Getting Started

[r6_philly]

I understand that oem put progress rate springs in suspension to be able to accomodate different weight riders as springs cannot be swapped to fit each person when bikes are sold, if straight rate springs are used.

While I cannot, and don't have the expertise to state that straight rate is better than progressive, I can see that straight rate springs is easier to set up than progressive. To be able to set up a progressive rate spring, you have to accurately predict suspension travel and set up around the spring rate at the furthest point of travel. So lets say if you change the preload on the springs, then at the point where the springs are compressed the most, you will encounter more spring forces than you would have before you made the preload change. At which point your rebound damping may be too little. so changing one setting would presumably change all setting, which would seem to make getting the right setup a lot harder without the usage of simulation software and a lot of testing and data aquisition.

Also even progressive springs have different progressive rates, so which one would we choose from? I can see that pro teams with the necessary equipment and expertise can make use of the progressive springs and their benefits, but for us, it would be easier to set up a straight rate spring.

[Super Dave]

I'll be brining my 72 Waterbuffalo! You will then see the power and superior handling of the mighty GT750! ;D

Well, get started.  But you'll have to our ride me.... 8)

[Super Dave]

Is a straight rate spring easier to set up?  Well, that's a good question.

I had an easier time working with my set up this year than before.  Got my geometry set, then we make the whole bike taller, front and rear, with the help of http://4and6,com .  Can't thank them enough.

You really don't have to make personal selections on the changing spring rates for the rising rate springs.  Hyperpro has done that.  Jesse Janisch and I both had basically the same set up.  We have completely different wieghts.  I probably out weigh him by forty pounds, yet when I checked his spring for the amount of preload, we both ended up with the same numbers and we were using the same springs front and rear.  

With the straight rate spring you're riding around in a straight line over bumps and all with rate X.  When you're loaded up, still rate X.  The spring supports the weight of the bike, the rider, and the traction load upon it.  When a 600 is wide open straight up and down, it doesn't have a whole lot of load on it.  You don't need rate X.  But now you have to compromise you dampaning to try to find a happy medium.

So, you've got a rising rate spring.  When you're running around straight up and down, you have rate X-Y happening.  Nice and plush, compliant.  When it's loaded up, rate goes into X+Z.  We're under a harsh load so we need the extra rate now.  The spring should support what is happening, and it does on a rising rate spring, pretty much automatically.

What was nice was that I didn't have to over dampen it to get good feel.  With the load changing, I didn't have a way of altering anything with a straight rate.  Dampening is a compromise too and can over come the spring.  With the rising rate, the spring does most of the work, as it should, and I could clean it up with the dampening...but not over dampen it.  

HRC does use rising rate springs.  Honda Racing.  They just aren't telling anyone.  (I've seen them.)

Hyperpro is unique in using the rising rate spring at the rear.  Works pretty slick.  I fully expect lots of misunderstanding.  This is the motorcycle industry, so others usually prove their point only by belittleing other products rather than actually trying something (not that you guys are, but some people in the know are bashing the other people in the know that are using them).  It wasn't that long ago, that we were all using Progressive Suspension springs and straight rate springs were no good.

Will it help the RC?  Should improve it, but the RC really could use a good amount of improvement.  It's a neat class, I agree, but the one TLR that I rode blew away the RC's that I've been on.  It's a geometry thing...and width and weight.  Still, it's fun to be on the track!  

[jmickle11]

Wow!  This thread is still going!  Anyway, The feedback has been great.  I'm still pondering what to do.  At the very least I'm planning on taking the licensing class.  I've got a lot of things and expense to think about as well before I go racing!  I'm just not getting much enjoyment riding on the street.  

[Super Dave]

The licensing classes are pretty simple safety classes.  I've taught them.

I look at my school as probably a racers best bet for their next school.  I'm rather opinionated, but I do have some straight forward answers.

Regardless, good luck and have fun.

[EM JAY]

I think Dave said it the best
2. Take a class or training from a school like daves
6. Listen to SD. he will tell it like it is from is years of knowledge.

 Opinionated but oh so wise! ;)

    Hows the Racer University coming along??

[chris_chops]

At 33 I will most likely not get real serious about this.  quote]
HAHAHAHAHAHAHAHAHAHAHA... HAHAHAHAHAHAHAHAHAHAHAHHAHAHA....hahahahahahahahahahahah..hehehehehehehehehehe...  Gee, he didn't mean for that to be funny...  HAHAHAHAHAHAHAHAHAHAHAHA...  That's what makes it funny!  Poor fool hasn't a clue what he's getting into...
BTW, I started at 35.  HAHAHAHAHAHAH!!!

