Arachnid Build, ... or is it! (Highly Modified)

[Silvergrizz]

Regarding the first part of the question about the length of the a arm and the tie rod. If they are both the same length it is ok, but for the pic shown if you did this then you will have to alter the arm on the spindle and this will affect the ackerman.

I am not planning on altering the arm, I was just trying to show where the might be equal, as the arm is about 3 inches long and even with the top of the spindle, I am guessing it might be close to equal. I don't have my 5/8 heim joints yet to finish the front end, so I can't install the spindles to measure. The spindles are just the cheap ones from BMI labeled 1 and 2. I don't think Bill has his heim joints yet either, or he would have completed the assembly.

If you are going to use a short shock so less travel, you could most likely dial bumpsteer out by moving the rack. Town the road though you might want to go to longer shocks. Bumpsteer is bad because it feeds back up the steering to your hands and the front end dart from side to side if bad.

Those are the shocks specified in the plans

The best thing to do is to make a new front end, save a lot of time and headaches.

Actually, before I do a redesign, I need to completely assemble the front end according to current plans to see how it all measures up, so I can fugure what needs to changed.

Do the plans show ackerman??

No

 

[theo]

What shocks do they call for?

You should add ackerman,

 

[Silvergrizz]

What shocks do they call for?

These ones here
Mechanical Adjustable Shock
This is for the Yerf-Dog Spiderbox Go-carts with the 150cc Howhit Engine. This is the front shock.

9 3/4" from eye to eye
0.4" I.D Mounting Hole
3/4" approx. Mounting Thickness
1/4" Spring Gauge O.D
The approx. diameter of the shock is 1 7/8"
SKU Number:06019
They are second from the botton on this link

http://www.bmikarts.com/shop/?shop=1&cat=264

You should add ackerman,

Will I have to rebuild my front spindles to achieve this? From what I understand it is the angle of the tie rod attachment point on the front spindles forming an intersection at the center of the rear axle? Is that correct?

 

[theo]

Will I have to rebuild my front spindles to achieve this? From what I understand it is the angle of the tie rod attachment point on the front spindles forming an intersection at the center of the rear axle? Is that correct? [/QUOTE]

Yes, and to do this on those spindles you need to cut the arm off and reweld. Or install a small tap and weld it to the arm to bring the hole toward the frame a little more.

Have you bought those shocks yet?

 

[Bill CNC]

Bill does your rod ends bottom? Can you cut a little off the rod end? Can you turn a little off the rack in the lath?

Problem solved, ... well in my case at least. I remade the suspension block. The old block was 5.0" wide, ... the new one is 6.0" wide. 5 - 6 who the hell cares as long as it works. Here is a cell phone picture to hold you guys over until I get home and shoot it with a good camera.

 

[Bill CNC]

Who said I don't have any joints, ... um, ... I mean Heim joints.

I have done a lot today but I'm getting ready to leave for home, .. Agrrr, .. another daily 200 mile commute. I don't have the time right now to post everything so I will do it tonight.

 

[Bill CNC]

Have you bought those shocks yet?

Yes, ... I bought the fronts and they will be here Tuesday. I am still thinking I might want to go to the 12" ones for the front, but I am still not sure. I wanted to see the travel of the 9.750" first and then decide. The only thing would be to change the shock mount, which is easy enough.

 

[Silvergrizz]

Yes, and to do this on those spindles you need to cut the arm off and reweld. Or install a small tap and weld it to the arm to bring the hole toward the frame a little more.

You mean I can just weld a plate to the top of the arm to move the hole over to the correct angle? That would certainly be easier than cutting and rewelding the arm. This will effectively shorten the tie rod and reintroduce bump steer will it not?

Have you bought those shocks yet?

:toetap05:Ya I have, they are just Chinese junk as far as I can see, but at this point I want to get this up and running and I will upgrade what is required after the fact.

 

[Silvergrizz]

Who said I don't have any joints, ... um, ... I mean Heim joints.

Ah that would have been me, you know what they say about assuming something Since you did not include them in your pictures well you know the rest. I will wait till you get this all together for verification before I make these mods, but they look awesome

 

[Silvergrizz]

And BTW, what are planning to do with Ackerman, since you have not decided on total length of mainframe yet? And I thought if I purchased a set of plans this all would have worked out for me. :toetap05:

 

[Silvergrizz]

Do I see a couple of spacers on your spindles? would that not effectively be a way to increase the placement of the brackets on the frame block?

 

[Bill CNC]

And BTW, what are planning to do with Ackerman, since you have not decided on total length of mainframe yet? And I thought if I purchased a set of plans this all would have worked out for me. :toetap05:

Ackerman, what the hell is an Ackerman?

Wait, ... I have a friend named Dave Ackerman, ... would he count?

 

[Silvergrizz]

It looks like I may have hijacked your thread Bill. I was asking Theo a few questions based on your pictures since you are farther ahead than me on the front suspension build. Sorry, did not mean to do that.

 

[Bill CNC]

Why yes it would! They are .250" tall, ... they are just for test purposes. I will post more on it tonight, ... I gotta get out of here.

 

[Bill CNC]

It looks like I may have hijacked your thread Bill. I was asking Theo a few questions based on your pictures since you are farther ahead than me on the front suspension build. Sorry, did not mean to do that.

You didnt, ...'m glad you did.

 

[Silvergrizz]

Ackerman, what the hell is an Ackerman?

Wait, ... I have a friend named Dave Ackerman, ... would he count?

Some how I don't think so. I saw a real good explanation here, but I just can't find it at the moment. I will continue searching and post the link when I find it.

 

[theo]

Check ebay for quad or sled shocks, much better pieces.

Yes you can weld on a tab to get ackerman but it won't help bumpsteer.

Somewhat like this..

[/IMG]

 

[Silvergrizz]

Bill, here is a very understandable explanation of the Ackerman principle.

http://www.diygokarts.com/vb/showthread.php?t=7710&highlight=ackerman+principle&page=2

 

[Silvergrizz]

Check ebay for quad or sled shocks, much better pieces.

Yes you can weld on a tab to get ackerman but it won't help bumpsteer.

Somewhat like this..

[/IMG]

OK thanks, will keep the sled shocks in mind for upgrading and will see if Ackerman is already built in once I get this welded up.

 

[Wobbly]

Hey guys. Just thought I'd say hello as I'm in the process of building my own Arachnid. Some nice work there so far Bill, looks very professional. Your post has made for some interesting reading, I followed the link from the Spiderkarts forum. I have run into many of my own problems so far, mostly to do with finding suppliers for some of the off the shelf parts listed in the plans. I'm in the UK you see, so the postage costs for the US suppliers make them prohibitive.

Mine is coming on quite well, with the main frame now nearly complete. I have made 2 main changes to the plans; I've stretched the chassis by 5" and I have made the front suspension frame 1" wider too. I have the engine sorted, a 13HP Honda clone mated with a Honda 2:1 reduction wet gearbox. It was a nightmare trying to get the two to fit, as the engine has a 1" output shaft and the gearbox has a 25mm input. Some careful bodging was needed.

I won't take up anymore of your post, I'll start my own once I upload a few pics, but hopefully with 3 of us building the same thing we'll be able to bounce a few ideas off each other (as support from Spiderkarts is a little thin on the ground )