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Posted: Sun Apr 26, 2009 5:36 am
I just upgraded from an RT-S to a splitfire rear and I came across some questions. Ive got it on a randal 28* baseplate and mounted on the tail of my AXE Lynn Kramer. I cant seem to dewedge it as much as I had my tracker. I was running the RT-S with the kingpin perpendicular to the board or 2 or 3 degrees less. With the splitfire, even with the 19* of dewedging i have on there now, its still about 12* off from perpendicular. Is this a problem? Does the split need to be dewedged less or should i invest in some more wedges? Im also using venom green barrels top and bottom and it still feels turnier (turnyer?) than the RT-S (although more precise). Should I get some harder bushings or is this more of a geometry issue?
Thanks for any help.
Posted: Sun Apr 26, 2009 5:59 am
David, I have in the past, posted about keeping the kingpin close to perpendicular on 'normal'(such as the RTS or Madrid) trucks for the Rear in Slalom. With the Randal DH baseplate, this isn't quite true, because the pivot is not 'kinked', as it is in Trackers or similar trucks (this analogy would include Indy Offsets, as the geometry is also 'skewed' at the pivot in relation to the axles). So, you need to be aware of things like wheel scrub, bushing hardness, and wedge angles in 'fine tuning' you rear truck. Start out with what used to work, then refine from there. So, if more steering is needed, let the rear steer more by lessening the rear wedges, but really only by a few degrees at a time (here-in, 3* can make a HUGE difference in pumping thru!), so Khiro's 'Race wedge kit' is advisable (not to worry, it'll pay for itself easily). Lilkely, you'll get the turn-in settled before the final bushing combo[es] are settled-in. The kingpin on these bases can be as much as 180* of of being perpendicular to the deck and yet provide good traction. The Vemon bushings (provided the Durometer suits) are good stuff. Stiffer bushings may be needed to on 'top' (Near the top-nut) to keep the pump stiffness up to par. Experiment, but note the changes made, then run what feels And times-out the best.
Posted: Sun Apr 26, 2009 6:05 am
Oops, Typo!! this bit- [ 180* of of being ] should read : "18 degrees of being" on the previous post. Sorry, my beer must've intruded on the 'caps lock' button somehow. dagnabit !
Posted: Sun Apr 26, 2009 7:54 am
Thanks for the response Eric. I guess I should clarify somewhat. I guess im wondering how much other people are dewedging splitires on a 28* baseplate and tail mounted. It seems like if i wanted to run it perpendicular i would have to use 30* or more of dewedging which seems excessive. If thats what i have to do then ill have to buy some more wedges but I have a hard time believing others are dewedging it that far.
I realize that a lot of it is trial and error but i guess im just looking for a good starting point, how other people are running their splits.
Posted: Mon Apr 27, 2009 12:45 am
David Johnson wrote:im just looking for a good starting point, how other people are running their splits.
David, I run that truck with a 35° Randal DH baseplate on 3 of my setups and I absolutely love it. Use whatever dewedge you need under the tail to bring it to flat (parallel to the bottom of your board), then add 3°. It shoud give you a 25° geometry. That is a very good starting point.
Posted: Mon Apr 27, 2009 12:55 am
Ditto what Mig said. Mine is on a 35* Randal base, at neg. 6 to 7 degrees wedge (after bringing to flat under the Fullbag kicktails - about 5-6 degrees). So I'm running it at 28-29 degrees for GS, which is the only thing I use the Split for. I weigh 210 lbs. and use a black (95) or yellow (92) Khiro barrel bushing top, over a blue stim (92a) bottom.
Posted: Mon Apr 27, 2009 2:58 am
Awesome, thats the kind of info I was looking for, thank you. I tried it out on a decent hill today and it felt a little squirley at around +11* so ill grab some longer hardware and another wedge kit and try to bring that down closer to +3*.
Posted: Mon Apr 27, 2009 3:27 am
David, you mean -11* right? If you are positive wedging +11*, meaning you now have a truck running at 39*, then yes, it might feel squirrely, but still shouldn't be too bad. Minus 11* with the 28* Randal DH plate would give you a truck at 17*, which if anything should be super dead, not squirrely. If you were at 17*, then my guess is that the front truck is what was making it feel squirrely. What are you running up front for truck/wedge/bushings? Remember to take away 5-6*, or whatever it takes you to get to flat (0*) under the kicktail - i.e. if it takes -6 degrees to get to flat (parallel to bottom of board), and you want to de-wedge -7 degrees, you'll need -13* of total de-wedge. I hope that all makes sense.
