Yeah, insertion does matter. Several years ago I bought a bike that came with a 350mm post (pre dropper) that I felt like was too short. I found a 400mm post I liked and threw it on the bike. It turned out, the frames on these bikes were prone to breaking in two places, one of which was the top tube/seat tube junction. While a lot of tall guys had frames break there, mine never did, although I broke two at the other problem spot. So, while that won't necessarily apply to you, if your gut tells you that you might need more post inserted, you might be well served to heed that gut.

 

4" or 100mm of insertion is sort of the industry standard. Looks like you've got that covered.

 

I've got a Guerrilla Gravity Pedalhead and it's not even possible to insert a seatpost as deep as the point you indicate on your bike. The frame is reamed 190mm deep, just a couple mm before a bend in the seat tube. My dropper uses every last mm of what the frame allows.


0908191147_HDR by Nate, on Flickr

 

What you have to be careful of is overall length of the seatpost. Even when you have the "min insert", all that will do is prevent the seatpost from breaking, the frame will break if the lever arm is long enough, which an ultra-long seatpost or ultra-long amount of exposed seatpost can do. I think what you are asking is, did this manufacturer take this into account with their design. I would say yes, based on the very low seat-tube height and position of the saddle in the picture relative to the rear wheel and handlebars. But it's always good to have a healthy dose of caution, this is where riding a bike too-small can get you, that usually requires a longer seatpost and can get you into the above situation where you can crack the frame. Your frame looks pretty heavily gusseted.

 

Well, I'm 5' 11" and this is a large frame. I don't have any excessively long legs either; I think I'm pretty normally shaped.

Here's what I think I've decided to do. I have an enve post laying around that is about 10mm longer than the other seat post I had and so that will give me a touch more length inside of the seat tube. My gut tells me that this will be fine since nearly half of the post is in the frame.

In the meantime, I've emailed Ragley to get their take but I was planning to ride tomorrow anyway.

 

You have forgot to say how much you weight, and how aggressive do you ride.
If you are not a Clydesdale, and you do not make jumps bigger than 1m, you should be fine with at least 2cm below top tube, no matter the frame, provided that your seatpost is not longer than standard 400mm).


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I'm 210 or so with my backpack, but I did hear back from Ragley on this. The gist of the conversation seemed to be that as long as I'm past the minimum insertion mark on the post, I should be fine. Where I have it is more than enough (according to the gentleman I spoke with).

 

As someone already said - those marks on seatpost are for the seatpost itself. And till roughly 240-250lbs you should be fine.

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why would you not get another dropper ?