The calculated distance (air line) between Grenoble and Bourg-de-Péage is approximately 34 miles respectively 55 kilometers.
By car or train, the actual journey to Bourg-de-Péage is certainly longer, as only the direct route (as the crow flies) between Grenoble and Bourg-de-Péage has been calculated here.
Air line (approximately)
55 kilometers
30 nautical miles