Mr. Smith:
I rode on the Darkside for 25,000+ miles on two VTX 1800s and for about 7,000 miles on my Rocket. I've owned about 15 motorcycles, ridden hundreds of different makes., models and types since I began to ride some 46 years ago and I am an occasionally aggressive rider who sometimes enjoys pushing the envelope a bit.
Here's the truth:
No car tire made is designed to conform to the bead on a motorcycle tire rim. If you experience a tire failure with a car tire on the rear of any motorcycle with a motorcycle rim, there's a very good chance that the tire will separate from the rim.
Most, if not all car tires will ride on their sidewalls to some extent, some more than others, when cornered and leaned over hard. There is nothing, other than a thin sliver of un-reinforced rubber, between you and potential disaster, especially if you push a car tire hard on our bikes. I won't speak for others here, but
for me, ignorance of that fact is simply unintelligent. this particular risk is nonexistent with a motorcycle tire. Others here play with a wide range of tire pressures to try to diminish this and other effects or consequences of running on a car tire. I'm not interested in the gamble, thank you.
A car tire on this bike will
absolutely rob you of rear wheel horsepower and torque... no me interesante!
A car tire on the rear will more than likely cause irregular or premature wear of your front tire, more than likely killing a good part of the argument that a car tire will save you money. Additionally, a number of folks running on the Darkside have gone down with bad tank slappers or due to self-reported low to high speed shakes and wobbles, more than likely caused by the use of improper tires and the aforementioned unusual wear they cause on the front tire. Some of such mishaps may be attributed to how all that extra contact patch of the car tire can grab a bad camber in a roadway, pavement grooves, gratings or other irregularities which the roads ahead often throw at riders unexpectedly. I and many others I know suspect that other, maybe most accidents caused or contributed to by the use of car tires go unreported or are not publicized for several reasons that should be obvious to most seasoned motorcyclists.
Any car tire will slow down a bikes response time when you try to react to
any unforeseen, emergency-type situation requiring a quick, evasive maneuver, possibly making the difference between a safe escape or a very bad result.
All car tires will necessitate greater and more constant rider input and countersteering effort. That can be tiring.
No motorcycle sporting a car tire on the rear will steer as easily or be as flickable or responsive as that same bike shod with a motorcycle tire. To do so would defy several
laws of physics and the professional opinions of literally any motorcycle or tire expert or engineer you might care to consult.
Despite the ardent opinions of the devotees here and elsewhere, I can tell you with 100% assurance that the experts are right and that their expertise is based on hard facts and experience.. Naturally, that is just my (unwavering) humble opinion.
The cost of our rear tires has come down considerably just in the last year. I recently bought the B'stone Exedra Max for about $155 delivered to my door by denniskirk.com, so the dollar saving argument is diminishing rapidly over time. In most cases, the perceived dollar savings argument is further diminished by the parasitic effect of the larger, heavier car tire on rear wheel power and, hence, overall fuel efficiency.
Many if not most aggressive riding darksiders will have to replace their CT by about 15K miles due to sidewall scuffing and wear. The Metzeler, properly ridden on decent quality roads and normally maintained should last at least 8-10K miles and the Exedra Max should deliver 25-40% more mileage if utilized properly. Should you do most of your riding on straight roads and if you don't enjoy playing in the twisties, obviously, this will be of lesser concern for you.
Other than for those few things, I think car tires are great...
for my cars.
