Thomson Elite Dropper Details
• Telescoping seat post
• 5''/127mm drop (internally adj. to 4''
• Infinitely adjustable travel
• Hydraulic internals
• Nitrogen return spring (not adjustable
• Lever-adjustable return speed
• Weight: 450g (prototype
• Availability: March/April 2013
• Projected MSRP $380
Thomson stirred up a hornet's nest of activity when they teased riders with a few quick photos of their upcoming telescoping seat post on their Facebook page a few months back, but no other information was available at the time. Fast forward to Eurobike and they were showing off the new post, dubbed the 'Elite Dropper', in their booth, which we made our first stop of the show. The post is still in the early prototyping stage, with only a few functioning samples in the wild at this point.
The Elite Dropper offers 5"/127mm of infinitely adjustable travel, meaning that it can be positioned anywhere between and full extension fully lowered . The travel is controlled with a sealed cartridge (it can be worked on by a service center, though) that separates the post's hydraulic oil from the non-adjustable nitrogen return spring that is set at 135psi. Thomson has employed a clever second check valve within the cartridge that keeps the post from pulling up through its travel when lifting the bike by the saddle, thereby remedying a somewhat annoying trait of some other hydraulically controlled posts.
While it looks as if Thomson has refined existing dropper post technology rather than reinventing it, they have done something completely different to eliminate any side to side saddle wiggle from the Elite Dropper. Rather than use multiple keyways to keep the round stanchion from rotating, an interesting sixteen-point shaft - that fits within a matching sixteen-point profile within the outer tube - is attached to the bottom of the stanchion. This requires assembly to involve sliding in the stanchion from above, then threading the sixteen-
point section into place through the bottom of the outer tube, followed by screwing the silver bottom cap onto the bottom. This layout allows Thomson to utilize traditional round bushings from Norglide to keep the post's travel smooth, although the upper, stationary bushing sports a custom finish to further enhance the post's movement.Head-mounted actuation
Thomson is being very clear about one thing: reliability is the focus of the new dropper post. They are aiming to have the Elite Dropper trump everything else on the market when it comes to longevity, a goal that will likely make the Thomson post a favorite among riders if fulfilled given how unreliable most current designs are.
The Elite Dropper's actuation arm is located on the side of its two-bolt head (that features the very same rail clamp as used on their standard seat posts
), with a bolt-on cable stop and arm that is pulled on by a standard shift cable. Hidden from view within the post's head, the actuation arm pushes down on a plunger located at the top of the cartridge, thereby opening the oil port and allowing the post to stroke through its travel. Interestingly, Thomson allows riders to choose from varying rebound speeds despite its shift cable actuation thanks to a cam design on the plunger that determines the amount of oil flow allowed when engaged - pushing the lever completely through its travel will result in a faster return speed than if the rider only depresses it partway. While we didn't get to try the system on a bike, it should allow riders to easily find those partially dropped positions.Remote or under seat
Two activation options will be available, allowing riders to pick from either a remote or under-the-seat lever. While still likely to receive some minor changes before production begins, the lever employs an ultra-slim footprint that easily fits between the other controls on your bar, as well as being hinged for simple installation and removal. The under-the-seat lever is likely going to be less popular than the remote, but using it will reduce bar clutter, if that is a concern. It is bolted to the same mounting location as the remote actuation arm, and pushes the cartridge's plunger down in the same way when pulled.Hydraulic cartridge
Thomson isn't shy about admitting that the Elite Dropper's cartridge is outsourced to another company; they wanted to focus on the machined structure and design of the post and let a team with experience in hydraulics design take care of the internals. The hydraulic oil is held within the upper section of the cartridge (right
), with the activation plunger at the very top. At the bottom is the nitrogen chamber that is pressurized to 135psi. This pressure is not adjustable, something that many riders have used in the past to adjust their seat post's return speed, simply because the cam design on the plunger allows the user to select rebound speed by how far the lever is pushed. Non-adjustable nitrogen
The Elite Dropper's outsourced internals are laser etched at the bottom of the post (left
), including the nod to its Norglide bushings and Motul oil. The threaded silver bottom cap (right
) allows access to the post's internals, while a specially-shaped plug at its center keeps users from letting the nitrogen gas escape accidentally.
Thomson also had a few other goodies on display, including an X4 stem that was fitted with a carbon fiber faceplate. How much weight does it save? Likely very little, but it sure does look rad.
They also had a neat seat binder tool that uses a magnetic 4mm hex wrench. The production version (note the very roughly shaped handle - this was just a sample
) will likely use a 4mm hex key with a strong magnet placed behind it, allowing the tool to be held securely to the seat clamp but still allow riders to pull it off quickly to use elsewhere on their bike.bikethomson.com