GStwin.com GS500 Message Forum

Main Area => Projects / Builds, Racing and Tech => Topic started by: chrishiggs on June 02, 2009, 10:37:02 AM

Title: Fork spring diameter?
Post by: chrishiggs on June 02, 2009, 10:37:02 AM
Hi folks,
Hoping someone might be able to tell me the diameter of the springs in the GS front forks. I just found a pair of new WP Proline progressive fork springs that I've had for several years and having measured the length it seems they're 3mm shorter than the standard Suzuki ones according to the Haynes manual. I can't find any info on the diameter in the manual and would rather not have to open up the forks right now. I don't actually know what bike(s) the springs are designed for- I bought them from EBay for my Bandit 600 but the length was wrong so I'm now hoping they might work in the GS. Thanks in advance.
Title: Re: Fork spring diameter?
Post by: chrishiggs on June 02, 2009, 11:12:10 AM
Cancel that request folks!
Did a bit of searching and got the size off another post. The wp springs are too big...
...Probably way too stiff anyway.  :dunno_black:
Oh well...
Title: Re: Fork spring diameter?
Post by: lamoun on June 02, 2009, 01:53:04 PM
Just for future reference then
GS500 2006 (EU) Front spring

outer diameter  ~ 30.6mm (1.20")
Inner diameter  ~ 22.6mm (0.89")
Coil diameter    ~ 4.05mm (0.16")
Spring Length   ~ 342mm (13.46")
Number of Coils ~30

Which gives approximately, a spring constant 0.5Kg/mm
http://www.calculatoredge.com/new/spring%20const.htm (http://www.calculatoredge.com/new/spring%20const.htm)
Title: Re: Fork spring diameter?
Post by: intergalactic on June 03, 2009, 05:18:44 AM
Racetech lists it as a .58 kg/mm spring. How they got at that number, I don't know. so your calculation is in the same ballpark.

Quote from: lamoun on June 02, 2009, 01:53:04 PM
Just for future reference then
GS500 2006 (EU) Front spring

outer diameter  ~ 30.6mm (1.20")
Inner diameter  ~ 22.6mm (0.89")
Coil diameter    ~ 4.05mm (0.16")
Spring Length   ~ 342mm (13.46")
Number of Coils ~30

Which gives approximately, a spring constant 0.5Kg/mm
http://www.calculatoredge.com/new/spring%20const.htm (http://www.calculatoredge.com/new/spring%20const.htm)

Title: Re: Fork spring diameter?
Post by: lamoun on June 03, 2009, 05:44:00 AM
Where in the site did you find that info?
I search the racetech site and all I got is "Call kg/mm (stock)"  :dunno_white:
Title: Re: Fork spring diameter?
Post by: intergalactic on June 03, 2009, 08:51:32 AM
oops, .59kg/mm

http://old.racetech.com/evalving/english/Srchpr.asp?bikeid=396&manufacture=Suzuki&model=GS500&year=91-00&TABLEINFO=street&langname=english


Quote from: lamoun on June 03, 2009, 05:44:00 AM
Where in the site did you find that info?
I search the racetech site and all I got is "Call kg/mm (stock)"  :dunno_white:
Title: Re: Fork spring diameter?
Post by: intergalactic on August 02, 2009, 03:55:28 PM
BTW, just installed my 0.95 kg/mm springs and I like them. I wouldn't go firmer, but they are nice.
Title: Re: Fork spring diameter?
Post by: Punkalflufen on August 14, 2009, 11:02:10 PM
Quote from: intergalactic on August 02, 2009, 03:55:28 PM
BTW, just installed my 0.95 kg/mm springs and I like them. I wouldn't go firmer, but they are nice.

How heavy are you and have you done anything to the rear shock?
Title: Re: Fork spring diameter?
Post by: intergalactic on September 01, 2009, 10:27:02 AM
80kg, GSXR rear shock. I like that. .95kg/mm is stiff on rough roads. Or I overfilled the fork oil, but I did measure.
Title: Re: Fork spring diameter?
Post by: Punkalflufen on September 02, 2009, 05:17:37 PM
Quote from: intergalactic on September 01, 2009, 10:27:02 AM
80kg, GSXR rear shock. I like that. .95kg/mm is stiff on rough roads. Or I overfilled the fork oil, but I did measure.

Thanks, I am 95KG (i know, i know... i was 75kg 3 years ago... i HAD a 6 pack and everything) so i was thinking about .95kg/mm or 1km/mm, i think that will be hard enough for track days but still soft enough for some of the roads down here
Title: Re: Fork spring diameter?
Post by: intergalactic on September 04, 2009, 03:57:30 PM
I am considering changing down to .80-.85 kg/mm. Like a dummy, I sold my .80kg springs a few months back...