Bontrager Drop Line dropper seatpost review£239.99

Bonty's first dropper works well, but shows consistency issues

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Way back in the early to mid 2000s, many of us who spent the majority of our non-eating, non-sleeping hours thinking about bikes often wondered why Trek's component powerhouse Bontrager hadn't released a dropper post. All the big players had their own label dropper posts, but the folks from Wisconsin held off.

The answer might have been that Bonty engineers wanted to get it right. So did they?

Branding is low key
Branding is low key

Bontrager Drop Line dropper seatpost features

  • 31.6mm diameter only (more sizes coming)
  • 100mm drop / 350mm post length
  • 125mm drop / 395mm post length (tested)
  • 150mm drop / 445mm post length
  • Remote cable actuation with under-bar lever
  • Air-sprung hydraulic locking cartridge offers infinite adjustability within dropping range
  • Keyed chassis prevents saddle rotation
  • 2-bolt rocker head with micro adjustment allows saddle tilt adjustment
  • Internal cable routing
  • Includes cable, housing, and 1x under-bar remote lever
  • On-Bar Drop Line Universal Lever sold separately
  • Claimed weights: 565g for 350mm, 599g for 395mm, and 624g for 445mm

The cable ends at the lever and tucks nicely into the concave of the lever
The cable ends at the lever and tucks nicely into the concave of the lever

Teething issues?

As boring as it may sound, the Drop Line worked like a dropper post should for me.

Bontrager's slogan for the Drop Line is "It just works," and that's an admirable goal as almost every rider who's used a dropper post for a while has run into issues.  

No squinting required; length, size, drop and minimum insertion are all clearly marked
No squinting required; length, size, drop and minimum insertion are all clearly marked

My UK-based co-workers have had mixed luck however. One received a Drop Line with a malfunctioning air-spring cartridge out of the box and the other experienced binding and restricted movement on the down stroke after getting swathed in British mud.

However, to complicate matters the final UK tester's experiences mirror mine, but he noted it hasn't seen a ton of use.

When basic maintenance is necessary, Trek claims it only takes 2, 2.5, and 8mm Allen keys to tear the post down. Refreshingly, no special tools are required.

A hydraulic, air-sprung cartridge resides inside, which isn't user serviceable, but can be swapped out should it fail. 

Function

Most importantly, the drop is smooth and hiccup-free throughout. The extra pressure required to get some droppers into the stroke is not needed here.

There's a tiny amount of side-to-side saddle play, but it's minuscule, nothing I could ever feel while riding. In comparison, the Drop Line has more play than a Thomson and KS Lev, but less than Fox Transfer and Reverb. It's splitting hairs really and again it's nothing that can be felt while on the bike.

The return speed is far from quick (unlike Specialized's ball-poppingly quick Command Post), but is adequate if even on the slower end of return rates. The speed can be regulated by feathering how far you push the remote in, although I'm not sure why you'd ever want the return slower.

The main seal has a tough job but has faired admirably through a sloppy winter season
The main seal has a tough job but has faired admirably through a sloppy winter season

The Drop Line makes a reassuring tap as it tops out. I've grown to like hearing dropper posts clunk as they return to full height. It's a little auditory reassurance that when I sit back down the saddle will be right where I expect it.

The under-bar remote is beautiful and well executed. Its placement, paddle shape and lever throw are all spot on, with easy ergonomics and use. It features a hinged clamp, so popping it off the bars is relatively simple.

The clamp itself is narrow, so while it doesn't pair up with SRAM's MatchMaker clamps or double as a lock-on grip collar, it's still pretty unobtrusive on the bars.

While not compatible with SRAM's clamps or lock-on grips like other remotes, the Drop Line remote clamp is hinged for simple installation and removal
While not compatible with SRAM's clamps or lock-on grips like other remotes, the Drop Line remote clamp is hinged for simple installation and removal

One of the nicest features is that even with the saddle lowered, the post is still locked. This means you can grab the bike by the seat and the post won't pull up, which prevents air getting into the oil and causing all sorts of issues. 

So far, so good

So far the Drop Line I've been testing has worked as advertised. I've ridden it throughout the winter season and honestly haven't done any more than wipe away visible dirt from the seal. Even that minimal maintenance rarely happened, to be honest.

The ease with which it initiates the drop is appreciated. It's noticeably smoother off the top than a Reverb or Command Post.

The remote has remained a highlight, as mentioned above. The cable remained snug and I haven't had to touch the barrel adjuster. 

Bontrager's Drop Line dropper post was worth the wait
Bontrager's Drop Line dropper post was worth the wait

Russell Eich

Tech Writer, US
Russell fell head over heels in love with bikes in the '90s, and has been involved in the bike industry ever since. Between wrenching in bike shops, guiding professionally, and writing about bikes, Russell has honed an appreciation for what works, gained knowledge of what doesn't, and can barely contain his enthusiasm for what comes next. His two-wheeled passion continues in the Rocky Mountains high above Boulder, Colorado.
  • Age: 39
  • Height: 6'3"/190cm
  • Weight: 175lb/79kg
  • Waist: 34in/86cm
  • Chest: 42in / 107cm
  • Discipline: Mountain, road, cyclocross
  • Preferred Terrain: High altitudes, forgotten singletracks, bike parks, roads without cars
  • Current Bikes: Custom Meriwether steel hardtail, Specialized S-Works Enduro 29, Kona Jake the Snake, Trek 69er, and a bunch more
  • Dream Bike: Yeti SB5c, Intense Tracer 275C, Black Cat custom road
  • Beer of Choice: Gin + Tonic
  • Location: Rollinsville, CO, USA

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