[bergs]

Disclaimer - First off, before you go on reading the bible I'm about to type, let it be known that, unless I do it myself, I will question it. It's how my personality is wired....I cannot change that, nor do I want to. Please accept that as you read this post.



I keep hearing about the supreme awesomeness that is GMD. I'm aware of the chassis equipment for checking a given bike's straightness. I'm also aware of the "Sweet numbers" that GMD has archived (and continues to do archive) over many years of development through hardware and software...and that's all good and dandy but one question I have that has never been answered is "What about rider preferences?"

I'm not saying the good folks at GMD are anything less than amazing from everything I've been reading, be it testimonies, the equipment or even the company's history.

But, even after reading all this information I have always wondered how much of said "Sweet numbers" really makes that much of a difference.

My history has always been to set my motorcycle up with the way I like it to feel. Admittedly, even after all the books I've read (and am currently reading), I've never done the static sag measurements, I've never done the zip-ties on the forks and yet, with minor tweaks here and there, I manage to acheive what I percieve to be excellent suspension performance throughout many surface conditions.

Is this possible? Can a given rider prefer a certain type of ride feel over what a computer recommends?

Furthermore, does a given rider have the ability to diagnose the chassis' reactions on the fly and know enough to make the applicable adjustments to correct that?

It has been my experience that the adjustments I make to the motorcycle I'm riding are done through what I can feel in the chassis' reactions and feedback and the type of ride I'm looking for (aka "preference").

I've done a good bit of reading, tried many different suspension settings of all kinds and yet I still have the burning question of "rider preference vs computer preference".

Please don't come back with "well, if you spent the money you wouldn't have wasted all that time." That is exactly what I'm NOT after for answers. To me, I learned a hell of alot by "wasting" all that time. The only thing left is the question of possibility...

[union]

I think youre a bit confused on what is going on. The computer (computrack) doesnt do suspension settings. It measures the bike and determines adjustments need to the ride heights, among many other neat things. From there we set the geometry of the bike. Front ride height, rear ride height to get the bike to the rake and trail we are looking for. It made a world of difference for my RC51.

As for the settings. Preload, compression, rebound. Its a matter of personal preference. When a set of forks get revalved we do have initial settings we tune them to. That just gets you in the ballpark. From there its up to you to make the adjustments to the clickers to find whats perfect for you. Once again it made a world of difference in my RC51. If you can find someone with a set of forks done and are willing to let you ride their bike, try it. You will see.

[RyanNicholson]

from my experience with GMD...its more than just revalving and adjusting clickers. The amount that I've learned just by discussing what I'm feeling on the track be it control under the brakes, mid corner feel, or rear end movement on the drive, etc....is priceless. Theres so much more to suspension than I ever imagined and all the reading in the world about it hasn't cashed in like having a "go to" guy that knows why certain things happen and how to improve it. Theres a million arguments as to why the hardware/geometry will improve your bike, but this is what I consider the advantage of working with GMD vs just installing parts on your own.

[Pittenger5]

Bergs the one thing I learned when I was down at VIR is how much better things could be. My suspension hadnt been touched basically since the bike left the dealership, I mean, its my street bike, I didnt care. I had it to a point where I thought it felt perfect. I had no problems with it, well when we were at VIR, it didnt feel real good even at my slow speeds, so I had GMD down there just do the basic adjustments. Holy crap does it feel better. I had no concerns on the track, and now even turns that used to make my butthole pucker on the street are absolutely nothing. It just feels infinantly better. Ask Dan and Wookie I dont stop talking how awesome this thing feels.
So basically what Im saying, is how do you know your bike CANT feel better? Maybe at least have the basics done, and ask them to note (which I think they do anyway) what they do to adjust it, and worse comes to worse you dont like it, you can always go back to the way you had it.

[Doc]

Originally Posted by bergs

Disclaimer - I manage to acheive what I percieve to be excellent suspension performance throughout many surface conditions.

This sentence stood out. I think perception is the key here. MAYBE you percieve what is good from your adjustments and MAYBE they are fine but I think there is nothing like a professional taking a look. EVERYONE I have heard that has went to GMD has came back impressed.

I plan on taking my bike to them sometime early this season.

(Can they do trackside stuff?)

[Paul_E_D]

Bergs, to answer your question, yes, it's possible that you have set your clickers to work fine for you, but you're not asking much of your bike at this point.

Not to dis you, but until you realize exactly how far beyond your limits even a mid level expert club racer is taking their bike, you won't really understand. The day may come when you are good enough to push your bike so hard it will simply misbehave badly in certain spots on the track. You will need to change more than clickers to get past the barrier. The need for professional help from guys who have solved problems for riders at an extremely high level will be self evident at that point...

[bergs]

Originally Posted by Paul_E_D

Bergs, to answer your question, yes, it's possible that you have set your clickers to work fine for you, but you're not asking much of your bike at this point.

First off thank you, Paul, for your excellent response.
I'm not understanding what you mean about "not asking much of [my] bike".

