Servo888

90% done with my new build. Major issue I'm having is securing the seat post down. The post is set to the limit (because the frame is a bit too small for me, but being young, stupid, and flexible I still plan on riding it), and the post is greased. In fact it's very greasy; I'm wondering if I used too much grease? Also should I try to rough up the surface at the bottom of the post a little bit?

Regards!

nlerner

Use a bigger post or use a high-tech shimming device known as a cut-up aluminum can.

Neal

hxzero

Do you have a 26.8 post when you need a 27.2?

Servo888

Nope, 27.2 seat post and not a .1mm to spare! The previous owner clamped a 27mm post into it, so getting a 27.2 in took a little bit of careful widening, and now it fits in snug, but doesn't clamp with full force. Hmm... Is there suppose to be a spacer attached to the clamping bolt? A .2mm bolt spacer would give me an extra .2mm of clampabality at the post...

unworthy1

you might need a shorter bolt, they come in a couple lengths, and since the PO used too small a post, the tube/clamp may be slightly deformed and need some help. IMHO, grease should not be a factor if the post is the correct size and tube and clamp are not bunged-up: the grease is not a lubricant but a corrosion preventer.

cudak888 

If you caked that thing full of grease, I wouldn't be at all surprised about it spinning.

Best thing is to wipe off any excess grease to leave a thin film to protect the dissimilar metals - but make absolutely sure there IS a smooth film of grease lining the area.

-Kurt

caterham

if all of the above advice fails, try using a film of valve lapping compound rather than grease

unworthy1

now THAT is a clever bit of advice...for them that don't do their own valve jobs: lapping compound is fine emery or carborundum powder suspended in heavy oil, it would supply "bite" but the oil might still provide the moisture barrier that grease would.

vjp

Your bike looks VERY nice.... BUT.... please run your brake cables behind your bars not in front, it messes up the rotation of our planet =)

luker

dang. That's why my head hurts when I see that cable routing. The Earth is going a little slower! (Or...is it faster?)

vjp

fast then slow. then fast again, with a little wobble

hhabca

My bet is on the seat post bolt being too long - it's bottoming on the threads and feels tight yet the post is still loose. I think a washer will help.

Servo888

X2 - two washers and it's holding great! The scary part is that this is the SAME bolt which was holding in the thinner 27mm seat post! Must have been a slightly frozen post ;-)

bikingshearer 

For those of us who have never even heard of "valve lapping compound" and wouldn't know it if it bit us in the butt, rubber cement is worth a try. It's worked for me.