buy 17t sprocket, put it on the bike with the 44t chainring - about 68gi
put the 18t sprocket on the bike with 48t chainring - about 70gi
You can then enjoy both bikes for the price of a single sprocket.
As for worrying about skid patches, why not do as jbcommuter says and rotate your sprocket a couple of teeth inside the chain every few weeks.
I have had a set of conti gatorskins on for almost a year, although not the most prolific skidder I have been known to let a big one rip on occasions. Having rolled on 3 skid patches for 6 months, then 9 for the next 6, my tyres are hardly marked and will probably do another year. 10,000 miles on one set of rubber is good value in my eyes.
@Numeryk: Why not:
You can then enjoy both bikes for the price of a single sprocket.
As for worrying about skid patches, why not do as jbcommuter says and rotate your sprocket a couple of teeth inside the chain every few weeks.
I have had a set of conti gatorskins on for almost a year, although not the most prolific skidder I have been known to let a big one rip on occasions. Having rolled on 3 skid patches for 6 months, then 9 for the next 6, my tyres are hardly marked and will probably do another year. 10,000 miles on one set of rubber is good value in my eyes.