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| Truck Reviews (15215 Posts)
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joel's randalls
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On 9/12/2005
Derik
wrote in from
Germany
(193.7.nnn.nnn)
Hello Joel,
I hope You find the right setup. I came to the conclusion, that it is difficult to talk about whats right for your Randals in theory. Every rider has its own style, when just cruising around. I drive my front truck loose with the soft bushings (after the kingpin has contact with the bushing a half turn tightend). The aft with mediums is a little firmer, just to eliminate oversteering in hard turns. I like that.
Last week I took a ride with a few guys arount town and we changed boards just to test each others setup. Although everyone had his everyday-cruising-board with him, I wondered that every board was so different. And I wondered that a verry experienced rider fell of my board trying to take a double bend I could ride at much higher speed. With his board I could even go faster, but with less carving and a lost of centrifugal force in the carves that I like so much. Its all about style and usage. And this is the great thing about this ncdsa-site. To find so many different ideas and styles and find what suits You best. Because to find the right cruising setup is so different from finding the race setup. Cause You can not time-proof the setup, just feel-proof. (at the first opportunity i'll try seismics)
Enough of my hooey, let's ride!
Derik
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Mr Rawls
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On 9/12/2005 Ghooste
wrote in from
United Kingdom
(193.113.nnn.nnn)
bravo!
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truck testing, component testing
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On 9/11/2005
buddy rawls
wrote in from
United States
(64.12.nnn.nnn)
I know what I like and I stick with it. Can i argue slalom truck designs? no. But I can argue component level testing. I am in structural test field as a career engineer, but i am also into race engines, specifically airflow and camshaft design. As an analogy, people always try to determine the best camshaft for their motors. they view a camshaft as the end-all component, in that what is good in one motor, is ofcourse good in all motors. It does not work that way. a camshaft is (or should be) the calculated result of engine flow parameters and volumetric geometry and desired operating band. a cam is simply a hunk of metal, when taken outside of its design criteria. A truck is very similar. swapping a truck and running a timed event to determine success or fail is not a valid test. Just the same as simply swapping a camshaft of unknown origin or specs. If the cam's valve events are nowhere near the motor's needs the motor output will suffer. does that make the cam bad? no. It just means the parameters are not correct. it could be the case, that the parameters can never be correct. to really see the benfits of a component swap in a "system", the system has to be sufficiently tuned. rider style, lean versus turn ratios, wheel placement, body placement, wheelbase, etc. Once all these aspects are tested is where the true winner comes out. the only problem is, we are dealing with humans with differing weights and styles. so a winning component or system for one person may be sure loss for someone else.
I am not argueing for one truck versus another, I am just saying that in the marketing, a winning truck simply means that a good combo was utilized at some point. Is it good on everyboard, with every wheel, with every rider? no . It still comes down to what works best for "you". so trying stuff out, deserves a fighting chance. not a make-or-brake changeout test. If it gives good results, so be it. However, bad results does not necessarily mean anything good or bad, until all the parameters are investigated. outside of that, the result of testing simply proves that, for the individual, the tested configuration did not show an improvement. its not a winner or loser, until it can truly be determined that in any conceivable combination it simply does not get the job done.
Just trying to add some extra input on component level versus system level testing.
buddy Rawls
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My 83mm 75a Flywheels ROCK
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On 9/11/2005
Don J
wrote in from
United States
(65.139.nnn.nnn)
Hey Chris, since were on the subject, I do need something more stable than whats in my Randal DH trucks, black bushings and pivot cup. My luge rolls from side to side to easy, need to be stiffer. Went with Doh Doh for now, but cant wait for yours. By the way, my Flywheels rock, over 14 runs, and still see the extra rubber like it was new. I run the Xtreme Wheelz luge, heavy. I havent taken them into a 50mph turn yet.
Don
www.geocities.com/djackson9504
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Thanks Chris
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On 9/11/2005
Greg Olsen
wrote in from
Canada
(206.172.nnn.nnn)
Thanks Chris,
The way I ride my 72As will never wear out. Smooooth no. Sloooow yes. :)
Greg
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Print / Duros
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On 9/10/2005
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
Brady, My DoubleWides have printing on the inside and out. They require an extra 1" of axle on each side because there are 4 bearings in each wheel.
