Dropper seat-posts, cartridges...

[Stefan Mikes]

As the Forum "Search" feature seems to have stopped working, let me create this thread about dropper posts and related matters.

For a few for you who might not be even aware what the 'dropper seat-post' (the dropper in short) is for, a short explanation:

1. Mountain bikers need to be able to ride downhill on technical trails standing on the pedals with their bottom above the rear wheel to move the centre of gravity rearwards. That allows them avoiding Over-The-Bars, ensures a better control over the bike, and is a must on jumps. As the saddle would obstruct the free body movements, the rider presses a lever on the handlebar and pushes the saddle all way down with their weight; the seat remains dropped until the next lever push is done. The seat-post then returns the saddle to the original height by means of a compressed air cartridge.
2. The saddle may be partly dropped so the rider's body is in a lower position, which makes a ride on a difficult surface (mud, sand) more secure.
3. A dropper allows setting any saddle height between the minimum and maximum position, which allows easy sharing the bike with shorter riders...
4. SUV e-bikes are often equipped with a dropper to make it easy for us -- old farts -- dismount the e-bike

In my opinion, only functions 1 and 2 are essential for the dropper user.

Formerly mine 2020 Giant Trance E+ 2 Pro was originally equipped with Giant Contact Switch dropper. Giant droppers belong to the least expensive and the most hopeless products in the market Suffice to say, mine broke within the first month of use! I bought a replacement OneUp V2 dropper 150 x 30.9 mm immediately; fortunately, the Giant handlebar lever and the cable could be reused. The new seat-post was good for 4 years!

However, the life of the compressed air cartridge is not infinite, and you have to replace it once in a several years. That is the situation of the OneUp dropper now.

This year, I will participate in several E-Sprint gravel races. Because of some difficult singletracks paired with massive descents on the rocks, I will need to borrow the Giant from my brother. However, I will definitely need an operable dropper! Therefore, I ordered a new OneUp V2 cartridge. In a wrong size

Now, I'm returning the unpacked wrong cartridge and ordering a new one in the proper size...

 

[Chargeride]

Therefore, I ordered a new OneUp V2 cartridge. In a wrong size

Now, I'm returning the unpacked wrong cartridge and ordering a new one in the proper size.

Remember measure once, cut twice.

 

[Stefan Mikes]

Remember measure once, cut twice.

A stupid, stupid mistake! My brother said "order the 120 mm one" and I was too lazy to search for the original order! I have had an account on EU OneUp since 2020!

 

[mogulman]

Just saw this. I have a Giant Reign e+1 with a contact switch dropper about 5 years old. Going to try getting the Giant dropper service kit. Doesn't seem very easy to get.

Next choice would be a new dropper. One up is on my list. V2 or v3. Would you still go one up all over again?

 

[Stefan Mikes]

Just saw this. I have a Giant Reign e+1 with a contact switch dropper about 5 years old. Going to try getting the Giant dropper service kit. Doesn't seem very easy to get.

Next choice would be a new dropper. One up is on my list. V2 or v3. Would you still go one up all over again?

The only proper/good cable operated dropper seat-post I have ever enjoyed was One Up v2. No experience with any new version. Here are some remarks from my brother who overtook my Trance E+:

• The dropper has been very reliable for 4 years
• My brother was riding the e-bike all year long. The dropper seat-post was susceptible to winter dirt, especially to road salt
• After 4 years, the cartridge turned out partly damaged and stopped working properly
• We bought a replacement cartridge from One Up. These is a detailed video how to replace the cartridge on YouTube. Post the replacement and inflating to 250 psi the dropper seat-post works like new.

I cannot help you more but I can attest One Up dropper seat-posts are good and spare parts are available.

 

[MrClortho]

I have a TranzX dropper post with 100mm travel and honestly don't know how I did without a dropper on my mountain bikes in the past. I go up high for easy paths, drop for single track and drop more to get on and off the bike. It's the best thing since sliced bread.

 

[Rás Cnoic]

I got a cheap KS lever operated dropper post. It's an older design with the lever operated under the saddle. Reasons I got this one was:

> I didn't want more cabling, this is fit and forget
> I'm not racing so don't mind stopping top of a rocky steep drop.
> Cheap, had just bought my Cairn Brave and mudguards and kickstand so budget was stretched.
> It's fine for my use, would not suit someone going fast on a rolling single track where you might want instant drop and raise and drop again.
> Handy if my son is riding with me and we swap bikes can drop it a few inches and off we go.
> It works fine. Heavy, bit clunky. But cost £40 not over a £100 as most cable ones. 100mm drop.
> Sizing not perfect - you have to work out the internal length of seat post versus the visible part and how much you want to drop for your correct seating length and what the frame can allow, as in the water bottle bosses seem to stop it going further so I took that into consideration. Mine works but be nice to have one that drops further.

 

[mogulman]

Ordered a oneup V2 150mm. 30.9. for $180. Giant service kit was on backorder. Didn't want wait until never for Giant to have the service kit in stock. Plus hopefully this is better than stock.

 

[Stefan Mikes]

Please keep us up to date! Very interested! I think you can reuse your cable and the lever.