HEEEEEEHEEEEEEEEHEEEEEEHEEEEEEEHAAAAAAAAHAAAAAAAAAHAHAHAHAHAHA!!!!!!!!!!!! THAT IS FUNNY!!!!  He'll be living in a van down by the river, but he'll have one or two nice racebikes to sleep with.

[GSXR RACER MIKE]

I fully expect lots of misunderstanding.  This is the motorcycle industry, so others usually prove their point only by belittleing other products rather than actually trying something (not that you guys are, but some people in the know are bashing the other people in the know that are using them).  It wasn't that long ago, that we were all using Progressive Suspension springs and straight rate springs were no good.

     Great point Dave, in this day and age it does seem as though many people/companies bash things that they know nothing about. That very reason is why I have so much respect for Paul Thede's point of view, he has worked with not only straight rate springs but also variable rate springs for years. I reread my original statement about variable rate springs and admit it kind of comes across as a negative statement, I will clarify what I meant.

     Variable rate springs are not a bad thing, they are just too often used to make up for incorrect valving, which they can actually do quite well. The theory taught to me about using straight rate springs is that no matter what your motorcycle with you on it weighs, it will basically always weigh the same during a race. When cornering you now take that unchanged weight and compress the suspension due to cornering forces (which acts like more weight). This is where the approach to handling this extra load differs between variable rate and straight rate springs. Variable rates (as I understand it) increase the spring rate at some point in the travel to compensate for this increase in force generated during cornering, therefore allowing a lesser rate during lower forces like bumps and rises/drops in the elevation of the track when not cornering or taking lower load corners.

     Straight rate springs used in conjunction with Race Tech Gold Valves handle these same situations in a slightly different approach. As the suspension compresses during cornering loads the air trapped in the forks compresses and acts as an additional spring which gets progressively stiffer the more it is compressed. By changing the oil level in the forks you now change the amount of additional pressure generated by the compressing air in the forks (adjusting the pressure in your shock resevoir creates a similar result). This gives a similar result as a variable rate spring and is easily adjustable by changing oil level in the forks or pressure in the shock resevoir. This is also why blown fork seals will affect your suspension with either type of spring. The Gold Valve approach is to create a valving shim stack which is allowed to do all the work of damping/controlling fluid flow (thru unrestrictive ports) and is set to your level of riding and weight. When set correctly the valve will allow the fluid to flow fast when needed and taper off as needed. As the straight rate spring compresses, the Gold Valve lets the fluid flow at a fast rate until the spring begins to reach the amount of compression required to support the generated corner load. At this point the valve begins closing and restricting the flow of fluid to help the spring not over shoot the amount of compression it currently needs. Rebound damping of the valve then stops the pogo stick tendency of the spring trying to release the extra amount of compression that happened when the spring slightly over compressed. This is where the variable rate springs should have the lighter rate in their spring that shouldn't try and uncompress as much.

     The straight rate spring handles the weight of you and your motorcycle thru valving that works under light loads as well as heavy ones by using very accurate valving. Variable rate springs use increased spring tension at some point in the spring to handle the extra load. What I was taught was that variable rate springs can be somewhat of an on/off situation having less feel during the lighter portion of the spring and then being somewhat abrupt when reaching the heavier rate in the spring (as compared only to a Race Tech set-up). The other concern was how do you change (if needed) the point at which the spring is stiffer? A simple change in oil level or resevoir pressure would change progressiveness in a straight rate system without affecting corner loaded ride height. Not a challenge against variable rates Dave, just a concern which was brought up during the seminar I attended.

     The improvement going to a variable rate spring on non-Race Tech valved suspension would be very noticable in a good way. Two different approaches to the same result (controlled handling), kind of like the reason all of us are not riding the same type of bikes!

[Super Dave]

And new valving or shim stack set up will allow for better dampening.  But remember that the bike has to be supported.  Spring.  

A proper rising rate spring is pretty much seemless, it isnt abrupt.  The Hyperpro springs are not like Progressive Suspension springs.  

If you wanted a spring that has the ability to change when the change point is, then you can use something like Works Performance.  

But the assumption is that the change is abrupt, which it isn't again.  The rates are not so substantially different, but having the difference is really good.  Complient ride with firmness under load.  I'll stop there.

[lil_thorny]

Wow!  This thread is still going!  Anyway, The feedback has been great.  I'm still pondering what to do.  At the very least I'm planning on taking the licensing class.  I've got a lot of things and expense to think about as well before I go racing!  I'm just not getting much enjoyment riding on the street.  

you see what you've gotten yourself into?
it only gets better...er...worse from here on out in the grass!!!

lil-thorny.