about reversed kingpin wedging

Mimosa · about reversed kingpin wedging

Hi everybody,

A few month ago, I bought a Khiro wedging kit and decided to test several setups on my Holeys. Well at first I tried 15° front wedges and 10° back dewedged being sure that it would be something. I was quite disappointed because the front became very hard to turn. Then I thought about it concluding that it makes sense. Of course wedging adds steering but if we consider that the kingpin is becoming more horizontal, it seems evident that the turning becomes harder. In my opinion, this make the great difference between reversed and non reversed kingpin. My conclusion is that for a given bushing duro wedging more than 10° is useless for reversed kingpin. I would be curious to read your opinions about that.

gldsndz · this weekend

I just got a new Bustin Sojourn, and I'm going to look into this question. It has a natural wedge in the front, maybe I'll try and dewedge it and see if it helps the pump.

Will report.

gldsndz · hmmm

This is a great topic for discussion, here are my thoughts... Can't wait to hear yours.

Background: I had my Bennett 6.0's on my new Bustin' Sojourn, which has an upturned nose and I wedged an additional 10 deg, pumped just fine, was really getting a hang of it. But after biffing it because my kingpin caught on a bump, I'm running 71mm Alligators, I decided to put on the Randall 180's again, which was going to happen next week when my Roe Mermaid makes it to the Bay Area.

So, the question: What is the most optimal wedging for a reverse kingpin truck for pumping?

I tried out the Sojourn with a 15 deg wedge and the natural wedged nose, which is probably about 5 degrees, for a total of about 20 degrees. It was way to much, my turning radius became much less than no wedging. I then skated my Dewey Weber which has Randall 180's with less than 5 degree wedge, it worked ok, I could pump, but it got me thinking.

Is it better to wedge a reverse kingpin truck at all?

geolemon

I just set up my first pumping board - so given my novice state, my opinions are pretty worthless since they are inherently without relativity...

But I wanted Randal R11's because of a friend's longboard setup, and I've got a Gravity 35" Diamondtail which I selected because of the rocker that seemed slalom/pump-like.

While quickly doing research, someone suggested that I wedge the front truck and dewedge the rear truck - so that's my initial setup, and I'm definitely learning to pump (I can make it around two suburban blocks in my neighborhood before passing out on my front lawn).

I definitely observed that with the rear truck dewedged, it virtually goes limp. I had to upgrade to harder bushings because I squeeeeshed the stock bushings, tightening the truck so much.

I'm not noticing any kind of massive effort to turn, with the front truck - but maybe I should simply try it without any wedging - or at least with no wedging in the front? Would you suggest leaving the rear wedged?

I ask this, because my understanding was that a lower-angle truck in the rear, and higher-angle truck in the front was desirable for LDP...
Maybe that isn't true?

I am looking to learn, and glad to experiment! I'm glad to have the success I have so far... my guess is that comes from 20 years of pumping on ramps. Cool

jdnorthrup

I've learned with a pair of Gullwing Chargers, which are similar to a Randall RII or a Paris. They may be a bit more turny, but they're essentially reverse-kingpin, around 45-50 degree angle trucks. Very soft, snappy stock bushings.

I tried for a good 4 months to learn to pump on it with no wedging. I'm running on a very flat 46" bamboo cruiser.

Then I wedged the front a good 15 degrees, and dewedged the rear about 10 degrees. It made an immense difference, especially once I levelled the board by adding a flat riser to the rear truck (since dewedging had lowered the rear wheels relative to the wedged front wheels).

Suddenly, I could pump like nobody's business, up small hills with little problem. Night and day difference.

So in my experience, getting the correct geometry is essential -- even on a reverse-kingpin truck. I think part of it was keeping the front truck very easy to turn, even at the high angle. The stock Charger bushings worked fine, with Randals I'd throw a pair of very light Khiro barrels in for the same effect.

The idea is to get the front truck to tack back and forth laterally, while keeping the rear of the board close to the line of travel (kind of following behind the front trucks, not turning in parallel like you get on a more "carvy" setup).

