I know on tricycles the angle of the kingpin is vital but what about cycle cars. Down here in Tampa I've been looking at the cars and a lot of the cars do not account for the kingpin angle, I've only noticed about 2 cars that have it, one being a kit car. So how much does this help with the steering? Thanks for your input
Ryan--look at the EA handbook page 19. It is explained in there. The Camber is a must to reduce tire scrub and make you go farther. Otherwise you slow on corners and have to use energy to get back up to speed
The Camber is up to you. I tell my kids to set this at 10 to 25 degrees. The more angle the 'distance' to the rear tire is increased so it is a little harder to set up your steering arms and not have scrub when doing a tight corner. I set mine at 25 degrees and got it so there is not any tire scrub at all from lock to lock on turns. Because to the steep angle the car rolls straight great and both tires lean into the corners and dig into the pavement more and I can turn at a higher speed that nearly any other car in the NW.
With that high angle of camber does it limit the steering at all? Since when the angle is 0 all turning is put to the left/right movement, with the higher of an angle the less rotation is out to left/right and more to tilting. Because at 90 degree camber (i know it's straight up/down) all turning is put to leaning and not left/right. Would I be able to modify the steering to account for that loss for turning radius?
My car has less than a 25 turning diameter...so it turns twice as sharp as is required by EA rules. This way I can try to avoid other cars that spin out etc.
Ryan,
I think there may be some confusion here. You asked about kingpin angle, but Mike's answer sounds more like he is talking about the Ackerman principle. I won't try to explain Ackerman here; you would do better to look it up online where there will be diagrams and pictures to explain it.
Kingpin angle is related to caster, camber, and kingpin inclination. If you have seen my cars run (#13 and #94) you know that they are always competitive, so maybe I can be of some help to you. Caster is the angle that the kingpin is tilted forward or backward as viewed from the side. If the top of the kingpin is tilted toward the rear, that's POSITIVE CASTER. On my cars I build them with 7 degrees of POSITIVE CASTER. I have found that 7 degrees is enough to make the car want to straighten itself out when finishing a turn without making the cars hard to steer. NEVER tilt the top of the kingpin forward for NEGATIVE CASTER in a lightweight vehicle. It will cause the car to oversteer and make it unstable at speed.
Camber is the angle that the wheels tilt in or out at the top when viewed from the front. If they lean in, that's NEGATIVE CAMBER. If they lean out, that's POSITIVE CAMBER. I build my cars with 7 degrees of NEGATIVE CAMBER. If you have looked at my cars at any of the races last season, you may have noticed that the wheels lean in at the top. I do that to relieve some of the stress on the spokes of the outside wheel in a corner. You can increase this angle if you want, but too much NEGATIVE CAMBER will cause the tires to scrub and create rolling friction.
Kingpin inclination is the relative angle of the kingpin in relation to the spindle. I build my spindles with 0 degrees of kingpin inclination so when I'm building my front axles I can set the kingpin boss (the tube that holds the kingpin and spindle) at 7 degrees positive caster and 7 degrees negative camber. The wheel is then set at the angles I want when it's assembled. If you build your spindles with positive or negative kingpin inclination, you can make the caster and camber angles change as the wheels are steered. This takes some advanced design skills that you can also get online, but I have found that it can overcomplicate the building process and doesn't seem to add any handling advantage.
One last thing is toe angle. That is the amount the wheels point toward or away from each other when viewed from above. I use 1/16 toe IN on my cars. That is, if you measure the distance between the rims, they are 1/16 inch closer at the front than at the rear.
We have just set up the steering, it has 15 degrees kingpin angle, points directly below the wheel, 0 degrees and camber, and 15 degrees of castor, our old #80 car it had 0 degree everything (im still surprised a wheel never busted), but it had no toe in or out, we thought that if we we're to add some it would make the car less efficient, why do you add a little toe in? If you remember the Wharton race, HCC had 3-4 blown tires from to much toe (I forgot if it was in or out). So what do you feel is the advantage from your toe in?
