I have an old (2000s-era) Rockshox suspension seatpost on my drop bar bike. Was something I picked up locally for a tenner.
Anyway, I'm fettling all things bike just now and was looking to see if it has adjustment at all as it just seems to drop to almost full travel when i sit on it. The guy gave me some "spare" elastomers. Not sure if they are stiffer or softer for tuning it?

Does anyone remember them?

Well, after some research I found some info online. People are selling the original owners manuals on eBay USA so I pinched their pics:





The last one needs translated from Italian:

An AI translation of that image says:

Congratulations!

Correct Use of the Seatpost and Performing Maintenance

By a qualified mechanic.
We also recommend following our tips for safety.
Installation

Seatpost Installation
Tightening Torque
Head Tube Spacers
Safety Information

Bicycle
Riding
Can be dangerous
Installation

Seatpost action

Calibration

Special

Preferred position

Regulation

When it comes to calibration

SModifica della rigidità (Modification of stiffness)**

The stiffness is modified by turning the locknut one turn at a time. After making adjustments, it is impossible to know the exact preload without measuring the distance between the top of the seatpost collar and the bottom of the seatpost tube.

RockShox Seatpost Setting

Setting the Clamp**

Optimal settings

Zero the road seatpost

45-45 kg

75-100 kg

30-115 kg

Tighten the clamp and install a seatpost clamp with a locking mechanism: get on the bike assuming the normal riding position

Measure the distance between the bottom of the clamp and the top of the rings

Road Seatpost

If the sag is excessive (the seatpost sinks too much), it means the preload is too low (looser). If, on the other hand, the shock absorber is too hard, use the following procedure to determine the correct preload for your needs.

Tighten the clamp once calibration is complete. Tightening the preload affects the sag and the initial stiffness of the seatpost.

Preload adjustment screw at the base of the seatpost. Tightening the preload screw in a clockwise direction (pre-load on the stem increases) reduces the travel of the elastic groups. Tightening the preload screw counter-clockwise (pre-load on the stem decreases) results in a softer seatpost and more sag. Do not tighten the preload so much that the threads on the lower part of the seatpost are exposed.

Rider Weight - Travel

45-73 kg - 45 mm

55-75 kg - 50 mm

75-100 kg - 55 mm

90-115 kg - 60 mm

Maintenance

To maintain the high performance of the seatpost, periodic maintenance is recommended. If you ride in extreme conditions, maintenance should be carried out more frequently. Use the recommended tools for maintenance, which are listed below.

Oil Service every 25 Hours of Riding

Remove the shock absorber

Unscrew the seatpost pin from the seatpost sleeve

Push the sleeve out

Before Each Riding Session

Check that the clamp bolts are tightened to the correct torque.
Check that the retaining ring is tight.
Check that the seatpost fixing bolt is tightened to the correct torque as specified by the bicycle manufacturer.
Check for play.
Tightening Torques

Important: Remember to use RockShox products
Maintenance Tools

Safety glasses

Vise with soft aluminum jaws

Grease

Lint-free cloth

Degreaser (compatible with all RockShox forks)

Allen key

Important: To obtain the best performance from your RockShox fork, use the recommended RockShox service oil and a specific grease. Some products may not be compatible with RockShox products.

Some of the terminology may be specific to RockShox seatposts, so you may want to consult the RockShox manual for more information.


Anyway, off to fiddle with it - thought this might be useful for someone google searching about these posts

Good luck! I seem to remember they were very similar to USE posts, just a bit more tunable and less well sealed.... I remember deciding to get the USE version instead, in about 2000, but it being a close choice.

In the end it was quite easy to take apart/tune.

There is a preload screw in the base that you can adjust pretty easily.

However, cranking it up all the way was still too saggy for me.

Taking it apart I found one long elastomer and a spacer (like the fork tokens you get now).

Reading the charts in the instructions I posted above, I cut the spare elastomer down to 101mm and put two spacers in.

This worked well - found that this made the preload adjustment to give a good range for me. Having the preload around halfway with the two spacers have me the right amount of bounciness.

Glad I found those manuals online though, wouldn't have tuned it right without them