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| Truck Reviews (15215 Posts)
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Why they're breaking
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On 12/8/2005
Geezer-X
wrote in from
United States
(63.138.nnn.nnn)
Cause the fast guys (on Radikals) ride their trucks tighter, and have a good line.
Cause they don't bind the hanger against the kingpin from overturning.
At the Winston-Salem DHB soapbox derby hill race, there was a clearly visible racing line emerging as the day wore on. There was THAT much urethane being laid down on the asphalt.
When you'd watch a guy like Mitchell, Mollica, Noah, you'd see that they were ALWAYS on the very inside edge of the visible area where people were riding.
In car racing parlance, they were "early apexing" setting up, getting the steering cranked in, and getting the power back on early.
The less uhhh...accomplished riders tend to run in wide and late, and crank in a ton of steering to make the cone.
Titanium has about the highest notch sensativity of commonly used metals, and even with the bottom thread in the hanger, without a shoulder on the kingpin to convert the load from bending to tension, binding the hanger against the kingping is an *enormous* flexion input.
Also, the area which threads into the baseplate should be shouldered to the minor diameter of the thread. A 3/8-16 thread would work better here than 3/8-24.
There should be a generous radius at the juncture of the flange and the body of the kingpin.
This is nothing groundbreaking. This is engineering 101, aka common sense.
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Limit Screws???
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On 12/7/2005 BoBo
wrote in from
United States
(24.91.nnn.nnn)
Funny that..
Never heard of em till some of you made boggles of your buns.
Here it is.
Never use a rear truck that'll bite.
The use of big wheels over that last couple of years is the problem.
Turner or Roe Cut-away or Ful nose.
TTC or offset in the rear.
No bigger than is 65mm wheel.
The use of anything bigger has puzzled me from the beginning and still does. Why the big wheel?
the 62mm wheels work great. Anything bigger begs for a bite. All that free urethane is asking to go somewhere.
I am not sure why but the big wheel thing will not go away so I say this.
Get yourself some risers or some sense...
I had the descency to go down on hard wheels. What happened to nearly breaking loose at every turn?
I loved it.
See you all in the spring and I'll bring nothing larger than 65mm's and still be plenty fast.
Bob
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My Limits
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On 12/7/2005
Geezer-X
wrote in from
United States
(68.239.nnn.nnn)
If I had been riding my usual setup at SSS 3 weeks ago, I wouldn't have ended up in the ER getting CT scans 'til 5 AM.
PVD with limit screws in the rear, wedged spherical pivot indy in the front set up so it cannot wheelbite.
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kingpin breakage
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On 12/7/2005 herbn
wrote in from
United States
(64.12.nnn.nnn)
tightness of the truck is sort of an issue,two equally tight trucks;one with minimally tensioned hard bushings another with very compressed soft or med bushings. The second on is more likely to break. Limiting screws will eliminate a lot of kingpin stresses. I think what would work very nicely as a kingpin would be a well heat-treated kingpin with minimal threads,allow only for three turns of compression on large bushings,an accurate fit in the baseplate with a clamping bolt that goes through a notch in the kingpin. The base should have a nice camfer where the bolt comes out , the clamping bolt should be deep in the baseplate, think of the clamping bolt that holds a balljoint into an auto motive suspension/steering linkage.
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turn limits
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On 12/7/2005 tim
wrote in from
Australia
(203.214.nnn.nnn)
Its easy to see if you are abusing the trucks by standing still and leaning until 2 wheels come off the ground or are running too soft bushings. the K pin will touch the soft hanger near the bearing and leave a small dent. This puts a lot of strain on the pin. which is fixed at the base. Cleaning ,oiling and checking tightness of everything is easy on these trucks so there should be no reason for neglect. The 5/ 16 nut should only take up the slack on the bush. I think for me atleast it was rough surface.
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McPVD
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On 12/7/2005 pvd
wrote in from
United States
(24.5.nnn.nnn)
i will never build any slalom truck without limit screws.
i question any truck designed for racing without them.
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Pvradikald
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On 12/7/2005 Chief Red Beef
wrote in from
United States
(24.185.nnn.nnn)
Imagine..
In my imaginary world Radikals are not made with Titanium.
They cost 70 bucks a truck.
They also don't make that silly spacejunk looking swingarm rear truck and instead make a less complicated version of the PVD truck intended for use strictly as a rear truck. (no turn limiter, fixed angle plate [30*],permanent axle).
These cost 80 bucks.
