Broken Kingpin and Cracked Helmet (repost!!)

pavedwave · Broken Kingpin and Cracked Helmet (repost!!)

well I was waving around the magic Admin wand, and managed to wipe out one of Parson's latest posts.... luckily I saved the content... here 'tis:

Parson Adams

Joined: 03 Jun 2008
Posts: 14
Location: San Antonio

PostPosted: 30 Jun 2008 02:10 am Post subject: Broken Kingpin and Cracked Helmet

I took a spill today when my front kingpin snapped. Mad

I was doing about 15 mph. My head hit like a melon. The road cracked my helmet. My neck feels like I've been weightlifting with it. Twisted Evil

To add insult to injury, my local hardware store is out of kingpins till Wednesday. Confused

Of course I'll just swap with another set of trucks...but

edp_swakakin

Wow man very sorry to hear that. Hope your ok. What kind of truck was it? And what was your setup?

pavedwave

it's good to see you're connecting words and sentences, the helmet is all about that.

not sure what trucks you were riding but this page is about rev-kingpin setups,

http://home.comcast.net/~jampet99/rides/grooveboarding08.html

it was back when we were riding our bushings down to mush, and just kept on riding them that way, which thinned down the middle of the kingpin. the far more common scenario is the kingpin not being flipped. hope you can get grade 8's at that local shop!

Parson Adams

I was able to find grade eights at the shop. It was the stock Bennett that broke. Things are groving today, and I've already been on a 17 mile ride.

edp_swakakin

pavedwave

yeah it's a bummer, but not a total surprise. i've worn a bennett pin down where the hangar was wearing directly against the pin right in the middle, for too long, so I replaced it before it busted. the other common failure case I could see is if you were riding over a lot of cracks, i.e., sidewalks versus smooth asphalt trails. but usually that results in axle rather than kingpin fatigue.

however, replacing a bennett pin is not quite as easy a task as a randal-type truck, as you can't just use any pin -- most pins have a smooth shaft between the threads and the head, but on a bennett you need it to be splined, so you can tighten a nut down on your bushings and the whole pin won't spin. either splined, or use JB-weld, but I don't like that stuff because then the fix is semi-permanent.

i'm curious to see some pics of the shear point, hopefully? and very curious what pin you end up solving this with. personally, I think I'd try to find a slightly shorter replacement pin, to help solve the pin from high-centering issue that happens with a highly wedged bennett.

on a happier note, good to see you're back up again already James!!

Parson Adams

The king pin I purchased this morning is just a standard kingpin. I guess, after reading James' advice, that it will not work. I rode today on a backup truck; hence, my fast recovery from equipment malfunction. I'll post pics of the Bennett stock tomorrow.

Jim

Parson Adams

So James, am I SOL with the kingpin?

Eric,

I was in the middle of a pump regular stance. If I remember correctly, it was a heelside-hence, my rolling over onto my left shoulder and hitting the back of my head. My camelbak kept my back nice and comfy though. It may have actually aided in hitting my head too since I couldn't roll my back as if doing a situp. I have fallen many times, but have never hit my head like that before because after 19 years of skating, I've learned how to fall. I'll try, on carpet, of course, to fall with the camelbak on and see if it hinders me from tucking during a fall.

Front Bennett 5.0 and is wedged 20 degrees...rear dewedged 10. Big Zigs, Tracker cone, Barrel White, hanger, Barrel Orange, and then Kingpin nut. Flat washers on top and bottom. 92a Gullwing Charger cones in the rear on an 129 RTS.

Road conditions were good to fair. Nothing too bumpy. Well, I should add that there are two sets of railroad tracks that I ride through...they are for a little train that takes visitors around the park. Even the tracks are pretty easy to go over. I can do it with wheels as small as 66mm. The BZs and and my Gummys cruise right over them without a hitch.

The pop was LOUD. No time to react. Just splat.

pavedwave

no i don't think you're necessarily SOL with that pin, if you've already got it mounted, then I assume you bought a pin that has splines near the head? or else how did you secure the bolt head when tightening it?

the big thing you want to make sure though is that it's grade 8. anything less is asking for another snap. it will work fine, but it's really just a matter of time.

if you have a way to take a shot, it would be interesting to see where the bolt snapped to better understand the shear. was it where the threads end and smooth part of the pin begin?

i'm really glad you had that helmet on... back of the head is about the most gnarly place to impact.

camel

Same thing here. Broken Bennett stock KP on a brand new (well 200 miles or so) 6.0. Running BigZigs and 18º wedging in the front. No wear on the KP at all, just broke clean at the splines just below the baseplate hole. I figure it was faulty. Tried to tell the guys at Bennett but neither JP nor I could find a working contact email for the company at the time. Replaced with ACE Hardware grade 8 bolt. Used a little JB Weld top keep it in place ant not rotating or leaning. So far, so good. I have found that two part, white, 2-ton epoxy works a bit better since it has a minute amount of give and is less likely to crack and lose hold of the bolt.