seapost insertion on an extended seat-tube....

[choppstar10]

After bending my original seapost on my 95 kilauea I have now purchased a Ti affair off ebay, not too bad but it's come up a little shorter than I was expecting. I'm not sure how the seller can measure 400mm when the most I can see is around 370-80 at a push!!

The seatpost doesn't have a minimum insert line, and with konas having the extended seat-tube I kept away from the USE and shim set up because of worries of stressing the frame at this point.

I was wondering if anybody has damaged a frame this way? will it be fine or am I just stressing too much?? Bearing in mind I probably have 14.5 stone on the end of 270mm ish protruding seatpost(120 still in frame).

 

[tintin40]

my USE post recommends 4'' of post in the frame. USE shim are 2'' long from memory.

 

[marin man]

I would think it would be ok as you have four inches in the frame,so long as it is below the top tube join you should be fine.

 

[dyna-ti]

I would think it would be ok as you have four inches in the frame,so long as it is below the top tube join you should be fine.

+1

 

[choppstar10]

cheers fellas,

think I should just about be ok. I was waiting for people to say get a bigger bike, but those 20 inch plus konas start to look a bit special, and I couldn't be riding about on something I didn't like te look of!

Yes I'm a bit of a retro tart, 250 miles round the south of france on a flite proves it, not the most comfortable on the long rides but they look great!!

 

[WD Pro]

my USE post recommends 4'' of post in the frame. USE shim are 2'' long from memory.

Pretty sure they are 4" but I cant confirm as one is in the Marin to stay and the other I have is partly converted to a bar shim

 

[WD Pro]

cheers fellas,

think I should just about be ok. I was waiting for people to say get a bigger bike, but those 20 inch plus konas start to look a bit special, and I couldn't be riding about on something I didn't like te look of!

Yes I'm a bit of a retro tart, 250 miles round the south of france on a flite proves it, not the most comfortable on the long rides but they look great!!

Does the kona have a shim already in the frame ? (might be ally or ti) ?

If so, measure it - no need to go any deeper

 

[choppstar10]

cheers fellas,

think I should just about be ok. I was waiting for people to say get a bigger bike, but those 20 inch plus konas start to look a bit special, and I couldn't be riding about on something I didn't like te look of!

Yes I'm a bit of a retro tart, 250 miles round the south of france on a flite proves it, not the most comfortable on the long rides but they look great!!

Does the kona have a shim already in the frame ? (might be ally or ti) ?

If so, measure it - no need to go any deeper

no shim, just good old steel!!

 

[WD Pro]

Sorry dude, I somehow read into your post it was also a ti frame

 

[Anthony]

After bending my original seapost on my 95 kilauea I have now purchased a Ti affair off ebay, not too bad but it's come up a little shorter than I was expecting. I'm not sure how the seller can measure 400mm when the most I can see is around 370-80 at a push!!
The seatpost doesn't have a minimum insert line, and with konas having the extended seat-tube I kept away from the USE and shim set up because of worries of stressing the frame at this point.
I was wondering if anybody has damaged a frame this way? will it be fine or am I just stressing too much?? Bearing in mind I probably have 14.5 stone on the end of 270mm ish protruding seatpost(120 still in frame).

I think you're right to be concerned. I try to get 13.5cm minimum insertion on a Kona, based on 8.5cm to the bottom of the top tube/seat tube junction plus 5cm (admittedly a guess) so that the end of the post isn't against the part of the seat tube that was subjected to welding.

If you go with 12cm, you have your potential pivot point 3.5cm from the weld. I guess that'll be ok, but I personally wouldn't go any lower.

As you say, the minimum insertion mark on the post itself is irrelevant to a Kona or similar frame. If the frame needs more than the post does, then more it must have.

Make sure you put plenty of copperslip in there, not feeble grease. Ti posts can get stuck and there are plenty of reasons why you don't want to have to saw a ti post to pieces!