Blah blah blah,
-jd

LD skater since 1971

I don't wedge my seismic on my boards because I run the 45 degree base plate on booth front and back. The truck are already pre-wedged with king pin and turning geometry set up. With the truck mounted on the front of both my Bustin complex and Spliff. I noticed the trucks pivoting on a almost parallel king pin because of the pre wedged nose.
So IMHO I don't think the wedging helps on the reverse king pin trucks.

The reason wedging works on the traditional trucks like Bennett or
Tracker RTX/RTS is your are changing the angle of the king pin and hanger to almost match the turn geometry of the reverse king pin truck.
That is why the RAD Pads angled riser were invented back in the 1970's
to change the angle of attack or turning geometry of the truck

I had a pair if Gullwing split axle reverse king pin trucks back in the 1970's they were the best turning truck on the market. But the king pins were very fragile. I was using them to skate street acid dropping off curbs and then, I would lift my tail of my board in wheelie to get up the next curb when I came to the next sidewalk and then step on the nose real quick to clear the back truck.
The flatland ollie had not been invented and you had to 3 choices swerve in to traffic and go in to the next drive way cut. Do the nose and tail grab bunny hop/ curb hop air and maybe crush your fingers. Or do the the tail wheelie to nose wheelie up up the curb. Thank god for all the sidewalk curb cuts at every intersection that the Americans with disability act created now we can go really fast.
With out a worrying about ollieing up curbs any more.

Maybe James the expert on the trucks will chime in on this subject to help you out.

pavedwave

I definitely can't claim expert status when it gets down to the mathematical theories behind angle, rake, pivot axes, and offsets between these truck architectures, but I do have opinions based off experimentation--

Flatland distance pumping needs to be as effortless as possible. So when adding angled risers to a reverse kingpin truck (and other architectures), what is considered best for a downhill setup, is not optimal for a flatland LDP board. In short, for flatland, we're adding more "gravity" to the truck by angling it more. People complain how "divey" the Bennett is, or how angled Randals "dive" too much -- but this is exactly the kind of feel we need where we cannot assume speed right out of a racing start ramp.

The benefit behind adding wedging in front and dewedging in rear holds true for all of these truck types -- indy/bennett, rev kingpin trucks (randal, holey, paris, gullwing cruiser60's), seismics, and trackers. The split-fire truck which I've used in slalom both front and rear is basically an improved-upon reverse kingpin truck design, a Randal on steroids. Splitting the axle is the upgrade, but the architecture is almost the same. And looking over all these setups in slalom, you'll notice everyone adding angles.

Granted, each truck starts out with its own built-in angling. I've seen the question raised before: "Wouldn't a truck designer build all the necessary wedging into the baseplate already anyway?" but all of these in their "stock" form, have a built-in stability, as they were all designed to handle more speed. Truck designers and manufacturers of these classic designs were likely shooting for a truck that maintained at 30mph as well as 10mph. And this is why in LDP we start compromising the stability with added angle risers for the constantly slow speed of generating energy with flatland pumps. When we turn on flats, we need an instant, effortless turn, which is what jdnorthup is getting by wedging the gullwing.

Now there's a point beyond which the wedging starts to get counter-productive, and with a reverse kingpin truck I find it's when the kingpin's angle starts getting too close to parallel with the deck / ground -- the feeling is that the hangar "surfs" side to side underneath the deck, but no longer has enough downward angle, where your weight and force into the truck actually come into play.

Think about the "gimmicky" trucks that have come to the market, like Carver C7's, CX's, Revenges, RTR's, Thrusters, etc. These are all inherently "loose" trucks that sell themselves on how surfy they feel straight out of the box. And notice that if you read any reviews on them, riders will always mention the same thing -- not good for speed, not good for going down big hills!! That's what keeps these types of trucks in that category: built-in IN-stability.

Most retailers of complete boards don't like to and don't want to consider or add credibility to the wedging argument -- because after all, it is far more simple logistically (and thus more profitable), to slap on a set of trucks with at best a couple of the exact same risers on each end, and call it "complete." Simple, fast, time-saving complete setups. All this extra wedging and dewedging logic would just cost them effort, and make the board too specialized.

jd - talk about blah blah, eh?? mornings, caffeine, and verbosity, they go together. Very Happy

about reversed kingpin wedging

this weekend

hmmm