Suspension question

[*GSXR~SNAIL*]

First off, I liked to preface my question(s) below with stating I know NOTHING about the suspension settings on a sportbike. I know there are some local resources in the area that many use and perhaps they can chime in on this...that would be great.

I was wondering about the default or factory set suspension that manufacturers set-up their bikes with. Do we know if it's a known value based on the manufacturer or is there a set value based on some average weight of a rider, perhaps a 180 lbs.? With me being the fat-ass I am, I know that my suspension is not ideally set. I can feel that it gives or is too spongy at times when I'm riding at a more aggressive pace. Is it all a feel thing or is there a good starting point/setting for a K6 GSXR 1000 where someone at 220 lbs. should use as a coarse adjustment then fine tune it based on feel? I would think that these suspension settings would also vary based on how one uses the bike too, right? I mean, you wouldn't set-up the suspension the same for road/commuting/twisties as you would for track/racing...or would you? When you make the necessary adjustments what does it really do for the bike/rider? Is it just a comfort with the bike, which develops a confidence in the rider or can you really push that bike to limits it just wasn't physically set-up to do before the adjustment?

Again, sorry for the ignorance in this area. I figured this forum can be a great resource and thought I would throw out this question that's been on my mind for a bit.

Thanks.

[~Barn~]

Great question. I'll let others get into the minutiae of actually dialing it in. There are a couple schools of thought, but I'm of the opinion, that there's not really a set of guidlines based on pure numbers. W/out question, the element of "feel" comes into play.

But first things first, everything I've ever read about stock suspension, is that they come "sprung", for a person of an average weight of 145-160. So yes... it's not ideal for you out the box.

Having Marcus McBain tune me in on my former R1 was one of the most noticable things I've ever felt on my bike. It's everything you talk about, both a mental comfort, and also a physical feel to the bike, that just inspires confident riding.

I think to describe it in general terms (for me).... You know that feeling you get when you're just droning along straight down highway, and you pin it, and the bike just goes? The suspension sets itself for the thrust, and there's no wobble, no drama, no shake, just straight ahead Pow.

Setting my suspension better, got me very near that feeling. But rather than being in a straight line, it achived it while I navigated through turns. No wallow, no wobble, no scary compression or rebound, just a nice "solid" feel, while turning. The suspension was working, to be sure, but gone were the days of "feeling" it work. Feeling it work wrong, more specificially.

Anyway, it's well worth the treatment. I hear irdave does some magic on this kinda thing, so hit him up. Or whoever you decide on. They'll get the bike setup for your weight, and after some discussion, it can be taylored for the kinda riding you do, your preferred comfort/feedback levels, and the like. You'll feel like you have a new bike!

[MetaLord 9]

Thanks for posting up on this one, I had similar issues/questions!

[rybo]

Hey kids,

I'm also in the "basic" category on this subject, but have worked extensively with IRDave and will recommend his work highly. www.fixmybike.com

There are a number of factors that go into setting up the suspension on a bike.

1. Ride height (front and rear)
2. Spring rate
3. Spring pre-load
4. Compression Damping (sometimes high and low speed)
5. Rebound Damping (also sometimes high and low speed)

The ride height and damping adjustments are variable as is the spring pre load. The spring rate, however, is fixed based on the springs installed in your bike.

It may be necessary not just to adjust the equipment you have, but to actually replace certain parts (springs almost for certain) to get the bike properly set up. After you have the right springs in you'll move to setting up static sag. There is a good article listed here for how that is done and what the benefit of it is: http://www.gostar-racing.com/club/mo...ion_set-up.htm

From there the factor of "feel" enters the equation, and this is the part where some good professional help is a big benefit.

To answer your other question, I've never seen two bikes come off of the showroom floor set up the same way, so I don't think we can count on the manufacturers for baseline set up.

I hope that helps, I'm sure Dave will be chiming in here soon to bring light to this area of slightly black art.

s

[Sortarican]

Here's a great article:
http://www.sportrider.com/tech/146_0402_susp/index.html

+1 on irdave www.fixmybike.com) if you want someone to dial it in for you.

[jplracing]

Originally Posted by RYBO

Hey kids,

I'm also in the "basic" category on this subject, but have worked extensively with IRDave and will recommend his work highly. www.fixmybike.com

There are a number of factors that go into setting up the suspension on a bike.

1. Ride height (front and rear)
2. Spring rate
3. Spring pre-load
4. Compression Damping (sometimes high and low speed)
5. Rebound Damping (also sometimes high and low speed)

The ride height and damping adjustments are variable as is the spring pre load. The spring rate, however, is fixed based on the springs installed in your bike.

