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The SP4 is a 3-piece wheel and every set is made to order in Japan so expect at least a two month lead time on your new wheelset because they all come over on a boat! Is the wait worth it? One look at the sizing chart and you have your answer–there’s literally hundreds of different of size combinations with pretty much every bolt pattern we’re familiar with and that’s just for the 18-inch wheel!
Recalling the results from the offset calculator a -17mm offset will give us the same poke as the On Point RX-7. The closest we can get a 13-inch SP4 to that is with either a -14mm or -22mm offset—the latter extending an additional 5mm out which by the looks of it we could afford.
So in the rear we could get away with a deep profile rim for maximum caliper clearance and also maximum offset. Up front though we have to be a little more careful. With just as many offset choices for our front wheels we wanted to choose an one as close to the stock 50mm as possible to avoid excessive scrub. The stock FD has a scrub radius close to zero with a 50mm offset wheel. All else equal as we decrease the offset of the wheel we increase the scrub by that same amount. Excessive scrub increases steering effort, tendency to understeer on turn in and road feel—meaning more of the road undulations and irregularities will be translated back to the driver through the steering wheel—which we’d like to avoid (think tramlining). The closest we could get to our ideal 50mm offset on the 11-inch SSR SP4 is 37mm if we chose the SL disk. The “SL” stands for Super Low and offers the least amount of caliper clearance in exchange for that offset—that’s not a problem with the stock brakes we have now but it might be a problem with our planned big brake kit.
Feeling confident our selection would fit we ordered our wheels (highlighted on the sizing chart above) and the waiting began! Our final selection was 18×11’s for the front with the 37mm offset and 18×13’s with the -23mm offset for the rear.
Sorry this article ended up being more of a teaser for the wheels, but you won’t have to wait long for gratification, we promise. Stay tuned, next week we will be getting some big brakes worthy of filling these hoops!
