Arachnid Build in NOLA

[theo]

I believe the upper attachment brackets on the suspension block are 1/2" back further then the bottom, this should give you the caster angle, being that both a arms are nearly the same.

What are you using for bushings on the a arms inboard at the suspension block?

 

[redsox985]

You may want to check your tie rods because I bight the same set and the ends would slip over the threads when pulled. I had to tap a 3/8" rod and make my own so that the that's wouldn't jump. The rods seemed to have a slightly too small of an od as the threads were very shallow.

 

[summitman]

I think it is meant to be back a bit to put same angle on the wheels when turned so the tyre pushes into the corner which= more grip

 

[Austin_40]

I believe the upper attachment brackets on the suspension block are 1/2" back further then the bottom, this should give you the caster angle, being that both a arms are nearly the same.

What are you using for bushings on the a arms inboard at the suspension block?

You are correct. The upper attachment brackets are set 1/2" further back than the bottom brackets. Something is slightly off though, because when I put on the spindles, the left one is angled a just a little steeper than the right. It's not catastrophic, but if you stare at it, you can definitely see it.

For the a-arm bushings, I bought 5" long, 1" O.D., 5/8" I.D. steel sleeves and cut them in half, giving me two bushings per 5" sleeve. They just fit inside the brackets, and seem to work.

 

[Austin_40]

You may want to check your tie rods because I bight the same set and the ends would slip over the threads when pulled. I had to tap a 3/8" rod and make my own so that the that's wouldn't jump. The rods seemed to have a slightly too small of an od as the threads were very shallow.

Interesting... mine seem pretty tight, although I haven't put them under any stress yet. Where did you get your from?

 

[theo]

You are correct. The upper attachment brackets are set 1/2" further back than the bottom brackets. Something is slightly off though, because when I put on the spindles, the left one is angled a just a little steeper than the right. It's not catastrophic, but if you stare at it, you can definitely see it.


For the a-arm bushings, I bought 5" long, 1" O.D., 5/8" I.D. steel sleeves and cut them in half, giving me two bushings per 5" sleeve. They just fit inside the brackets, and seem to work.

Moving the top brackets gives you the caster, figure out that angle between the upper and lower brackets, and that's your caster angle.


with no bushings you should install grease fittings.

 

[sideways]

with no bushings you should install grease fittings.

You should install them even with bushings.

Thanks

Hayden

 

[Austin_40]

Moving the top brackets gives you the caster, figure out that angle between the upper and lower brackets, and that's your caster angle.


with no bushings you should install grease fittings.

I understand what caster is... I'm just not sure how much caster I should be shooting for. At this point I can dial in as much or as little caster as necessary. Is there a rule of thumb for this? Or should I just make sure both sides are equal and move on?

I was thinking of drilling and tapping each sleeve for a grease zerk fitting. There won't be any seals of course, but it should be functional. Any thoughts?

 

[theo]

I think that they use about 7 deg. but anything from 5 deg. up. I use 5 deg. in my buggies. For tight maneuvering you don't want to much caster, if you are after hi speed straight line stuff then more caster but it's harder to turn.

 

[Austin_40]

I think that they use about 7 deg. but anything from 5 deg. up. I use 5 deg. in my buggies. For tight maneuvering you don't want to much caster, if you are after hi speed straight line stuff then more caster but it's harder to turn.

I just did the math, and I should be in that range. The brackets are offset 1/2" horizontally, and they are spaced 4.25" vertically from hole-to-hole. That should give me a caster of 6.71 degrees. Now I just need to do some investigation as to why one side has more caster than the other. Probably something pulled out of alignment while tack welding. I'll stare at it some tonight and try to figure out what went wrong.

 

[bajagokart]

I just did the math, and I should be in that range. The brackets are offset 1/2" horizontally, and they are spaced 4.25" vertically from hole-to-hole. That should give me a caster of 6.71 degrees. Now I just need to do some investigation as to why one side has more caster than the other. Probably something pulled out of alignment while tack welding. I'll stare at it some tonight and try to figure out what went wrong.

What would happen if you say made it only 1/4" offset for the caster angle? Would that give you a better steering ability?

 

[Austin_40]

I assume it would turn sharper, but be less stable at speed.

 

[bajagokart]

how fast are you going to go in it though? and with that caster angle when is it going to lose stability

 

[Austin_40]

For the speeds we're talking about, the discussion is probably academic. I think the important thing is that the caster angle be equal for both spindles. I'm not sure that a few degrees one way or the other is going to dramatically affect performance, as long as both sides are set up the same.

 

[Justin]

Interesting build. Nice work. I would love to build a cart such as this but don't have the ability.

Keep up the good work.

 

[Justin]

Interesting build. Nice work. I would love to build a cart such as this but don't have the ability.

Keep up the good work.

 

[theo]

Justin, what do you mean you don't have the ability?

 

[bajagokart]

For the speeds we're talking about, the discussion is probably academic. I think the important thing is that the caster angle be equal for both spindles. I'm not sure that a few degrees one way or the other is going to dramatically affect performance, as long as both sides are set up the same.

if both top a-arm's are exactly a half inch out then how is your caster angle now equal?

 

[Austin_40]

if both top a-arm's are exactly a half inch out then how is your caster angle now equal?

On paper, I would agree with you. It should be equal. But there's a lot of parts being assembled here. Something could have moved while I was tacking it together, either in the a-arms or the suspension block itself. I'm going to spend some time investigating it this weekend. I'm sure there's an explanation. We'll get it figured out! Hell, this is the fun part of fabrication!

 

[bajagokart]

On paper, I would agree with you. It should be equal. But there's a lot of parts being assembled here. Something could have moved while I was tacking it together, either in the a-arms or the suspension block itself. I'm going to spend some time investigating it this weekend. I'm sure there's an explanation. We'll get it figured out! Hell, this is the fun part of fabrication!

what i would guess is that one of the pieces that hold's the brackets is too far out or too far in