It may be necessary not just to adjust the equipment you have, but to actually replace certain parts (springs almost for certain) to get the bike properly set up. After you have the right springs in you'll move to setting up static sag. There is a good article listed here for how that is done and what the benefit of it is: http://www.gostar-racing.com/club/mo...ion_set-up.htm

From there the factor of "feel" enters the equation, and this is the part where some good professional help is a big benefit.

To answer your other question, I've never seen two bikes come off of the showroom floor set up the same way, so I don't think we can count on the manufacturers for baseline set up.

I hope that helps, I'm sure Dave will be chiming in here soon to bring light to this area of slightly black art.

s

Scott,

In my opinion you missed one item and that is the tires the rider is using. As some of you know each tire maker uses a different profile shape to the tire. Michelin for examply likes to make a triangulated (sp?) front tire were dunlops are a little more rounded.

So...this also has to be taken into account. With that said get ahold of Dave at fixmybike.com, he will be able to help you out

Joe

[rybo]

joe,

that is a really valid point. Setting up the bike has to take tires into consideration along with the kind of riding you do, body weight and all of the other factors mentioned above.

[Sortarican]

Originally Posted by jplracing

...In my opinion you missed one item and that is the tires the rider is using. ..

Never thought of that.....and I kept setting my suspension without tires on the bike.

And sorry to highjack, but anyone have good recommendations on outlets for springs, valves, and such?

[pilot]

Originally Posted by Sortarican

Never thought of that.....and I kept setting my suspension without tires on the bike.

And sorry to highjack, but anyone have good recommendations on outlets for springs, valves, and such?

Race Tech.

[Jayock]

Originally Posted by pilot

Race Tech.

Yeah..... im going to have to disagree with you there bob.

I've had issues with my racetech internal valving. Never had any issues with my ohlins.

The racetech were great until I started dropping lap times. I was fighting with the front end forever. Multiple rebuilds, stack changes, etc, couldn't get them to work right for me. Also, some of their valveing kits only include compression valves, neglecting rebound damping improvements for some models.

Then again, I know that there are a lot of people who like them, so im sure they work well for some riders, just not for me.

[*GSXR~SNAIL*]

Good stuff everyone...thanks.

[pauliep]

Just put rear take on the and got to ride it a few blocks so no reviews yet. I have yet to dial it in but it sure looks pretty.

[Ricky]

Great thread. I've been thinking about the suspension on my new bike, and since I'm the exact opposite (bag of bones with no weight @~140lbs), I probably need to adjust the suspension from its stock settings.

[pauliep]

Speaking on race tech and suspension...

I picked mine up off ebay and I have no clue as to what spring is on there. Does anyone know where the serial number or any information is on the rear shock spring? Mine's red and that's really the only way I've been able to identify it so far. I'm wanting to know if I have to right spring for my weight.

[pilot]

Originally Posted by pauliep

Speaking on race tech and suspension...

I picked mine up off ebay and I have no clue as to what spring is on there. Does anyone know where the serial number or any information is on the rear shock spring? Mine's red and that's really the only way I've been able to identify it so far. I'm wanting to know if I have to right spring for my weight.

see this link: http://www.cosportbikeclub.org/forum...771#post277771

[lovinCO]

As an alternative to Race Tech...

Traxxion Dynamics is excellent, I used to use Max for all of my suspension work.

www.traxxion.com

[pauliep]

Per the calculations done with Race Tech...

on a 03 Suzuki GSXR1000 stock spring - ideal rider weight is 195lbs - spring rate 8.6kg/mm

for the small guys like me, I weigh 150lbs - recommended racing spring rate is 8.06kg/mm

Haven't looked at other makes but Race Tech increments in 0.5 on their springs.

[pilot]

Originally Posted by pauliep

Per the calculations done with Race Tech...

on a 03 Suzuki GSXR1000 stock spring - ideal rider weight is 195lbs - spring rate 8.6kg/mm

for the small guys like me, I weigh 150lbs - recommended racing spring rate is 8.06kg/mm

Haven't looked at other makes but Race Tech increments in 0.5 on their springs.

Excellent research, Paul. Are you going to use the 1000 strictly for the track or to state this another way, what % of time will you be on the track/street with this Suzuki?

Were you able to find a number stamped on the spring?

If not, perhaps you can take some measurements of the spring wire diameter as well as outside/inside diameter and overall length.

I'm away from my RT files, but perhaps we can figure this out. Also, there are several other members on the board that may be able to provide you with helpful information regarding this matter.

