How to measure seatpost size

Is there any way to measure what size seatpost I need without buying an expensive measure-gauge-thingy?

sheldon's seatpost size database

is there any homemade way? my Viner isn't on the database

nice one, cheers

Sheldon must have karma points over his ears by now

not accurately..

you need to be within .2 of a mm

vernier gauge on the original seatpost or take frame to LBS to measure

You can lay a decent ruler across the seat tube and try and sight it from the inside of the tube edges but you won't be able to tell a 27.0 from a 27.2

TBH I would buy a cheap Vernier gauge from ebay - I got a secondhand old fashioned Sheffield Chesterman engineers metal one (non digital) for about £5. Once you have one they are so useful for this and that...

http://www.victorcen.com/UploadFile/2007-5-29_17-53-21.jpg

£10 from maplins / ebay / wherever

well worth it, so many sizing standards on bikes are like within 0.5mm of each other :/

yeah maybe not a bad idea to get one of those, they are after all pretty cool

ok i found a accurate ish way if you have a seatpost already. Take a large rizla and wrap it around your seatpost and drop a line where the rizla overlaps. that's your circumference. measure that length really accurately and divide that by pie (or 3.142) and you get the diameter. ok so not necessarily mm perfect but i got a circumference of 85.5 mm which translates almost exactly as 27.2mm! Perfect for that campag chorus i have my eye on! mmm...

tynan probably knows a way involving some glue, a shoelace and a ten pence piece, he is kinda handy like that...;)

Get some glue, a shoelace and a ten pence piece.

Glue the ten pence piece onto the end of the shoe lace, lace this up on one of your trainers leaving the ten pence dragging on the floor behind you.

Go into Maplins and pick up a set of digital calipers, go over to the counter and say 'excuse me someone has dropped some cash here' (pointing at the ten pence).

When the cashier comes around to pick up the money kick him in the head and run out of the shop with the calipers.

best plan ever

tynan Get some glue, a shoelace and a ten pence piece.

Glue the ten pence piece onto the end of the shoe lace, lace this up on one of your trainers leaving the ten pence dragging on the floor behind you.

Go into Maplins and pick up a set of digital calipers, go over to the counter and say 'excuse me someone has dropped some cash here' (pointing at the ten pence).

When the cashier comes around to pick up the money kick him in the head and run out of the shop with the calipers.

Brilliant.

Even with some digital calipers whats the best way to get a measurement from the seattube? I'm getting between 26.70 - 26.00 depending on angle.

Get some glue, a shoelace and a ten pence piece.

Glue the ten pence piece onto the end of the shoe lace, lace this up on one of your trainers leaving the ten pence dragging on the floor behind you.

Go into Maplins and pick up a set of digital calipers, go over to the counter and say 'excuse me someone has dropped some cash here' (pointing at the ten pence).

When the cashier comes around to pick up the money kick him in the head and run out of the shop with the calipers.

Damn, wish I'd tried that when I bought my calipers!

Even with some digital calipers whats the best way to get a measurement from the seattube? I'm getting between 26.70 - 26.00 depending on angle.

Try your LBS, mine has this kind of seat tube looking length of steel thats graduated going from thin to think, they slip it in the seat tube and read off the measurement. Simpsons Cycles in Kentish Town if you were wondering.

Get some glue, a shoelace and a ten pence piece.

Glue the ten pence piece onto the end of the shoe lace, lace this up on one of your trainers leaving the ten pence dragging on the floor behind you.

Go into Maplins and pick up a set of digital calipers, go over to the counter and say 'excuse me someone has dropped some cash here' (pointing at the ten pence).

When the cashier comes around to pick up the money kick him in the head and run out of the shop with the calipers.

lol

I'm crying now.

has anyone got Digital Caliper I could borrow?

thanks!

nice

There's one method I always use, which has worked so far.

Clean your seatpost, obtain a large post-it note (or some other very thin sheet of paper), and wrap the post-it note around the post. It need to overlap itself. Make sure that the long edge is exactly lined up as it wraps around itself. That way you know that the post-it note is square to the seatpost.

Now mark the overlap point with a very sharp pencil. Take the post-it off, and measure along the edge to the mark. Divide by 3.142.

That should give you a sufficiently accurate measurement of the diameter.

Sorry, I guess I should say that this only works if you are replacing a seatpost and can measure your old one.

Going to try the risla / post it trick as the bike I picked up for my first SS build, a Raleigh Scorpio must be the most unpopular bike ever, never in any databases.

At least the seatpost isn't stuck though, read horror stories about that

Get yourself a set of digital Vernier calipers: less than a tenner off Ebay and will pay for themselves time and time again, if you are rebuilding a bike.