Things I pay attention to are ride quality, how the chassis reacts when entering, apexing and exiting a given corner..regardless of throttle or brake inputs. The results I try to acheive have to be "seamless" in all aspects.

I also try to notice if whether or not my tires are staying planted...after all, that is the point of all this right? Keeping the tires on the ground?

Not to dis you, but until you realize exactly how far beyond your limits even a mid level expert club racer is taking their bike, you won't really understand.

No offense taken. I wouldn't write off my limits so early in the conversation though...


I guess my biggest fear about all this is dropping 100, 200, 300 bux on something that I can figure out on my own or worse, end up disliking.

[Paul_E_D]

I'm not assuming anything. You gave a lot of info in your post. I have raced and ridden tons of different bikes, won a lot of races, a championship, etc. This is my field.

When you say you've always had success by just tweaking clickers I know you're not pushing your bike very hard. Again, no offense, it's just that my experience tells me that everything works just ducky up to a certain point. Then things become complicated very quickly.

You CAN feel your way through this, but your competitiors will be smokin you on professionally set-up machines. You can waste years chasing problems around. Most people just become satisfied with a certain level and then quit. That's fine. But if you want to win at a high level, Pete and Mike will be there to help you do it. Guaranteed.

[Doc]

Just a little example.

I am going along on my Hawk at my pace, thinking I am going pretty fast but only riding at about 90%. Fastest lap of a 1:27 I believe (Yes I know SLOW). Bike is planted, I feel NO issues.

I swap bikes toward the end of the season to the Duc. Duc's have been my streetbikes for years so I get comfy and up to speed pretty quickly, going faster than I did on my Hawk in my first session... Bike feels good, no suspension issues, feels like it is on rails.

Long story short I am in a race and trying to keep in the lead pack. I'm into the 1:23-24 mark and the front starts sliding around 9. I want to go faster but something I am doing is making it feel like the front is gonna wash while I am leaned over so I have to back off a little there and then it feels fine. The guys in front of me are going faster through there and I can't figure out why.

I chalk some of that up to suspension. I have a strange feeling that with some tweaks I wouldn't feel that anymore. Then again maybe it was the way I was riding or I wasn't putting enough weight on the front.

Point being that I to have listen to the advice of others without "trying it for myself". At some point (and I think my "point" comes LONG before yours) I don't know enough about it and I am happy to search out good advice, listen and use it.

I see the point about the money though. Once I learn, then there is no reason to spend money. (Just did my first fork rebuild a couple days ago)

[gmdboston]

Bergs, it sounds like you have very mis-lead about what Computrack is and what we do. I'll try to clear this up for you, but the explanation is very long and I'm a hunt & peck keyboard jockey, so if you have any lingering questions call me.

First a word about stock suspension. When a manufacturer designs and builds a bike, there are many committees involved. There is the engineering dept. that designs the parts and makes it work, the marketing dept. does the styling and graphics, the accounting dept. sets the budget for each of the other dept, and lastly the most powerful dept, the legal dept, approves the whole bastardized mess. All of these committees fight and bicker over how the bike will look, be built and be sold. What happens is we get a watered down version of the engineer's dream to build a high performance machine, a look designed to appeal to as many buyers as possible, a cost most buyers can afford, and settings designed to avoid law suits.

In choosing the actual suspension settings two major considerations must be taken into account. First is the "Showroom Appeal", this means that if you have settings firm enough to control chassis pitch, it will feel stiff when Joe Shit The Rag Man plants his/her ass on the seat and gives the bike a bounce. Marketing depts mandate soft low speed compression damping. Second is the manf's never know where any specific bike is going, other what country. So they have to allow for the 78lb Japanese Girl and the 350lb Bratwurst scarfing German man. The settings end up being quite Vanilla. The range of the Clickers is actually very limited and can not accommodate all riders under all conditions, in fact they do very little until the last 1/4 of a turn. On the whole stock suspension components are a poor compromise between engineering, marketing, accounting and legal depts.

As for the Computrack machine, there have been many bull shitters on the web that are glad to tell you what we do, when in fact they have never even set foot in a Computrack shop. The Computrack machine is really just a very accurate 3 dimensional tape measure. We can measure a chassis to with 0.01mm and 2 arc seconds of a degree. It does not give any answers (nor does data aquisition, but every one thinks by plugging in a computer to a bike all the mysteries of the universe will be revealed including reconsiling the quantum theory of gravity and quantum mechanics. I wish it was that easy) it only gives me a very, very accurate report of the alignment and geometry parameters. With this information we develop our "Sweet Numbers." This is simply a range of geometry settings that give the best feed back, feel, grip, turn in, drive grip and rider comfort. Not only is every model different, (some idiots think we use the same settings for every make, model, year bike we do) but each chassis/tire/rider/suspension component/ application is unique as well. In one case I had a customer bring in two bikes with consecutive VIN numbers that required 5mm different front ride heights to get the same geometry settings. Even with the same geometry the two bikes did handle differently because one was higher than the other.

