you did that from zero to 17 km , that is a problem , the speed you were at exceeds the speed of horses going for a mile or two .
GSD are not speed dogs , they are distance and length of time dogs .
Condition needs to be kept and then this kind of extreme exertion be introduced slowly to allow lung capacity and cardio fitness to develop, not to forget muscle and co-ordination.
The GSD in conformation is a trotting animal , not galloping .
Look at the results for the fastest speed records for racing greyhounds
What is the fastest speed recorded for a greyhound?
"Alternatively, the fastest time achieved over a race distance of 480 metres or 525 yards was recently recorded (September 8, 2007) in the U.K. at Monmore Green near Wolverhampton in the midlands (track circumference 419 metres) and is 27.81 secs by Blonde Dino trained by John Mullins (Unattached). This represents an average speed around a track of 38.60 mph"
If they exceed this it would be in a spurt of energy . I am talking about the greyhound , not the GSD.
Your speed on the bike was faster than the 2013 Tour de France competitor who went 40.5 kms an hour .
For those not metric , 47 km per hour is 30 miles per hour (approx.)
The GSD is built to comfortably distance run at 7 miles per hour which is 10 to 12 km per hour.
I saw your Ty dog --- when you don't feed in preparation for this , provide energy , your dog is going to start stripping its own muscle for energy .
My friend , a professional sled dog racer - Iditarod and Yukon Quest gave me opportunities to study extreme dog sport, preparation, feeding , consequences - injuries , immune system assaults and depression when over extended .
I'm surprised your dog didn't have bloody diarrhea .