Progressive springs and sag help GS1000E 1980

[GSthou]

Hi all,

My bike is a UK Suzuki GS1000E 1980 model fitted with Hyperpro progressive fork springs been in the bike for 7 years and done approximately 8000 miles on them. I am looking for some advice on where to do next with my progressive fork springs. In order to measure the sag I measured the distance from the top of the dust seal on the forks to the underneath of the triple clamp with the forks fully extended and this was 145mm. I then placed two cable ties on the forks resting on the dust seals, took the bike off the stand and sat on it and remeasured the distance from the top of the dust seal to the cable tie and it was 51mm. That looks like just over over 2 inches of sag whats your thoughts. I removed the top caps off the forks and there are no spacers fitted just the progressive spring and top washer. I have measured the progressive spring and it is 491mm in length. In your opinion is the sag too great. Many thanks

[salty_monk]

Yes, 2" of static sag is too much on a 4" fork. It should be about an inch.

You have two choices.... You can either fit a spacer & add more preload. ABS pipe with a penny washer at each end works for that.

If that still doesn't work for you then you can chop the closely wound part of the spring off, dress the end & add spacer to compensate. That will actually raise the spring rate of the spring rather than just add preload. You can usually get away with cutting 3-4" before you risk making the spring "spring bound" - i.e. more travel in the fork than there is space between the remaining spring coils...

[GSthou]

Yes, 2" of static sag is too much on a 4" fork. It should be about an inch.

You have two choices.... You can either fit a spacer & add more preload. ABS pipe with a penny washer at each end works for that.

If that still doesn't work for you then you can chop the closely wound part of the spring off, dress the end & add spacer to compensate. That will actually raise the spring rate of the spring rather than just add preload. You can usually get away with cutting 3-4" before you risk making the spring "spring bound" - i.e. more travel in the fork than there is space between the remaining spring coils...

Thanks Salty for the reply. Is it just trial and error with the length of the spacer to get the 1 inch sag.

[RichDesmond]

You need to measure sag correctly.

[salty_monk]

You need to measure sag correctly.

I agree it could be done a better way but it's probably close enough for his purposes if he was careful in the transition....

Here's a "how-to" if it helps.

https://www.cycleworld.com/sport-rider/ask-geek-set-your-static-sag/

To answer your other question - yes, trial & error (or educated guess) I'm afraid.