I’ve just pushed the button on a new bike and this one is going to have 700c wheels while my current bike has 650’s. My current gearing is as follows:
12-23 rear, 42,53 front.
I’m going to put a 39 in place of the 42 with the same range cassette on the new bike. Will that give me about the same gearing as I currently have?
On hills I’ve found myself having to work pretty hard to get up, even in the lowest gear and I’m concerned that I’m losing my run legs as I just can’t spin it up enough. Would a 12-25 be a better option do you think?
My big races this year will be Timberman, which I understand has some tough climbs and Phuket which apparently is a heck of a climb, Would a different gearing setup be worthwhile?
Thanks,
Justin.
Yes, replacing that 42 is a must.
As for the rear cogs, it’s really a matter of power output. I run 12-25 with my 50/34 front, but I never exceed 230 watts on a climb. If I had a 39, I’d run 12-27. I don’t need that biggest cog all that often, but when I want it, I really, really want it.
I’d get a 12-25 for starters and see where that takes you.
Thanks. Yesterday I did a hilly 106km, and for the first time, I was in the small lead group at the end (3 of us) with the rest tailing back. My training seems to be working, but I had virtually nothing left in my legs at the end, certainly not enough to go run a half marathon. Admittedly, if it was the half iron, I wouldn’t have chased them up the last few hills, but I wanted to see whether I could stay with them, and it was certainly a great workout.
I don’t have a powermeter, but I know I’m putting too much power down to get up the hills and it will come out of the run. I’ll get hold of a 12-25 when I build the new bike up in a few weeks and see how that works.
Anyone know of a good way to compare the different gearing ratios to see how close the various combinations are? ie, 39-27 and 34-25 etc?
Cheers,
J.
Thanks for that. I’d completely forgotten that Sheldon had a gear calculator. Perfect.