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| Truck Reviews (15215 Posts)
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"unbreakable"
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On 12/9/2006 herbn
wrote in from
United States
(64.12.nnn.nnn)
I have made and sold,at my store, numerous(not really)"unbreakable" kingpins for the tight truck set,i buy grade 8 bolts that are about a half inch longer than stock and cleanly cut them, they have never ever broken. That was back when kingpins were regular bolts. Those new bolts seemed to break a bit when they first came out,recently they've gottan alot better,i also have more and more newer skaters saying they like their trucks loose,is there hope?
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China?
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On 12/9/2006 Michael
wrote in from
United Kingdom
(87.114.nnn.nnn)
Funnily enough in all the time Ive sold Seismic trucks, NONE were returned because of a broken kingpin.
'Where' they are made doesnt matter. Only quality does, and design.
The clips on the kingpins come from a different country than China, which does prove to me that the Seismics arnt just built down to lowest common denonminators.
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Easier Yet
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On 12/9/2006 PSR
wrote in from
United States
(75.68.nnn.nnn)
Simple enough to do, but as we've seen on Randal's, not a liked configuration;
Run the bolt Down INTO the baseplate, being certain that exact tolerances are used in the baseplate bore that match the MACHINED kingpin shank above the threading, put the Locknut in the Baseplate...Oh, and use high-quality U.S. (or German) bolts, nothing from China or Korea, regardless of 'grade'.
I'm no Architect, just a lousy draftsman/machinist/mechanic/snowboard instructor/SKATE bum. Ooops, sorry, just halfway described Gilmour/Geezer/Herbn there. ;-)
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Relief
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On 12/9/2006
Chris Chaput
wrote in from
United States
(71.254.nnn.nnn)
Civ, Two questions:
Did the kingpin break where the collision with the hanger occurs, or did it break where there was a stress riser?
Have you ever broken a "precision" truck's kingpin that doesn't have a stress riser on it?
My point is that it doesn't really matter whether or not the side to side forces on the kingpin are being applied by the bushings and the bearing, or just the bushings alone. The force is about the same, and the kingpins are not failing in that area. We're not "hammering" the kingpin with the hanger or bearing ring. The hanger is usually being stopped from turning into the kingpin by the bushings, or the bushings slow it down almost completely before any collision occurs. It would be easy to come to a false conclusion about what is breaking the kingpins in a precision truck unless (and until) you try out a kingpin that has no stress riser and/or one that is given some relief from the loads being placed on it.
Imagine that you put a grade 8 kingin up through the bottom of the baseplate, and that you had an oblong shaped ring in the spherical bearing (see above image). The sphere can slide in the "sleeve" of its ring, and it allows the pivot rod to bottom out on the pivot cup bearing. You'd have essentially eliminated the stress riser of the kingpin and allowed the pivot cup to shoulder some of the load of the rider, even when the hanger isn't perfectly perpendicular to the kingpin. This is "relief" and not "slop", so it would still turn precisely without putting unnecessary stress on the kingpin. If the slot were long enough, you may even be able to easily assemble the hanger onto the baseplate, more like a Randal. I think that this would all but eliminate kingpin failure, even if the hanger collided with the kingpin. If you want to get fancy, you could actually just use the "sphere" of the spherical bearing, fabricate two straight concave steel slides that are inserted into the hanger's bearing seat. If you do it right, there's no need to remove the kingpin or the pivot cup when changing the bottom bushing...
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Kingpins
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On 12/9/2006
civ
wrote in from
Canada
(24.141.nnn.nnn)
CC, when I broke my older model Radikal kingpin, there was a clear indentation in the hanger where the kingpin smashed into it from turning too far pumping on the flats. I really do think that over turning the bearing in the hanger is a major part of the breakage problem.
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New Trucks? Pshaaaaw......
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On 12/9/2006 BoBo
wrote in from
United States
(68.49.nnn.nnn)
This is why a wedged Tracker Ful on the front and de-wedged TTC on the back still cannot be beat.
They DO NOT break, and they do a fantastic job.
I always found that the simplest ideas are the most elegant.
My .02 worth.
Bob
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measure
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On 12/9/2006 herbn
wrote in from
United States
(64.12.nnn.nnn)
put this to bed,measure how far in degrees(although it's probabely a given factory spec),a spherical bearing will turn. Then measure how far the truck will turn,to wheel rub ,with small wheels.
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What's the problem?
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On 12/9/2006
Chris Chaput
wrote in from
United States
(71.254.nnn.nnn)
I don't think that the breakage problem has ever been because the spherical bearing turn to the point of collision with the kingpin. I do think that the most force that can be put on a kingpin is when the truck stops turning and the two outer wheels come off of the ground. But this happens with hard bushings and/or tight trucks that don't even have spherical bearings, and we're not breaking those kingpins.
I think that problems occur beacuse:
1. There is a bigger load on kingpins that have spherical bearings
2. Threading a kingpin can put a stress riser on it
If we proceed to bend it back and forth in rapid succession for a period of time, it will break. If these are the problems, the solutions would be to either reduce the load on the kingpin, to eliminate the stress riser, or both.
