| Archive for pavedwave longboarding distance longboarding, flatland pumping, cross-country adventuring, boardwalk cruising, and all things skateboarding and good times |
| Parson Adams |
Broken KP PicsHere you go.http://picasaweb.google.com/jamesdsimpson/Broken |
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| camel |
Yup, that is exactly what my 6.0 did. Isn't it a pain to bang that thing out? I know I hammered the crap out of it to get those splines loose. | ||
| LD skater since 1971 |
We use to break them all the time on Freestyle boards when we would run are trucks really tight. I still have about 50 tracker king pins they gave me that got oxidized because the box was left out side in the rain to replace the broken ones. Then I started to go to looser trucks to avoid the problem.
I just came back from testing out your guys bushing truck set up verse my seismic set up with a bennett on front and track RTS on back. Because it night time I could here the king pin getting torqued back and forth. l thought to myself I will snap a king pin one of these days. I also tried different bushing sets and I have found that the 3 stack allow you the most movement but you can really torque that king pin back and forth and get wheel bite. Because the truck is turning way beyond it designed turning motion. Plus it tears the hell out of the pivot cup. So then I tried the 2 large with the stock bushing cups you don't get as much pump but it safer no wheel bite or king pin torquing. |
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| camel |
Well yeah, but safe isn't fun....
Hehe.. C |
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| pavedwave |
2 things that have struck me as odd w/recent breakage reports:
one is that I haven't yet broke a bennett pin, and on trucks that have gone for literally years and thousands of miles. i guess it's really dumb to say somethng like that, because that's usually exactly what tempts fate :-O the other is that I've had the same bushing setup now for about four months, which show very little wear, on my Mermaid -- on that setup, have made a couple huge rides, and put it through every day 12 mile commutes in that time frame. haven't changed the bushings, nor the pivot cup. so I'm incredibly curious on maybe how snug, or how loose, or how far over the front truck Jim has been riding, or how deep you power into each turn, or if your wedging is angled even more than mine? i used to bust a lot of randal pins, mainly I found it was from 1. riding over a lot of concrete "cattle guards" head on, instead of diagonally, which is like riding over 20 sidewalk cracks all at once. and 2. running my bushings super loose to where the pin was beating on the hangar sometimes. this is obviously "happening" there's no doubting that! but i am curious which exact physical differences are at play here. could just be the fact that I weigh only 165lbs as well? but believe me this scared the #### out of me to read just before Ted and I embarked on our adventure to Portland... |
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| LD skater since 1971 |
Weight might have to do something with it I weigh 190 lbs. so That may be the reason I feel the king pin torouqing back and forth.
Also the hammered in king pins that have a spline that is knurled in to the king pin have a weak structural point at the spline. Compared to the tracker or other king pins that have the nut hole molded in to the base plate. The tracker king pin and others are just bolts don't have the spline ridge mark knurled in to the bolt to hold the king pin in to the base plate. The only reason we broke the tracker king pin in freestyle was we were running 2 tracker clear top bushings that were really hard. We did this mostly because 1 wheel tail wheelies and 360's were the rage back then the Ray Meyer, Rodney Mullen created. But after breaking so many king pins doing this kind of trick for awhile I grew bored with it. Tried of taking my board apart to change king pins so I loosened up my trucks. |
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| camel |
I am about 200 lbs. I run loose, but not hanger slappin' loose. I think this has to do with a run of kp's in the 6.0's. It would be nice to be able to contact Bennett. How is it that a company can exist without any contact info on the web or a website in this day and age? Guess you don't have to when you have a product people want.
