Speedometers are calibrated to specific tire circumferences, if you can find and mount a front tire to your Spdy that is the same actual circum. as a Bonnie, than you can assume an accurate readout at travel. To answer your question, research Bonnie as built Specs. and find out if the front tire is similar in size and your query will be resolved. I was able to use a TBS 17 inch front wheel and maintain a factory ratio by mounting a fat 130/90-17 tire, the circum. of the tire worked out to 3/8ths of an inch less than the OEM 18 incher and my speedo reads out close enough for me. If you want perfection though, go get an Acewell electronic.
