Chainrings size, help!

[Raging_Bulls]

I know this is the -> 1997 section, but I'll say this anyway :

42T is the norm nowadays. In fact most MTBs that are less than 10 years old and use a triple crankset, run a 22-32-42 setup.
For normal XC and road use, that's plenty. If you start drafting cars or trucks however, you might want to consider bigger chainrings or a full-on road crankset (and better brakes and tyres, as most aren't really suited to speeds above 30MPH)

Oh, and if you replace the 42T with a 46T, be sure to replace the other 2 chainwheels with bigger ones as well. Otherwise the rear mech might get into trouble because the difference between the small and large ring on the front is too big.

 

[elPedro666]

Back in the day when 14T small cogs were the norm, 48T big rings seemed to be most common. Once freehubs with 11-12T small cogs became standard then 44T seemed to become most prevalent, at least on the bikes I've had.

If you want a bigger chainring beware that some frames don't have clearance for the big ones.

Yup, that's my take too. You can happily spin up to 30mph on a 32/11, so unless you're riding on the road a lot really can't see the need for anything bigger than that.