Posted: Mon Apr 27, 2009 3:34 am
David Johnson wrote:Awesome, thats the kind of info I was looking for, thank you. I tried it out on a decent hill today and it felt a little squirley at around +11* so ill grab some longer hardware and another wedge kit and try to bring that down closer to +3*.
Longer hardware and more wedges is going to INCREASE your negative wedge, not decrease it. Just to be clear, Eric, Mig and I are all talking about the degrees difference between the board bottom and the bottom of the truck baseplate, not the degrees the kingpin is away from being perpendicular to the bottom of the deck. I know from your first post that you get the idea of what de-wedging does, just want to keep the terminology clear.
Posted: Mon Apr 27, 2009 3:50 am
Yeah, sorry, terminology mixup. Right now i have 21* of dewedging on the splitfire with green venom barells top and bottom. As i understand it, that should put it at 7* (28-21) plus whatever the kicktail comes to (have this mounted on my AXE 2.5 now). In front im using a chopped down bennet spaced at about a 4" hangar with 15* of wedging and orange khiro cone/orange khiro barell bottom, orange venom cone top. The current course im running is on a decently steep hill with eight foot centers and pretty easy offsets (i think). The skennet is probably a little unstable for this hill but my only other option is a dart hangar on an rts baseplate or dropping more dough. Thanks for all the help!
Posted: Mon Apr 27, 2009 5:31 am
If you have 21* of de-wedging, with lets say a 6* kicktail on the Axe, that means you are de-wedging a 28* truck and additional -15* (21 minus 6) - so your actual truck angle is -13* (28 minus 15) - that is considered REALLY dead for a Splitfire. To compare, my 35* Splitfire has -13* of de-wedging on a 6* kicktail, for a total of -7* de-wedge (13 minus 6) - making my total actual truck angle is 28* (35 minus 7).
If you have a Bennet wedged +15* then I guarantee you that is where your squirrely feeling is coming from. And the cone/barrel bottom bushings aren't helping either. I used to run my Bennet at +5* for hybrid, and flat (0*) for GS - AND used a yellow 75a stim on the bottom WITH the cup washer, on top of either a shaft collar tower extension (http://speed-dealer.ca/bennettac.asp
), or alternatively a stack of 3-4 fiber washers (fiber washers are quiet and won't wear the kingpin etc.). Then whatever soft barrel (73a-81a-ish), NOT a cone, you want on top. Two cone bushings on a +15* wedged Bennett is asking for disaster at speed if you ask me.
Remember too, that these are all personal setups. Do what works for YOU! Make changes ONE at a time and take notes. Good luck David!
Posted: Wed May 06, 2009 6:02 am
Thanks for all the advice. Ive been making a few changes per your suggestions and was hoping I could get some feedback. I have my first race (yay!) in a week and a half and unfortunately the weather here has been terrible and i havent been able to do much practice on a hill. Ive been able to do some testing in a garage but its not the same. Any further suggestions would be really appreciated. And yes, i know my wheels are pretty soft but as im still pretty new to slalom i like the extra traction as opposed to speed.
Front: Chopped down Bennett, wedged 5* (ish? its a hard khriro wedge) shimmed up orange khiro barrel bottom, orange venom barrel top.
Rear: Splitfire 90 on 28* randal plate, dewedged 13* (mounted on tail), green venom eliminator bottom, red venom barrel top.
Posted: Wed May 06, 2009 4:01 pm
Nice David! A couple things, and these are just "extras", since it's hard to give more advice until you've ridden the board more in a course. You have an excellent starting point now though.
On the rear Splitfire 90 - try spacing it out to 100mm for TS, 108 or so for HY. Take the cup washers off entirely, and use a regular steel 3/8" flat washer on top under the nut. If you have the bushings, try a harder or equal one on top. For TS/HY I'd go 90/90 or 90/92 or 90/95...I'm 210 lbs. though, so adjust accordingly. Keep this truck a bit tighter than you think you should. Looks like you could de-wedge even more, another 3*+? Pretty steep tail on the Axe.
