Telescopic mechanism by Giant Manufacturing • On wheels

In this article we will discuss a telescopic mechanism from Giant Manufacturing, American publication 20240067289. The publication date is February 29.^th2024 (jump) and the filing date is August 28^th2023.

As big as Giant’s footprint is on the global bike trade, this is the first time I’ve written about them. Oddly enough, they don’t file much, and when the documents are finally released, the product is already out. At least in the United States.

In honor of the new and expensive Fox Neo dropper post (and perhaps the new SRAM Preverb), which seems to be generally berated by our fellow keyboard warriors, I wanted to bring in the antithesis of Fox’s Neo.

Giant is working on a new simple, spring-loaded, cable-operated drip post with only two positions: minimum and maximum. It aims to provide a more affordable alternative to traditional, expensive seat posts while solving issues such as lack of seat post position feedback. The design is ideal for occasional cyclists or commuters, requiring minimal maintenance.

The modern dropper post, which we all love (I think), uses a system similar to that of a telescopic suspension fork in which it uses both an air chamber and fluid chambers for control of the height.

The air side is the spring that pushes the seat up. The fluid side, being incompressible, allows the rider to lock and unlock (for lack of better words) the seat post. The fluid side generally has at least two chambers separated by a valve. The system remains locked when the valve is closed, preventing fluid from passing between the chambers.

When the rider wants to move the seat post, they press a switch on the handlebars, the valve opens and fluid can pass between the chambers allowing the seat post to move. Actuation can be managed via cable, fluid or electronic components.

At one point, a few companies were trying to do this with a spring.

The concept of a spring-loaded dropper is not new, and you don’t need to tell me about it because I’m about to tell you.

My research suggests that the Gravity Dropper was very early (perhaps number one) compared to the modern dropper post using the telescoping design we see today. This was a spring system with a pin to adjust the height.

Another similar product is the e*thirteen TRS+ dropper from ’16/17. Based on this diagram, this particular dropper appears to be quite similar to this new giant dropper in this document.

What we’re seeing here at Giant is a reinvention of an older concept.

Traditional seat posts, while flexible, are expensive.

Although the user has great freedom of adjustment, the relative cost is too high.

Stop (park) the bike.

Thanks to the parking height adjustment, the user can lower the height when parking and thus improve safety with both feet touching the ground.

This is a bit of a stretch for me (but I may not be at risk for this issue), but Giant also says the lack of feedback on the seat post position can be an issue.

…the design does not tell the user the exact position for adjustment. As a result, height adjustment is not intuitive enough and errors are likely to occur when the user makes an adjustment between driving height and parking height.

And again, the price. Since they say it twice, I’m going to assume that this new position would be relatively inexpensive.

…a high price prevents most consumers from enjoying a safer driving experience.

FIG. Figure 1B shows an exploded view of this new dropper. We want to focus on cable 166 (purple), small spring 167 (blue), pusher block 165 (pink), balls 162 (red), clamps 150a and 150b (green), and large spring 180 (orange). ).

FIG. Figure 2A shows a cross section of this seat post in the fully deployed position. The pusher block 165 is controlled by the cable 166, and the pusher block is biased upwards (towards the right in the image) by the small spring 167.

Long story short, when the cable is pulled by the jumper, the push block is pulled down, allowing the balls to move into the open space (OG annular groove). So now that the cable is pulled and the balls have moved inward, the post is unlocked. The rider can sit on the saddle and lower it all the way, release the cable actuation and it will lock to the bottom of the seat post.

An animation is probably a better way to visualize this. This shows the unlock sequence. You can see the cable pulling, the pusher block moving and the balls moving to release the seat post.

FIG. The 2D shows the post in an intermediate position, so it is not locked in any position and can move between minimum and maximum positions. Remember there is no locking position in this area between the collars.

FIG. 2E shows the post in the fully compressed position. The balls are now locked in collar 150b. You can unlock it the same way as before, and the big spring will push the seat post up and probably hit you in the nuts like the specialist command did to me on several occasions.

I had a friend a few years ago, my boy Dane, who sold me on his preference for droppers. The argument is that seat posts really only need three positions: max, min and trail. Max for climbing, minimum for downhill, and trail set at about 80% max for pedaling on flat terrain. The infinitely adjustable seat post is simply not necessary. Personally, I never need such granularity on a ride.

In support of the two-position system, I’d like to see someone’s driving data plot seat position over time. My guess is that a dropper spends the vast majority of its time either fully extended or fully compressed. If true, it would support the hypothesis that a two-position seatpost is perfectly acceptable. I know Fox or SRAM have this data somewhere. All it takes is a small data logger and a powerful pot. Hell, a camera and a stopwatch would do the trick.

I’m speculating, but I’m pretty confident that the actual product would be heavier, while being simpler, easier to maintain, and perhaps more reliable.

My only main question here is: how do the balls move inward? I don’t see a bias mechanism, so are we just hoping they will move inward as the pusher block goes down? If one of the four gets stuck, the whole message doesn’t work, right? Would the motion/vibration of the bike move the balls enough to move them inward?

Application wise, this would be perfect for the casual cyclist or commuter. They basically made a seat post for riding and for a brake light. That being said, if this thing is weighted correctly and performs as intended, I wouldn’t hesitate to not use it, especially on my gravel bike. Either way, this dropper is only at maximum or minimum.

And it’s unlikely to require much service (which I’m simply fascinated by). Less service means more trips.