When you purchase a GMD Computrack Geometry Optimization you are not buying a product, like you would buy an exhaust system. It's a process and a service. We start by measuring your bike to find out exactly what we have in front of us, do what work is appropriate, set up the chassis at our Sweet Numbers starting point, then work with you to fine tune the settings for your specific needs. It's not uncommon for the starting point to be good enough for a while, but as you go faster you will have to make adjustments to the chassis and we are here for that back up and support. We have thousands of measurements, and thousands of set ups to draw from. Many times the solution to a problem is counter intuitive, or is just a millimeter or two away. One case comes to mind where Eric Wood was having fits with his new 1998 ZX 6R. He was 2 seconds a lap slower than he was on the older, less powerful 95-97 version. I measured the bike and raised the front 2mm and the rear 3mm. The next day he posted practice times that would have qualified him on the front row of the AMA 600 Supersport race. He was 2.5 seconds quicker. He had been raising the bike up with no improvement and was ready to lower it back to lower than stock. With out a very accurate measurement, he would have been chasing his tail all year. From that day on he only moved the bike 2-3mm from track to track.

So while you can develop setting based solely on feel, unless you have hard data to track where you are, what the changes were, how the ride was affected, and what the next step should be it's all but impossible to find the best set up. To that end almost the entire AMA paddock uses Computrack on some level. Some have there own machine, some use the machines at the race shop some use the services of the retail shops like myself and Mike. Paul Thede has a very true saying "The best you've ridden, is the best you know."

[gmdboston]

Originally Posted by Doc

I see the point about the money though. Once I learn, then there is no reason to spend money. (Just did my first fork rebuild a couple days ago)

Did you take apart the cartridges and valving, surface the pistons, polish the damper rods, use low friction seal grease, deburr the bleed holes, replace the bushings and seals, set the clickers to know good starting point, or did you just dump out the oil and refill them? Some times the best tool for a job is your check book.........

[Doc]

Originally Posted by gmdboston

Did you take apart the cartridges and valving, surface the pistons, polish the damper rods, use low friction seal grease, deburr the bleed holes, replace the bushings and seals, set the clickers to know good starting point, or did you just dump out the oil and refill them? Some times the best tool for a job is your check book.........

Umm... no.. I replaced the fork seals and wipers too... Not really much of a "rebuild" :

Any consolation it was my YSR50.

The Ducati I am bringing to you. Wanna take it after Tony's April 29th?

[mmracer37]

Originally Posted by gmdboston

Did you take apart the cartridges and valving, surface the pistons, polish the damper rods, use low friction seal grease, deburr the bleed holes, replace the bushings and seals, set the clickers to know good starting point, or did you just dump out the oil and refill them? Some times the best tool for a job is your check book.........

Don't forget about setting the proper air gap and resetting the metering rod!

[gmdboston]

Originally Posted by Doc

Umm... no.. I replaced the fork seals and wipers too... Not really much of a "rebuild" :

Any consolation it was my YSR50.

The Ducati I am bringing to you. Wanna take it after Tony's April 29th?

yeah, not much of a rebuild at all.....sort of like the title "Sanitation Engineer"

I can bring the bike home on Tuesday from TTD, but I'll be leaving around 2pm.

[Doc]

Originally Posted by gmdboston

yeah, not much of a rebuild at all.....sort of like the title "Sanitation Engineer"

I can bring the bike home on Tuesday from TTD, but I'll be leaving around 2pm.

Ok so that means I need to bring a back up bike for the later sessions.

[bergs]

PK,

Very interesting.

So what you're saying is I shoulda brought my FZ1 to you about 38,000 miles ago...

I'll give you a shout soon.

[Wishbone]

Hahahaha looks like you will have your 3rd fz1 in the shop! Told ya there are a few of us :

Bergs, you can take my fz around the track if you want at ttd. I got the 2k gmd special and It fells good to me. Which makes me VERY happy since last year I only had the front done and the bike was fighting itself. Now it feels like its on rails and Pete never yet has done the push push click click. Nor do I have sweet number...yet.

You could also ask Hoser to take his fz for a rip, I belive he has sweet numbers.

Originally Posted by gmdboston

Some times the best tool for a job is your check book.........

Not always. My bike has felt better and better since the first day I walked into your shop and tried to feed my shock my wallet.

[bergs]

Is Hoser even alive? I haven't seen or heard from him in months!

He should be coming out of hibernation soon I imagine...


John, was your bike checked for straightness when it was at GMD?

I'm fairly certain my bike was made on a Friday and am curious if there were any findings on your bike with regards to the swingarm location in particular.

[Wishbone]

No, just had the fork straitened when they got the love.

Swingarm problems?

Mine was great before I got the Penske. It did most of my dampening out back ....don't ask

I'll have to do some tripple didgit passes by Pete's house to wake his ass up

[bergs]

Originally Posted by fasterthanu

Swingarm problems?

I wouldn't say "problems" but I know it's not the straightest bike to ever leave the Yamaha factory.

I'll have to do some tripple didgit passes by Pete's house to wake his ass up

Don't forget to throw up the finger and yell "BERGS SENDS HIS LOVE!!!!!" as you blast by.

[Hoser]

Is this where the Putz Party is?