Progressive spring help?

Peepz

Peepz

Joined
Dec 20, 2025
Messages
9
Age
40
Location
Billings MT
Bike
Yamaha xs650
High guys, in the process of installing progressives in the front tubes of my 99' st1100A ABS/TCS. I started with the left leg, the non anti-dive side, and immediately noticed no spacer came out. Progressives springs are one inch shorter (18") than the stock springs (19"). Just curious if anyone has done this install? Curious on spacer length and oil level? Thanks in advance!
 
I think the ABS2 are reversed from the non-ABS of that era, so the left leg is the one with the retaining nut on the top of the damper rod, right? According to the service manual, there's no spacer in that leg.

Doesn't progressive give installation guidelines along with the springs? Or are they a generic replacement spring with many possible applications? not ST-specific.
 
dwalby said:
I think the ABS2 are reversed from the non-ABS of that era, so the left leg is the one with the retaining nut on the top of the damper rod, right? According to the service manual, there's no spacer in that leg.

Doesn't progressive give installation guidelines along with the springs? Or are they a generic replacement spring with many possible applications? not ST-specific.
Click to expand...
You are correct, the left leg has no spacer and the damper is attached to the cap, the right leg is the anti-dive leg with a 100mm spacer. Progressive is very vague and I can't find anything for these later LBS-ABS/TCS models. I opted to re-install the stock springs for now, until I can figure out the correct spacer length needed.
 
Peepz said:
You are correct, the left leg has no spacer and the damper is attached to the cap, the right leg is the anti-dive leg with a 100mm spacer. Progressive is very vague and I can't find anything for these later LBS-ABS/TCS models. I opted to re-install the stock springs for now, until I can figure out the correct spacer length needed.
Click to expand...
What I did when I first got the bike was cut a bunch of different spacers 10mm apart out of PVC pipe (1" IIRC), and used trial-and-error to sort out which one worked best.

Use the right leg spacer, which is very simple to swap, and change the length until you get the road feel you're looking for.

Then, if you feel better balancing the spacers between the two legs you can do that, but putting all the preload into one leg accomplishes the same thing.
 
dwalby said:
What I did when I first got the bike was cut a bunch of different spacers 10mm apart out of PVC pipe (1" IIRC), and used trial-and-error to sort out which one worked best.

Use the right leg spacer, which is very simple to swap, and change the length until you get the road feel you're looking for.

Then, if you feel better balancing the spacers between the two legs you can do that, but putting all the preload into one leg accomplishes the same thing.
Click to expand...
Ok, excellent, I'll give that a shot. Thanks!
 
The typical fork spring install should result in 15 mm of initial preload, i.e., you would need to compress the fork cap 15mm to engage the threads at the top of the fork tube.... simple measurement will get you there..... now in the case of progressive springs, I would increase that to 20mm. Try it out and if you need more preload, then you can either add washers or cut new spacers.

What I don't know is if you can buy adjustable fork caps with preload adjusters..... try AliExpress or Amazon. Just need to know diameter of forks....
 
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