spring replacement or adjustment?

[scaramanga]

My s2r1000 sagged too much when i plopped down on it so last week i adjusted the spring for a 25mm sag. The ride is harder but i like it. At 215lbs should i have changed for a stiffer spring instead? If yes then why the adjustment capability?
I keep reading about guys being advised to change out the spring instead of adjusting it.

[Howie]

Stiffer spring is the way to go at 225.

[Greg]

My s2r1000 sagged too much when i plopped down on it so last week i adjusted the spring for a 25mm sag. The ride is harder but i like it. At 215lbs should i have changed for a stiffer spring instead? If yes then why the adjustment capability?
I keep reading about guys being advised to change out the spring instead of adjusting it.

Because if you screw the preload all the way in, then the spring is close to binding up.

[scaramanga]

Because if you screw the preload all the way in, then the spring is close to binding up.

There is still alot of adjustment left.

[Speeddog]

You need stiffer springs.

The adjustment is provided to allow proper preload.

It cannot correct for an inappropriate spring.

[Slide Panda]

Yep spring rate is a physical constant. Adding preload doesn't change how much the spring will deflect when a force is applied

[scaramanga]

The stock rate is 7.74kg/mm. How would i choose the proper rate or  should it be left to the supplier to calculate?
Any preferred vendors for suspension products?

[oldndumb]

This is one mfgr's chart for reference. I'm sure there are others. 

http://www.penskeshocks.com/Motorcycle-Spring_Chart.php

[Speeddog]

I'd set you up with a 650 #/in spring.

Stock shock will work with any number of domestic springs:
Eibach 0700.225.0650
RaceTech SRSP S5818116
They'll fit a bit better with a pair of spacers, RaceTech SPSC5855

Or an Ohlins 1092-41/115

Best to work with a local suspension house.
Whereabouts are you located?

[scaramanga]

I'm in montreal. I was actually looking at the Racetech but never would have picked the ***116(its the stiffest one for my ride) , but what do i know. Springs are cheap so i can play around with different rates if need be. I Appreciate the help, thanks.

[Tmod]

I would suggest checking to see how much preload is applied to the spring and what the sag numbers are. For conversation sake let's say the spring measures 7.0" (177.80mm) in free length and when installed to arrive at 35mm sag you had a installed length of 6.5" (165.10mm), You would have .5" (12.70mm) preload. If we know the numbers it would help arriving at the spring rate that would give you the sag you are looking for at about 8mm preload. Also another step is to check free sag and that would be the difference between 2 reference points with the rear fully unloaded and then see how much the bike drops after setting the rear back on the ground. You normally should have about 2~8mm with the preload set about 8~10mm and the rider sag right about 35mm.

As others have said just because you have the available preload adjustment range does not mean it will work properly just by cranking the adjuster down. A soft rate spring with more preload will have more initial force then a stiffer spring with less preload within reason.

So if you don't mind grab some measurements and and let's see what you actually have the bike set at.

Tmod   

[ducatiz]

Check these guys out:

www.sonicsprings.com

He makes all the springs to order.  You tell him what you want by dimension and he makes it.

I converted a set of 40mm Showa cartridges to use in my 35mm Marzocchi forks (Pantah).  He cut the springs perfectly, and it was a lot cheaper than going to the big names.

[scaramanga]

Tmod
Let me start by saying i'm honored that you popped yur cherry on my post    welcome to dmf
Starting the adjustment from scratch again is a pain since i don't have the proper tools yet. What i can tell you is that in order to get a 25 mm rider sag i compressed the spring about 8mm more from a ducati stock 25mm preload.Hard for me to measure static sag but it doesn't look like there is any.I'm a little short on time right now to check that properly.

[scaramanga]

just ordered my spring from racetech. they have a powdercoating service so i had them paint it yellow for 40$.
I ordered a SRSP 5818107, just a little less stiff than S5818116, it'll be incentive for me to hit the treadmill

thanks for the help