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words
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On 12/8/2006 herbn
wrote in from
United States
(64.12.nnn.nnn)
i don't know if i used the right words, or was just to brief to be precise. It would just be strange for ANY truck manu to use someone elses (kind of) published design,to fix a problem.AND if there is a problem with the ball joint(range) the new kingpins will snap just the same,same,if they really just have a few breakage problems all that redesign may not be worth it,though with wuarentees going through germany, just having a regular grade eight bolt as a kingpin makes that easier. I wonder if the new indys (low) have kingpin breakage trubs,they have especially short and soft bushings, so a lot of kids will probabely tighten them alot,this results in a restricted turn(metal on metal) and break those new,"regular" kingpins.
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"Fixed" Kingpin
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On 12/8/2006
Chris Chaput
wrote in from
United States
(71.254.nnn.nnn)
Paul, It's funny that you mentioned loctite in the baseplate's threaded insert. Once when I was trying to remove a Radikal kingin, the insert unthreaded itself from the baseplate instead. It was as if the kingpin was held into the insert by loctite, but I think that it was probably just a bit rusty.
Anyway, when I looked at that nice fat insert stuck to the end of the kingpin, I thought to myself, "Why not just cut both of these from just one piece of steel and put a generous fillet where the lien part meets the fat part?" You could probably get away with threading this into an anodized aluminum basplate and still have a pretty strong system. Isn't that a bit like a Radikal/GOG axle?
In any event, if someone tries to use this idea I want a huge royalty, and I want the maufacturer to say, "I am a dumbass without Chaput" every night before going to bed. That is, of course, if it doesn't break. If it breaks, we'll just call it the G.O.R.E. (Gang Of Radikal Experiment).
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Radikals/GOG's and Pauliwog's 2-Cents on kingpins......
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On 12/8/2006 Pauliwog
wrote in from
United States
(65.122.nnn.nnn)
......Don't be a dumbass like me and put your Radikal or other removable and threaded-in kingpin into the baseplate with LocTite just for the sake of "keeping it in place". WRONG! Just check it frequently and use a GOOD box end wrench properly sized/matched to the hex tip and keep it snugged in. Friends Don't Let Friends LocTite Their Radikal/GOG kingpins In. - P
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Pride
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On 12/8/2006 Michael
wrote in from
United Kingdom
(87.114.nnn.nnn)
herb, you wrote: I doubt GOG can incorporate the CC mod, it might be a matter of royaltys or even just pride
I think you assume two things there, neither of which I think would stop GOG from improving/refining their trucks.
I 'doubt' that royalties or pride would be limiting factors knowing both CC and Donald.
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DEJAVU
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On 12/8/2006
MARK MCCREE
wrote in from
United States
(67.76.nnn.nnn)
I have to say that I --- Don't have anything to say-- I've been down this king pin road and it was bumby.
King pins screwed into aluminum don't work--- we tried it--been there, done that. The bearings-- If allowed to go beyond thier designed extention distance--will cause undo stress on the king pin-- literally beating it like a hammer. Geeze is right on with that.
We have SS inserts into the base plates that receive the recessed threaded king pin that is the beefiest known to science. It's not the best situation-- I agree, however, none of these have broken.
I do like CC's pinn'd Pin - non threaded idea. I like his new truck concept.
All I can say Don is---- good luck and best wishes.
Over and out.
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copywritten?
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On 12/8/2006 herbn
wrote in from
United States
(152.163.nnn.nnn)
i'm pretty sure the CC mod was brought up for radikal's as well,and obviously they have choosen not to use it. I doubt GOG can incorporate the CC mod,it might be a matter of royaltys or even just pride. Well maybe they just need to find a better bolt. I think it's a matter of deflection angle in the ball joint. Not that your idea wouldn't be a great way to make the kingpin and the bushings easy to replace,but if the balljoint hit's the end of it's range on a regular basis it's gonna be trouble. What's the range on the ball joint's used in frye trucks?
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fity
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On 12/8/2006 hneumann
wrote in from
United States
(152.163.nnn.nnn)
that was a typo, but i liked the way it sounded so i didn't correct it,lean to me is low fat meat,no one told you right away that lien was neil spelled backwards,i always did them very liened over into the ramp,and very light foot placement ,if you want to call 6 inches away from the tail "placement" very scary for spectators,i was always sure i'd make it, and hung in. I don't care what you spelchek says when i talk skateboards it's lien.
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chaput
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On 12/8/2006
donald20
wrote in from
Germany
(84.62.nnn.nnn)
"herb" is the short form for "herbert",right?
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Wikipedia
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On 12/8/2006
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
Aerials (skateboarding) - Wikipedia, the free encyclopedia
Lien Air: Lien air is another name for a frontside air backside grab. It was named after the inventor Neil Blender (Lien is Neil spelled backwards)...
