Turbo speed so slow - why?

[NotSpeedyAt All]

I have a very basic Crono indoor trainer - one where you attach you road bike's back wheel to the trainer via the through axel and the wheel spins on a small roller. To record the speed/distance on my Wahoo, I have fitted some Moofit speed and cadence sensors. The issue I am having - and that I hope people can help me with - is the very unrealistic speed/distances I am recording when I use it. on the road, I normally average about 15mph and would expect a static bke where I have no hills to contend with would be about the same. On this trainer my speed is WAY less - often only around 6 mph average. It is very frustrating as I am including turbo miles as part of my annual mileage on Strava and would like to think my efforts are being properly accounted for. I've tried changing the battery in the Moofit, tried putting a book under my front wheel (someone suggested this - it made no difference), tried Garmin sensors instead and had a similar problem and tried taking the bike off the turbo and putting it back on again in case something was wrong with how I'd mounted it. So far I've had no success. What's weird is that this year, when I first attached my road bike to the turbo, the speed was roughly correct for the first couple of sessions (I was averaging 13/14mph) but then it dropped and dropped to the point where I am now pedalling like crazy for over an hour to achieve about 3 miles in distance! Can anyone suggest what I am doing wrong and how to fix this please? It is putting me off using it, and I can't afford to replace it with an all bells and whistles smart trainer so I am a bit stuck with what I have. Thank you.

 

[Alex321]

I should think that is down to the resistance of the rollers.

Probably they were very free running when you first got it, but have got a bit gunked up, causing more resistance since then.

 

[Yellow Saddle]

I have a very basic Crono indoor trainer - one where you attach you road bike's back wheel to the trainer via the through axel and the wheel spins on a small roller. To record the speed/distance on my Wahoo, I have fitted some Moofit speed and cadence sensors. The issue I am having - and that I hope people can help me with - is the very unrealistic speed/distances I am recording when I use it. on the road, I normally average about 15mph and would expect a static bke where I have no hills to contend with would be about the same. On this trainer my speed is WAY less - often only around 6 mph average. It is very frustrating as I am including turbo miles as part of my annual mileage on Strava and would like to think my efforts are being properly accounted for. I've tried changing the battery in the Moofit, tried putting a book under my front wheel (someone suggested this - it made no difference), tried Garmin sensors instead and had a similar problem and tried taking the bike off the turbo and putting it back on again in case something was wrong with how I'd mounted it. So far I've had no success. What's weird is that this year, when I first attached my road bike to the turbo, the speed was roughly correct for the first couple of sessions (I was averaging 13/14mph) but then it dropped and dropped to the point where I am now pedalling like crazy for over an hour to achieve about 3 miles in distance! Can anyone suggest what I am doing wrong and how to fix this please? It is putting me off using it, and I can't afford to replace it with an all bells and whistles smart trainer so I am a bit stuck with what I have. Thank you.

You don't say where your speed readings come from. Do they both come from the same source - i.e. measured from a wheel magnet on the bike's wheel?

Secondly, you don't say whether your speed has dropped because of the effort required to keep it up or whether you feel you're putting in the same effort but get a lower reading.

Clarify this and we can try and find the problem.

 

[CXRAndy]

If the resistance feels somewhat the same as outside riding, then it's the speed sensor calibration.

Unfortunately budget is usually inaccurate

 

[HarryTheDog]

Have you set the wheel circumfence on your computer correctly ?
Garmins default I believe is for something like a 23mm tyre on a 700c wheel. If not and you are using a garmin
Select Settings > Sensors > Speed/Cadence > Wheel Size

roughly 23 mm tyre circumfrence 2096 mm
25 mm 2105
etc etc,

 

[Alex321]

You don't say where your speed readings come from. Do they both come from the same source - i.e. measured from a wheel magnet on the bike's wheel?

Secondly, you don't say whether your speed has dropped because of the effort required to keep it up or whether you feel you're putting in the same effort but get a lower reading.

Clarify this and we can try and find the problem.

They say "I have fitted some Moofit speed and cadence sensors".

Those are sensors which attach to the bike on Amazon, it is shown attached to the hub of the wheel, which seems a little odd.

 

[Ming the Merciless]

Thats because your speed on a turbo is 0 mph unless the bike falls off then it is 0.000002 mph.

 

[Bristolian]

They say "I have fitted some Moofit speed and cadence sensors".

