The calculated distance (air line) between Saint-Jean-de-la-Ruelle and Rennes is approximately 164 miles respectively 264 kilometers.
By car or train, the actual journey to Rennes is certainly longer, as only the direct route (as the crow flies) between Saint-Jean-de-la-Ruelle and Rennes has been calculated here.
Air line (approximately)
264 kilometers
143 nautical miles