How do I measure for a seatpost binder bolt?

[Fishbike]

Hi Gang --

I need a seatpost binder bolt for a Colnago super. I see that the bolts come in different sizes including 17mm, 19mm, 22 mm and 25mm? How are the bolts measured and how do I measure the seatpost binder to determine what size I need?

[R2D2]

It most likely took the standard Campagnolo binder bolt. I don't think they came in different lengths.

[ultraman6970]

You grab the clamp ears in the lug and measure that outside to outside. In the bolt you close it all the way and then measure inside to inside.

Pretty much almost everything I have seen will take the 19 or the 17 mm, If you grab something like 20 mm (suginos), be sure to get an extra washer just in case, second option is to cut the screw side of the bolt a couple of millimeters. The only thing I would advice you if you cut or dremel one is to put paint ot something in the cut area because that will get rusty quite quick.

Hope this helps.

[nighthawk]

It most likely took the standard Campagnolo binder bolt. I don't think they came in different lengths.

The two Campagnolo binder bolts I have seen were both something like 19mm long, but different diameters (8 and 10mm). The 8mm would be the likely fit for the OPs Colnago. I think the 10mm was for old Cinelli's and some other "weird" frames.

[ultraman6970]

Always you can use the 10 mm in the rather old oversized clamp holes too :D

[Fishbike]

Thanks everyone! Very helpful. Just gotta get a $5 one and not a $25 one.

[R2D2]

Thanks everyone! Very helpful. Just gotta get a $5 one and not a $25 one.

Be aware that some have a nipple that fit into a slot in seat lug and some are knurled all the way around as the seat lug does not a have a slot. Good luck.

[oldpotatoe]

Thanks everyone! Very helpful. Just gotta get a $5 one and not a $25 one.

The 5buck one may have a notch on it that won't talk well with that frame..and most decent LBS sell Campagnolo ones for $20..

[Fishbike]

Good to know. Thanks folks.