rushhour944

hey guys,

so i would like to find out the thread on my old bianchi road bike. there are no labels, serial numbers etc to help me identify it so im looking at just finding out the size of the crankset and find out the bottom bracket size/ thread from there. (bike shop is charging me too much to just found out the size)

i currently have a Shimano FC-A452, Sport LX crank arm on the bike. looking around on velobase.com ive found that it is an english thread
(VeloBase.com - Component: Shimano FC-A452, Sport LX)

im going to go with that my bike has an english thread but can anyone else confirm that the shimano crank arm i have only comes with an english thread?

CACycling

Make/model of cranks have no relation to threading of bottom bracket, only spindle length. Need to remove the existing BB to determine what you have.

rushhour944

so im trying to order a new groupset off of ribblecycling. and the options for the bottom bracket are english or italian. does this mean that there is a possibility that the bottom bracket wont fit on my bike?

JamesRL

Ok, your crank can be used with many different square taper bottom brackets. And while you need the right length (115 from Velobase), the threading would depend on the frame you are installing it in. You don't say how old your Bianchi is, but if it is the same age of the crank(which was only made for a a couple of years), but I would think a 1987/88 Bianchi is going to be British/ISO threaded.

BTW I have that same group waiting to be installed on an older Bianchi frame (early 80s Tange with Chrome fork), and I'm ordering a British threaded BB.

If your Bianchi was a high end made in Italy, it might have an Italian threaded. What is the model and tubing? If it is a Sport SX with Tange tubing I'm betting it would be British.

rushhour944

im assuming its columbus tubing because it says "bianchi formula columbus" on it. i cant find any model number or stickers on the frame to tell me what year it is but i called the bike shop that placed a sticker on the bike and the lady said that they went out of business around the 90's so i would think early 90's frame would be correct.

and its sport lx not sx. im not sure if that was a typo but just making sure were on the same page.

JamesRL

Re the typo, no it wasn't a typo. Bianchi made a Sport SX bike and put Shimano Sport LX components on it at one point. Since Shimano Sport LX was only available for a couple of years(87/88 if I recall correctly), I assumed that might be the one. But Bianchi didn't equip all the bikes in every market the same, so there could have been another bike. The Sport SX was Tange tubed, Japanese made.

The Columbus stickers would indicate that it was Italian made, and probably then the BB is Italian threaded, but you can buy those stickers off the net, and I have seen them stuck on bikes that weren't authentic.

Can you buy a crank puller and get the crank off and see the BB for yourself?

wrk101

Ordering on line is a really bad idea unless you know positively exactly what you need. The way to find this out is to remove the existing parts and measure them (assuming they fit properly). After all, those original parts will have to come off to install the replacements anyway. I would trust what I have in my hand, measured by me 10X more than any helpful comments from the internet.

One reason internet sellers can undercut your local shop is that they do not provide any assistance. Take your bike to a good LBS, and he will be able to get you exactly what you need, at 50% to 100% higher cost. Knowledge can really save you $$.