Boardman Road Comp: Advice on change of cassette/inner chain ring

[Mark Edgerton]

Hi

I have purchased a Boardman Road Comp which runs (i think) Truvativ GPX chain rings (50/36) and a Tiagra 11-25 rear cassette (9 speed) with a Shimano 105 compact rear derailleur

I would like to change the inner chain ring to 34 and the rear cassette to 11-27 (legs aint what they used to be)

Q. Is this possble if so are suitable inner rings available for such an old set up

Cheers

 

[T.M.H.N.E.T]

Any 110BCD inner ring will do and a new chain

 

[Mark Edgerton]

Thanks