Bianchi classica circa 80s seat post size help
 

I bought my girlfriend a late 80s Bianchi Classica and its in dire need of a seat post. its Japanese made and has a decal that says Hi-Mn. i believe its strait guage tubbing but built up with some newer parts it only tips the scales at 21.1lbs.

anyway, the seat post in it measures about 26.4 with my calipers but the stem that came in it was the wrong size, so who knows if this is right. (the binder looks correct) any guesses to what it should have??

Bianchigirll is the expert here, but I am willing to venture a guess that a. it is not a straight gauge tubing and more likely a DB Tange 900 main triangle and b. it takes a 26.8 seat post.

thanks, its a lower end frame (stem shifters) and after looking again it says P.G. OJI Original Tubing. nothing about Tange, nothing about butting. the 26.4 that is in there seems very tight. i hope all is well...

here is more evidence for 26.4

http://www.bikeforums.net/archive/in.../t-178678.html

i jut want to verify before purchase

Tight is the way you want to fit a seat post (with a lot of lube on it). On the other hand... does the frame have any down tube shifter bosses? I cannot think of a Bianchi leaving any factory with stem shifters...

Pictures, pretty please :)

I'd stay away unless it is about $50 or so... Still the stem shifters bug me (even that bike you linked to had DT shifter bosses)

i already own the frame. i just want to verify seatpost size before i buy one of those. it has no shifter bosses. i bought it for the brand new bontrager wheelset, saddle, tires, 9spd shimano cassette and platted 9spd chain that came with it.

i know its not a real high end frame but i currently have it built as a 1x9 up with:

kenissis aluminum fork
chorus headset
Giant adjustable quill stem
stock aluminum bars
nashbar brake levers
nashbar front caliper (stock dia comp rear for extra reach)
veloce bottom bracket
campy racing t crank arms
racing t rear derailur
ultegra 9spd cassette
kmc 9spd chain
bontager saddle
mks slyvan light pedals
dura ace bar end shifter (front) friction hooked to rear
and the heavy steel seapost

after all of that it weighs 21lbs

i figure that none of those parts are all that light so the frame cant be too bad quality wise...

i'm ebraised to say what i have invested in the actual bike but there are a lot of BRAND NEW parts:

bottom bracket
pedals
cranks
derailur
cassette
chain
saddle
bar tape
bottle cage
power grips (great for commuting in nice leather shoes)

and these parts are like new:
chain rings
front brake
stem
headset
shifter
brake levers
wheels

total investment is less than $300

http://i280.photobucket.com/albums/k...e/DSC00837.jpg
http://i280.photobucket.com/albums/k...e/DSC00841.jpg
http://i280.photobucket.com/albums/k...e/DSC00843.jpg
http://i280.photobucket.com/albums/k...e/DSC00844.jpg
http://i280.photobucket.com/albums/k...e/DSC00845.jpg

Your Classica is early 1980s. It has the Piaggio decal, indicating it is no newer than 1984, which would be my guess, based on the decals. Please submit the serial number for my database.

The tubing is plain gauge (non-butted) manganese alloy. But this is only in the main tubes, The stays and original fork are hi-tensile steel.

As previously stated, other samples using this tubing have turned up with 26.4mm seat posts. It is certainly in the ballpark for a plain gauge, manganese alloy tubeset and there is no reason not to believe that it is correct.

I think you have done a very nice job in modernizing the Classica. It may be a bit overdressed, but provided the girlfriend likes it, it is well worth the investment.


Ideally, a seat post should be a line fit, which means the size of the post does not exceed the inner diameter of the seat tube. A tight fit will mar the post during insertion, removal and adjustment, even with lubrication. The post should be the same size as the inner diameter of the seat tube or 0.2mm undersize. A lubricated post should slide easily into the seat tube.

Thanks!

where is this database???

i agree that it is a tad over dressed. i would like put a simple classic quill stem in it and a silver 32 spoke wheelset but i had this stem laying around and the wheels came attached to the bike. (i basically bought the wheels, chain, cassette, and saddle and the frame came with it.

we wanted to use the stock fork but the original headset was not useable, and the fork required an odd race size. the headset and fork were readily available so we used it.

with all of that said, the girlfriend loves it and it works very nicely.

nice looking bike. someone put alot of money onto that old frame. is that an aluminum fork or just an odd crowned steel? I agree on the seat post it likely is 26.4. (if I ever find that seat tube guage, I am going to buy it then rent it out LOL) I see a red Classica in '83 *dark* + '84 *Cardinal* for 300 I don't think you did too bad, I guess the builder did not realize what kind of frame it was.

taking a third look at the pics something about that HS and stemm bother me are the spacers under the stem for looks?

OH "E" yes Bianchis did come with stem shifters. in the early to mid '80 most of the lewer end bikes had them and the Classica was one of them

My ~85 bianchi (italian) track bike takes 26.8. Don't know if that is the spec for their 80s track bikes, italian bikes, or both.

yes, those are spacers under the stem. it was a stock adjustable stem from an original Giant compact road bike. the stem is the proper size, they just used tiny spacers with it apparently to give it a smoother profile. we want a nice quill stem, this was jsut a freebee

it is in fact an aluminum fork. it was also free (just had to pay to get it threaded)

Looks good - nice to see an old frame put back into use. Seems pretty light too, how does it ride?

we've got ice and sub zero temps... i cant wait to find out.