PVD and Mcree vacation together, enjoy using metal detectors down at the beach, and have a secret handshake.
They make enough off of there trucks to pay for Holliens entrance fees and plane fair with enough left over for a few nice cigars.
My imaginary world. It's nice.
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radikal breakage
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On 12/7/2005
Bob
wrote in from
United States
(65.112.nnn.nnn)
Guys, are you really satisfied with an expensive slalom truck that will supposedly hold up under extreme pumping conditions and NOT on an occasional sidewalk clack? Gee whiz, I would certainly expect more.
I'm not talking about slamming one of those Ti beauties into pool coping in a pool, but they should certainly be able to hold up to a sidewalk crack or two. If they don't, they aren't worth putting on a board at all. Demand more. You deserve it.
I've been riding cheap sand cast Indy trucks over sidewalk clacks for a very long time with absolutely no failures. They cost me $18 each. For $200 each, a person should be confident that the kingpin will not shear.
As for another theory, Ti is pretty good in terms of fatigue, generally speaking. (the bending the paperclip back and forth) Ti is rather sensitive to notches and cracks though. That means that if you have ridden them for two years without a problem, they're probably ok. If they develop a crack, they will likely give you a "POP" "Bang" sudden failure without warning when they go.
My advice, if you're worried about failure of old parts, inspect them. Remove them and give them a visual inspection. If you have the means, do a dye-penetrant inspection to look for tiny cracks. Kits are available for this and marketed under "Dye Glo" or something like that. If you suspect there is a problem with it, DO NOT USE IT. That's the safe bet. If it looks fine, it probably is.
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Radikal fix
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On 12/7/2005
Drew Lunsford
wrote in from
United States
(24.6.nnn.nnn)
I have a Radikal Dragons claw that i recieved within the last couple months, I think it is of the lastest design batch. Thanks Sparky!
I have read with interest the complaints of a few Radikal truck kingpins breaking. CBark summed up areas to keep on top of, and pay attention to, including the absolutely very important pre-ride checkout on the secure retorque of the kingpin. As Sparky has mentioned in the past, using a 7 mm, 6-point socket or a box wrench with six points, fits correctly without chance of rounding the flats and or spreading a open ended wrench jaw.
I did not want to wait and "see what might happen" so i spent time fussing around.
I believe i have come up with a easy fix for the concern, a fix that has given me trouble free confident rides lately and i will add that just love this design with hiem joints designed for precise turn/tracking. I don't use my Radikal on the sidewalk or other crack clicky clak concrete paths, only my mostly smooth surface slalom runs. Thanks Sparky Mark Keith Jack...nice trucks!
My front Claw fix has come through observations of the trucks' action while weighted in use. I'm just over 200 lbs. The weighted hanger needs to be supported not only by the kingpin's base threaded end, but also by the pivot's contact in the base. I find there is no weight support at the pivot end. The pivot is freely twisting within its heim bearing and only holds/guides the angle of turn.
The hanger's pivot-to-bearing fit, needs a spacer (for now) between the inner race of the bearing and the hanger's pivot aluminum base. I assemble the hanger back into the base and use a .065 flat steel washer, finding it just spins loose, several thousanths of free play, while unloaded. While standing on the board i reached down to feel this washer get pinched snug after i did a few side to side wiggles to set the hanger's bearing load.
This loose-to-tight spacer movement, while in static weighting shows that there is flex in the king pin... but with the spacer in place the flex travel is much more limited and the KP load is more evenly carried between the hanger conical bearing and the pivot bearing.
Works well for me so far... any comments very welcome!
-Drew
PVD wrote:
"firstly, it may look like a bolt, but it is truely being used as a stantion. it should be refered to as a stantion or "kingpin". the rules for bolts need not apply if the stantion is properly designed.
now, i have tried in the past to start a rumour as to why the radikal trucks keep breaking kingpins. the reason is obvious and has nothing to do with matiral choice. they can all be improved with the addition of 1 part. i cannot give it away. i will leave the solution to come from the designer.
for the record. from my knowlage, only 1 PVD truck has ever failed. the actual forces that caused it are still in question, but the fix is known."
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Radikal Kingpins
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On 12/7/2005 Chuck Gill
wrote in from
United States
(192.249.nnn.nnn)
I wonder if another factor is having one of the Radikal crew explain proper care, feeding, and operation live and in-person vs buying by mail and running blind?
