front end geometry

[Rick Steed]

So I'm getting ready to replace the front axle on my new-to-me Go Kart 800. From what I've read and found in searches, a good setup would include the following:

Kingpin inclination (KPI) 7 degrees
Caster 12 degrees
Camber 0
Toe 0

The NOS spindles available from Azusa appear to have zero KPI. I'm not certain what the KPI is on my existing GK 800 spindles, although they've taken a beating over the years so who knows what they were originally. 

I could fabricate new spindles, and suspect this is what I'll do, which opens up a lot of possibilities and a big can of worms. Anyone have any advice or thoughts on this? Should I build the spindles for 1/2 inch kingpins with bushings or just straight 5/8 inch bolts no bushings? And should I build them for 3/4 inch spindle and run tapered roller wheel bearings or are the plain old sealed roller bearings adequate? What's standard practice on karts in general, and what is original to a GK800? How do you get correct Ackerman angle when the tires are so close to the spindle? Thanks.
-Rick

[ted johnson]

According to the Karting World 1200 test, Oct. 62, 0 degrees camber, 0 degrees kingpin inclination, 14 degrees caster and 31-1/2" front track width. If I were building spindles, I'd use 5/8" axles with sealed wheel ball bearings, 1/2" kingpins with bushings, and angle the steering arms outward as far as you can and make sure the tie rod ends clear the tires. The 800 had a narrower track, but the 1200 is a better handler. The extra axle length outboard of the frame rails allowed more flex, but, remember, the Go karts were always prone to getting the axles bent back, and the extra length may well enhance that "bendability". TJ

[steve miller]

1961 gk800 ..
wht.81 lbs .,
lgth 55"
wdth 35
wb 43 1/2
track f31 - r 32
wt.dist.44-56
front end
cast 5
camb 1
kpi 5
t-in 1/8th


I have book with specs for almost every kart built from 1960 -1967 ..also states wheels tires steering wheel axle and seat options that came on karts ..
how accurate ..??? ...

[ted johnson]

Steve, I'm pretty sure the caster isn't 5 degrees. TJ

[steve miller]

like I stated ..not sure how accurate ..I just copied whats in book .. lol..

[doug tenney]

I saved a previous thread on this topic. Hope it helps. See attached.

[ted johnson]

I'm still at 12-14 caster, 7 kingpin and 0 camber, with 1/16" toe-in. The new photon has these numbers, and drives very easily, and handles super. The n1ke was at the same numbers. TJ

[Rick Steed]

I'm hearing and seeing a lot of folks running 7 degree KPI. So where do folks get their spindles if not fabbing their own?

[ted johnson]

I build my own. Sometimes I use Azusa kingpin barrels and steering arms, but the Azusa arms are pretty soft. Lately I've been using 3/16" X 1" steel flat for arms. I built a jig. It's adjustable to a limited degree. I need to build a better one. Ted

[David Luciani]

considering the go kart series karts were some of the fastest and best handling rear karts built why would you change the geometry?
i'll bug mike out in cali and get the correct specs posted.
steve that spec i can assure you is wrong. i guess it shows books written by humans aren't always right.
changing the king pins and axles is fine i'd bush them as if you run them alot and wiegh in over 200# the holes will wear fast.
my gk800 is due for new bronze bushings after only two seasons but i'm a little rough on equipment.
you can use either bearing i prefer the tapered bearings but they do limit your rim choices. 
definitely make the front spindle axle longer than stock to allow more rim choices and cotter pin access.