C |
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| Parson Adams |
To answer your questions, James, here you go:
I weight 190. I ride right over the front Bennett. I have broken KPs on 5.0 and 4.3. It takes about a month for the stock Bennett KP to break. Both breaks have been in the same spot--at the spline--just within the baseplate. My trucks are fairly loose. I only tighten the nut enough to run the KP flush with the nut. When I was pumping Randals with grade 8 KPs, this never happened. Since I replaced the stock kP, this has also not happened again. Perhaps it's just a bad set o KPs. This happens sometimes--I once had a set of screws that would snap under any kind of pressure for no reason what so ever. I also have freakishly strong legs. As of this morning, I max out in my squating at 435 lbs. So, what is a little pressure to me, may be a lot to someone else. My front wedging is 20 degrees front, 12 degrees rear. Should I lower the wedging? |
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| LD skater since 1971 |
Since were talking about king pins how long is the king pin for the Bennett trucks? Because I can't find parts for them I may have to use the
Khiro or other brand I can get at Mc Gills skate shop. |
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| Parson Adams |
2.5". I've been using 2.25. This seems to keep less KP and nut from sticking out. | ||
| Belegnole |
just a thought....IF this is just surrounding a certain time frame or production run I may have an idea why. The diameter of the kingpin may be less, or the pin weaker at the splines....BUT , if the oddity of breakage is recent then it may be more that the metal was stressed during manufacturing. I did a touch of research a month or so back, and found that grade 8 bolts are considered to be stronger but also brittle. To what degree they are brittle I am not sure but some may be more than others. Also; iron and steel products are worked hot. If the temperature was not sufficient when the splines were hammered in. The metal at the end of the splines may be weakened due to cracking at the grain boundaries. Now I'm NOT a metallurgist but I am a goldsmith and have worked with precious metals for a number of years. I have dealt with bad castings and stressed metals quite a bit. This might ....just might be something like I described....then again not.
If this keeps happening I might suggest doing some more research and finding a class of bolt which works better. Say one that may bend over time but not have a critical failure and cause a crash. When the bolt has bent enough it can then be replaced..... |
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| pavedwave |
Man I haven't done proper squats since college time, right now 435lbs would explode my groin or something!! Appreciate the input. It sounds increasingly convincing that the 2.25" grade8 bolt solution is a must for the bigger guys. The other thing that seems crystal clear here is the splines are the weak point. Just for insurance I'm thinking this may be worth it, besides it's a good way to reduce the high centering issue. I'll keep the new, 2.25" grade8 pin in the same orientation, with the head under the baseplate, and JB-weld it there. Now that it's been said, maybe it will actually happen. 
I liked the elegance of samhell's solution where he affixed the nut under the plate, but it seems to put the threads in the same place where the splines are now, so I'm not sure it would solve the breaking issues -- although so far it seems he hasn't broken any, so I'm not discounting his workaround. I think his original purpose wasn't so much to solve breakage as to simply use a shorter bolt to avoid the high centering thing. On the side-note of wedging.... IMO, it's always good to tinker with alternate wedging just to see how it feels, you might find that lowering a touch even works better sometimes. I know some racers who don't LDP think that there's way too much wedging going on here, but my experience has always been that since we assume "flat" most of the time with little assistance from gravity, we need to set up our boards differently from the average downhill slalom setup. |
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| Barry |
How Do James & All;-) When you mention using JB weld to fix the bolt in the base plate, how would you intend removing it if the worst happened, or if the threads became damaged? Have you considered using Loctite 243 Threadlocker, with this stuff the bolt would stay in place and not revolve when tightening the lock nut, but still be easy enough to remove should you need to change it for any reason. I use the 243 at work in high vibration applications and it does the business. I actually changed the Bennett KP For a Randall one on Tuesday for my Dorney session, the randall KP is about 2 mm longer but is only threaded at the very end, I did this to help save my bushings till I can make a permanent fix, I did not use the Loctite as the KP fit snug and did not rotate when tightening down the lock nut, But I will use the 243 if I need to fix it more permanently. BTW the Randall KP helped a lot with the bushings and did not shred them like the Bennett as there was hardly any thread there. the only wear was from the hangers bushing cups, I need to smooth these out a little more. Take care, Barry
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