[pauliep]

I like to spend my weekend riding at IMI, future projections to get some track days done at pueblo, and who knows with the new track when if it's going to have available track days this season. I have no gripes riding the street and canyons with a "race setup." A good suspension makes the bike easier to ride according to some more experienced riders.

No stamp yet.

Well I got off the phone with tfog and learned that RT springs are normally yellow or black (maybe he said gray). So having a red springs rules out that I have a RT spring. I may or may not have an aftermarket spring. I think the 600's have a red spring. I'm planning on just going along with getting the sag set and seeing what my preload plays out to be. If we can get it to be 1&1/4" then I'll be leaving that spring on there.

About going by measurements, that might entail taking the spring off the shock and the shock off the bike. More work then needed just yet,

[pilot]

Originally Posted by pauliep

I like to spend my weekend riding at IMI, future projections to get some track days done at pueblo, and who knows with the new track when if it's going to have available track days this season. I have no gripes riding the street and canyons with a "race setup." A good suspension makes the bike easier to ride according to some more experienced riders.

No stamp yet.

Well I got off the phone with tfog and learned that RT springs are normally yellow or black (maybe he said gray). So having a red springs rules out that I have a RT spring. I may or may not have an aftermarket spring. I think the 600's have a red spring. I'm planning on just going along with getting the sag set and seeing what my preload plays out to be. If we can get it to be 1&1/4" then I'll be leaving that spring on there.

About going by measurements, that might entail taking the spring off the shock and the shock off the bike. More work then needed just yet,

It "could" have been painted to make it pretty for sale on the web. It isn't a big headache to change your suspension for a day at the track. A couple of basic tools and you can adjust it at the track for your time there and then back to street at the end of the day. Track set-ups generally have less travel for "holes" and thus allowing more for compression and ground clearance. But, it is pothole season and it would be a shame to loose contact in a corner on Federal and Mississippi after a clean set of laps at the track. Also, getting run over by a garbage truck at IMI is a lot rarer than in the city. Just something to keep in mind as it relates to keeping your contact patch in contact.

Also, I guess you have presented to all that phrase, "buyer beware" when it comes to E-Bay.

[irdave]

Sorry about not seeing this- had an Aeronautics mid-term exam this morning, amongst other stuff.

If the spring is red, it's possibly an Eibach. I use them almost exclusively.

There's a bit to suspension, probably more than can be easily explained on a message board...

To start with, I usually try to steer people to someone that is basically local- someone that can meet you at the track, actually push on your bike, help you to adjust it. I'll be honest, it's not the parts inside that make the difference, it's the range of adjustment you get that allows one to adjust the suspension appropriately for what's going on.

I mean, ordering stuff from 2,000 miles away is great and all, but what if you've got a little too much of anything and you can't figure it out? Example; 2 mm too much preload on the rear shock can make the bike seem like there's no rebound damping. Really. Doubt it? We ran into that with Aaron's Penske last season. That's why I think someone local is better.

As to that, Single Track Mind (www.fixmybike.com) is an authorized Ohlins dealer, as well as we do springs and valving from GP Suspension. I tend to keep springs in stock (I have about 15 rear springs right now, ranging from 400 lb/in to 1000 lb/in) because I feel they are important- they control so many variables that it borders on ridiculous.

Well sorted suspension helps to control the chassis. What does that mean? On the track, stable on the brakes, comfortable on turn in, good feeling midcorner, ability to hold a line on the way out, and nothing silly at WOT.

This page I wrote a little to help define some terms that people use... http://fixmybike.com/Technical.html

Here's a little that I wrote about springs and the role they play... http://fixmybike.com/Springs.html

There really is a ton to it- I mean, you can start with figuring out the critical damping based on the spring rates and the sprung masses, and you can figure out the spring rates based on what frequency you want, but it gets a little heavy. That's where all the rules of thumb come from- front sag at this, rear sag at that, rider sag this and that. Observed from setting the thing up by the equations... Beyond that, once you get in the ballpark, then it usually takes someone that truly understands to help get the most out of it. That's why we're here. No joke, no smoke-and-mirrors, no trying to baffle you with bullshit. Just helping you to get what you want from your bike.

[pauliep]

Dave, how often will you be at IMI in the coming weeks? I'd like to get together to dial in after the sag is set. You think you will be available down the road?

[irdave]

For sure, meeting people at IMI is pretty easy for me, and if you wanted to get the bike sorted out, it's actually a pretty good place for it.

Just let me know when's good, and we can figure something out.