Beautiful… What damper were you using please? Big skewer point in that design though , needs a mushroom on top, but exactly what I’m talking about, design out the speed wobbles, rather than rely on carefully setting up the geometry. We did this on bikes years ago , you always had this vid on the back if your mind before steering dampers…After steering damping, not an issue.
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I find it all quite hard to grasp what is going on with speed wobbles and the geometry of split angles behind it (and of course damping is like the quick shortcut to solve it), but geometry? amazing! like someone else said here : magic!
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I think I need a physics lesson on split angles… I fail to understand why it works, but it does! that’s mindblowing
Because when you go to a lower angle the trucks do less side to side “steering” and more up and down “Leaning” when you lean on the deck. That more up and down motion is why you need harder bushings I think.
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No worries! This stuff is a little confusing at first. Just remember that angles are relative between the hangar and deck(ie baseplate plus angled risers if you have them).
Higher angles allows for more turning per lean while lower angles allows for less turning per lean all else being the same.
You want to stabilize your rear in a wobble situation so having low angles will help with that but you still want to be able to turn so having higher angles up front preserves that.
Look at your trucks, let’s think of extreme situations where the hangar is perpendicular to the board (90 degrees) and the hangar is parallel (0 degrees).
When it’s 0 degrees, you can see how leaning left and right doesn’t turn the wheels and when it’s 90 degrees it can easily turn the wheels
Going to make an edit to stop referring kingpin and deck to hangar and deck for easier understanding
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First step is replace the rear base plate with this: https://shop.paristruckco.com/products/paris-43-v2-baseplate?variant=15962911539251¤cy=USD&gclid=Cj0KCQiAuefvBRDXARIsAFEOQ9F8t0r0YiBKarYxJkfiBK_dKVncX9yyAYJt42ceAk-UoqdK4-LZ30YaAmXxEALw_wcB
Then get RipTide bushings that are specifically designed for Paris trucks the Canon and Magnum in the KranK compound so you have a lot of adjustability. Pivot cups also. What is your weight?
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Ok - will look into that the next step of getting the trucks. Canon and Magnum in Krank - both canon and magnum where do they go? into that rear truck only? - I’m 73kg, Linny mentioned 90A for that weight.
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Wobbles are harder to correct as they are less “Turney”
I should have been more specific, pick up two pair of Canons in KranK 90a and one pair of Magnums also in KranK 90a plus some small flat washers for additional tuning options. Set up the front with Canon / Canon with the cupped washers you already have and a Canon / Magnum in the back truck. I am listing the bushings Roadside / Boardside. Start with the bushings just tight enough to take out all the slop then you have bout two full turns of the king pin nut for adjustment. With that combination of bushings you will have several different combinations you can try if the initial one I suggested is not the feel you are looking for. Links are below:
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Thanks heaps Brad, keen to look at purchasing tomorrow as it’s super late over this side of the planet now (3am).
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This is the one I used
PROCNC Motorcycle Steering Damper Stabilizer For Yamaha Honda Aprilia Suzuki KTM https://www.amazon.com/dp/B07KG2P6DX/ref=cm_sw_r_cp_apa_i_rFN-Db73JZ9QT
If I were to use it again, I’d design a TPU sleeve to cover the adjustment knob to prevent dirt from getting in there as much as possible, and make it easily removable for adjustment. On the sliding rod, dirt didn’t seem to make a difference, but after a while the adjustment knob would bind up a bit.
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Is turn radius affected by truck width or wheel base?
wheelbase yes.
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Both actually
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How does truck width affect turn radius? I know wheel base but width too?
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Probably larger turning circle
indirectly. let a non physics guy try to explain physics.
Narrow trucks take less force to move a wheel a certain distance for the same turn radius as wider trucks, wider trucks have to move the wheels further since the wheels are positioned further out. You get the feel that narrow trucks are more agile and wider trucks are more stable. Is this why? I’m not sure, but it makes sense to me. I say indirectly because it’s not exactly clear, the effect is marginal compared to truck geometry, bushing setup, axle rake, how open or restrictive the bushing seat is, how soft or hard your risers are, the thickness of bushing seat between the bushings, whether you use flat or cupped washers, whether you use wide or narrow flat washers, whether your bushings are lower or higher rebound… it’s just another more marginal factor compared to many other variables that can affect turning radius on any setup given how hard you force the turn.
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Shouldn’t really matter that much as the distance between the pivots remains the same (the pivot of the front and the pivot of the back). Think of a compass (the circle drawing one, not the pointing to north one). Making one end fatter doesn’t change the way a circle is drawn. Only changing the distance between the two will affect the size of the circle.
@Skatardude10, this makes a lot of sense. However I would say turn radius is unaffected. You are still able to turn in the same space regardless of needing more or less force. Turn radius is not dependent (unless we’re talking about the extreme end where you can’t force it anymore) on force.
Missed this part so yes, if you consider force to also be a factor for turn radius then yes I agree. This could then be argued too for better bushing setups which helps with rebound/return to center (forcing the truck back) and overall stability.
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exactly, which is why I emphasize (or didn’t) marginal, that there are so many other factors that make a bigger difference when it comes to turning radius.
really, I’m talking out of my ass here, but I’d gamble to say that the only real prominent effect of narrow vs wide trucks is agility (there are other discussions to be had not related to speed wobbles such as grip characteristics… look at slalom and ultra narrow trucks for example, some very high speed, ultra agile, with stability as a requirement for high speed slalom). lack of agility can feel stable, great! for speed wobbles… but the feeling of stability doesn’t = stability. just like negative rake on a 50° baseplate feels stable, wobbles like you are riding 50° rears will still sneak up on you like you are riding 50° rears. Why are high-speed downhill riders favoring narrower and narrower trucks? the feeling of agility is real, and valuable when racing. what really affects stability? truck geometry. that’s why we see low angle rears with higher angled fronts combined with narrow trucks these days. they don’t cancel each other out, they compliment each other- a stable and agile setup. IMO, I agree 100%, truck width does not play a role in turning radius realistically.
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