Minimum seatpost insertion

Hi All,

After opinions on seat post minimum insertion on a lugged steel frame.

I need a longer post due to getting a smaller frame. I have a dura ace ax post (27.2) which is too short, I have found a nice slightly longer 600 ax post which will extend under the top tube by about 15mm set to the height I need.

Will be be far enough?

Cheers, Lewis.

I honestly think you need a minimum of 100mm. Maybe even more. 15mm is nothing. I'd be very careful unless you like your local A and E department.

Maybe I worded that badly.. The post will inserted about 45mm.

On my old seat post the minimum insertion mark is 60mm from the bottom, not that far off 45mm.

15mm (or 25%) less than minimum. 45mm is less than 2 inches. Is it really worth the risk?

There's a minimum insertion mark for a reason.

You need a modern seatpost, which are available in longer lengths than the OG options you've listed.

I am totally not an engineer, but I have a vague recollection that (in addition to being past the minimum insertion mark) the bottom of the seatpost should also be below the top-tube/seatpost/seatstay junction. That may indeed be bollocks, but it makes some sort of intuitive sense to me.

That may indeed be bollocks...

It's not.

Uve bin Indra'd

Humm maybe I should go for a nitto 65 or something then, but it's going to ruin my shimano continuity..

Better your "continuity", than your bollocks!

Well said. Just buy a longer seatpost. It's easier and safer