OE Radials - Lean Angle

Rim-Protector Revenge

This month's exhaustive 600cc sportbike comparison generated far more than loads of performance data, test notes and inner-helmet grins. It also sparked considerable discussion on the current state of the sporting motorcycle

One debate centered on details AWOL on too many of today's hugely competent sportbikes: items like well-positioned-and clear-mirrors, centerstands, minimally acceptable carburetion, etc. (See this month's Megaphone column for deeper insight on these issues.)

Our comparo also got us talking about componentry that hasn't been ignored: Original-equipment tires, especially those fitted to late-model sportbikes. From-the-factory rubber is so good these days that the term "rim protector" has pretty much been banished from the lexicon. Stock skins are so grippy we've even begun using them during the morning hours of track-test days. And considering how much we hate to fall off test bikes (and how much I hate writing checks to pay for them), that says a lot.

It hasn't always been like this. OE tires with grip and handling characteristics matching the machines they're fitted to is a fairly new development. (Unequal development of bikes and tires makes this a cyclical thing; tires fitted to 1930s Harleys and '50s-era Brit bikes were a decent match for the performance the bikes offered.)

Why the change? Recent strides in tire technology, of course, and more importantly, a realization by manufacturers that putting just-average tires on performance motorcycles can cost them more in reputation and bad press than they gain on the bottom line. Years ago a bike with sticky rubber out-of-the-box was the exception. Nowadays it's a rule.

Enthusiasts have been spooning high-performance rubber on in place of OE skins for years, and while there remain solid reasons to do so, it's not a "must-do" thing anymore, especially not immediately following your bike's 600-mile service. These days, the tires your bike comes with are likely to be an excellent choice when it's time for replacement rubber.

For one thing, today's OE radials offer plenty of grip. We've thrashed the latest stock tires-Bridgestone BT56SSs and new 010s, Dunlop 207ZRs, Metzeler MEZ3s, Michelin Pilot Sports-on the fastest, curviest asphalt we know of, and all offer enough grip to bevel knees, footpegs and bodywork right down to the nubs. For another, the zero-degree belt design used on today's OE radials offers more stability and compliance than the cut-belt, cross-ply construction of many race-spec radials. And because a bike's standard tires are chosen for (or developed in accordance with) the bike in question, you end up with the handling and ride qualities factory engineers and test riders have determined to be ideal-a good thing in all but a very few cases

Some riders will insist on running DOT-approved race tires-or worse, racing slicks-on their sportbikes, though this is more ego trip than necessity (unless track days are involved, of course). Slicks and DOT race tires not only need higher temperatures to work properly (tough to achieve on the street), but are designed to do one thing: give max cornering grip. Stability, mileage, ride quality, funky turn-in characteristics, none of these matter much, which means there's a good chance your streetbike won't be happy on them.

The bottom line? Tossing those OE tires and instantly replacing them with "racier" rubber is a fine fantasy. But the reality is you don't need to.

Ride wellMitch Boehm, Editor