Modern Road Chainrings...

[Hugh Manatee]

Are they 110 BCD? My mountain bike cranks are very creaky. Before a ride later on I trout I would sort then out. You know how it goes; a quick tighten became a quick clean first. This became a removal to clean the BB axle. That lead to taking the chainrings off the crank and that is when I noticed how worn the middle ring is.

I want to stick a new one on but, FC-M730 is getting a little long in the tooth now! I thought the tooth count was 36 but it turns out I've been spinning a less butch 34 which I believe is the same count as the small ring on a compact is?

I only have the old 39/53 setup although I have a custom 38/50 on old cranks.

Will it work? Are modern rings 5 bolt? Please help an old duffer with a little advice! I'm off to rebuild the chainset and clean the BB axle.

Thanks.

 

[smokeysmoo]

AASHTA

 

[Rickshaw Phil]

There are various ones available. Have a look here: http://www.spacycles.co.uk/products.php?plid=m2b0s149p0 or here: http://www.sjscycles.co.uk/chainrings-dept49_pg1/ where I'm sure you'll find something suitable.

 

[Citius]

Double chainsets are typically either 110bcd, or 130bcd. If you have a 39/53, then it is almost certainly a 130bcd. The 38/50 is more than likely 110bcd.

 

[lpretro1]

Most modern mtb chainrings are 4 bolt. So for 5 bolt you need to work out bcd then get right ring - this may be helpful
www.bikeman.com/bicycle-repair-tech-info/bikeman-tech-info/1628-chainring-bcd