Greg, When our Flywheels had bigger hubs, they felt harsher on really rough surfaces and 72a helped to smooth it out. It is a great formula, but it doesn't last as long as most consumers expect. Now that every one of the new generation of Flywheels has more depth of urethane than the one it replaced, we decided to drop the 72a formula and add the 81a formula. Now 78a is our "middle" formula. Here's a little chart showing the old and new depths:
Old: 74mm wheel, 50mm hub = 12.0mm depth
New: 76mm wheel, 45mm hub = 15.5mm depth
Old: 83mm wheel, 50mm hub = 16.5mm depth
New: 83mm wheel, 45mm hub = 19.0mm depth
Old: 92mm wheel, 50mm hub = 21.0mm depth
New: 90mm wheel, 45mm hub = 22.5mm depth
Old: 101mm wheel, 70mm hub = 15.5mm depth
New: 97mm wheel, 45mm hub = 26.0mm depth
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is this a test?
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On 9/10/2005
Brady
wrote in from
United States
(68.223.nnn.nnn)
Chris,
I noticed the graphics on the wheel shown are faced inward. Is this a test or just another variable?
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72A no more why?
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On 9/10/2005
Greg Olsen
wrote in from
Canada
(206.172.nnn.nnn)
I bought some 83mmFlywheels in 72A. They do not seem to be offered new anymore. Wonderin' why? thnx.
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Jolly Green Giants
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On 9/10/2005
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
I'm already testing the tallest, widest, gummiest cushions on the planet. When you start with gobs of glorious green goo, you can can cut it and shape it down into any size and shape that you want. The duros may look a bit familiar - 75a, 78a, 81a, 84a, 88a, 92a...
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Truck Testing -- what was the question?
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On 9/10/2005
Pat Chewning
wrote in from
United States
(67.189.nnn.nnn)
Kaspian: No, I do not believe that in the "real world" of testing trucks anyone uses the Design of Experiments approach. Probably because they are not trained in this approach, and probably because it takes a specialized computer program to take the results of the experiments and do the statistical analysis to determine which variables contribute the most to the success of the outcome.
Chris: Yes, changing only one component might be a good way to determine if that one component improves the outcome. However, it will not tell you if changing that one component and changing a second component will give you an even better outcome.
An example might be useful: You want to determine the optimal setup for cyberslalom when changing 5 factors on your skateboard over 4 levels. The 5 factors and their 4 levels might be:
Wheelbase: 18" 20" 22" 24"
Durometer: 75 80 84 90
Wheel size: 60mm 62mm 65mm 70mm
Front Wedge: 0deg +5deg +10deg +15deg
Truck tightness: 0 (just touching bushing), 1turn, 2 turns, 4 turns
To exhaustively check each of these 5 parameters over 4 levels it would take you 1024 experiments (4*4*4*4*4). After the experiment is done, the best outcome that might be possible using the "old school" method would be something like this: 20" wheelbase, 84 durometer, 70mm wheel, front wedge 5 deg, 2turns tightness gives the best result.
Using the DOE methodology you would do 16 experiments in array like this:
http://www.freequality.org/doc/attach/L'16%20Array.htm
Notice that many variables are changing at the same time. After the experiment, just looking at the data, you might not be able to draw much of a conclusion because more than one variable is changing at a time. However, applying the statistical analysis to the results should give you information on the optimal setup.
One possible outcome is that the optimal setup is not even a combination that was tested! The outcome might point to a solution like this: 22.6" wheelbase, 92 durometer, 70mm wheel, front wedge 7.375 deg, 2.125 turns tightness. Notice that the statistical analysis of the results has suggested intermediate levels that were not tested and extrapolated the results beyond the levels tested (92 durometer is beyond the 90 durometer tested).
Yes, you would want to do a verification experiment (a 17th experiment) using the suggested levels. But 17 experiments is a lot fewer than 1024 experiments, and the results are optimized rather than just sorted by outcome.
This really does work. We use it to design elements of HP printers which have hundreds, if not thousands of variables that we might want to optimize. It may be difficult to apply to skateboard racing because the skill of the rider is a somewhat uncontrollable "noise" factor. But by expanding the array and including more experiments you can effecively eliminate the "noise factors".
