Bike test on KK trainer?

mcstrangelove

So I have my Kurt Kinetic ready to go for my first bike test (never used a trainer before, strictly rode outdoors).  I did some trial rides to test it out and found that it seems much more difficult to maintain a particular speed than it does on the road (18 mph on the trainer feels more like 23 mph on the road).  Is this normal for a trainer?  Is this something I should take into consideration for the test?

Also, the trainer came with the KK 12 lb flywheel. Should I bother with this for the test?  I assume it increases the resistance so I'm wondering if it might skew my test results.

Thanks...just want to get this test right!

michaelgasser17

I just did my test on the KK Road Machine. Check how compressed your rear tire is on the trainer. I originally had it pumped to 110 PSI and too compressed by the trainer contact point. It is now at about 90 PSI and compressed just enough so that when I start pedaling, there aren't any major squeaks from the tire slipping at the contact point.

The heavier flywheel has a higher rotational inertia at an equivalent speed. That means that the coast down will be longer and more smooth. It also means that it will take a bit longer and a bit more effort to get up to speed. Once at speed, the resistance will be a bit more consistent and smooth. It shouldn't affect perceived resistance in the middle of your workout.

On a side note, the way I understand training with power indoors, it is all about effort in tuning the crank, not wheelspeed. If I turn the cranks with 200w of power and that translates to 10 MPH difference between indoors and outdoors, my workout shouldn't be affected because the focus is on work performed not distance covered. I'm pretty sure this applies to HR athletes as well. If a coach or WSM could help clarify that, I sure it would be helpful. I'll definitely defer to them for absolutes in answering.

gmc219

You can't really judge your effort by comparing speed on the trainer and outdoors. Trainers all have a different powercurves, some steeper than others. My Cycleops tempo would hit 250watts before I was at 17mph whereas my Cycleops Fluid 2 would be over 20mph @250watts. My teams Blackburn was similar to the Tempo. I have never ridden the KK but the profile looks the same as the Fluid 260watts@20mph.
Like Micheal was saying there will be a difference in distance covered also. You shouldn't compare your distance covered between indoors and outdoors for the above reasons.

Jeff Unruh

Mac - I think a consistent tire pressure is key. I run mine at 120 and follow the same protocol for tightening between workouts (remove tension after my ride).

The formula for watts on the KKRM (not sure how the 12lb flywheel changes things if at all) is...

(5.24482 * Speed) + (.01968*Speed^3)

17 = 185.85
18 = 209.18
19 = 234.64

The only basis for comparison is trainer ride to trainer ride. I always note my gearing and cadence and then use speed as a metric (not as perfect as true watts but better than HR alone).

mcstrangelove

I'll keep an eye on the contact point.  I think I had it pretty loose (just enough to spin the roller on the resistance unit).  It's kinda like going back to square one since 18 mph feels like I'm seriously hammering!

Should I only use RPE and my average HR and just not concern myself with speed or distance on the trainer?

mimsrd

Mac, your KK speed does not matter in regards to the work. I've found that for the same effort (HR or watts), my "speed" on the trainer is a good deal slower. If you are power athlete, you don't even need to display the speed on your computer. If you are a HR athlete, you can use the speed as a loose estimate for your power (or effort). Once you think you have found your zone, you can use a combination of speed and cadence to maintain a more consistent output than you would if you chased HR. This is not a perfect method, but it gives you a little more real-time feedback. Try to maintain the same speed for the entire interval.

It does not matter how fast or far you go on the trainer. If it makes you feel any better, the resistance on the KK is calibrated feel like a "standard" rider on a road bike and effort increases similarly to what you would feel on the road as you go faster. This does not correlate well to a typical triathlete in the aero position. Just do the work based on your power or HR zone and you will be able to see the difference when spring rolls around and your back outside.

Coach Patrick

The only reason to use speed/distance is to measure if you are progressing on the trainer (not to compare to outdoor numbers). So if you rode 20mph in your first 20' for 6.33 miles, and then do it again in a few weeks but go 22mph for 7.33 miles, I know you are fitter regardless of HR b/c you did more work in the same time...