Looking to install new steering linkage in minix.

machine · #1 02-14-2004, 05:45 PM

Anyone got a pictures that will get me started on replacing the servo linkage with something that i can adjust?

ben1112 · #2 02-15-2004, 03:27 AM

there are a few... one of them who did it is takumi 3 series.. look it up

cdog4w · #3 03-06-2004, 04:59 PM

I just did mine. Took some modification to get it done since I needed longer screws than I could find. I used dubro 2mm swivel ball links (2 packs), some 2mm threaded rod cut to size and 2 extra 2mm x 12 dubro socket head cap screws for the extension. To do the extension (and to make the ball links fit at this scale, I sawed off a little over a 1/4" with an exact saw blade. I then used these as couplings to extend the screws to raise the links up higher. I chopped the heads off the 2 extra screws and threaded those into the collar with some CA glue. Then you can just screw the normal ball link screws into the other end of the collar. I put a slight bend in the link between knuckles to give enough clearance to the 2 links on top of each other. Seems to work ok, tho I did it last night and have not had a chance to test outside. Heres a pic:

3series takumi · #4 03-06-2004, 07:14 PM

nice work!

Cian · #5 03-07-2004, 03:57 PM

looking good, Cdog!

Does this allow you to change the Toe angle of the front wheels as well now??

cdog4w · #6 03-07-2004, 06:27 PM

Yup. Its a bit of a pain in that the best way to do it is to unscrew one side and go one twist at a time on that side only, but with the fine threading, should give pretty accurate tuning.

Now if only I had a place to race where the toe in mattered. Rough asphalt is not the place where you notice a .5degree change in toe in.

mde · #7 03-08-2004, 11:08 AM

That looks good cdog,

For a quick and dirty fix I was thinking of a steering arm made of aluminum plate with slots or multiple holes since I had the material lying around.

Your idea is better though so I'll probably do something like you did. It looks like you had to bend the long bar to fit unless it is some kind of flex bar for tension.

If not you can cut screws with side cutters and still have a useable thread if you put a nut on the bolt above the cut and unscrew it after making the cut. As you remove the nut it cleans up the the thread so you plastic ends work.

If you want to go really trick you might be able to get the correct size and pitch aluminum bolts from a high end bicycle shop especialy if they sell Magura hydraulic brakes.

cdog4w · #8 03-08-2004, 12:36 PM

The long bar was cut to size from 2mm threaded rod. The reason for the bend is so that the two ball links atop one another don't hit and obstruct one another. I would have put a spacer in, but the longest 2mm screws I could find were the 12mm ones that came with the swivel ball link kits, which were not long enough to fit 2 links and 2 spacers and still have any threads left to screw into something.

If anyone knows of longer 2mm screws, hook me up!

Anyway, the total on parts for this was $5 at my LHS (i got a foot or so of that 2mm threaded rod for $0.35, so its dirt cheap).

I got to run it outside yesterday and it ran great. The 2WD that I had to switch to after burning out my 4WD motor is a dif story. No traction. I was donuting all over the asphalt, in OL tires no less. I took some video (crappy, hard to drive and film at same time) and I'll try to put it up sometime. The car runs a lot faster on 6 cells and 2WD. Plenty of nice traction rolls, tho it always rolled back onto its feet since the batt pack I have gives a nice low CG. Ah, now to continue work on the shaft mod and mount that 180 :P

mde · #9 03-08-2004, 01:05 PM

Hi cdog,

You could make a turn buckle by cliping the rod into 2 pieces and then using a piece of styrene tubing to join them at the length you need.

If you have a snug fit and screw it onto the rod when you install it it will give you another point of adjustment. You might even be able to make minor adjustments with 2 pairs of pliers without having to disassemble the steering linkage.

cdog4w · #10 03-08-2004, 02:37 PM

I could probably do it with pliers now (since the middle doesn't need to be threaded, its no biggie if I squish the threads). Tho unless I'm missing something, if you twisted the rod with pliers, wouldn't you loosen (lengthening) one side while tightening (shortening) the other side, resulting in no net change of length between ball links?

What is styrene tubing? Sounds like a rubber type of material?

Oh, NM, I see what you're getting at. Had to re-read it :P Great idea.

I have one more of those plastic bits I shaved off the ball link attachments, so I can try using that in the middle.

mde · #11 03-08-2004, 03:29 PM

Styrene is the same material as plastic model kits are made from, I think the mini z bodies are syrene too. If your lhs is into scale rail they will likely have it in sheets, tubes rods and stripis in different thicknesses, shapes and sizes.

cdog4w · #12 03-08-2004, 07:32 PM

Not totally off topic, but has anyone expanded and used the upper servo horn hole to increase steering throw and give a smaller turn radius? Is this a bad idea? I notice that they chopped off the top of the servo horn, widening that hole to accomodate the screw might be a bad idea. I assume you can buy replacement servo horns?

Thanks.

avenan · #13 03-08-2004, 08:22 PM

The horns are chopped on some mini-x's due to it coming in contact with certain lower-slung bodies. I use the top hole -- my linkage is entirely different since I don't have a stock chassis, but it hasn't caused any problems. The only potential issue is exacerbating the dogbone retention issues some people have. Never been a problem for me, but I've had fuel tubing in the cups for quite some time.

mde · #14 03-08-2004, 09:21 PM

Avenan,

What do you mean by fuel tubing in the cups?

cdog,

I think you could ream out one of the holes on the servo arm if you have small enough drill bits. Your lhs should have minature drill bits and a hand driver to use them in bot cost me about 25.00 cdn.

The drills go right down to the sizes you'd need to drill holes for the axles you find in Bit Char-g size cars. The drill bits and drivers I have are perfect for this kind of work.

cdog4w · #15 03-09-2004, 12:01 AM

Avenan, thanks for the tip on the fuel tubing, I think that will work much better than my current clipped spring.

mde, he means basically some elastic rubber hose about the diameter of the cup/socket in the diff that the dogbone goes into. This is to prevent the dogbone from popping out due to excessive slack which is a common problem for the mini-x. I've been using about 1.5 loops of a ballpoint pen spring, and I've heard of many different solutions to the problem. Also, I think I saw some of those exacto hand drill things you're talking about, thanks for the tip.

Anyway, the servo horn is iffy. It came with just a hint of the 2nd hole from the one used and then it is chopped off. I might be able to squeeze in another hole, but maybe not.

To top it all off, I just realized that the steering linkage hits the body a bit. Redesign time :P