Which gear to use?

mcstrangelove

 When on the trainer doing the z4 intervals, I try to ride at a 90 rpm cadence.  But I can't seem to stay in one gear to do so and settle between 2 different gears:  one is easier and causes my legs to spin at about 115 rpm, but the next gear up is much tougher and slows my cadence to about 70 rpm. 

An "in between" gear would be great, but since that's not possible, for the purposes of OS z4 intervals, should I go with the easier gear (faster cadence) or the harder gear (slower cadence)?  Thanks for your suggestions!

grosso27

I don't know what chainring/cassette combination would lead you to go from 70rpm to 115 with only one gear change, but I'd love to hear what sort of setup you are running.  Maybe you need to shift up front too, not just the rear?

For reference, I have an 11-23 on the rear, and a single rear shift (with power=constant) leads to a 10-15 rpm cadence alteration.

General guidance tells you to self-select whatever cadence your body prefers, but higher cadence is generally a better habit to get used to in trying to save your runnning muscles.  But 115 is a high cadence. 

GMAN 19030

I can't find a sweet spot gearing on the trainer either. I usually ride in the mid-70's for cadence inside and the upper-80's outside. It doesn't take me but a training ride or two to adjust to the higher cadence once I get back outdoors.

Chris G

I recently put a 12-23 on the trainer wheel. Much tighter grouping. Cant imagine a cassete which would have a jump from 70 to 115. Even with my 11-26 it was only a 10-12 rpm jump at FTP.

tuckerm

@Mac, what is your gearing combination? I'm no bike expert but it seems awful odd to me that you go from 115rpm to 70rpm with the shift of one gear. Must be missing something here.

mcstrangelove

My front rings are 50 & 34.  My rear is 12-25.  The crazy shift comes between the 3rd and 4th cog, the 4th being the one that drops my cadence so drastically.  I typically stay in the 3rd so I don't burn out my legs, but they are definitely spinning fast.  Please note that I am a crappy cyclist so it's probably operator error and not the bike

I'll go ahead and err on higher cadence, rather than pushing the heavier gear.

Norton

Mac,

That big a jump in cadence with that cassette means you need to clean your drivetrain! You're jumping a gear...ask me how I know...

kmepham

Mac, Bill's right, if you're seeing that large of a cadence gap between 3rd and 4th on a 12-25, you're skipping gears and you need to adjust your rear derailleur. (Lots of good Youtube videos on how to do the adjustment; after I saw how easy it was, I felt pretty stupid for all the times I'd hauled my bike into the shop just for that.) The largest cadence gap on a 12-25 is between 4th and 5th gear (19 and 17 tooth), and it's about 10RPM. I did my start-of-OS test in 4th gear at over 90 RPM, couldn't sustain a higher cadence so switched to 5th gear and 85RPM immediately after the test and I've been in 5th ever since, gradually pushing the cadence up and the power along with it. I'm most comfortable with a low-90's cadence so I'm looking forward to getting my power high enough to get back in that zone.

gmc219

I am going with Bill and Kevin you must be skipping a cog to get that cadence jump. If you have a 9 spd cassette your biggest cadence jump on a 12-25 would be from you 15 to your 17 of 13.1%(4-5). Your geat ratio from 3-4 is 7.1%. If you are skipping a gear your cadence would really jump with that 20% difference. I would look real close at where your derailler is dropping your chain.

Keith Wick

I feel like I'm in the same boat here, but to less of an extreme. I'm in the 10-12 rpm difference where I'm at either 84/86 or 94/96 ish. In the upper range I feel like I'm not really in control of my pedaling (kind of like pedaling down a really steep hill), but in the 80's cadence I feel that my legs are just adding size (almost like weight lifting). It makes them feel heavy. Should I just try to keep adjusting to the higher cadence even though it feels like I'm sprinting? I'm trying both and think I just need to settle on one and accept it. I know what I'm thinking is best, but just want some confirmation. Thanks everyone.

Spokane_Al

I don't know if this helps but I use one gear that keeps me in a cadence of the low 80s and a second that moves my cadence up to the low 90s. I switch between the two every minute.

Keith Wick

Did the 80-85% at high cadence today, which averaged about 96-98. Definitely feels harder to maintain, but my legs don't feel as heavy vs. the 84-86 range. I'll keep playing with it, but hopefully I'll get out of this range at the next test.