My son is 9. He’s about average or slightly less in height and is on a 24″ Saracen with 26″ Fox 34s and BIG Hans Dampf tyres. It’s a great bike but if he’s in the correct body position for pedaling uphill he can barely touch the ground with tip toes when we stop.

I’d like to get him a dropper as he’s been asking for one since he realised I had one and use it all the time.

So the question is with an max travel available of 2-3″ between fully up and bottomed out what dropper fits the bill? Would be great if it’s possible to add shims to reduce travel if that’s an option like on the OneUp Mk1 as that’ll allow it to extend as he grows.

Spec would be:

Remote
Stealth
30.9mm (I think)
Reducible in height so I can get it to fit him and extend it as he grows.

Oh and if anyone has one for a 2nd hand sale that’d be great. ;o)

Any scope to trim the seat tube?

Even though its a slightly messy solution, I’d be tempted by a brand x post, and a bit of dyneema (or similar bit of string) to limit the travel on the post. Easy to adjust and cheap as.

Any scope to trim the seat tube?

Not really.

Not sure about the thread limited actuation it’s pragmatic but as you say messy.

Thinking about it it doesn’t have to be stealth – so long as it’s at the top of the fixed bit not the movable bit. A lever under the seat type would even work.

Spesh did a command post with 75mm drop, but it wasn’t easy to find when I wanted one for Mrs P – hers was 31.6 and non stealth though. Their website lists a 75mm 30.9 but its out of stock.

What max insertion does the frame have and how much seat post is showing at the moment?

Bikeyoke do one buts it’s expensive…

I tried the string/fishing line thing and it doesn’t work, plus it snags and looks a bit daft

If you do enough googling you’ll find hacks for all of the major posts to limit extension. It was an issue a few years ago before bike manufacturers caught on and started producing frames with lower seat tube heights

I limited my 100mm Reverb to 85mm (stumpy legs!) but it was messy and took a bit of trial and error to find the correct spacer ID/OD

I read somewhere about using a longer dropper, then using string tied from the seat rails to the frame to restrict how high the dropper goes. As he grows, adjust the string. Not as neat as shims but cheap and easy.

Anyone know if you can limit travel on a Brand X post? Found one on PB that’s fairly local.

I think Dan Hodge (Bird) has already done this.

Internal or External?
I’ve got a “as new” (full service – their description but it is photos can be available) Thomson 125mm external and unused Raceface turbine 1x lever. Never used cables..

I paid for the service fitted it to Jnr’s 24″ and he rode it 1-2 (literally) then decided he was going to ride his adult bike.

I’m not for selling it for less than the cost of the service though…

KS do droppers with 75mm travel.
I have just bought a KS Dropzone (75mm) from the classifieds for my son’s bike.

Brand X do a 75mm travel one in 27.2 so could be shimmed.

Lever action is something I’ve always thought could be dodgy for kids with not so strong thumbs though. So a under saddle lever could be a better option…

Brand X do a 75mm travel one in 27.2 so could be shimmed.

I don’t think the CX lever will fit the bars anyway.
I have one on my XC HT and the lever is designed to clamp in the middle of the bars by the stem.

Lever action is something I’ve always thought could be dodgy for kids with not so strong thumbs though.

I thought the same but in reality it’s not been a problem with cable operated.
Jnr’s 10 now but he’s used Brand-X, Fox, Thomson (really crap), ZTTO … from age 7 or so on…
I can’t remember what remote he has now (I think its a Thomson one) but I asked the other day if he wanted a different one off one of my bikes and he just said “meh..this works fine”

Weight was more of an issue and being able to depress the seat…

I don’t think the CX lever will fit the bars anyway.

Actually that is an even bigger problem as he’s running the SDG Grom cockpit setup so using smaller dia bar/grips. Might need to make a shim.

I think Dan Hodge (Bird) has already done this.

Internal or External?
I’ve got a “as new” (full service – their description but it is photos can be available) Thomson 125mm external and unused Raceface turbine 1x lever. Never used cables..

I paid for the service fitted it to Jnr’s 24″ and he rode it 1-2 (literally) then decided he was going to ride his adult bike.

I’m not for selling it for less than the cost of the service though…

Dan Hodge did what Steve?

AND how much/any pics etc? email in profile.

Cheers

Gary

I got Mrs G a KS Drop Zone 75mm drop and maybe only 300mm in total, (but lever under saddle operated). Her Specialized full suss is a M and good size for her, but she didn’t need a longer post. They do a lever version.

Think it was just over £100. Good bit of kit.

@speeder

Dan Hodge did what Steve?

He modifed a Bird branded one for kids. (Initially his eldest) I don’t think it was a “for profit” item but he did post on kids riding FB groups.

AND how much/any pics etc? email in profile.

I’ll email… I always mess up trying to post pictures on here!

dropper travel adjust

Apparently works for other posts than just the oneup post

Just wait a couple of months, his legs will grow…

@speeder

No email in the profile (I’d guess it went with the new format like mine) but I sent you a forum message and link to photo’s.

Just wait a couple of months, his legs will grow…

Both me and the wife are relatively short so he’s not getting long legs any time soon and I feel bad putting him on a slightly too big bike already. #dadguilt

Brand X / TranzX and many others have same internals and can take the OneUp shim to limit rise;

Shim a dropper

I’ve also used a loop of brake cable fixed with an electrical block to create a tether to limit rise, worked fine. Another issue is rider weight, something like the old X Fusion HiLo can be set at quite low pressure so children can press them down. Finally if you are having trouble getting a dropper fully into a frame because the frame tube has kinks / ridges try a 27.2mm dropper with a 30.9mm (or whatever frame tube is) shim as it might then clear obstruction.

The OneUp V2 posts have the shortest stack height for a given travel on the market. My 210mm one has barely any less outer tube showing above the seat clamp than my old 170mm reverb. You can also reduce the travel on them with the supplied plastic shims. Shortest travel they do is 120mm but that can be shimmed down to 100 & will probably still be shorter overall than most 75mm drop posts. They’re Cheap too, bout £160 online but that’s without a remote. Only had mine about 3 months So can’t comment on long term reliability but it’s been perfect so far.