I’ve tried and tested many seatposts over the years in all price ranges. The only purpose of a seatpost is provide support for the saddle & to offer simple adjustments of the saddle (vertical & horizontal seat position plus saddle angle). Some seatposts costing hundreds of dollars do not even meet these simple requirements!
For my rental bike fleet, my preferred seatpost choice is one made by kalloy uno (believe it or not). I found one model in a 100% black finish that particular that I like: SP353 ‘ultra lite’. It is a 100% aluminium seat post with an elegant, funcional extruded head unit. The one shown here is rebadged by Massi.
The first thing that I like about this seat-post is that it is practically indestructible. The seat NEVER slips in the seatpost cradle. They are adjustable over a wide range of seat-tube angles (including the Mrazek bikes which use a very laid back seat tube extension). I’ve also noticed that they can be used with all types of saddles, including ones that have non-horizontal seat rails. They have a sensible amount of set back, not too much and not too little.
Perhaps the best part of this component is the simple, single bolt clamp mechanism. While other manufacturers always seem to try to re-invent ways to clamp a bicycle saddle, Kalloy/Uno maintains its functional design. Why? Because it works! There’s only one large bolt to deal with, not two. While that aspect makes the adjustment for saddle tilt a little less precise, this seatpost enables you to change seat positions easily and quickly.
Another feature which I particularly like is that the shank of the post maintains its diameter throughout its entire length. So unlike many other curved & flared seatpost designs, the entire range of vertical adjustment of this seat post extension can be utilised.
They are anodised and hence not very prone to scratching. But perhaps the best part is that they can be bought for as little as about 10-15‚¬. Yes they are relatively heavy, weighing in at somewhere between 240-280 grams, but I couldn’t care less. In short, they do everything they are supposed to, very cheaply.
The other model(s) that I have tried are SP-373 / SP-374. The SP-342 / SP-343 also look like a similar design should also work well for my intended purpose. Kalloy changes their seat post designs often, so it might not be best to special order this product otherwise you could easily end up with the wrong item. So make sure you know what you’re getting. The best thing to do, is if you see one, buy it on the spot.