You are hereForums / By Discipline / Mountain (off road) / MTB Gear / New seat post length

New seat post length

Rune's picture

By Rune - Posted on 23 September 2012

Hi guys,

I've finally decided on the KS Lev as my first dropper seat post, mainly because I don't think the Fox is worth an extra $100+ and because I can't test it without buying it! I've got a question about the size I'd need/want though.

My current seat post is a 31.6x350mm carbon fiber one, with approx 140mm inserted from the bottom (90mm minimum insert plus an extra 50mm). I'm not sure which would be a better post for me:
1) 335mm post / 100mm drop
2) 385mm post / 125mm drop

Any recomendations? I'm fairly sure that the 335mm will fit, and I've got an extra 50mm of insertion room on my current post so the 385mm should be okay too, but not sure if it makes any difference for usage.


hawkeye's picture

Depends on what's more important to you: a slight weight saving for the shorter one, or better frame longevity and more travel on the longer one. I'd probably go the latter myself.

Will be interested to hear your report. Am thinking about one for my dually.

Rune's picture

Better frame longevity? Does having a longer seat post make that much difference?

hawkeye's picture

Ah, probably not that much. So long as you have the minimum insertion line covered, you should be right.

*In theory* a longer amount of the post inserted into the frame stresses the seat tube less, and that may be more of a factor with these stiff gaslift units than a more flexy carbon or light alloy post, but in practice you'd probably be fine.

Rune's picture

Fair enough. I won't stress too much about it then.

ChopStiR's picture

Depending on your frame and rear shock/swing arm set up, frame can have an impact on size choice.

Some Seat Tubes have a kink for a shock/swing arm pivot point and the post may be to long and not get past this point causing the post to be to high.

Some frames barely even have a seat tube.

If you have a straight seat tube then I would go with the longer length for better strength especially if its a carbon frame. Unless your a weight weenie.

Rune's picture

I've got a Merida Ninety-Six Carbon 3000-D frame, which has a long straight seat tube as far as I can tell.

I'm not a weight-weenie, but I figure there's no sense adding additional weight that's not necessary. I'm already adding 400g+ with the dropper seat post, I think.
What you're saying about the strength with a carbon frame is definitely something to keep in mind.

Thanks guys!

Magnum9's picture

Did you get the Lev and if so how do you like it? I just received mine but Wiggle sent the wrong length so I have to see if it will still fit. Looks and feels nice though.

Rune's picture

I did get it. Installing it was really quite straight forward with the help of the KS installation video.

Through a series of really annoying accidents I haven't actually had more than a superficial chance to ride it though, and definitely not on anything worthy of it. A friend who got one at the same time has done more riding on his though and says it's awesome.

Heading to Rotorua next week and will put it through it's paces. I'm doing my best to get all my various injuries healed before then!

Magnum9's picture

I ended up with the 435mm with 150mm drop rather than the 385mm one I ordered. It will just fit though so I ended up with the better post for less money. Going to Rotorua next April, make sure you give us a ride report when you get back.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Best Mountain Bike