August, 1977, IKF Nationals, Atwater California. I remember it like it was yesterday. That’s Doug Sharp behind me. The kart is a Magnum, built by me for Richard Burton. My wife came up with that name and I won a free frame.
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I’m trying to come to a conclusion of what is being said, so are we hypothesizing that:
- KPI is not needed (i.e. it can be zero), with just caster. Camber is adjusted without modifying KPI.
- Small scrub radius is the better.
- Wide front track with small scrub radius is better (i.e. the kingpins are closer to the front wheels but the kingpins are far apart from each other)
Is this the Mayko Shark:
I can see it has no KPI from this angle
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Yes it is. It’s one of the original, I think 3 or 4, that I built. Later models have the Nerf bars mounted in rubber. That’s the original color also.
This is a cool photo (racing shot) Al. Got any others?
Personally, I’m not hypothesizing any of those things. Merely pointing out that most modern karts seem to in fact be opposite those points.
Pretty good looking kart! Interesting to see a lateral tube that connects ahead of the spindle “c’s”. Definitely something you don’t see these days.
Maybe I don’t know what bullet points are because I don’t see anything above the photo. Explain if you would.
Maybe not today, but after I pioneered that idea, Comet Kart and Invader Both included that Feature in their karts. Cole Nelsons invader won a national championship using a kart with that feature. Jeff showed me the kart when I visited California kart sales in San Jose California. He generously admitted it was a feature he had copied from my kart…
Seems to me that the question we are moving towards is: Are modern karts inherently faster than their counterparts of say 40 years ago.
No good asking me but I can describe the karts of that time as driven in UK by the likes of Coulthard, Mcnish etc.
In general karts were simpler, lighter, narrower front and rear, no bodywork.
30 mm.rear axle 17mm front stubs with integral bearing front rims. Yes they all had kpi rightly or wrongly but stubs were short so little scrub radius.
Ackermann effect was limited to that built in to the steering arms.
On most karts the only adjustments were front wheels in and out ,same at rear.
Brake, rear axle only, were all spring return pads no auto adjusters.
Frames superficially at least were pretty much the same as today’s but no removeable bars.
Engines were all multi manufacturer air cooled 100cc rotary valve, direct drive , bump start. No clutches.
Tyres varied from Bridgestone YBN ( similar to YDS around 60 shore,) to something a bit softer in faster classes.
Senior weight was 132kg.300lb.
Racing took place on the track not the other side of the kerbs,as demonstrated by @Alvin Nunley above.
I have no idea what you’re talking about. As can be seen in the picture, I’m at least a foot off the inside curbe.
Exactly Alvin you are just where I think you ought to be, not bouncing off the top of the kerb as seems to be the norm these days. Cheers!
The fastest way is the fastest way, whether it’s 2021 or 1921. If someone is looking to prioritize comfort over speed then they should be on the couch not on a racetrack!
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This statement does not apply to sim seats, btw. 
I discovered this the hard way. Comfort = faster.
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I’m sorry @alvinnunley but I have so many questions.
With your kart, the maylo shark you had:
- zero kpi?
- zero camber or some built into the spindle?
- similar scrub radius but attained by decreasing the front track?
- what was the difference in feel?
- how was the front track in relation to rear, similar to other karts?
Zero camber, zero kingpin inclination, 14° caster. Inside tread width on the front was the same as the inside tread width on the rear. All these things were arrived at after careful consideration. Never measured the scrub radius. Wheelbase was 42 inches. Frame was 1 inch OD chrome Molly, condition N.
I have no doubt these things could have been improved on, but that kart was easy drive and had no handling problems.
Mayko kart, Mayko aluminum fuel tank, Mayko pipe, Mayko header, and engines built by yours truly (91, 101, open 91) we did pretty well.
Super interesting. Just looking at the kart, the scrub radius looks really small compared to modern day karts.
Just hypothesising on the difference in feel between a kart with 10+ degrees of KPI and a kart of your design, i’d think a modern day kart would feel relatively numb on turn in then increase in feel as one turns the steering wheel (following the arc of the wheels movement). But with the zero kpi kart it should be a straight line, no arc, and probably feels more precise. As a result of the straight line, you can run less caster, which in turn effects dynamic camber, allowing more of the front tire to be contact with the road with the steering turned.
Am I talking sense?
Can’t really say if there is any difference in feel, I didn’t notice any.
I don’t know much about scrub radius, other than what I read in Wikipedia. Even then, comparing a car to a kart is of no use as far as I can see. Cars have very little caster, they depend more on kingpin inclination to keep the tires rolling straight. They don’t need to lift the inside rear tire, unlike a kart, with its live axle.
Karts today need very wide front and rear tracks. The reason for this, I believe, is to lower the center of gravity. What surprises me is; they keep making the axle and spindles longer rather than making the kart frames wider. Although I’m not saying this is wrong, I do wonder way there are no wider frames!
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