39T to 36T Chainring for lower gears

Mettan

If you bought a 53x39 double road bike, would it be possible to change the 39T chainring to a typical Compact 36T chainring to get lower gearing? If it is possible, are there any other bits that'd need changing to complement it.

Also has anyone here done the 39T to 36T swap on a Double to get lower gears?

Thanks

Steveorow

Someone will probably come along and prove me wrong but I think 38 tooth is the smallest chainring you can get for a 130mm BCD ( Bolt Centre Diameter ie the diameter between the bolts that hold the chainring to the crank spiders ) . So if its 53/39 then you probabaly limited to 130BCD without changing the cranks .

Smokin Joe

You would need to get a compact chainset. Standard Shimano chainsets will only take a 38 as Steveorow says, Campag won't go lower than a 39.

John C.

Dito to the above , 38 is the lowest you can go. If you go for a compact check what the smallest ring is that can be fitted, some only go down to 36

ash68

Mettan, which bike were you thinking of buying?

Mettan

Thanks guys, that's cleared that option up.

Ash - Regards what bike, although there have been good suggestions for Decathlon and a few others, I quite like the 06/07 Giro 300 - its very affordable, well made, good pedigree for what it is and has reasonable basic components - (admitedly it's a bit of a hodge-podge mixture) - it also comes with a low gear of 39x28 which is ok-ish - and if after a few months I can't get uphill with 39x28 as a last resort, it'll have to be a larger cassette/chain and rear mech job. The Shimano 14-34 's cheap, the chain's cheap, not sure about the cost of a complementary rear mech to go with those potential changes.