dia comp brake cable clamp strap question

[oldskoolbmx]

http://www.ebay.co.uk/itm/Dia-Compe-Brake-Cable-Clamp-Blue-Oldschool-BMX-Fixie-New-Free-UK-Delivery-/261305511491?var=

Hi, I measured my top tube on my frame which measures about 90mm circumference,  these brake cable clamp straps I want  which are in the link above for you to see only go to 31.8mm, which is tiny so how the hell do these fit??? It might be a daft question but this is my first build

Thanks
John

[oldschoolace]

John, what are you running with a 90mm diameter Top tube 

[Gary72]

Pi   Is your friend

[john4130]

90mm circumference means a 28.6 diameter tube.

[oldskoolbmx]

Thanks alot lads