MR03: ATM knuckles

What's up folks! It seems forever since the last time I posted a tut or even a blog. It's ok though because all that wait will pay off after reading this tutorial.  Most of you guys had probably seen my setup list for my MR03's in both stock and mod and if you notice, I use stock knuckles even though both PN and ATM are already available in the market. The reason why I dont use PN knuckles is because its too low. It has 1mm drop from stock. For my setup, I don't need it to be this low and if I need to raise the front of the car, I have to put shim/s on top of the knuckle. Now, that shim/s slides up and down the kingpin can cause binding and I don't like that. As much as possible I want less part to slide up & down the kingpin. Although I like PN's weight as it has pretty close weight to stock plastic knuckles. For the ATM knuckles, I like the .5mm drop but I don't like the insert that it comes with (it binds on the kindpin) and I also don't like it being almost 1 gram heavier than stock (combined weight). All these aluminum part adds up... This is why I chose to use stock knuckles even though the stock knuckles has a lot of slop. Check out the gap between the stock knuckle and the kingpin:

stock kyosho knuckle:

Now take a look at this custom knuckle that I call, PNTOMIC. LOL  I will tell more about this knuckle as we go.

Atomic Knuckle:

notice the gap? ...none.

I haven't tried this PN/ATOMIC knuckle on the track but so far, it is as smooth as the stock knuckles with very minimal play. When I say, "very minimal" play, I'm talking about .20mm slop on PN/ATOMIC knuckles vs 1.0mm slop on stock knuckles.  How did I get these numbers? What I did was I held onto the top and bottom part of the kingpin making sure it wont move. Then I wiggled the wheel back and forth holding it on the top and bottom to see how much play/slop it has. I then placed the caliper inbetween the kingping and the wheel and measured the distance on both stock and PN/ATOMIC knuckles. Not the best way to measure it but you get the point.

How to get an aftermarket knuckle that as smooth as stock? It is very easy. First you'll need the following tools:
1. super glue
2. ATM bearing tester tool
3. .009" blade

Then get yourself a set of PN inserts made for MR02. Yes, MR02!

Using the bearing tool, push the insert out.

This is how the insert looks like once it's out of the knuckle.

Left: PN MR02 Right: ATM MR03

Using the ATM bearing tool again, insert the PN delrin inserts. This should slide right in.

If you look at my knuckles closely, I already have the inserts in so let's just pretend that the insert is inside the knuckle. The excess material from the MR02 delrin inserts should be cut using the .009" blade. You want to use a sharp and thin blade, this way it wont crack the insert and only use very minimal effort to slice it. Using this type of blade, you get the leverage you need and you slice the plastic insert as if you were slicing a tomato. *Please be careful when using these blades.* Make sure the cut is clean and has no left over material sticking out or else, when the knuckle is placed back into the lower arm, it wont be straight or leveled.

When all the excess material is cleaned out, you can push the insert out  just a little using the bearing tool and then pply a tiny drop of glue. Not too much so that its easy to replace  just incase you need to in the future or try the knuckles first without glueing them.

And you're set!

Before we go to comparison between PN/ATOMIC knuckles vs Stock,  I want you guys to know how I check my knuckles for a smooth up & down stroke. I use motor cleaner straw and lift the wheel upward while the spring is compressed all the way. The knuckle (no matter if its stock or aftermarket) should slide up and down with no sticktion or binding.

Here's the video on how I test the knuckles smoothness:
MR03: knuckles

In this video, I'll show you the difference between PN/ATOMIC knuckles and stock knuckles. You'll see how much play stock knuckles has..
MR03: knuckle slop

This is to give you guys an idea on how much these knuckle weighs:
1. ATM

2. PN

3. Stock

So that is it for this tutorial. If you want this knuckle to work, you should definitely consider using PN's insert. I will also give an update on how the knuckles performs on the track. Just check on this post from time to time.

Update: 5.28.2010
So is the knuckles any better? Well, it really cant get any worse than what I had to start with.  My stock knuckles are so bad that I had .8mm-1mm slop (when measured on top of the wheel to the kingpin) and I was driving it like it was suppose to have that much play. Imagine changing camber on every corner?! With the better knuckles, I'm able to hold my lines more consistently and I can put my car where exactly I want it to go. Especially on those tight corners. The best part of this too is that, you're also able to adjust the offset of the wheels, lower the tie rod pin so that it wont pop out easily and also, you now know exactly which one is Right and Left knuckle is! lol  ATM logo would be best instead of "R-L" but anyway... If you wear out your inserts, you can always replace them & replacing them is easy! No need to buy new sets of knuckles just like what I did for my stock once. I wear them so fast that after few months I had to buy another set and the once posted in the above pic is my 2nd set! That just shows how much time I put on the track, very minimal.

Update: 6.1.2010
Oh yeah, one very important thing you guys would want to do when doing this mod. I think this is the key in making this insert work is to, round-off the corners on that inserts. The top and bottm edge of these inserts that rubs against the kingpin are sometimes sharp. This sharp edge catches on the kingpins irregularities/scratches thus making the knuckle stick to the kingpin and causing it to have bouncy, inconsistent frontend. What I did was, I cut a very small amount of material on that edge using a countersink bit or if you dont have access to this bit, you can also use 3mm drill bit. (btw, thanks to Ray Leung for hooking us up with the countersink bit!)

On this pic, I've also included the pipe cleaner that I use to clean the insert. Just soak the pipe cleaner with alcohol.

Using the countersink bit with your hand, cut a very small material off of the knuckle's insert. ***You may also use this technique on your stock knuckles. Just don't get carried away with this bit as it is very sharp and it will cut more than enough material and can definitely cause too much slop on that kingpin/knuckle***. I didn't use this on my stock knuckles. My stock knuckles (on the pics above) were just worn down. On my new sets of stock knuckles however, I tried to use this technique on one of the knuckle since It had sharp edge (was catching on the kingpin) and without doing anything to the kingping, the knuckle is now sliding up and down the kingpin very smoothly. Smoother than the PN inserts as a matter of fact!

When you're done, make sure there's no burr or excess materials from the plastic inserts. The knuckle inserts should look like this:

That should do it for this knuckles modification. Before I end this tutorial, I would like to add few more things that I noticed while running this inserts and aluminum knuckles. I am very familiar racing/running stock knuckles so, moving into this inserts with different plastic material than stock is very noticeable on the track (for me at least). I noticed that I had to constantly clean my knuckles almost every run. The knuckles feels sticky after 10 mins of run time. As if I had applied 3000 kyosho grease on the kingpin but I didn't (I dont put any lubriation on the kingpin/knuckles. Not even the dry lube.). Although it was a pain cleaning the knuckles everytime I pit, by swithing over to these PN/Atomic knuckles, I gained a little bit more steering than my worn down stock knuckles. Probably because of the minimal slop that I now have on my frontend. With the more precise frontend, this MR03 just keeps getting better and better. Now, all we need to wait for is for USA drivers/mini-z'ers to adapt into a track with minimal bumps like Japan's carpet track and we'll be DIALED!

Hope you guys enjoyed the read because it took me (hours cross that!) days to do this. LOL Oh, btw. Dont forget to rate it. Thanks!

-Tj Macabuhay