Chainrings, Campagnolo BCD's etc

pinno

I have recently purchased a Campagnolo Record Chainset Compact UT 34/50. In over 20 years of riding, suddenly there seems to be an upsurge of hole sizes widths or something. Having previously had 7 or so chainsets with no problems, I now do not know which inner chainring to purchase so that I can make my 34/50 into a 36/50. I.e a 110mm/ 135 BCD ?!?!?! Ribble sell a whole load of inner chainrings and although a Record inner is hens teeth, I would be content with something compatible.

I'm confused. Please help and unravel the terminology for me.
Thanks
Rob

redvee

Sheldon Brown might help you here, he seems to help others

http://www.sheldonbrown.com/gloss_bo-z.html#bcd

synchronicity

Campy has always been 135mm BCD apart from their compact which is 110mm.

But I am certain for compact cranks, they use one or all bolts at a diameter of 112mm, just to lock you into buying their own brand of chainrings.

gkerr4

synchronicity wrote:

Campy has always been 135mm BCD apart from their compact which is 110mm.

But I am certain for compact cranks, they use one or all bolts at a diameter of 112mm, just to lock you into buying their own brand of chainrings.

This is true - one of the bolts is at a different measurement - just to be annoying - you need to ensure it is a campagnolo specific chainsring.

I know this isn't any help, but you can specify the record compact chainset in 50/36 (or 48/34) - is it too late to swap it?

pinno

Hi Folks - thanks for the posts.

I have tried in vain to get a 36/50 Compact. Everywhere is sold out. Parkers, CRC's, Evans, G Butler, Ribble (you know - the usual comic suspects). I even tried to get a chorus 36/50 UT. If you pay full whack: 450 plus i could get one but thats way over budget. A little bird at Ribble told me that to get back stock through now from Italy won't allow them to offer discounts because of the awful exchange rate.

I currently have a Carbon Chorus Sq Taper but hoping to shed bucket loads of weight by employing a UT BB with overboard cups as well as the fact it is a 39/53. Huge. I did the Caledonia on a compact 34/48 and the 1st gear was just way too small coupled with a 13/23cassette. (I'm only 62kg's). And thats the other thing, Campag Record Cassettes don't have many options unless you buy the mega expensive titanium blocks, so I opted for a Chorus 13/26 cassette and that gives me a 34/26 1st gear which is almost an MTB granny gear in my book. I have sourced a Record compact 34/50. Its paid for and in the post.
Cheers
Rob

mrushton

You need a Campag OE ring or a TA Nerius the latter having the offset bolt behing the arm.

pinno

Thank you, the Nerius is available at Parkers. Now I understand about the offset arm, to cater for the 112mm bolt.

Cheers
Rob

kozzo

redvee wrote:

Sheldon Brown might help you here, he seems to help others

http://www.sheldonbrown.com/gloss_bo-z.html#bcd

useless