-- Pat
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BUSHINGS!!!!! part II
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On 9/10/2005 Pauliwog
wrote in from
United States
(64.5.nnn.nnn)
I think that bushings have a HUGE part in how ALL of our trucks operate, and on that note, I'd like to reiterate that everyone should stop talking about everything else except for bushings and harass/encourage/use shame as a leverage tool/etc and direct it in Chaput's general direction to get him to produce some truly great bushings for slalom(and everything else) made from his champion formula urethane to replace the much-sought-after Tracker Stimulators(another moment of silence please). Thank you so very, very, very, very, very, very, very much-Paul
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"Old School"
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On 9/10/2005
Chris Chaput
wrote in from
United States
(66.116.nnn.nnn)
If by "old school", you mean something that has stood the test of time and is known to work, I agree. And in this particular case, changing only one thing is THE most efficient way to draw a conclusion about a single component. For purposes of this discussion, we are only interested in one component's performance in a single setup. Lock it down, try it. Unlock it, try it. Rinse. Repeat. Changing other things would only cloud the issue.
On the other hand, if we were trying to find a combination of components that worked well together, I would test a number of different combinations and look for components (or combinations of components) that are common among the setups that performed the best. Otherwise, yes, we may die from boredom before we find anything that we like.
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testing trucks
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On 9/10/2005 kaspian
wrote in from
United States
(65.99.nnn.nnn)
Pat, that's very interesting. But wouldn't you say that, in the real world, this "Design of Experiments" approach is more or less what we really do? I mean, generally speaking, we are aiming for an optimal setup, and we are not particularly focused on one specific piece of hardware.
If you're setting up a new board, you tend to think kind of holistically about it. You figure, this ought to ride really nice with Tracker Darts and Avalons. You don't bother to test every component individually. And that's precisely because, as the umetric.com guy might say, you want to arrive quickly an an optimum. Also, you already probably have some knowledge of the characteristics of the components from other "experiments" on other boards.
On the other hand, we also do COST-type comparisons all the time -- for instance, trying out different wheels. In this case, a "change one specific thing at a time" approach is the only thing that makes sense.
The key to this Design of Experiments approach would seem to be the phrase "X variables over Y experiments." To provide meaningful results, the value of Y has got to be significantly greater than 1. So, getting back to what prompted this discussion, you can't simply perform one "experiment" in which you skate around on two completely different setups -- different boards, wheels, trucks, bearings, age of components, the works -- and declare, as one poster persistently did, "Board A is better than Board B, BECAUSE OF THE TRUCKS."
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Advantage of testing one variable at a time
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On 9/9/2005
Pat Chewning
wrote in from
United States
(67.189.nnn.nnn)
It just occured to me that there is one big advantage to testing one thing at a time on your skateboard: You will spend a HUGE amount of time experimenting and your skills, strength, and endurance will increase. And you'll have a lot of fun doing it.
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Traction Lab - Experimental Design
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On 9/9/2005
Pat Chewning
wrote in from
United States
(67.189.nnn.nnn)
In the discussion below on the TL truck (see last 75 postings or so), a number of people mentioned that experimentation with the truck should only vary one thing at a time to be a valid experiment. This idea that you only change one variable at a time when experimenting is "old school". The new way of running experiments on complicated systems is called "Design of Experiments" and it involves changing many variables in a mattrix of X variables over Y experiments.
If it were not for this new technique, complicated systems of several variables could not be experimentatlly tested in a reasonable amount of time while you test one variable at a time.
The "Design of Experiments" approach allows you to find the independent variables that contribute the most to the outcome (perhaps wheel base, truck width), the interactive variables (perhaps bushing durometer and bushing compression "tightness"), and the variables that have no effect (perhaps color of the axle).
A good introduction to the approach: http://www.umetrics.com/methodtech_doe.asp
======================================================
"The COST approach (Changing One Separate factor at a Time) is, however, very inefficient. As shown by Fisher around 1925, changing one factor at a time does not give any information about the position of the optimum in the common case where there are interactions between factors. Then the COST approach gets stuck, usually far from the real optimum. However, the experimenter perceives that the optimum has been reached because changing one factor at a time does not lead to any further improvement. The COST approach is said to be pseudo-convergent.
