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Front Axle design measurement Question

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Neto Ernest B
Berlin, OH, USA   USA
I was reluctant to start a new topic for this, but have searched a good deal, and have not found the information I'm looking for. I know that if I had wheels already, much of this would be answered, so please bear with me.

What I'm wondering is the typical distance from the center of the king pin out to the center of the tire (in line with the spindle). (I would say to the center of the hub, but realize that some may be offset like the rear hub on a bicycle, at least if the measurement is made from the spoke flanges.) I've looked at some drawings of front axles here, but none that I have found include these measurements.

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gearguy Charles Schultz
Oil City, PA, USA   USA
Drawing of wheels, tires, spindles, axles and hubs are in the cycle kart drawing files. I made pdf files of those parts from actual pieces I purchased for my project. All the info you need can be deduced from those drawings.

Woodysrods Brian Woods
Westbank B.C., Canada   CAN
Hi Chuck
I think I know the PDF you mentioned in the above post, but where is the attachment?
Brian

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Neto Ernest B
Berlin, OH, USA   USA
Maybe I'm not using the right search terms, but I didn't find any drawings that had these measurements. I did see one hand drawing of someone's axle plan that would have had useful measurements, except that measurements written into the drawing were contradictory. (Measurements written in along the top gave a different total than the sum of 3 separate measurements written in along the bottom.)

If you can point me to the drawings you are referring to, that would be most appreciated.

dBlast Avatar
dBlast Vince De Blasi
Maple, ON, Canada   CAN

Neto Ernest B
Berlin, OH, USA   USA
In reply to # 28419 by dBlast check post# 17 of this thread

Thanks for that. I see that the spindle (stub axle) shoulder is 2.37, and then it is 1.25 from that point to the king pin center. If I assume that the hub is centered over the shoulder portion of the axle, and that the wheel (and therefore the tire) is not offset in relation to the hub, then tire center to KP center should come out to 2.435. I was guessing that it would be more like 3.5 to 4 inches, but that was just a wild guess. I know that the "right" way to do this is to get the wheels first, but just trying to work ahead of that. Thanks again.

Woodysrods Brian Woods
Westbank B.C., Canada   CAN
In reply to # 28419 by dBlast check post# 17 of this thread

That was the right thread Vince.
But I think post #10 has the front axle drawing (but it was not the one I was thinking of that included the wheels and showed the camber and king pin inclination lines??)
But, I found one of the most useful tools was the two views of the Motor and TAV in post #29
I had these printed to actual size (used measurements) then cut them out and used them on my fulls drawing of my Miller to locate the motor, sprocket, TAV clocking etc.
Sort of like pin the tail on the donkey.
Brian

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dBlast Avatar
dBlast Vince De Blasi
Maple, ON, Canada   CAN
In reply to # 28424 by Woodysrods
That was the right thread Vince.
But I think post #10 has the front axle drawing (but it was not the one I was thinking of that included the wheels and showed the camber and king pin inclination lines??)

Brian

Was it this drawing:

Woodysrods Brian Woods
Westbank B.C., Canada   CAN
Similar.
Was this the one from Al Lies?
Brian

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dBlast Avatar
dBlast Vince De Blasi
Maple, ON, Canada   CAN
In reply to # 28428 by Woodysrods Similar.
Was this the one from Al Lies?
Brian

Yes, it was from this thread:
Midget Racer/ 27 Track Roadster

Neto Ernest B
Berlin, OH, USA   USA
Vince,
That drawing shows what I'm after, but no measurements. Maybe I should explain more. Assuming a KPI that meets the road surface in the center of the contact patch (as depicted in the drawing to which you linked), I am attempting to determine the distance from a plum line up from that point inward to the center of the king pin, at the spindle (stub axle) center line.

Rhys, in post 7 of his Essay on Suspension Design [http://www.cyclekartclub.com/phorum/read.php?2,18126], states that the real turning point is where the KPI meets the road surface, not some other center point on the king pin itself. This has also been my thinking, but in a discussion I started on a hot rod forum, there was quite a bit of disagreement, and they basically agreed that the pertinent point would be King pin center where the spindle (stub axle) center line intersects with it. I still feel that the true point of importance for suspension design is as Rhys describes. (This pertains mostly to implementation of the Ackerman principle, but also has influence on turning radius, and scrub.)

Notso-Chinsee Avatar
Notso-Chinsee Gold Member Albert Lies
Spokane Valley, Washington (WA), USA   USA
1927 CycleKart American
1938 CycleKart American "Burd Piston Ring Special"
Ernest,
The drawing I posted is measurable copy and enlarge it, make 2 prints and cut the scale from one and use it to measure what you need.
Hope that helps Iwould send you a DXF file but my CAD computer went to that bad blue screen last year.
Al Lies



Al Lies
The "Not-So Chinsee" guy



Edited 1 time(s). Last edit at 2018-01-05 01:40 PM by Notso-Chinsee.


Attachments:
IMG_0499.jpeg    38.3 KB
IMG_0499.jpeg

Woodysrods Brian Woods
Westbank B.C., Canada   CAN
No need to even enlarge. as the ruler is in the picture.
Just print and use the increments on the ruler to get your measurement.
You could even cut a pice of of the ruler on your printed copy and us it as your ruler???
Brian

Neto Ernest B
Berlin, OH, USA   USA
In reply to # 28433 by Notso-Chinsee Ernest,
The drawing I posted is measurable copy and enlarge it, make 2 prints and cut the scale from one and use it to measure what you need.
Hope that helps Iwould send you a DXF file but my CAD computer went to that bad blue screen last year.
Al Lies

Cool, I didn't think of that.....
Thanks!

(Appears to be 4" from the center line of the wheel to the center line of the King Pin. That's more like I was guessing.)

No. It is 3 inches. The measuring tape was clearest in my print copy at the end where the first part is cut off, and I started at 1, not at zero.



Edited 2 time(s). Last edit at 2018-01-05 06:02 PM by Neto.

Notso-Chinsee Avatar
Notso-Chinsee Gold Member Albert Lies
Spokane Valley, Washington (WA), USA   USA
1927 CycleKart American
1938 CycleKart American "Burd Piston Ring Special"
Ernest,
Not knowing your spindle configuration of choice I will say you can change the the king pin angle by reducing that measurement. My spindle is not the norm used by most today study some of the axles setups and you will see the difference.
A



Al Lies
The "Not-So Chinsee" guy

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