Noticed that my new (to me) R172 didn't have the short wheel nuts in the tyre well. My R171 had them, are they needed on the newer model? The garage I got it from weren't aware that the nuts were needed. :surprise:
Don't have a R172 myself, but I would think that it is not very different from the R171. Meaning that your regular bolts will be to long. Why not try to fit the space saver and see if the bolts fit.Better to find out in your garage than on dark rainy night standing on some remote road in the middle of nowhere...
Checking the owners manual 2011 it looks like the shorter lug bolts are not needed. The list of items in the kit for changing to spare tire does not list them. Check page 289 in manual of what is in the kit and pages. Pages 328 to 331 is instruction on changing tire and does not mention using different lug bolts.