The basic idea is to devise a small set of experiments, in which all pertinent factors are varied systematically. This set usually does not include more than ten to twenty experiments. The subsequent analysis of the resulting experimental data will identify the optimal conditions, the factors that most influence the results and those that do not, the presence of interactions and synergisms, and so on.
The most important aspect of design of experiments is that they provide a strict mathematical framework for changing all pertinent factors simultaneously, and achieve this in a small number of experimental runs. Most of us can only grasp the effect of one factor at a time in our minds, and that leads to the inefficient COST approach. We need the mathematics (and the computer) to keep track of the factors and their combinations."
====================================================================
I just thought you might want to know about some advancements in the area of the scientific method of experimentally finding the optimum outcome of a complex system. It might make development of wheels, trucks, boards, etc more efficient.
I have no idea how well the Traction Lab truck works. I know for my own skating the single most important variable seems to be how many days I get out out and skate. I did not do a rigorous experimental design to figure this out.
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Randal help
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On 9/9/2005 Joel
wrote in from
United States
(63.134.nnn.nnn)
Man you guys have been really helpful. I appreciate the offer to try out the Radikal's lonerider. Actually I think I'm getting the Seismics dialed in.
I had the Seismics on a much wider and shorter board than I'm using now which completely changed how I want them to feel. I had them on a 38" BDS and the Gravity Hyper I'm using now is much longer and much more narrow.
It's certainly an eye opener seeing how much a turn or two affects these Seismics. They do rattle a bit (I've been running a soft 1/8" pad under them) but not so much that I can't deal with it. The performance is more inline with what I'm looking for.
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Correction
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On 9/9/2005 Same Guy as Before
wrote in from
United States
(64.5.nnn.nnn)
In the posting below: Hedy should read as "Hey". Too many fingers flying too fast on too manyt keys. Hmm, did it again.-P
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Looks like Sputnik may finally reach the launch-pad
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On 9/9/2005 Pauliwog
wrote in from
United States
(64.5.nnn.nnn)
Hedy Eric, Cool! I sent my 100mm Seismic hanger for some ends-of-hanger-trimming, hopefully you got it by now. Thanks-P
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Joel's Randals
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On 9/9/2005
lonerider
wrote in from
United States
(65.249.nnn.nnn)
Joel Wrote:
=========
However it's not really the fact that the Randal's don't turn well enough but I can't seem to find a middle ground. They're either tight which has a good positive feel to it but then I really lose to ability to carve (and I'm talking about within Randal's ability to do so) or when they're loosened they're just dead and feel like I'm riding without any bushings. It feels more like the bushings are in there as a "bump stop" or something. I only feel any energy in them at the extreme.
=========
I had similar problems as you, I had a set of Khiro inserts in there for a while. Then I tried Radikal bushings as the bottoms and that *dramatically* improved the ride in my opinion in that the extra thick, wide barrel shape gives you a very progressive feel to it. Like it lets you start leaning the board over nice and easy, but progressively resists you as you lean it over more. I really liked that combo. The Seismics are fun too, but different. They are much easier to lean over in the beginning, yet at the same time, they have a much strong return to center pull once you are in the turn. If find this leads to a more pumpy surfy style of carving (not that it is like a surf board, just more in that direction). In contrast, the Randals with Radikals lean over a little less quickly in the beginning and then kind squish down as you lean over, while there is a good amount of rebound, the return to center pull is much more mild so you can see in a long, tight carve it you want without the trucks pulling you out of it, the different is there is less energy return once you do come out of the carve. Main issue with Radikals is that it takes roughly 3-4 weeks to get them shipped to you once you order from their website. I think I have an extra set of Clear 75a (VERY carvey) or Red 80a (carvey) if you want to try them out, I've even sanded off the edges already to make them ride Randal trucks.
