Seat post shims ?

davidphilips

Veteran
Location
Onabike
Any one know if seat post shims are worth fitting or is it better to just buy correct size seat post?

Reason i ask never used one but when fitting a seat post i always like at least 90mm of post inside bike frame and looking at seat post shims (pictures of shims) they look less than this.
 

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ChrisEyles

Veteran
Location
Devon
Good point - I'm using one on a dropper post at the moment after stupidly buying the wrong size (at least it was too small rather than too big!).

Seems to work absolutely fine in practice but it's got to be stronger using the correct size post, especially if you have a lot of post showing out of the frame.
 
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davidphilips

davidphilips

Veteran
Location
Onabike
Starting to realise that theres a bit more to lenght inside frame than i thought, Theres MTB, touring and road bike plus different types of frame material added to that the amount of seat post above the frame?
Perhaps a shim say 50mm in lenght would be more than adequate for a steel frame road/ touring bike with up to 100mm or more seat post above the frame but would not be all that good for a carbon framed race bike with 200mm or more seat post above the frame, then theres consideration of where the top tube meets the seat tube plus the stays etc?
Thanks for the replies guys, always good to run some thing i am not sure of past you, far better than making a mistake and ruining a frame.
 
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davidphilips

davidphilips

Veteran
Location
Onabike

raleighnut

Legendary Member
Now you have me thinking, are there longer types of seat post shims? Seen this on net https://bike.bikegremlin.com/3144/minimum-seatpost-insertion-length/

Think for me unless i find a long shim i will just go with caution because i am sure if some thing can go wrong in my case it usually does .
I'm sure mine is about 100mm (4inch) I did toy with the idea of having a seatpost made that was longer like I did on my Saracen 'Jump' bike but a 400mm one was just enough,

DSCN0207.JPG



That's as low as the seat will go, freaks guys in bike shops out, they tell me "You'll break the frame with that much post showing" so I just show them how high the seat will actually go.:becool:
 
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