The 295g XC dropper you might be seeing more of soon

A closer look at FRM's €590, 60mm drop OBI1 seatpost

Walking around the pits of the cross-country world cup in Albstadt, Germany this weekend, we spotted this 295g (not inclusive of lever or cable, claimed weights) dropper seatpost for XC racing from Italian brand FRM.


The OBI1 dropper is incredibly simple in construction; the seat clamp is attached to an external sleeve that slides over the top of the seatpost itself, which is anodized with a hard and slippery finish, similar to on a fork stanchion.

The keyed section stops the saddle from rotating and feels very solid on the bike
Jack Luke / Immediate Media

This external sleeve is in turn attached to a hex-shaped internal section that moves inside the post.

The whole control unit is bolted onto the back of the seatpost and contains…
Jack Luke / Immediate Media
…a simple pivoting pin that engages with divots machined into the internal hex shaped section
Jack Luke / Immediate Media

The lightweight lever toggles a small pivoting pin that engages with stops cut into the hex-shaped section, locking the seatpost in place. This whole unit attaches to the back of the seatpost and is held in place by four 2.5mm head bolts.

A simple spring sheathed in plastic takes care of, uh, springy business
Jack Luke / Immediate Media

A simple spring encased within a plastic sheath returns the saddle to its original position and the return action feels plenty quick.  

Easy to service and live with

To take apart the seatpost, you remove a small circlip…
Jack Luke / Immediate Media
…and undo a 4mm bolt
Jack Luke / Immediate Media

All that is required to take the seatpost apart is a 4mm Allen key, to remove a bolt at the bottom of the post, and a set of needle nose pliers, to remove a circlip that holds the post together. Once these have been removed, the seatpost can then be pulled apart for cleaning and servicing.

All in, the FRM team mechanic took less than ten minutes to take the post apart and put it back together for us, which is seriously impressive

The wiper seal pushes filth away from the internals
Jack Luke / Immediate Media

That said, as the wiper seal on the external sliding portion of the post pushes dirt and grime downwards and away from the internals, it’s very unlikely that the internals would ever become contaminated, with FRM claiming the post is among the most reliable on the market

The tidy lever feels very lightweight and well made. Sadly we didn’t have a set of scales to hand to check the weight
Jack Luke / Immediate Media

Overall, the whole thing feels very sturdy and exceptionally well made, but you would hope that of a post that costs €590.

Wide compatibility and easily adaptable

As the moving portion of the seatpost is located externally, it’s easy to make the dropper in pretty much any size, including the rarely available but very popular 27.2mm diameter. It is currently available in this diameter, as well as the more common 30.9 and 31.6mm standards.

The current seatpost only provides 60mm of drop, but FRM says that it would be fairly easy to scale the seatpost up for those that want a larger drop.

Likewise, although the seatpost only has two positions in its current guise (fully up or fully down), it would be very easy to add additional stops if requested.

Who is using the seatpost?

Although you won’t see any racers using the post at this weekend’s race, FRM claims it is in talks with a number of teams who are interested in using it and developing a version with 25mm of setback for riders who don’t get on with an inline post.

Does a dropper post actually make sense for XC racing?

With tracks getting more technical and XC bikes more capable by the year, it makes sense to take full advantage of the extra control a dropper affords you. But is it worth the increase in weight?


Joe Norledge did some testing with dropper posts for XC racing last summer and you can see the results in the video below.

Dropper or fixed? Which is fastest for XC?