Those are sensors which attach to the bike on Amazon, it is shown attached to the hub of the wheel, which seems a little odd.

I have these same sensors on my bike and they give accurate speed and cadence when on the turbo trainer. Yes, the speed sensor sits on the rear wheel hub - it's not magnetic like the older spoke mounted ones.

 

[Bristolian]

I have a very basic Crono indoor trainer - one where you attach you road bike's back wheel to the trainer via the through axel and the wheel spins on a small roller. To record the speed/distance on my Wahoo, I have fitted some Moofit speed and cadence sensors. The issue I am having - and that I hope people can help me with - is the very unrealistic speed/distances I am recording when I use it. on the road, I normally average about 15mph and would expect a static bke where I have no hills to contend with would be about the same. On this trainer my speed is WAY less - often only around 6 mph average. It is very frustrating as I am including turbo miles as part of my annual mileage on Strava and would like to think my efforts are being properly accounted for. I've tried changing the battery in the Moofit, tried putting a book under my front wheel (someone suggested this - it made no difference), tried Garmin sensors instead and had a similar problem and tried taking the bike off the turbo and putting it back on again in case something was wrong with how I'd mounted it. So far I've had no success. What's weird is that this year, when I first attached my road bike to the turbo, the speed was roughly correct for the first couple of sessions (I was averaging 13/14mph) but then it dropped and dropped to the point where I am now pedalling like crazy for over an hour to achieve about 3 miles in distance! Can anyone suggest what I am doing wrong and how to fix this please? It is putting me off using it, and I can't afford to replace it with an all bells and whistles smart trainer so I am a bit stuck with what I have. Thank you.

I use the same Moofit sensors on my bike and they work very well. I think @HarryTheDog is on the right track but there is another thing that might make a difference. Do you have GPS speed measurement enabled for when riding on the road and have you disabled it for use on the turbo trainer? If not, give it a try - it might solve your problem ... but might not.

I'm not familiar with how the Wahoo works, but some Garmin head units compare the GPS to the sensor speeds and default to a stupid number if there is too much difference. On my Garmin I have two profiles set up, road and indoor, so I don't need to keep making changes.

Hope this is of some help

 

[NotSpeedyAt All]

Thank you so much for these really useful replies. The sensors are on the wheel hub and left crank - one measuring speed and the other cadence. @yellowsaddle - I feel I'm putting in the same effort but getting a much lower reading. I will check to see if the roller on the crono is gunky - maybe I can oil it, I'm not sure but it might be worth a try. I will also have a look at the Wahoo settings and see if there is anything wrong there. I really appreciate all the feedback.

 

[NotSpeedyAt All]

I should think that is down to the resistance of the rollers.

Probably they were very free running when you first got it, but have got a bit gunked up, causing more resistance since then.

I'll check that - it sounds plausible. Thanks.

 

[NotSpeedyAt All]

You don't say where your speed readings come from. Do they both come from the same source - i.e. measured from a wheel magnet on the bike's wheel?

Secondly, you don't say whether your speed has dropped because of the effort required to keep it up or whether you feel you're putting in the same effort but get a lower reading.

Clarify this and we can try and find the problem.

I'm putting in the same effort but getting a lower reading. For a couple of rides it seemed accurte and then the speed reading dropped like a stone.

 

[NotSpeedyAt All]

I use the same Moofit sensors on my bike and they work very well. I think @HarryTheDog is on the right track but there is another thing that might make a difference. Do you have GPS speed measurement enabled for when riding on the road and have you disabled it for use on the turbo trainer? If not, give it a try - it might solve your problem ... but might not.

I'm not familiar with how the Wahoo works, but some Garmin head units compare the GPS to the sensor speeds and default to a stupid number if there is too much difference. On my Garmin I have two profiles set up, road and indoor, so I don't need to keep making changes.

Hope this is of some help

That's interesting. Im not sure the wahoo has this function but I will check. I have just dicovered it has an indoor and outdoor setting so I will try the indoor one and see if that helps.

 

[Yellow Saddle]

I'm putting in the same effort but getting a lower reading. For a couple of rides it seemed accurte and then the speed reading dropped like a stone.

Thanks for clarifying. Others here have more experience with your system than me, so I'll leave it to them to help you.

 

[stephec]

Are you using the same gear ratio on the turbo that you would normally cruise along on a flat road with?