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k pins
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On 12/7/2005 tim
wrote in from
Australia
(203.214.nnn.nnn)
cbark , I agree I am a newbie who broke a king pin. From what I know now it is because of sidewalk cracks. I mainly ride a smooth bike track but to get there I ride a section of paving bricks.. Say no more.................. having said that I think my pin was not of the recessed thread type. Now I ride my cruiser with the slalom deck under my arm and just ride a small section of track or walk. I'm sure sparky is looking at ways to fix the problem for good.
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Radikal Kingpins
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On 12/7/2005 cbark
wrote in from
United States
(63.227.nnn.nnn)
Does it seem strange that some of the most aggressive Radikal riders don't snap their kingpins more often? I broke one, but that was before they hardened them up a notch. I don't change my kingpins. If you have ever seen me ride, I think you might agree that I can throw some force down to my wheels through my trucks. Probably more than the average rider. Mitchell hasn't broke one. Bam Bam Mandarino rides as hard as anyone and has no recent failures. What about the Bomber, Maysey, Pirnack, Dong, Hackett, OlSoN, Chicken. Those guys and others all ride hard and stress their gear.
So why is it that newbie/intermediate riders are breaking all the kingpins?
I thought one issue might be using them to cruise streets and sidewalks where there are lots of cracks/drop-offs in the surface. This would probably cause more issues with rear kingpins. I know a guy who broke one, but he was pumping bike trails quite a bit. You know, clickety-clack, clickety-clack and some clacks are louder than others.
Here is my best guess about the fronts. You aren't paying enough attention to your setup. Does the potential exist for wheelbite? Not just between the board and wheel, but between the inside of the wheel and the truck base itself?
They still ship 1/4" axles as stock and if you use those or 3/8" with an inside-lipped wheel, you have the potential to get inside wheel bite.
The other issue is running your trucks loose or sloppy enough that the inside of the front hanger (where top bushing goes) can hit either the washer or kingpin nut. Most likely the washer. I believe this is the #1 culprit.
If either of these situations can occur, then it would seem that a hard turn could produce a side-force on the kingpin. The kingpin is not supposed to be used as a lever-arm from top nut to it's threaded baseplate insert.
This is just my opinion, but I have made as many turns on Radikals in the last two seasons as anyone. My only kingpin failure was around Jan 2004, before they upped the hardening factor on the kingpins. On two sets of my trucks, I have ridden the same kingpins since that time.
One last thing, whenever I am racing or practicing, and someone mentions the word "kingpin", I reach for my 7mm wrench and check the kingpins of all my setups within reach. A few times, I have caught one just starting to loosen up. It's just something I decided to make into a nervous habit.
Maybe this info will help someone avoid painful breakage...
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Tracker B2 or Randal
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On 12/7/2005
Derik
wrote in from
Germany
(193.7.nnn.nnn)
I will set up a new Board, the deck is a gravity 39, double kick. I'll use it for cruising around, a little sliding and will ride it in a pool from time to time. I've some spare 73 mm Gravity super G's and the only things missing are the trucks.
Gravity uses Tracker B2 on this deck, some riders prefer Randals. I have some Randals 180 on my other 44 board and I like them.
Any suggestions if I should take Randals 150 or Trackers 149? Anyone hwo has ridden both trucks? What are the differences?
Thanks for help!
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Kingpins 1%
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On 12/7/2005 Dave
wrote in from
United States
(71.193.nnn.nnn)
My worry is that the more you ride and stress the
kingpin the more likely it will break.
Like bending a wire back and forth until it breaks.
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Gracias Mark
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On 12/6/2005
Eddy
wrote in from
United States
(207.69.nnn.nnn)
Mark enjoyed the conversation this morning. Sorry for the run of bad luck. It is allways good to catch up. Thanks for listening dude. I remeber I got those Rads from you at LSJ 2 years ago. They will be missed. Thanks for replacing them. Here is hoping to seeing you out there in 2006. Your Amigo Eddy Texas Outlaws.
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Thanks Mark
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On 12/5/2005
tim
wrote in from
United States
(60.225.nnn.nnn)
Thanks for the update Mark. I know its been hard for you guys in the past months , thats why I havn't said anything. Just thought I would get it off my chest while everybody else was.
Hope every things sorts itself out for you all over there. Look forward to getting my baby back, have been skating a RTS/X combo and it just doesn't do it for me.
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HEY GUYS
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On 12/5/2005
MARK MCCREE
wrote in from
United States
(69.69.nnn.nnn)
Hey Tim, Sorry you sent your stuff right when the hurricane hit and fubarr'd the factory. Jack will take care of you --e-mail him at radikaljack@yahoo.com. It's a bitch when hundreds of thousands of dollars worth of equipment is destroyed along with 1/2 a building worth the same. But we will still make sure YOUR truck is waranteed.
