I have a tough time averaging much more than 30km/hr on my bike trainer, but I’ll do that fairly easily on the road over a similar distance. It might also depend on how tight the clamp is on my CycleOps Fluid trainer.
What are observations from others on ST?
I use my Kurt Kinetic for intervals or base training. I find that it mimics the road resistance pretty well, but overall, getting my power numbers up is harder on the trainer. I think some of it is lack of movement of the bike and the other is that it is hard to shed the heat when riding indoors…even with 2 fans going full blast.
Bob
Speed on the trainer is relevant only so far as the resistance curve of the trainer in question. Forget speed.
It also does depend on clamping force, and tire pressure, and on the trainer you can’t coast and can’t get nearly as much cooling on your skin.
Really, the solution is TrainerRoad, or PeriPedal, or anything else that will estimate your power output from your trainer, then prescribe workouts based on that. Wattage is what matters.
… ** Forget speed**… Wattage is what matters.
Too true, but pretty ironic given your signature line 
The point is, ladies and gentleman, that speed, for lack of a better word, is good. Speed is right, Speed works. Speed clarifies, cuts through, and captures the essence of the evolutionary spirit.
But yeah, trainer speed is only relevant to your make and model of trainer and even things like the tires and pressure you run as well as press on force. In a general sense it has no relationship to speed on the road. But for specific trainers there can be a rough mapping like the way a Kurt Kinetic trainer attempts to emulate a 160 pound rider on a 1% uphill grade but it still won’t map to flat riding in arbitrary wind conditions.
-Dave
Speed on the trainer is almost a worthless metric. Even if you ensure that every ride uses the same tire pressure and clamping force it would only be used to compare day to day trainer rides. But, that would still not have any bearing as a comparison to road riding.
Instead use RPE (good), a heart rate monitor (better) or a power meter (best) to equate trainer riding to road riding.
Great replies so far. Very good information. I’m very Impressed with ST today! 
The two are really different. On my Computrainer I don’t get to coast and the energy conserving techniques I use on the toad just don’t work.
I haven’t done the comparison but I definitely have to put out more on the CT than outside for the same given speed. Plus, if I decide to do a 40 Km flat TT on the Computrainer, there is no respite of any kind, I have to pretty much keep the same power output whereas on the road I’ll have small bumps (or larger hills) which allow me to change cadence, pedaling style etc.
This past weekend I road for 3 1/2 hours on pathways around the city and had no issues with sore spots or anything similar. If I attempted that long a ride on my CT I would have been seeking relief from being in the same position all the time. Now, my speed outside on pathways wasn’t all that great but I was out for an easier day to put in some saddle time.
I would not call trainer speed a worthless metric when it is compared to day to day trainer rides, which can happen when outside riding is not possible. No doubt a power meter is best for trainer to road speed comparison.
My Kinetic Kurt is spot on with speed, consistent day in and day out. I usually do intervals of 2x20’, 3x10’ or 4x10’ and aim at going 20.5mph. Each time, the effort is very similar. From looking at my power meter numbers, the effort to achieve 20.5mph on the intervals is very consistent with the power meter as well.
My tire pressure is between 100-110psi and I always turn the clamp number 5 turns after it first makes contact with the tire. Anyway, to reiterate, I think speed on the training is a good number to rely on if you don’t have a power meter and your training is delivering consistent pressure as mine is.
My Kinetic Kurt is spot on with speed, consistent day in and day out. I usually do intervals of 2x20’, 3x10’ or 4x10’ and aim at going 20.5mph. Each time, the effort is very similar. From looking at my power meter numbers, the effort to achieve 20.5mph on the intervals is very consistent with the power meter as well.
My tire pressure is between 100-110psi and I always turn the clamp number 5 turns after it first makes contact with the tire. Anyway, to reiterate, I think speed on the training is a good number to rely on if you don’t have a power meter and your training is delivering consistent pressure as mine is.
5 turns? I think the recommendation by KK is 2 1/4 turns. I’ve broken the “Z” bolt at 3 turns, but made a new one that has held up. I do get tire slip at 3 turns when ramping up the power. I’m not saying 5 turns isn’t doable…just want to verify that that isn’t a typo?
Thanks,
Bob
5 turns? I think the recommendation by KK is 2 1/4 turns. I’ve broken the “Z” bolt at 3 turns, but made a new one that has held up. I do get tire slip at 3 turns when ramping up the power. I’m not saying 5 turns isn’t doable…just want to verify that that isn’t a typo?
Thanks,
Bob
Sorry, not 5 full turns. I just turn it 5 times and each one of my turns is about 1/2 a revolution… so that ends up being around 2.5 turns.
5 turns? I think the recommendation by KK is 2 1/4 turns.
FWIW, the manual says 2 to 5 turns.
my KK road trainer (2.5 revs) is very close to the speed I get on my road bike with about the same power based on my quarq. The tri bike is about 2 mph faster outdoors vs trainer.
my KK road trainer (2.5 revs) is very close to the speed I get on my road bike with about the same power based on my quarq. The tri bike is about 2 mph faster outdoors vs trainer.
"I used to wait two turns before I called my baby, but now it’s like everybody waits two turns and two turns has become, like, industry standard . . . "
There was a thread on this not too long ago and if I remember, the only official line was “between two and five turns”, like you microwave popcorn may take 2-5 minutes. Frustrating, but the consensus seemed to be then, as now, that 2.5-3 full turns will get you close if you’re using Virtual Power.
The most important think is doing it the same every time, also as noted above.
And to partially answer the OP on the speed question, I am several mph slower on the KK than outdoors; I go 3 full turns.
Speed on the trainer is almost a worthless metric. Even if you ensure that every ride uses the same tire pressure and clamping force it would only be used to compare day to day trainer rides. But, that would still not have any bearing as a comparison to road riding.
Instead use RPE (good), a heart rate monitor (better) or a power meter (best) to equate trainer riding to road riding.
It is a worthless metric :). We don’t show it in our software because it doesn’t mean anything. We do allow people to export their files and speed is in there…much to my pain :).
As others have said go RPE, HR or power.
To answer the OPs question, on a 10min interval, I can hit about 21mph on the trainer, 25mph on my TT bike on flat course, and 23mph on road bike on flat course. All these speeds are when I’m pushing around 250 watts.
So there is a difference as far as I can see in terms of speed for similar powers.
Good comparison! Thanks!
Its a STATIONARY trainer. You should expect a speed of 0.
Trying to correlate it to road speed is fruitless. Wind resistance goes up exponentaily with speed on road, but trainer resistance increases depending on what type of non-newtonial fluid you use (and then there are magnets and fans)…
If you have a powermeter - that works best.
HR is a acceptable proxy.
Amateurs like me simply use preceived effort to compare to road riding.
Wind resistance goes up exponentaily with speed on road,
power law, not exponential. (paging ZackCapets)
In addition to the tire pressure & number of turns of resistance on the roller, another condition enters in when the wheel/bike is removed from the trainer. The wheel must contact the roller in a marked spot each time, because no wheel is perfectly round. This does make a difference, as I have found.