Would like some advice whether I should consider changing out the rear cassette on my bike, in anticipation of an upcoming triathlon (Ironman 70.3) which is about a month away. The Ironman course is known to have some rolling hills...I think a few may be steep, but not a huge amount of total climb -- approx 1000m elevation gain over 90km.
I currently own 2 bikes - my road bike is geared with a compact (50/34) chainring and a 12-30 rear cassette (Shimano 105 components). My tri bike is geared with a standard (54/39) chain-ring and a 12-25 rear cassette (Shimano ultegra components). My current plan is to ride the Tri bike for the race but I have noticed that every time I go to do a training ride that involves hills, I instinctively reach for the road bike. Its easier to ride both on the gearing (I can get up most hills, albeit slowly) and also on the handlebar locations (shifters & brakes in same spot). On the road bike, I lose my pedal power at around 50-55km/h (pretty easy to hit esp with a little hill help, but not sustain). My top speed on the Tri bike is higher & I don't think I really ever hit a point where I can't pedal any more.
I am absolutely a weak climber (and faster on the descents) vs the rest of the group that I ride with where I am pretty well matched otherwise. Thanks to body weight for that!
This has got me wondering whether I should consider putting a different rear cassette on the Tri bike to give me one or two more low gears on those hills. I have looked at a few gear ratio charts online but I don't really know how to interpret the numbers.
Thx for any guidance on this!
I currently own 2 bikes - my road bike is geared with a compact (50/34) chainring and a 12-30 rear cassette (Shimano 105 components). My tri bike is geared with a standard (54/39) chain-ring and a 12-25 rear cassette (Shimano ultegra components). My current plan is to ride the Tri bike for the race but I have noticed that every time I go to do a training ride that involves hills, I instinctively reach for the road bike. Its easier to ride both on the gearing (I can get up most hills, albeit slowly) and also on the handlebar locations (shifters & brakes in same spot). On the road bike, I lose my pedal power at around 50-55km/h (pretty easy to hit esp with a little hill help, but not sustain). My top speed on the Tri bike is higher & I don't think I really ever hit a point where I can't pedal any more.
I am absolutely a weak climber (and faster on the descents) vs the rest of the group that I ride with where I am pretty well matched otherwise. Thanks to body weight for that!
This has got me wondering whether I should consider putting a different rear cassette on the Tri bike to give me one or two more low gears on those hills. I have looked at a few gear ratio charts online but I don't really know how to interpret the numbers.
Thx for any guidance on this!