Different cassette on trainer?
 

Hello forum,

I built my road bike for flat Florida speed with an 11-28 rear cassette (50/34 front). I now find that half my time is on the trainer on Rouvy and I am climbing lots of hills. I feel like I need a bigger gear back there. I’m wondering if I can use an 11-32 on my trainer and the 11-28 on my bike without any issues? I already have the larger Ultegra rear derailleur installed.

Thanks!

Not unless your existing chain is (1) very worn, which would prematurely wear out your new cassette or (2) sized just barely long enough for the existing 11-28 cassette, in which a case a shift to the big-big combo using the new 11-32 cassette may break your RD.

Thanks! The chain has 1200 miles, I sized it on big-big (not through the derailleurs) + 2 links.

Make sure the RD can handle it and that you have enough chain length. I do the same but opposite (30t on the wheelset, 28t on the direct drive trainer).

The alternative is to reduce the climbing resistance on Rouvy. Most apps have a sliding percentage scale for this which effectively lowers your overall virtual gearing. Your avatar speed is governed by power output, so your virtual climbing speed is unaffected.

This is a very logical and simple solution I should have thought of.. I’ll probably try this first. Thanks!

you could get a different sized cass for trainer and a different chain as well for it....lil more work but it may make it more enjoyable on the trainer.

I swap back and forth between my 30 and 34 all the time without changing anything.

Big big works, right on the limits, so I just avoid using it.

This will work in “Just Ride” mode using the “Reality” percentage setting. But unfortunately in Rouvy it apparently reduces the simulated gradient so your avatar climbs faster for the same power output. Unlike Zwift, where the reality setting reduces the trainer load without changing the simulated gradient for your avatar. The latter is better because your virtual climbing speed at a given power is unaffected. It is literally the same as climbing the same gradient in a lower gear.

So if you want to maintain a realistic virtual climbing pace on Rouvy then you need to keep the 100% reality setting. But if you are not bothered about that then reducing the reality setting will compensate for your higher gearing.

It's best to keep the same cassette size on both setups, but it works (if your RD allow it, of course).

The difference in diameter between a 28t and a 32t is just a little over half an inch.

You can but you will then need to adjust your RD

I did this with my bike when I had a Kickr. I used a 32 tooth and my bike had a 28 tooth. Worked fine and allowed me some better hill climbing indoors since I too live in flatlandia.

Awesome, thanks!