I’m getting a USE Vybe Suspension Seatpost for minipips for our tandem.

The spring (the softest) is rated for 38-55kg, he weighs 30kg.

What do you think about filing/grinding off some of the external diameter of the spring to reduce the spring’s strength?

Sounds messy, but it’s not car suspension or anything critical.

Other option is compress the spring with some weights and measure the deflection and then look for a comparable size spring with a lower rating.

Or load him up with about 10kg in a back pack!

Lathe access?

Bang a tight dowel down the center, chuck it up and spin it as you grind.

Bungee/string/wire/whatever the saddle rails to the top-tube to add some loading to the spring? How long till a 30kg kid becomes a 40kg kid? Can’t be /that/ long…?

You would have a job filing it as it will be as had as a file. Use a flap disc in a grinder and as wisywig says if you have access to a lathe get it spinning at the same time.

Thanks for the suggestions. 🙂