Does anybody know how many degrees has the standard caster in a kart frame? I mean, removing wheels, hubs, kingpin, and leaving just the C, how many degrees would we found if we measure the inclination of the C compared to the ground?
I’ve heard we can have caster between 15º and 22º, so I assumed the frame excluding kingpin would have something around 18,5º but reading some messages at KP forum I found some guys saying OTK has around 10º and we can go up to 15º when we have full caster with pills up and down, so I got confused.
Does anybody have this info?
When people are saying 10, 10.5 etc they are talking about the “camber” of the C section, the degree the C section is leaning in towards the center of the chassis.
The caster angle is different for every manufacturer (and probably between models) but typically ranges from 15 to 20. I don’t know of any that are 22. I think OTK is about 18 degrees but I haven’t measured it in a looooong time.
I just measured 19.7° and 18.0° of caster on the left and right sides, respectively, of the 2012 Kosmic sitting on my living room coffee table. I assume the difference comes from the chassis not being completely straight as it is pretty old at this point, so I’m going to assume standard caster is 18°.
Edit: specifically thinking about it, I got someone with the front left of that chassis at a club race like 4 years ago and never straightened it, so I would think that the left side is off by a bit
If you’re looking for the total caster effective at the wheel, one also needs to consider the rake on the stub axle which varies from manufacturer too.
Good times.
I’d be surprised if OTK have not changed the caster angle at the C over the models or years…
Absolutely, the effect is a combination of the kingpin inclination (longitudinally and latitudinally), scrub radius and the angle of the stub and they are all intertied.
Kingpin inclination will subtracts from total caster! When I built my first kart (1973) after studylng the interaction Between caster and kingpin inclination, I built a kart with no kingpin inclination. It worked quite well.
kingpin inclination is what increases or reduces caster, right?
So, if you built kingpin with no inclination, how you created positive caster in your kart?
Maybe you found a way to deal with it and I am curious to know how you did.
Thanks for the explanation.
I really like KP due to that. I always learn something. This is what excites me and motivates me to come here almost daily.
So, if I may explore a little bit of your knowledge on kart dynamics, what are the findings you have from the studies you did about interaction between caster and kingpin inclination. Besides that, what else kingpin inclination affects? For sure it affects camber, right? What else?
Thanks @NikG
Considering we have different caster angles for each kart frame manufacturer and different caster bushings, so should we talk about caster and measure it in degrees, right? I mean, full-caster for me does not necessarily mean full-caster for other drivers with different frame designs and caster bushings.
When anybody asks another driver/tuner: “how much caster you got?” the answer should be in degrees and not in dots.
Makes sense?
When I say “standard caster angle” I mean the caster angle the kart frame has in its design.
When I said “dots” I meant the dots we can find on the top of the caster bushing.
Yes, after your mention I went to youtube and watched both videos below and learned a lot about that. Thanks for your comment that made me investigate it further.
