Where can I buy the cheapest chainrings....

John Sanderson · Post by **John Sanderson** » 13 Mar 2009 11:20

Quite a timely post considering some of the other threads on the go at the moment....

I need to replace the chainrings on my winter/training/turbo trainer bike - and as it is quite frankly a 'nag' of a bike I want to do it as cheaply as possible....

I've already got Stronglight aluminium chainrings from Spa Cycles - replacements will cost me a grand total of £29 for a 110 BCD 38T and 50T with postage.

Can anyone recommend any cheaper sources?

David Farley · Post by **David Farley** » 14 Mar 2009 00:02

John..........if your not in a rush to replace your chainrings, why not consider going to one of your local cycle jumbles which take place this time of year

George · Post by **George** » 14 Mar 2009 20:17

Or, if you buy on line, it may be cheaper to buy a remaindered old-model c/set than to buy the rings separately.

Neil Compton · Post by **Neil Compton** » 19 Mar 2009 11:08

Looking at the chainrings on the web i notice it mentions 135pcd or 130pcd or 144pcd etc etc. Just wondered if anyone could explain what this means in simple terms.

Philip Whiteman · Post by **Philip Whiteman** » 19 Mar 2009 11:20

If you can face the long queue in the morning and the following bundle into the venue, try..

http://www.cycle-promotions.co.uk/

The next one is scheduled for Worcester on 28th

John Sanderson · Post by **John Sanderson** » 19 Mar 2009 12:42

Looking at the chainrings on the web i notice it mentions 135pcd or 130pcd or 144pcd etc etc. Just wondered if anyone could explain what this means in simple terms

pcd is the same as bcd - which is 'bolt centre distance'.

I believe (although could be wrong) that this it he distance between the 4 or 5 bolt holes on the chain ring. Obviously this needs to be the same as the distance between the 4 or 5 bolt holes on the crank arm - otherwise you'd find it rather difficult to fit the bolts in!

Neil Compton · Post by **Neil Compton** » 19 Mar 2009 12:47

Thanks John. I think i should just measure mine first before i order one.

Andy Terry · Post by **Andy Terry** » 19 Mar 2009 13:10

BCD = Bolt Circle Diameter

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

PCD = Pitch Circle Diameter (the same thing)

http://sheldonbrown.com/gloss_p.html#pcd

George · Post by **George** » 20 Mar 2009 10:27

Neil Compton wrote:Thanks John. I think i should just measure mine first before i order one.

It's easier said than done, actually, because, most chainrings have an odd number of fixing points. This means that diametrically opposite each fixing point you will usually find thin air. So, to measure accurately, you've somehow got to draw a circle right through the centre of each bolt hole.

However, measurement really isn't necessary. Just tell your supplier "I want a ring for ...". The supplier should know and, if he gets it wrong, the responsibility is his not yours. Besides, I'm as sure as I can be that you, Neil, need a 135mm ring.

Andy Terry · Post by **Andy Terry** » 20 Mar 2009 11:18

multiply the bolt centre-to-centre distance by 1.7 to get BCD

Neil Compton · Post by **Neil Compton** » 20 Mar 2009 13:31

Aye, measured it this morning with ruler although i didn't take the ring off to do it. Worked out at 135 which is what i've ordered and if i've messed up the measurement then serves me right for being lazy or i could just blame George instead.

. Gone for a 44t.

I have another question for you though. I have ordered a cheap sora rear mech. Can i just use it as non index, ie just put the cable through and change with my levers as i do currently.

Post by **CakeStop** » 20 Mar 2009 13:50

I don't see why not as there's no clickiness in the rear mech.

Neil Compton · Post by **Neil Compton** » 27 Mar 2009 10:39

Ok fitted my new chainring. 135 was the correct size.

Another question.

I have fitted my new rear mech but the top of the cage is way too close to the freewheel in fact i think it touches. I've tried ajusting the top ajustment screw but that dosn't seem to be doing anything.

Anyone have any suggestions as to where i'm going wrong.

Philip Whiteman · Post by **Philip Whiteman** » 27 Mar 2009 10:41

Neil Compton wrote:Ok fitted my new chainring. 135 was the correct size.

Another question.

I have fitted my new rear mech but the top of the cage is way too close to the freewheel in fact i think it touches. I've tried ajusting the top ajustment screw but that dosn't seem to be doing anything.

Anyone have any suggestions as to where i'm going wrong.

Chain length? Does it need to be shorter perhaps?

Try pinching a few links together and see what happens.