toddv@copper.UUCP (Todd Vierheller) (04/28/86)
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ ////////////////////////////////////////////////////////////////////////////// \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ ////////////////////////////////////////////////////////////////////////////// I recently put a set of Pirelli MP7 Radials on my bike, and the handling changed dramatically. (And I *love* it.) The new tires are narrower (particularly the front), more rounded, and of near radial design. I replaced H rated tires with V rated tires. (H is fine for me, the radials don't heat up as much and get a V rating.) The new tires also weigh about half of what a conventional tire would weigh and have a slighly lower profile. Front: 100/90 VR 18 Rear: 120/80 VR 16 After I replaced my rear tire, it stopped sliding in the curves and only my front tire slid. (I find front tire slides unnerving.) After replacing the front tire, I noticed the most change. The bike has an increased tendency to "fall" into the turns now, and I have better traction at steeper lean angles. (It doesn't slide at all.) I am not a canyon racer. I commute at 55-85mph on the highway or as fast as I dare up over a twisty swicthback type road--both often in the rain. My questions: Would the narrower more rounded tire account for the difference in cornering? How much of the increased handling can I blame on the radial design? On tread and tire shape? Do any of you racers have experience with radials? Has anyone read any evaluations of this tire? Do they break loose suddenly and without warning (as I fear) or do they warn the rider of immpending doom? I (with my limited experience) recommend these tires (at least for the commuter). They have excellent traction in the rain and in the dry. Time will tell what kind of tread life they have, but the radial design (and the sales hype) promise good mileage. Any comments appreciated, Todd Vierheller Software Development Products Tektronix Inc.
struve@calma.UUCP (04/30/86)
I had posted earlier on the subject of MP7's, but I want to second
Todd's favorable opinion and add a few questions of my own. I have used the
tire only on the rear (with a Laser front) and noticed no handling change
except almost total wobble-elimination. Qualitatively the steering feels
about the same. Tread life appears to have almost doubled over, say, a
Phantom. However, traction is not as good under hard accelleration as
the Phantom or even a Conti SuperTwin. Under pure cornering loads the tire
slides very predictably and it's great in the rain.
Now for the question, Todd: how's the front? My new lane-splitter is
a BMW K100 with the OEM Phantoms, and the ribbed front tire wiggles badly
on road irregularities parallel to the bike's path. This is annoying on rain
grooves at 55 and scary on rough roads at 130. I've been thinking of getting
MP7's when the Phantoms wear out but I'm leery of ribbed Pirellis.
P.S. How are the pickup truck drivers in Portland these days? :) donch@teklabs.UUCP (Don Chitwood) (05/01/86)
Todd, My gut feeling is that the cross-sectional shape of the tire will definitely have an effect on how the tire feels in cornering and setting up for cornering. However, the main thing I've noticed whenever I change a tire (mainly rear ones since they wear so rapidly) is how nimble and responsive my motorcycle becomes....regardless of the brand of tire I use. Certainly there are major considerations to keep in mind when selecting a tire, but I'm afraid my sensitivity to the attributes of one over another aren't very objective when my sampling rate is once or twice a year. I'd love to have a spare rear wheel that I could use for an A/B test in quick succession. Then I could be convinced of the subtler (or maybe the obvious) differences. As it is, I tend to stick with the ones that give me known performance for my style of riding, which in our part of the country most definitely includes traction in the wet.