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Joel's Seismics
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On 9/9/2005
Adam
wrote in from
United States
(198.144.nnn.nnn)
Joel,
You should be able to tell if you're maxing out your rear Seismic truck. If not, you may want to try a) riser pad to get more leverage, b) lighter springs, c) wider hanger/wheels if your wheel edges aren't at least deck-width, d) stiffer deck to mitigate torsional twist.
Having more steering aft than fore can produce some strange and unexpected handling (I prefer the exact opposite) though it can impart the surfy 'bottom turn' sensation you're probably liking.
p.s. Since you used the word 'energy' when describing a truck, you've found Your Trucks with Seismic.. just keep fine-tuning until you get it dialed.
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My Randal's
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On 9/9/2005 Joel
wrote in from
United States
(63.134.nnn.nnn)
Hey guys thanks. Yeah I realize that Randal's are never going to compare to a torsion truck and to be honest I don't want them to. I use this board for pretty much all-around skating and there's enough large hill in that mix to warrant not using torsion style trucks (at least for me).
However it's not really the fact that the Randal's don't turn well enough but I can't seem to find a middle ground. They're either tight which has a good positive feel to it but then I really lose to ability to carve (and I'm talking about within Randal's ability to do so) or when they're loosened they're just dead and feel like I'm riding without any bushings. It feels more like the bushings are in there as a "bump stop" or something. I only feel any energy in them at the extreme.
I've be messing around with the Seismics today and I'm actually pretty close to what I want. But now I'm thinking I might get closer by going with a quick rear and quick front. Right now I'm running a stable/quick.
Would this be an option? Or would I be better off trying a lighter rear spring and keeping the stable rear?
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joel's randalls
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On 9/9/2005
Adam
wrote in from
United States
(198.144.nnn.nnn)
toddc is right on with his comments. However, I wouldn't give up on your Seismics so quickly. Try the following: 1/8" urethane riser pads to provide some cushion; Tighten spring adjuster screws 3/4 turn or just enough to take up the free play between the spring caps and the hanger; Use proper bearing spacers. If you're still getting the rattles I'd opt for one of Geezer-X's 8mm converted Seismics.
I also like putting the front truck on a 1/2" riser to increase leverage and wheel clearance (when needed). And I detune the rear by using one level stiffer springs and de-wedging though if you're into pulling u-turns on sidewalks this may not be what you're looking for.
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joel's randalls
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On 9/9/2005 toddc
wrote in from
United States
(198.39.nnn.nnn)
joel, if you are used to the crazy turning abilities of Exkates, originals and other torsion trucks, you will NEVER get randalls to turn like them. Like wise, those trucks will never be as stable as randalls or RIIS. It's called a trade off. The only solution I can think of is, put the RIIS on a shorter deck than you are used to. This will make them turn more quickly and still give you the added stability/geometry. No single truck can do it all.
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joel's randal woes
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On 9/9/2005
Julien
wrote in from
United States
(129.133.nnn.nnn)
Hey,
I noticed you mentioned you had both the blue and black bones hardcores. For me however the yellows (meds) are really where its at. They're not quite as mushy as the blues and won't explode on you if they're tightened down. The still offer great return-to-center and are plenty stable in my opinion.
I had the bones yellows in my R2 180s on a 44" Comet Proflex spoon w/ gumballs and this board did just about everything: you could pump it on the flats, do some nice hard carves at speed and bomb without worrying about wobbles. You could always try a combination of bushings too, I often like to run harder bushings in the back nowadays to make the rear truck more of a trailing rather than steering truck, you can still carver real nice but don't have to worry about sliding out; you'll also end up going much faster downhill since you won't be able to get as perpendicular to the fall-line.
-Julien
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Help for my Randal's
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On 9/9/2005 Joel
wrote in from
United States
(63.134.nnn.nnn)
Hey Derik.......
Thanks for the suggestion. I actually did find that using two tall Bones Hardcores in each truck worked about as well as anything. Still it seemed that using the Blues I had to crank them down so much that they really started to deform.
I've got black Hardcores too but I don't have enough sets to use two large all the way. Funny thing is the Randal's are fairly cheap but I've pretty much spent as much if not more in bushings for them.
I mounted my Seismic 155's back on it last night. I'm going to play around with them more. I'm actually thinking of going with a quick/quick instead of the stable/quick I'm using now.
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