I just found out tonight that I have a 53/42 - I thought all this time that it was a 53/39.:o What's the deal with 42's anyway? I have a 12-25 in the back and can do the largest climbs in my area pretty easily. Would there be any benefit to switching to a 39? I checked the gear calculators and saw a slight difference in the lowest gears.
For example, I'm training for a 4 day stage race that has the road race stage of 64 miles and a couple thousand feet of climbing - not really rollers, but one semi-major climb in the middle. I'd like to have a strong day at this stage and the opening 8 mile uphill ITT stage (8.5% average grade I think). Would it be beneficial to swap out to a 39? I feel like if I do, I'll be cheating myself since I feel so strong with a 42...confused 😕😕😕
I just found out tonight that I have a 53/42 - I thought all this time that it was a 53/39.:o What's the deal with 42's anyway? I have a 12-25 in the back and can do the largest climbs in my area pretty easily. Would there be any benefit to switching to a 39? I checked the gear calculators and saw a slight difference in the lowest gears.
For example, I'm training for a 4 day stage race that has the road race stage of 64 miles and a couple thousand feet of climbing - not really rollers, but one semi-major climb in the middle. I'd like to have a strong day at this stage and the opening 8 mile uphill ITT stage (8.5% average grade I think). Would it be beneficial to swap out to a 39? I feel like if I do, I'll be cheating myself since I feel so strong with a 42...confused 😕😕😕
Thanks! 😄
Heh, you would have been in for a real shock going to a 34-50 eh? 😄
IMO if you don't need lower gearing don't bother. If you are in shape, you should have no problem pushing a 42-25 up a 9% grade... if you don't feel like you need a lower gear just keep it. It allows for a smaller overlap between big/small rings.
53/42 is normally the top two chainrings in a triple 53/42/32.
With a 42 and 25 rear cog you'll be geared at 1.680 wheel revolutions per pedal turn
With a 39 and 23 you'll be at 1.695.
Where you gain with a 53/39 is in having virtually all your 11-23 cluster a single tooth apart for fine tuning your cadence and also at the top end because a 53/12 gives you 4.416 compared to 53/11 4.818 (a 10% difference)
I just found out tonight that I have a 53/42 - I thought all this time that it was a 53/39.:o What's the deal with 42's anyway? I have a 12-25 in the back and can do the largest climbs in my area pretty easily. Would there be any benefit to switching to a 39? I checked the gear calculators and saw a slight difference in the lowest gears.
For example, I'm training for a 4 day stage race that has the road race stage of 64 miles and a couple thousand feet of climbing - not really rollers, but one semi-major climb in the middle. I'd like to have a strong day at this stage and the opening 8 mile uphill ITT stage (8.5% average grade I think). Would it be beneficial to swap out to a 39? I feel like if I do, I'll be cheating myself since I feel so strong with a 42...confused 😕😕😕
Thanks! 😄
I'd say stick with the 53/42 combo ......... but come race day make sure you have lighter /nicer/ better wheels on- more specifically proper tires for the job. I'd say you'd notice more of a difference there....... then going to a 39 ring. Also, in changing up your gear ratio's....... it may through you off come race day...... in that all along , your legs/body are conditioned on that 42 ring. Just my .03
