Bicycle Mechanics - Seat Post To Small?

I am presently in the middle of building my new read bike and ran into a little problem. I have a Syncros Titanium seat tube that is 27.0 MM. The seat tube dia. is 27.2. (Minimal but I didn't want to take a chance). I ran down to my LBS looking at possible shim options, and they had the part, cost was $8.99. The Mechanic there suggested I save my money, take and cut the ends off a Coke can, and use this as a shim. Through a little trial and error, I came up with a shim that is about 1¼" wide x 3¾" long, and it worked perfectly. My hats off to the Mech. Any one else w/similar 'quick and painless' (to the wallet) fixes out there??? ;)

I don't know about titanium, but aluminum bonds to steel eventually. For this reason, I don't use cola cans for shim stock.

Instead, I use pieces of plastic bottles for shim stock and it works well.

Most hobby shops and some hardware stores carry brass shimstock, which is not very expensive, that comes in different thickness.

BTW, Greg traded his tandem for a new one with S&S couplers.

("aluminum bonds to steel eventually")
If that's the case, how could they get away with using all the aluminum seat posts that are on the market w/the various makes of steel frames?


Originally posted by mike
Instead, I use pieces of plastic bottles for shim stock and it works well.

I like this idea though! :thumbup:

Originally posted by mike
I don't know about titanium, but aluminum bonds to steel eventually. For this reason, I don't use cola cans for shim stock.

Grease.

Originally posted by Cipher
("aluminum bonds to steel eventually")
If that's the case, how could they get away with using all the aluminum seat posts that are on the market w/the various makes of steel frames?



I like this idea though! :thumbup:

Better bikes don't mix aluminum posts with steel frames.

Usually, this combination is found on the lower-end bikes. Sure enough, though, just because it is being done doesn't mean there isn't a problem.

Grease does help to some extent, but common grease does not seem to prevent the aluminum and steel from eventually bonding.

Once you spend a day cursing and sweating trying to free up a frozen seat post, you will know what I am talking about.

"Better bikes don't mix aluminum posts with steel frames.
Usually, this combination is found on the lower-end bikes. Sure enough, though, just because it is being done doesn't mean there isn't a problem. "

....don't mix aluminum posts with steel frames?!? Almost every good steel bike (Serotta, Bianchi etc.) I've seen in the recent past has had an alumimum seat post. A few have had Ti posts, and even fewer have carbon posts.

Disimilar metals act like a battery, causing corrosion. Any interruption of the galvanic action by putting a barrier (grease) between the two metals will not allow the corrosion to take place. Any grease, when properly applied will prevent the corrosion.

Originally posted by mike


Better bikes don't mix aluminum posts with steel frames.

ROTFLMFAO...................where can I get lightweight quality steel posts to go with my quality steel frames??:lol: :roflmao:

Umm....Mike....A steel frame with a steel post is the epitome of a cheap-**** bike. All decent steel frame road bikes use aluminum posts. Have for 25 years......