Help!! Is my Sestpost long enough?? 🤕

[al-onestare]

That's not ok from my perspective.
I've seen so many aluminium framed bikes broken at the top of the seat tube, often with more insertion than this.
(I've repaired dozens of steel frames, but aluminium ones go in the scrap. )

You'll get away with it if it's a showpiece, but in regular hard riding, the post is flexing the top section and it will fatigue and snap, without a doubt.

In an older alloy frame, id look for a beautiful snug fit and at least a couple of inches below the bottom weld.

Yep, agree. IF this was a steel Kona I'd be more inclined to say you're ok (still with a "take it easy" warning) but with aluminium, it's not recommended.

Great Kula by the way, my fav iteration of that model.

 

[Monkeeee01]

Thanks @al-onestare

 

[brocklanders023]

Might be bucking the trend here but it looks absolutely fine. As a tall bloke who used to squeeze on to 19" retro bikes I've ridden plenty of seat posts at the min line without problem and yours looks miles off to me. Only Syncros I had snapped at the head though so avoid riding in the snow!

 

[troje]

Same here. It is perfectly fine.

Longer Syncros posts in 425 exist but they’re usually black.

What happened to the second S letter on the last picture?

Nice bike!

 

[bikeworkshop]

The less post you have in the frame, the more you are stressing the joint.

The more you ride the bike, the heavier you are, how hard you hit stuff also comes into play - as does saddle layback... and post extension obvs.

Its just probability, and what risk you're happy to live with.

 

[brocklanders023]

That's all true but there's also a minimum insertion line for a reason. Run above it and you're asking for trouble but the bikes were designed and manufactured to work within the set limits.

 

[al-onestare]

That's all true but there's also a minimum insertion line for a reason. Run above it and you're asking for trouble but the bikes were designed and manufactured to work within the set limits.

....at the point of manufacture and within a reasonable time/warrenty period.

This is 28 year old aluminium.

 

[bikeworkshop]

....at the point of manufacture and within a reasonable time/warrenty period.

This is 28 year old aluminium.

And the minimum insertion is marked on the post, not the frame.


Min insertion on a lugged frame like a galaxy with 3inches of post above the cluster is very different to a kona with raised seat tube and 10 inches of post showing.

The frame material will also change the insertion requirements.

These are extremes, but I've dealt with dozens of frames broken at the seat cluster where the post was inserted beyond the guideline.

It's just what risk is the owner willing to take?
If the frame is nothing special and easily replaced, it matters less than if its a valuable possession.