changing chainrings from 53/39 to a compact,can this be done

manimal

My bike has a 53/39 standard chainset(sram rival) which im not too keen on and want to go back to a compact the same as my old bike,can i simply change the chainrings or do i have to buy a whole new sram rival compact chainset?
If this can be done does anyone know who sells the chainrings?
Thanks!

rozzer32

You would have to buy a new crankset.

53/39 = 130 BCD
50/34 = 110 BCD

manimal

Thanks for the bad news mate, much appreciated!!

Full Merckx

http://www.jejamescycles.co.uk/sram-pg1 ... 57718.html

This is a far cheaper option and will give you ratios similar to most compact chainsets. Combining it with a compact, well then you're laughing

rozzer32

But if he had a short cage rear mech then he could have to buy a new longer one to take up the chain slack.

merak

Assuming the top jockey wheel doesn't foul the 32 tooth sprocket which it is likely to do on a standard SRAM Rival short arm rear mech which has a maximum of 28T AFAIK

Full Merckx

True, but a new rear derailleur and a £50 cassette is cheaper than switching to a compact chainset, although maths is hard

Full Merckx

True, but a new rear derailleur and a £50 cassette is cheaper than switching to a compact chainset, although maths is hard

Full Merckx

True, but a new rear derailleur and a £50 cassette is cheaper than switching to a compact chainset, although maths is hard

Full Merckx

True, but a new rear derailleur and a £50 cassette is cheaper than switching to a compact chainset, although maths is hard

merak

The total capacity is 31T so (53-39) + (32-11)=14+21=35T so it fails both on largest dprocket and capacity. Need to get a new cassette and rear mech (assuming short cage rear mech).

merak

Full Merckx wrote:

True, but a new rear derailleur and a £50 cassette is cheaper than switching to a compact chainset, although maths is hard

Hmm - cassette plus med length rear mech = £50+£75 = £125
Rival compact chainset= £114

So, no, not really cheaper.

Pokerface

YOu can go compact on the big ring (you can get 130bcd chainrings in 50T) but I believe the smallest small chainring you can get in 130bcd is a 38t.

So you can convert your existing crankset to 50/38 with new rings - but for a few extra quid, can get the correct compact you are after.

manimal

Thanks folks,appreciate ALL the advice but i think i will just look for a straightforward compact chainset to replace mine.

markos1963

Needn't cost too much if you think about it. Buy a compact chainset, sell the standard on ebay cost to you is the difference.

morstar

markos1963 wrote:

Needn't cost too much if you think about it. Buy a compact chainset, sell the standard on ebay cost to you is the difference.

Piffle!

Why on earth would any sane person sell spare bike parts?

Clearly they need to go into the collection of spare bike parts that denotes your status as a proper cyclist. Unless you've got enough bits to build multiple ramshackle uncordinated machines, you're simply not doing it right!

merak

morstar wrote:

Clearly they need to go into the collection of spare bike parts that denotes your status as a proper cyclist. Unless you've got enough bits to build multiple ramshackle uncordinated machines, you're simply not doing it right!

Still can't find a use for that Suntour 5 speed freewheel...

markos1963

morstar wrote:

markos1963 wrote:

Needn't cost too much if you think about it. Buy a compact chainset, sell the standard on ebay cost to you is the difference.

Piffle!

Why on earth would any sane person sell spare bike parts?

Clearly they need to go into the collection of spare bike parts that denotes your status as a proper cyclist. Unless you've got enough bits to build multiple ramshackle uncordinated machines, you're simply not doing it right!

Ha! rumbled. I tell my missus that I'm going to sell stuff off to justify upgrades but it all ends up in the 'spares' box in the workshop to be used on a future project.

manimal

Lol!!

Unfortunately im more of a "shoestring" cyclist hence why i asked on if i could do it on the cheap.

does anyone know how i can tell what bb i have on my bike(kuota korsa lite) so as i can look around for another one? as i said earlier its a sram rival standard chainset but i cant see any markings on the bb.

rozzer32

This will do the job

http://www.ribblecycles.co.uk/sp/road-track-bike/Bottom-Brackets-Road-Sram-GXP-Team-Cups/SRAMBTBR220

Not sure if they use English or Italian threads though. I'm sure someone will be along who knows.

merak

I'm not sure he wants a BB. He wants to know what BB spindle he has so he can buy a the right chainset - why not just buy the SRAM compact:
http://www.wiggle.co.uk/sram-rival-blac ... e-chainset
which fits the BB referenced by rozzer - in fact it might even be supplied with one. But I assume the SRAM Rival double that's coming off is fitted on a GXP BB and there's no need to take it out. Just swap the cranks over.

stevie63

You could even fit a Sram Apex compact crankset which is about £65 from Ribble. The only difference between it and rival is the arms are not hollow but its nearly half the price