Fluid trainer, flat pedals & Trainerroad. Pretty frustrated


#1

So I’ve had to cut my last two workouts short. I’ve found that to match the power goal I either need to spin at 110-120rpm or shift into a harder gear which puts my cadence in the 75-80rpm range. Obviously neither of these are optimal.

I’m wondering if it’s a setup issue or am I really in that bad of shape.

My setup is:
Cycleops Fluid 2 trainer
Mountain bike with 1x10 drivetrain (30t front/11t-42t rear)
Flat pedals

I have a really hard time spinning high cadences since I’m not clipped in. Of course that could be a practice issue. I’m pretty comfortable spinning at up to 95rpm and naturally spin around 85rpm. Switching to clipless pedals really isn’t something I want to do.

When I spin above 105 it feels like I’m out of control and there’s little to no resistance from my trainer.


#2

Without a smart trainer w/ erg mode, you need to shift gears in order to meet the power targets. The biggest jump between gears for you is probably the 20% jump b/w the 15-18 cogs in your cassette, so worst case you should be able to find a gear that puts you 10% away from your power target at the ideal cadence of 85rpm. In that worst case, you would then end up needing to pedal anywhere from 77-94 RPM (roughly) in order to make up for it. The difficulty you’re having is largely due to the fact that you only have 10 gears to choose from, and most of those gears are too low to use on a trainer that is trying to emulate flat ground. On a steep climb, your bike is geared perfectly, but your trainer doesn’t have a “hill mode” that will ramp up the resistance curve to emulate a climb.

TL;DR: you should be able to find gears that keep you out of the 110-120 range, but you will still end up pedaling at cadences outside your comfort zone due to your gearing. That is good training though! Also, it’s perfectly understandable to not be able to pedal at extreme cadences; I have a pretty quick natural cadence around 95-100 but 110 is significantly less comfortable for me


#3

The real limitation comes from the small 30t front sprocket. That is the reason you are having to spin faster. That is lower than a typical 34t on a road compact crankset.

With out changing to a larger front sprocket or changing the trainer, that is the situation you have to deal with for now.

Swapping the sprocket to a larger one means a new and longer chain and directly affecting your other uses of the bike. Another (not so cheap) option is a 2nd bike. Find a low cost MTB with a 2x or 3x crank and at least a 42t, or a road bike with a regular 2x.

Your current setup is just not appropriate for a “training” perspective.


#4

Ooh, yeah, just looked at the gain ratios with that front chainring. It maxes out at 5.3 in the small cog, so at 100rpm you’ll be doing around ~21 mph (depending on rear wheel size) based on wheel speed. Here is the CycleOps Fluid 2 power curve: https://www.cycleops.com/Uploads/Cycleops/2015/2/Fluid2.jpg. That means you’ll max out below 250W at 100rpm, which is just not enough for good training (unless you’re small)


#5

J,
With the equipment you have those differences are correct.
This is the downside of running 1x in the real world.
You don’t have enough gearing to be efficient at your preferred cadence.
You COULD move to a 34t for chainring just for training to shift your gear usage if you are using your 11t and run out of harder gearing. This will increase your potential maximum power output.

This is decent enough reference article here:

Also you can determine maximum speeds here:
(virtual power is reverse calculated from wheel speed)
http://www.bikecalc.com/speed_at_cadence

The Kurt Kinetic math is here:

I ran a Kurt Kinetic and TR for 4 years before I got a Kickr.
Don’t be too concerned about matching target power 100% with Virtual power.

If you are spinning at 85c at 30T x 15 and you hit 90% of the target power, but you can’t sustain 85C at 30t x 13, that is OK. It is more important to complete the interval and the workout than it is to match the values and quit the workout at 80%. If you know that you can only match the power target to 90%, you can always decrease the workout by 5% so your data looks better onscreen.

In order to better match the power, your best tool (and this is true on the bike trail too) is CADENCE. You need to be able to spin faster to get more wheel speed to hit the power target.

So that’s great ! After your Base Build, and Power Build training programs, you can find one that focuses on cadence because that is ultimately how you will get more power from the same drivetrain out on the trail.

It took me 3 winters of Trainer Road training move my comfortable (efficient) cadence from 80 to 95.
Now I can do 5 to 8 minutes of cadence at a 110 if I want to with full control.
My regular MTB cadence is between 85 and 95 depending on terrain.

You are doing things right .
Keep at it.

M.


#6

If you already run a different wheel on your trainer to not burn up your knobbies, consider swapping out the cassette for one with tighter spacing. Also, by having a smaller big gear in the back you could swap out your chainring for one quite a bit larger without needing to replace the chain making the swap onto and off the trainer a slightly involved but entirely manageable process that would get you ideal gearing for the trainer.

I have picked up an entirely serviceable wheelset on Craigslist for $50 so if your not already running a trainer wheel, that’s an easy option.


#7

That won’t help here, because the real limitation is is 30t front and the 11t rear.

He needs a bigger front sprocket (to get the trainer spinning faster to get more resistance), not closer steps between gears he is probably not using anyway.


#8

If that is the issue, and not that you’re topped out in the biggest gear then a cassette with tighter spacing will definitely help things


#9

I think both Chad and freedj are onto something.

I’m not topped out, it’s more that there’s a significant jump between gears as I go farther down the cassette. It’s either too easy or too hard. I’m going to take both of your advice and get both a larger chainring and a cassette that’s range is closer together than my current one.

I believe that the largest chainring that will fit on my Knolly is a 36t so I’ll get that and a micro road cassette to help make up for the lack of ability to run a bigger gear up front.


#10

If you’re considering a different drivetrain setup, have a look at the E13 cassette - it’s 11 speed and goes 9 to 46. It requires an XD driver so your current wheel may or may not work. With that setup, you could run a 34 on the front and keep nearly the same climbing gear while gaining about a third more wheel speed in your top gear.


#11

Based on his comments, I don’t see that as a good option. The 511% range will lead to HUGE steps in each shift, and that is one of the issues he seems to be fighting.

His plan to go for a tighter spaced cassette will give more minute adjustments in cadence from one shift to the next, and seemingly address one of his major concerns.


#12

Well that’s true. I was trying to think of a way for him to have his cake and eat it too.
Maybe a better option is to locate a close-ratio road cassette and just dedicate a trainer wheel with a slick tire and that cassette. Could probably even find a 10-speed 11-23 cassette and keep the rest of the current drivetrain intact.


#13

I used the same model trainer and was often in between gears when chasing the power number, you’ll probably find the resistance changes ten minutes or so into the workout when the fluid heats up and changes viscosity too? Bottom line is that a road cassette will probably help, you may also find that as you get stronger the harder gear will see you spinning at 85 rather than 75. I ended up buying a Kickr, highly recommended in the longer term.