
Lately i have been doing everything i can to avoid hidden or unknown tweak and i decided to post about to see what you guys had to add to it. What i mean by hidden tweak is sometimes your car is hooking up and all of a sudden you have to lower your right steering and increase your left etc. because your car almost seems to change itself. Of course things like grip level of the track changing and tires wearing are also factors in hidden tweak. In fact, i'm sure a lot of other factors come into play so please post them. Below i have listed some things that I have done to my cars to ensure that they always handle the same and for the past few weeks its seemed to work.

-whenever building up a car using brand new parts=sometimes i have found old parts to have warped or have different tolerances as new parts.
-plastic knuckles/tierod=i would rather break a platic knuckle/tierod in a race then tweak an alloy one unknowingly which would effect me in many races unknowingly.
-plastic wheels=same thing as above but they also lighten unsprung weight and put down more power to the ground.
-sanded/polished diff rings and ceramic balls and no diff lube= stock diffs are not smooth and true and the stock balls have pits and high spots. no lube because it attracts track dust.
-fine sanding the damper plates and friction diffs=avoid inconsistencies
-using fine threaded machine screws everywhere=they don't strip the chassis as much and you can torque them down more
-using blue loctite everywhere possible=nothings worse than your motor mount screws, damper plate screws etc. coming loose
-using good bearings/and cleaning them everyonce and awhile= bad bearings really really screw up handling
-keeping batteries cycled=nothing worse than early dumping batteries ruining your race!
-keeping motor cleaned and bushings/bearings lubed=have you ever seen one of these motors smoke? lol
-using new locknuts=don't lose your front wheels
-making sure to tape my tires really good and when they start to wear in a little, re-tape them=Some people glue their tires which would have an even better effect but i m too lazy and cheap to do it :P
-using long machine screws for the T-plate= loose t-plate screws means that if you get hit once in a race by your rear axle you have now lost steering to one side and gained it on the other!

I am sure that there are many other things that i have missed/forgot so please if anybody has any tricks i would appreciate your input. I am always trying to learn how to setup these cars better

Ibrake Ifry
2009.01.09, 11:42 AM
Does anybody have anything they disagree with, agree with, or want to add?

2009.01.09, 12:41 PM
Great start of the list here.

When I have tweak I look for.

Make sure my tires are glued. At our local track we have found it to be a big factor in performance. Use a white rim and run for 15 to 20 min at 100% and then peel the tire back.. Do you see any black from the RCP ? As the tire wears down it will become thinner and have a higher likely hood of peeling back causing chatter, tweak, and many other problems.

KINGPINS: Make sure your kingpins are smooth and ride VERY free. We sand ours using a drill. Take your spring out and test each race day. With no springs in they should move up and down by simply turning the car over. If you use lowdown springs you dont need to take the springs out.

Check for Tweak on a 02 by holding the car facing forward in front of you with the car facing forward and snap the rear tire up then down and make sure the tplate comes back to neatrual/flat.
If it stays low or high check the tplate and flip it over. if it does the same thing on the other side after flipping it over. Change it.

Check for uneven wear on tires. Or worn tires. Most of the experts at our local track will put new tires on for raceday and then after that the tires become practice tires. I am starting to count battery packs that I run. after 10-15 packs of 8-10 min runs chuck the tires or give them to a novice racer.

My lap times will drop off by .3 seconds per lap on tires that are worn more than 15 packs old. .3 seconds per lap at our club and your getting lapped within 33 laps.

keep in mind that this is for tracks that have low grip.. AKA: your running a soft tire like a PN 6 in the rear. If you have high grip just throw the tire away when it gets visibly worn out.

2009.01.10, 08:29 AM
if most are running alum knuckles look at the post that connects to the steering tie rod. i have bent one.i just check for tweak like to old days level surface and a x acto knife. find center line and slowly lift the front too see wich tire lifts fist then shim the t-plate if needed. but now pn has the high clamp t-bar holder its no necesary. most tweak issues are from the t bar/plate.

2009.01.10, 09:20 AM
One other adjustment that can sometimes be over looked is centering the chassis to the radio so that you only need to make fie adjustments on the radio to get the car to track straight.

One thing than can cause that to go out of adjustment is a hard impact. I had a chassis that had a very loose steering adjustment. I had to put a small piece of sticky tac on it to keep it from spinning after an impact or after a race.

If anyone doesn't understand what I'm talking about let me know and I can take some pics and show you.

EDIT: It's the screw on the bottom left above R11

2009.01.10, 10:31 AM
Is that a Mini-Z board on a Gen1 XMODS???

Tell me more... How do you hook it up and how much better is it???

2009.01.10, 12:37 PM
Is that a Mini-Z board on a Gen1 XMODS???

Tell me more... How do you hook it up and how much better is it???
Search for his thread about it...

Great thread here...

Allways check the way that the motor wires are run. If they touch the body, or the chassis, they can cause tweak. You can replace t-plates all day, but it wont help.

Make sure that your differential does not bind in the motormount, so it will spin as equally left/right as it can.

Check wheels for cracks/dents/warped areas....

2009.01.11, 10:49 AM
also remember that springs dont last very long either,in 1/12th scale i use to replace them every run,in mini-z i replace them once every two weeks,springs start to sag,also if you are going to set tweak try to shim the hplate instead of the front end you will be surprized at what that does

2009.01.12, 09:12 AM
Now how necessary is this? Does this sound like overkill? I have a set of PN springs that I have been using for almost 2 years and "visibly" speaking they seem fine.