Dropper Posts

midonogh

My 12 yr old son is mad keen on mountain biking at the minute and as a result we have both bought second hand dual suspension bikes. Looking to get dropper posts installed in as cost effective a way as possible.

He has Giant Lust XS with 30.8mm seat post
I have Spec Stumpjumper with 35mm seat post

His bike is a bit on the big size for him. He currently has 10mm showing on the seat post. Mine is a Medium. Its fine, maybe a little on the small side

Been looking at the Brand X Ascend II for him. Not sure for myself. There is lots of permutations looking at these on line that are new to me


Looking on advice:
1. Assume these have got to be externally routed
2. What measurement should I be looking at to ensure his is not too big and mine is not too small, height wise
3. Can see plenty of 30.8mm droppers but few 35mm. Saw it suggested that 35mm users should go with shims and a smaller diameter post
4. What value brands would you recommend that will not fall apart in a short time

Really appreciate any help any one can give
Cheers

bogmanfan

I can't help with sizes, but I would definitely recommend Brand X. I've had a Brand X for 2.5 years with zero issues. Works perfectly every time. Before that I had a Rockshox Reverb which used to break down and need a service every 8-10 months.

midonogh wrote: »

My 12 yr old son is mad keen on mountain biking at the minute and as a result we have both bought second hand dual suspension bikes. Looking to get dropper posts installed in as cost effective a way as possible.

He has Giant Lust XS with 30.8mm seat post
I have Spec Stumpjumper with 35mm seat post

His bike is a bit on the big size for him. He currently has 10mm showing on the seat post. Mine is a Medium. Its fine, maybe a little on the small side

Been looking at the Brand X Ascend II for him. Not sure for myself. There is lots of permutations looking at these on line that are new to me


Looking on advice:
1. Assume these have got to be externally routed
2. What measurement should I be looking at to ensure his is not too big and mine is not too small, height wise
3. Can see plenty of 30.8mm droppers but few 35mm. Saw it suggested that 35mm users should go with shims and a smaller diameter post
4. What value brands would you recommend that will not fall apart in a short time

Really appreciate any help any one can give
Cheers

boomdocker

midonogh wrote: »

My 12 yr old son is mad keen on mountain biking at the minute and as a result we have both bought second hand dual suspension bikes. Looking to get dropper posts installed in as cost effective a way as possible.

He has Giant Lust XS with 30.8mm seat post
I have Spec Stumpjumper with 35mm seat post

His bike is a bit on the big size for him. He currently has 10mm showing on the seat post. Mine is a Medium. Its fine, maybe a little on the small side

Been looking at the Brand X Ascend II for him. Not sure for myself. There is lots of permutations looking at these on line that are new to me
Really appreciate any help any one can give
Cheers

Looking on advice:
1. Assume these have got to be externally routed
On those bikes, yes

2. What measurement should I be looking at to ensure his is not too big and mine is not too small, height wise
Most are available in 125mm or 150mm, so just a matter of measurement
3. Can see plenty of 30.8mm droppers but few 35mm. Saw it suggested that 35mm users should go with shims and a smaller diameter post
34.9mm droppers will be a rarity, so yes you'll prob need to go 30.9 or 31.6 with shim
4. What value brands would you recommend that will not fall apart in a short time
100% gor for Brand X, I have 2 for approx 3 years, never had an issue. If u can't get then any other reputable make, but go cable actuated. Bike-discount sell RFR branded seatpost - which is the Cube finishing kit. I don;t have one , but would have no hesitation buying. Around 120 yoyo

Lemming

midonogh wrote: »

His bike is a bit on the big size for him. He currently has 10mm showing on the seat post.

... SNIP ...

2. What measurement should I be looking at to ensure his is not too big and mine is not too small, height wise

The above criteria stands out to me (bold in the quote is my emphasis) as requiring a question be asked as to whether your son will be able to use any dropper post currently available given what you have said about his bike and the height of his saddle. When factoring in the seat collar for a dropper post, the lowest position available for the saddle would be sitting in or around 10mm or so anyway meaning he would not be able to drop it any lower than he currently has his saddle set.

The smallest dropper post that I know of (and I didn't know one existed until I saw it a few minutes ago on CRC) is a child-specific one by BrandX that is internally routed and is 70mm of travel. That means that even if you could somehow get that dropper post to fit your sons bike from a cabling perspective, his saddle would now be 70mm high (plus maybe another 10mm+ for the seat collar), not 10mm high at full extension.

Unless I have misread what you wrote I think your son will need to put in a good 6cm (at a minimum) of growth before he sees benefit from a dropper post.

Wanderer78

bogmanfan wrote:

I can't help with sizes, but I would definitely recommend Brand X. I've had a Brand X for 2.5 years with zero issues. Works perfectly every time. Before that I had a Rockshox Reverb which used to break down and need a service every 8-10 months.

Bought a brand x before Christmas, still haven't fitted it, wouldn't go back to reverb if you paid me, just a pain in the hole

midonogh

Thanks lads
Some really good clear advice in here. Much appreciated

fatbhoy

I've the newer type RS Reverb for the past three years and not a bother. Never been even serviced yet.

Wanderer78

fatbhoy wrote: »

I've the newer type RS Reverb for the past three years and not a bother. Never been even serviced yet.

it does seem the newer ones are far better, but i wouldnt be too keen to go back

Lemming

fatbhoy wrote: »

I've the newer type RS Reverb for the past three years and not a bother. Never been even serviced yet.

I've got a revision B reverb stealth on one of my bikes (came with the old style plunger too). Served two and a half years before it started to show need of a service and being the tardy bugger that I've been through lockdown it lasted up until Christmas with a slight drop on the post at full extension (we're talking maybe 5mm and then holding steady). Got it serviced at Christmas along with swapping out the plunger for the 1x remote as a christmas present from the missus and good as new. So lasted nearly three years without a service and was still very much usable.

I have a Magura Vyron wireless dropper post on another bike; that's never been serviced as it's never shown signs of misbehaviour.

Mr. Grieves

Lemming wrote: »

The above criteria stands out to me (bold in the quote is my emphasis) as requiring a question be asked as to whether your son will be able to use any dropper post currently available given what you have said about his bike and the height of his saddle. When factoring in the seat collar for a dropper post, the lowest position available for the saddle would be sitting in or around 10mm or so anyway meaning he would not be able to drop it any lower than he currently has his saddle set.

The smallest dropper post that I know of (and I didn't know one existed until I saw it a few minutes ago on CRC) is a child-specific one by BrandX that is internally routed and is 70mm of travel. That means that even if you could somehow get that dropper post to fit your sons bike from a cabling perspective, his saddle would now be 70mm high (plus maybe another 10mm+ for the seat collar), not 10mm high at full extension.

Unless I have misread what you wrote I think your son will need to put in a good 6cm (at a minimum) of growth before he sees benefit from a dropper post.

'XC' posts can have shorter travel, but not sure you'd want the expense.

E.g. 60mm: https://www.bike24.com/p2425115.html