Eddie, nice to hear you're out there racing. You have MY #.
Geeze,
Always a pleasure to read your editorials,
Sparky has recessed the threads in the insert so they are below the "break point". Still--we are yet to reach the 20 mark with broken kingpins--there are well over 2000 units out there--that's 1%. Most all were pre-2005 changes. I do agree the "NO-THREAD-PIN-IN-PIN" idea, keep them coming. And yes .01% should be too much. What are ya gonna do!
Cknuck, Your on point, split-fires are great for PRACTICING when you need it.
Peter, Oh peter, those 48 sets of trucks you made will be priceless, I'm counting on my set to be worth alot in a few years. Don't flood the market any time soon and How the hell are ya!!!
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Radikal Kingpin
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On 12/4/2005
Tim
wrote in from
United States
(60.225.nnn.nnn)
Eddy I broke a kingpin in my Radikal Front in mid October , sent it off and even after sending a few e-mail I still have no idea if it even arrived. I know they have been re-locating but ???????. As for why they break , its a design fault no matter how you look at it. I know they are designed for racing but that should make them stronger not more delicate. I know people are going to say that if you drive a race car on the street it will break but the reverse is also true. 1/2 inch cro mo king pin would be easy or removable through the base plate. PVD please make your trucks again.
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Truck P0rn
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On 12/4/2005
Chuck Gill
wrote in from
United States
(65.139.nnn.nnn)
Did someone say Stimulators?
Wahaha!
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Texas Outlaw Series
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On 12/3/2005
Eddy
wrote in from
United States
(207.69.nnn.nnn)
Bro go to www.bonelessone.com that is where you can get info on our Outlaw Race. Look forward to seeing you. There will be plenty of loaner boards. Good Vibes and plenty of Slalom STOKE. Eddy Texas Outlaws.
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how tight are your trucks for sliding?
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On 12/3/2005 eddie
wrote in from
United States
(64.132.nnn.nnn)
still trying to pull the 180 and bring the board back around. got some 73mm 90a wheels. i can do it kind of half assed. but not really. all i can mostly do is drift around turns and slide to a 180 stop toe and heelside. i have refused to tighten my randall trucks up at all. i have them as loose as possible. should i swallow my pride and tighten my trucks up? i spent all morning getting tossed trying to pull off s#@! i cant do yet. YO EDDY! ps. whats up with the competiton in austin, tx. thats where im at. where can i get info?
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off topic
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On 12/3/2005 pvd
wrote in from
United States
(24.5.nnn.nnn)
a recent peice of work i did for a posting on concrete deciples.
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correction
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On 12/3/2005 pvd
wrote in from
United States
(24.5.nnn.nnn)
btw. none of the pvd kinpins has ever failed. ever.
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pins
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On 12/3/2005 pvd
wrote in from
United States
(24.5.nnn.nnn)
"Figure out some way of adjustment and assembly without having to remove the kingpin from the baseplate."
ahh! like i haven't been thinking of a better way for the last 20 years.
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Kingpins
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On 12/3/2005
Geezer-X
wrote in from
United States
(151.200.nnn.nnn)
In it's application in a "conventional" truck, the 3/8-24 x 2.75" bolt that is used as the kingpin it pressed into the baseplate from the bottom, and the bending load is applied to the smooth, stress riser-free, UNTHREADED part of the bolt.
The head functions merely to keep the bolt from pulling through the baseplate, The threads are there only to allow adjustment of the bushing preload, and if sized properly, are loaded only in tension.
It's not ideal, but it is within the realm of reasonably sound design.
A PVD uses a bolt to hold a ground steel tube in compression within inside a machined aluminum body. The tube rides in bushings in the baseplate. The bolt is in double shear.
A Seismic uses a pin with retaining threads in single shear.
I'll say it again, and recommend that people consult either a hardware application textbook, or better yet, Carrol Smith's "Engineer to Win" or "Nuts, bolts, fasteners, and plumbing" two difinitive books on race car construction and design.
There are things that one should NEVER do with a bolt, and screwing it into a fixed thing and applying bending forces to the other end of the lever is the biggest one.
I'll offer a fix.
Lose the threads. Just press a rod into the baseplate and retain it with a 1/8" high strength roll pin, which has a double shear strength of like 2100#.
Figure out some way of adjustment and assembly without having to remove the kingpin from the baseplate.
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