On the front Bennett - what's your spacer material on the bottom? Looks funky - if it's cut down bushing it's gonna keep the Bennett too "divey". Try those fiber washers if you can find 'em. Trade the top cup washer for a 3/8" flat washer on this truck too. Just for kicks, but not ON race day, try the Bennett with +10* wedge, then +5*, and note the difference.
Your wheels are fine - two fingers clearance is a good rule for checking height to prevent wheel bite, you look set there. And keep those bearings cleaned and oil (not grease) lubed.
With all this info you now need to go out and KICK BUTT!! :-0
Posted: Wed May 06, 2009 6:55 pm
Thanks for the tips, Rick. Just to clarify, when you say 'take the cup washers off entirely' on the rear, do you mean on the bottom too? So, you think i should run the bushing straight off the baseplate on bottom and with a flat washer on top? Its my understanding that would give it more turnyness, no? I weigh about the same, 200ish, so i could put in a green barell on top but i think thats the hardest i have. The course im running on the 17th is kinda between HS and GS, steep hill with pretty minor offsets and about 8ft spacing. When you say fiber washers, is that the same as nylon washers? I guess i could run out to the hardware store but the bennet feels pretty good the way it is. Thanks again!
Posted: Wed May 06, 2009 8:37 pm
David Johnson wrote:Thanks for the tips, Rick. Just to clarify, when you say 'take the cup washers off entirely' on the rear, do you mean on the bottom too? So, you think i should run the bushing straight off the baseplate on bottom and with a flat washer on top? Its my understanding that would give it more turnyness, no? I weigh about the same, 200ish, so i could put in a green barell on top but i think thats the hardest i have. The course im running on the 17th is kinda between HS and GS, steep hill with pretty minor offsets and about 8ft spacing. When you say fiber washers, is that the same as nylon washers? I guess i could run out to the hardware store but the bennet feels pretty good the way it is. Thanks again!
It is, ultimately, all about how it "feels" to you of course. And yes, try it with the cup washers off entirely on the rear - bottom too. You have taken the "turnyness" out of the truck with the 28* plate and wedging, now it needs to smoothly through its range, no matter how tight or loose the kingpin bolt adjustment is. A cup tends to limit the truck at the extremes, especially with a stim shape on it.
By the way, some people like the harder bushing on the bottom in the back, top is just my pref.
Fiber washers - they are in the hardware store hardware isle in one of those drawers full of stuff. Usually a brownish red color.
Posted: Thu May 07, 2009 2:54 am
Just for fun I broke out the measuring tape and measured the dimensions. Hangars are 105mm and the wheelbase (axle to axle) is 57cm or 22.5 inches. I dont seen any reason to change that at this point although ill probably drill another wb at some point.
Posted: Fri May 08, 2009 7:55 pm
While digging through my bushings I found a green superball. I think its 97a. I put this on top with the green eliminator (93a) bottom. If feels really dead on the flats but i wont get to try it on a hill until tomorrow (hopefully). What im wondering is are superballs any good? I know nothing about them really, ive always used khiros and just recently some venoms. Is 93/97 crazy hard for a 200 pounder?
Posted: Sat May 09, 2009 8:03 pm
David Johnson wrote:While digging through my bushings I found a green superball. I think its 97a. I put this on top with the green eliminator (93a) bottom. If feels really dead on the flats but i wont get to try it on a hill until tomorrow (hopefully). What im wondering is are superballs any good? I know nothing about them really, ive always used khiros and just recently some venoms. Is 93/97 crazy hard for a 200 pounder?
97 is crazy hard, or close. Superballs are not the best for slalom IMO.
Posted: Sun May 10, 2009 5:06 am
i run an orange superball bottom that was given to me by sk8kings as a complimentary gift.
Posted: Sun May 10, 2009 6:53 am
Yeah, i was able to get out on a hill today and get some pro help dialing in. its a lot more cofortable now. I ended up going softer in the rear, 90/90 vemon barells. added a touch more wedging to the front and pulled out the wheel base by an inch. feels much better now, looking forward to my first race. Thanks for all the help.