pavedwave longboarding

angelo_pb · Posted: Tue Apr 28, 2009 2:07 pm Post subject:

Grind King says they KPs are stronger than grade 8. I am not sure how the 300 year warranty works. Perhaps they will repair or replace a broken KP so long as you are the original purchaser, have your receipt, and did not abuse or misuse the product and don't die or otherwise quit skating 300 years henceforth.

I will try to find out if they have any mutant 3" KPs laying around or if they do custom orders. Any takers?

Ian the Groove Worshipper · Joined: 03 Dec 2008 Posts: 79 Location: Largo, FL

Better idea is to go to your local bolt supplier and buy 10 Grade 8 3/8 inch 24TPI bolts in the length of your choice.

I buy 3.25 inch, cut them with a dremel, bevel the edge on my bench grinder, clean the threads with the wire brush, and I have the perfect 2.5 inch kingpin with about 3/8" of threading.

The kingpins cost 60 cents each at my local supplier.

So it costs less than a buck a month to change a kingpin and have the peace of mind of knowing its way less likely to snap and cause at best a walk home, and at worse a severe joint or head injury. As a added benefit, I get major upgrade with regards to bushing wear, and the threaded part, which seems to be where they most often snap, is not on the fulcrum point of the hanger and is now quite a bit higher.

If you are not handy, you can just buy 2.5" kingpins and deal with the threading. If you change them frequently you'll have way less likelihood of a kingpin snap/bail/carnage/head injury/broken clavical/broken teeth/torn ACL/torn labrum or anything else that can happen when you are completely surprised by wheelbite that comes so quickly your reflexes are not quick enough to save you.

I also don't have to be as concerned about fatiguing my kingpin when riding over sidewalk cracks or cattle guards, if that happens in my path. I often find myself happy about that, I used to worry about that quite a bit. I know it's a fresh kingpin and will be changed before it gets old - peace of mind.

The common denominator in all of the broken kingpin threads seems to be that they have a few hundred miles on them. Also, heavier dudes seem to be usually involved. I weigh 198 right now, so I'm gonna change them frequently.

There is no guarantee that I will not snap a kingpin one of these days, but it is probably way less likely.

LDPanda · Joined: 21 Nov 2008 Posts: 418 Location: Seattle, WA

Classic 70's Bennett pro's were also made with a nut on bottom before the bottom bushing. Im not sure what purpose this served or why no modern manufacurers are doing it this way. I can only assume that since 0 truck designers are using this that it was shown to be faulty in some way, but who knows. I do know that cutting threads onto a rod reduces its strength by a minimum of 18% and that may be a reason not to have threading near the baseplate.

Grindking KPs (if im not mistaken, and im not a street skater so i might be) are mounted with the nut inside the baseplate. We already know that setup is VERY weak for the kind of riding we do and it is not suggested. Plus, the head of the grindking bolt is non-standard so i dont know if it would work to reverse it and mount it the way we normally do (nut on the 'top side')

I agree 100% with Ian, custom bolts and replacing them often is the best way to go. Theres info on this in another KP thread but James and i made several custom KPs from 3" grade 8 chopped down to bennett size (actually a lil shorter than the current bennet KP). This means they have very little threading at the top and no splines near the head. Its a cheap and easy item to replace and at least in the front can save you from some nasty falls.

model.citizen · Posted: Tue Apr 28, 2009 5:38 pm Post subject:

fair 'nuff about the GK KP having the weak side down.

but reversing them is sooooooo easy...since they have a rather wide head, simply grind down the sides a little so that it slots into the Bennett baseplate.

a little loctite wouldn't hurt, as from what i can see you only have to remove 1-2mm of material from each side, which won't give a terribly wide face (although perfectly sufficient since there isn't much torque used when tightening up the truck).

Ian the Groove Worshipper · Joined: 03 Dec 2008 Posts: 79 Location: Largo, FL

I think that the Grind King KPs are shorter than 2.5

egret · Joined: 18 Jun 2008 Posts: 84

At Milehigh they sell 3.5 inch kp.

On the far left is the Bennett stock. Far 2 on the right are the 3.5 inch minus an inch.

I lied earlier. I have snapped a kingpin on a rear Carver CX (rear is actually C2).