[pisgahproductions]

Semi off-topic but here goes...

I have a control tech seatpost in my steel '96 Torrelli cross bike that's slipping. The post is a 27.2 and I'm sure that's what the frame takes. Any advise out there on how to get this taken care of?

 

[Guest]

Problem seatpost

Try to rough up the seatpost with some sandpaper. Not to much, just enough to get a rough feel on the post. Then insert with anti-sieze grease or no grease. Shouldn't slip anymore after this little trick.

 

[Bertleman]

Clean the seatpost of all grease and check to see if it has worn down from all the slipping.
Even a few thousands of wear can cause slippege. I also used to apply a small amount of grease and then apply some dirt to the post for friction.

 

[teamdicky]

Hey Eric

Have someone take some calipers to your post. I had a Control Tech on my Bullit that was always slipping. Chris measured it with calipers and it came out smaller than it should have been. I switched over to a Thomson and it never slipped. The Thomson might have been better due to the ribs, but I am sure the CT being undersized didn't help.

 

[Elevation12000]

Had the same with CT. It was suposed to be 28.6, but it definately wasn't. Didn't even ride it; was so obvious.

 

[floibex]

... if both are named as 27,2 it might be a problem of the tolerances, the frame is on the upper end and the seat post at the lower end of their tolerances, this could cause a difference big enough to make it "slippery even without grease"

a very material, and above all, user friendly method to fix it:

take your favourite canned beer (or two), drink it, cut a slice matching the circumference of your seat post, wrap it around the post and try to insert it to the frame, if this is too much, cut small slices off this tin plates. try again.

it must be canned beer, softdrinks as coke or others are not recommended

ciao
flo

 

[rollercam]

Not bring up the obvious, but are the tabs of the seat collar touching?

 

[Elevation12000]

Personally I opt for the save mode. For me the post must be perfect fitting and at least 12cm in the frame. I don't use shims, as I don't know shims longer than 8cm. I also won't go for dirt, nor tincan solutions. Only stuff that goes into my seattube except for the seatpost is Mike Sander's Furthermore no excessive force to tighten should be required.

Maybe I am a bit overcautious, but I favour that over running the risk of damaging a frame. I also feel dirt and tincan solutions are not up to the quality of a nice frame. Just my two cents, but maybe you should try another post.

 

[floibex]

Not bring up the obvious, but are the tabs of the seat collar touching?

... yes for sure, did you check the seat tube inner diameter with a vernier caliper or an other 27.2 seat post? if the other seatpost will fit, it's this boring tolerances problem... if not, you'll go with a bigger sized post or shims, as 27.4 or 27.6 are very rare...

ciao
flo