Chain Ring and Cassette mixing?

[eposhea]

Hi Guys,

I recently replaced my rear derailleur (SRAM Apex) as it was damaged in a fall. While in the workshop they showed me how the chain, chain ring and cassette are worn. I decided to do some investigating before going ahead as their prices were ridiculous (twice the price) versus online.

At the moment my bike has a SRAM PG1050 11-32T cassette with an FSA Gossamer 34-50T chain ring.

My question is am I able to mix components. I have come across some chain rings that are priced well and have the same BCD (110mm) as my current one, but the whole spider, BCD thing confuses me.

Can I mix components between brands and what needs to be taken into account when choosing a chain ring?

This is my current front chain ring:


The shape of others confuse me as I cannot find info on how they connect to each other? (if that makes sense)

Both of these are 50T


Thank you!

[Duck!]

The spider is the collective of the arms on the crank that the rings are bolted to. The BCD is Bolt Circle Diameter, measured at the bolt centres. For a 5-arm spider, measure from the crank centre to the centre of any chainring bolt, and double it. For 4-arm spiders, just measure between opposing bolts. 110 & 130mm are the most common. Campagnolo use 135mm for their standard cranks. 120mm is uncommon, track cranks are often 144mm.

Generally the only thing to ensure is that the BCD of crank & rings match, but occasionally the locating steps on the spider may differ in distance from the bolt centre between brands, which can sometimes require the mount tabs on the rings to be filed back slightly.

[Bentnose]

Also remember you'll need some special tools to change to change the cassette, chain and to a lesser degree the chainrings, hence the double the online cost, or did they quote parts only? Don't know what your skill/tool ownership status is. If it was me I'd replace the cranks with external bottom bracket type, comes complete with chainrings, it will take a bit of weight off and all match, bottom brackets are extra and you'd be better off with a Dura Ace one, they aren't that expensive compared to the alternatives. Something like this http://www.this link is broken/au/e ... -prod50444 depending how much you want to spend, of course you need the tools to remove the square taper and install the external BB.