I am thinking about buying some sonic springs. In Australia it is probably the easiest option as motorcycle wreckers are a complete rip off as most of the time it is still cheaper to buy overseas than here. I have looked at the sonic springs threads and most are a few years old now so I was wondering if people are still happy with the springs they got or would they go stiffer or softer springs now with the experience they have. If you could state your approx weight and springs you are using it would help alot.

Thanks

sonic spring .90  175 without gear.  maybe 185-190 with gear.  works great but you have to change oill to 15w

If you have any questions about springs just fire off an email to Rich at Sonic.

http://www.sonicsprings.com/catalog/contact_us.php?osCsid=1bb05d7988e0cd39b2fada1482e9098b

I have bought springs from him for my two bikes and he has always been extremely helpful.  He's an industry member over on the Concours site and his knowledge has been helpful on several occasions.

Recently upgraded to .95 Sonics while keeping the original fork oil weight... and I love it.  I heartily recommend all GS owners to upgrade their springs to an appropriate stiffness.  Obviously .95 is pretty stiff (of course, I'm ~215 lbs without gear) but I have nothing but praise for this mod. I've only had them for a month or two, but I doubt I would want anything too much softer... but almost anything seems better than stock now.

Nf11624 I am about the same wieght without gear as you. So are you saying the springs are  a little stiff? In hindsight would you have gone for the .90 ones? Thanks to everyone else for the input.

Does anyone know if I do this mod if it will void my warranty? Flick likes to bottom out in the front at the slightest speed bump. I'm 175 without gear! Seems like a good thing but I'm not gonna void a warranty with three years still on it!

Mary

Adding aftermarket springs should not void your warranty. In the event of a failure the onus is on the manufacturer to prove that the aftermarket part was responsible for any failure.

here's a link to Magnuson-Moss act

http://www.impalaclub.com/naisso/magmoss.htm

I keep it bookmarked on my PC and when I would take my other bike in for warranty work I would print a copy and take it with me.  Consumer advocates love dealers that try and screw you over on warranty issues

Dread - I really enjoy the .95 springs, they eat up bumps, improve handling and don't bottom out during stops anymore.  I am not a suspension guru, but I don't think you can go wrong with the .90 or .95 springs.

Of course, everyone else - pick a rate that is appropriate for your weight and you will probably be very pleased.

Thanks everyone who replied I will let you know how I go when I get the springs

Thanks Blade!

Mary

Your welcome Mary, somebody pointed me to Magnuson-Moss shortly after I bought my Concours a few years ago and it has saved me a lot of grief

Good investment and good company.  I would recommend you get some.  You can use the spring rate calculator on the race tech website, then get the sponic springs.  I think I went one up from what the calculator said though.

Using .90 Sonics with the factory weight fork oil. I'm about 200lbs with gear.
Luv 'Em! 
I put a wite up on here when I first installed them.

Installed 0.85 Sonic Springs and test rode today , when people said it was a new bike afterwards I was skeptical ........

......well , it is     New excitement out of old GS !

i didn't want to spend as much for the sonic springs so i just got the progressive, but WOW...those with the 15w oil....

Do you think we could get some sort of matrix like the rejetting one where it has the riders weight, oil used, spacer made and the type of spring used so we have all the info in one place?

Good idea , we can use your thread to accumulate data and then post it in the wiki maybe  
So post your setups people it's helpful  
My bike is a Euro spec with 7 way adjustable preload on the fork caps so I did my calculations for 3 lines showing ( 4 in )

Here is my setup (mostly metric   ):
Rider with gear ~ 63kg / ~139lbs (I went stiffer than recommended 0.8kg/mm)
Sonic Springs 0.85 kg/mm
Spacer length 107mm ( 13mm of it preload   )
15W Silkolene Race fork oil ( expensive stuff   )
Oil level ~139mm

Useful stuff:
Length from the top of damper rod(where the spring rests upon) to the top of the fork tube(tube extended) - 518mm
Length of 0.85kg/mm Sonic Spring - 379mm
So it left 518-379=139mm of space to fill with spacers,washers,fork caps
Fork cap+original washers length was 45mm and I wanted 13mm preload so 139-45+13=107mm of spacer length for my needs
and I have preload adjusters to play with for proper sag