# 27.2 Dropper post for 21 kg (46 lb) child



## bruce-el (Dec 18, 2018)

I am looking to see if there is a 27.2 dropper post that would work for my 21 kg (46 lb) five year old child. It's for a 20 inch Saracen Mantra 2.0 bike. My last dropper post was circa 2002. I don't remember much about it and even if I did I am sure lots has changed. Some measurements I've gathered.

post insertion max: 210 mm
current saddle rail height (above seat tube): 130 mm
current top of saddle (above seat tube): 190 mm
internal routing: none available


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## Feldybikes (Feb 17, 2004)

Not 100% sure the lengths will work out, but gravity dropper makes a post that will work with that weight. Or close to bag weight anyway. I didn’t keep precise records on weight vs when my kid could easily drop the post under his own weight. You may just need to back out the coil spring preload all the way.


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## jestep (Jul 23, 2004)

This one would be pretty close: https://www.kssuspension.com/product/eten-r/

I don't know if these are adjustable like the KS LEV posts, so unsure what the weight requirements on this one are.

This is the one I have on my AM bike, and you can control the spring pressure so it would work for any weight rider.

https://www.kssuspension.com/product/lev/

You're going to need to do the math on the post insertion requirements. My fear on any dropper on this size bike is that you're going to be close to a point where you won't be able to raise the seat anymore at all when your child grows taller.


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## Demo9 (Nov 20, 2006)

I have found the Thomson Dropper to be really nice for lightweight kids.

https://www.bikethomson.com/product/elite-external-dropper/


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## bruce-el (Dec 18, 2018)

Thanks for the responses. I've come up with a list of what I've been able to find that are 27.2 and have external cabling. For the geometry to work it appears that the seatpost will have to be 350 mm or less. And the travel will need to be 80 mm or less. Unless I am mistaken these are necessary to keep the normal riding height of the saddle rail at 140 mm or lower.

KS Lev 335/65
TranzX (YSP-02) 330/80
TranzX (YSP-22) 300/65
TranzX (YSP-22) 350/85 (possibly but pushes the limit)
TranzX (YSP-36) 305/70
Gravity dropper 350/50 (prefer more travel though)
XLC SP-T08 295/60

Does anyone have any comments on these specific models? Any details that I haven't considered?


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## POAH (Apr 29, 2009)

trans-x ones won't go down with a light child and you cannot adjust the air pressure in them.


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## RMCDan (Feb 28, 2008)

POAH said:


> trans-x ones won't go down with a light child and you cannot adjust the air pressure in them.


Well, some of the TranzX's have adjustable air pressure, just not any of the 27.2 models. Sucks because they're great posts for the price otherwise.

OP - Have you checked any of the PNW Components posts?


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## Demo9 (Nov 20, 2006)

@RMCDan, I have a PNW Components that I installed on the Lil Shredder Fat Bike we built. A light kid cannot come close to lowering the post. My guess is most of the lower end posts are using the same sealed post cartridge with an internal spring that is non adjustable. I had even talked to the guy at PNW and he said their is no way to modify the cartridge.


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## RMCDan (Feb 28, 2008)

Some of the nicer PNW posts are adjustable pressure though? That was my recollection, but it's been a while. The nice ones are still cheaper than a Lev, and PNW is a solid little company to support. 

Don't know if it still works, but a while back the code CHASINGEPIC got you 20% off on the PNW site.


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## POAH (Apr 29, 2009)

Are PNW not just rebranded trans-x posts


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## bruce-el (Dec 18, 2018)

I received an email reply from TranzX that indicated that they aren't making 27.2 dropper posts that are suitable for children which is consistent with what POAH has indicated.

I also received a response from a rep at KS that indicated that at least the Lev 272 did work on their own 6 year old. Although, this doesn't help me as I believe they have 100 mm travel which pushes the minimum rail height too high for my child.

I did have a look at the PNW Pine but the lowest I can get the rail height would be 150 mm which is also too high.

And the 100 mm travel on the Thomson post also pushes the rail height too high.

Does anyone have any experience with the KS Lev or KS eTen?


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## RMCDan (Feb 28, 2008)

I've had a 30.9 100 mm Lev Integra with the Southpaw remote on my kid's Rokkusuta since October '17. No complaints at all, it's been great. Granted, I lucked into it used for pretty cheap. The retail price is definitely a bit hard to swallow.


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## bruce-el (Dec 18, 2018)

A bit of an update. My elder 8 year old child (60lbs) is able to drop the Brand-X Ascend II model now. We have a KS eTen-R as well that he is getting close to being able to operate as well.


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## Steve-XtC (Feb 7, 2016)

Demo9 said:


> I have found the Thomson Dropper to be really nice for lightweight kids.
> 
> https://www.bikethomson.com/product/elite-external-dropper/


I don't think it will work with 21kg though...
From something like 25-26kg they can bounce it down and about 30KG they can pretty much use it properly obviously rough figures depending on STA and my memory


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