Blockpass Seatpost

Setback is how far behind the seat tube the saddle sits. It decides where your hips end up relative to the pedals, which changes how you put power down and how much weight sits on your hands. More setback opens your position and suits seated climbing; less puts you further forward over the bottom bracket. The Blockpass gives you 15, 20 or 25mm and lets you change between them, so you can find the right one on the bike instead of buying a second post to try. Most posts fix this number at the factory.

One oversized M8 bolt does the whole job — it holds both the setback position and the saddle tilt, so you loosen it, move the saddle to the position you want, and do it back up. That is deliberately simple: fewer parts to lose on a trailside adjustment, and no need to strip the head down. Check the tilt again after you change setback, since moving the cradle back or forward can take the angle with it.

Your frame decides the diameter, and it is not worth guessing — it is usually printed on your old post near the bottom. The Blockpass comes in 30.9mm and 31.6mm, both in 350mm and 400mm. If your frame takes 27.2mm, the Crossfire is the one to look at instead. For length, measure how much post shows on your bike now and remember the minimum insertion line has to stay inside the frame; if you are close to it, take the 400mm. Weights run 380 to 410g depending on version.

If it has 7mm round rails, yes — that is the standard, and it is what our Adlib, Adlib HD, Skinny and Launch II all use. The exception is our DJ saddle, which has thicker 8mm rails and needs a head made for them.

Take the Blockpass if you want to move the saddle backwards, or if you are not sure yet where it should sit — 15, 20 or 25mm, changeable whenever you like. The Crossfire is the lighter, simpler answer at 265 to 295g against 380 to 410g here, with a twin-bolt head and a 27.2mm option the Blockpass does not have. If your fit is already sorted and you do not need setback, the 115g saving is real.