HerbN: HerbN is another way to pronounce "Urban" which is Herb Neumann's favorite country singer...
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dictionary
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On 12/8/2006 dictionary
wrote in from
United States
(65.91.nnn.nnn)
LEAN
LIEN
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Six to one...
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On 12/6/2006
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
I seriously doubt that it would cost much (if any) more.
Let's just say that:
The cost of the additional cap is the same (or less than) the threaded and tapped baseplate insert (that goes away).
The cost of the additional pivot cup mods is the same (or less than) the fabrication of the proprietary threaded kingpin.
The new kingpin, nut and bolt are off the shelf fasteners.
I'd say that the costs are about the same, maybe even less...
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how much?
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On 12/6/2006 herbn
wrote in from
United States
(64.12.nnn.nnn)
so chris punch up the next buttons on your mainframe and come up with how much more it would cost to make the baseplate like that,and that little extra piece and lastly the cost of the bolt,it would have to be one of those peletized or patched selflocking bolts and obviously you know if the "factory" has to pay the machine shop more then they need to charge the american distributor more, whose got to hand it down to the customers. 175.00 + ?, the herbn guess,,, fity bucks,maybe more.
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Solutions
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On 12/5/2006
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
Problem: When you put a spherical bearing in the bushing seat, you can't assemble the truck like you can a Tracker, Randal, or Indy.
Solution #1: Make the kingpin removable.
Solution #2: Make the pivot removable.
What you have to recognize, is that the problem is one of "assembly", and not of strength. We rarely see kingpin breakage in the non-precision Tracker, Randal, and Indies
Solution #1 is fine, but if you thread the kingpin into the baseplate, you've created additional (structural) problems. The message here is, "don't do that".
Solution #2 is fine, and there are a number of simple "pivot area" solutions that will allow for the quick assembly and disassembly of the truck for changing the bottom bushing. The best ones would probably include a single 3/8" or 1/2" hex head nut or bolt, because we already have that on our skate key.
If you choose Solution #2, you have to add a "cap", but you can eliminate a baseplate insert. You will also have to add a bolt, but instead of making that expensive proprietary threaded kingpin, you can use an off the shelf grade 8 cap screw, which is cheap and easily replaced.
There are several solutions out there, if you look for them...
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emachineshop.com
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On 12/4/2006
WAX
wrote in from
United States
(67.176.nnn.nnn)
Let the theorys fly, but remember...the Manufacturer has offered to fix the problem, they have isolated it to the kingpin/baseplate. 2 very prominent US racers and several Europeans have been racing them for quite sometime. If those guys arent breaking their Kingpins then there is a difference in the parts, Donald has adressed that...and says he will fix it...lets see what happens, not debate about it!
with all the improvement ideas people have about trucks, I am suprised there arent several more slalom trucks availabe.... I must give CC credit.... he has the nuts to get in the game and try and improve it with his ideas... when can I get a ChuckTruk?
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R&D?
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On 12/4/2006
Geezer-X
wrote in from
United States
(72.75.nnn.nnn)
Racing and Destroying?
I've been a SolidWorks user for about 4 years. It has a basic finite element analysis feature called Cosmos Express. It's very useful to explore the failure mode and safety factor of a part or assembly using this.
I've used it on numerous truck designs, and as I write I'm modelling the GOG baseplate and kingpin in order to do soem FEA studies.
I've inspected and measured a truck this evening and will be working in conjunction with the manufacturer and distributer to isolate a retrofit that will solve the problem.
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R&D
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On 12/4/2006
graf
wrote in from
United States
(64.12.nnn.nnn)
Can anyone tell how much R&D goes into truck design? Are these trucks designed using Computer-aided Engineering analysis (CAE)or Finite Element Analysis (FEA)programs such as ProEngineer? I guess when it come down to it we all are test pilots for slalom truck design. I feel its OK for the discussion to become heated as people exchange ideas & theories, but its too easy on internet forums to misunderstand someones post as being insulting when it really not the case. PG
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Rad/GOG/Randal/Gullwing Split
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On 12/4/2006
oldtimer
wrote in from
United States
(71.164.nnn.nnn)
While I've yet to spend time on the G.O.G. It's a simply matter of physics, you're asking too much from a king pin to be levered that much repeatidly with out failure. When you employ an added restriction, such as the spherical bearing into the mix it is, and has proven to multiply the stress even more! The geometry MUST be exact, or close to, in order to balance everything out. Bushing size, which changes with every turn of the nut alters the stresses.
Go WAY back to the Gullwing splits, they had the similar fatigue problems, even tho most of the weight was allowed to rest in the pivot cup, and not on the pin itself. Would their "fix" of a support bracket that was precisely manufactured to aleviate the free end of the king pin work? Other than that, I think Geezers solution would be an option worth trying...As Chaput stated tho, it's amzing that serious injury hasn't occured in these fast times!
Donald, I admire your commitment...please follow through and help technology eek it's way into our sport farther..
Facts is Facts, and math and properties don't lie! All of the referenced trucks suffer from the same weakness.
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