Cannondale Seat Height won't go lower

[GreenRider123]

Hi there - I bought a new (used) Cannondale road bike - 56 CM - I'm between 5-9/5/10 so right b/t a 54/56. Anyway I went to lower the seat and it's at it's lowest point and the seat height is too big and won't go any lower. Since it's a used bike I can't return it. Am i screwed and need to buy a new seat post or can you somehow hack it to lower the seat post? I believe I've read (if I understand) that you can 'saw' the seat post to get it to manually lower a little more.

Any advice would be appreciated or did i just throw money down the drain?

 

[Spiderweb]

Can you post a picture, this will help with advise.
I suspect your seat post is catching on the bottle cage mount in the frame stopping it lowering further. I would cut a couple of inches off using a plumbers pipe cutter, you can buy them for three or four quid on eBay. You can indeed use a hacksaw but the cut is unlikely to be as neat.

 

[AyJay]

Could it be that the seat post is hitting against the bolt on the down tube that is used to hold the bottle holder? The bolt maybe too long and is protruding inside the tube. I know it sounds like a long shot but it happened to me!!

 

[AyJay]

I was a bit slow there! Must type faster! Two minds think alike.

 

[roadrash]

photos would help, preferably with the seat post removed and held against the seat tube

 

[cyberknight]

Without knowing what bike its hard to say , some bike have compact frames so the measurement is the seat tube rather than the top tube, my current bikes have a 54 TT but are listed as a 51.5 measured seat tube.

 

[biggs682]

if its the post contacting the bottle bolts nothing stopping you from chopping an inch or what amount you need for the post to go lower in frame , but perhaps a smaller size frame should have been considered .

i use a pipe cutter for chopping seat post's down length wise .

 

[bpsmith]

How does a pipe cutter work on carbon? Anyone tried it?

I have a carbon blade and guide, which does a perfect job, but intrigued on the pipe cutter.

 

[Spiderweb]

How does a pipe cutter work on carbon? Anyone tried it?

I have a carbon blade and guide, which does a pe text job, but intrigued on the pipe cutter.

I wouldn’t use a pipe cutter on a carbon post, my original advice was given presuming the OP’s bike, like the majority of bikes has an Alu post.

 

[bpsmith]

I wouldn’t use a pipe cutter on a carbon post, my original advice was given presuming the OP’s bike, like the majority of bikes has an Alu post.

Was a genuine question and not having a pop. Just wondered if it worked, that’s all.

Not sure the majority of bikes have Alu posts though. There’s an awful lot of carbon ones out there.

 

[biggs682]

How does a pipe cutter work on carbon? Anyone tried it?

I have a carbon blade and guide, which does a pe text job, but intrigued on the pipe cutter.

i was working on the basis of the op's seat post being alloy

and as @Spiderweb said i wouldnt use a pipe cutter on a carbon one either

 

[bpsmith]

i was working on the basis of the op's seat post being alloy

and as @Spiderweb said i wouldnt use a pipe cutter on a carbon one either

Was genuinely asking, although that was a big assumption to make.

 

[jowwy]

9" angle grinder with cutting blade and lop off a few inches from the bottom of the tube - job done

 

[SkipdiverJohn]

Not sure the majority of bikes have Alu posts though. There’s an awful lot of carbon ones out there.

I'm not sure the majority of bikes have alloy ones either, steel is probably still the most commonly fitted type. Remember the bulk of bikes sold overall are either BSO's or just a bit better than a BSO. Carbons are a tiny minority in the scheme of things, even though your personal fleet might be 100% carbon!

 

[DRM]

If it’s an aluminium or steel seat post use a pipe cutter as suggested or a hacksaw, mark where you want to cut & don’t rush it, don’t forget to de-burr the rough edges with a file & apply copper slip if it’s going in to a metal frame (Ali, steel or titanium) if it’s a carbon frame use carbon assembly paste not copper slip & use a torque wrench to set the clamp correctly (usually around 5 to 6 Newton / meters) if it’s a carbon seat post a fine tooth hacksaw blade & sand off any rough edges with fine emery cloth, apply carbon assembly paste before fitting into the frame