Kris01 wrote on 12/29/15 at 16:40:09:I've seen car tires mentioned a lot lately. Would that not be a bad idea considering the sidewalls aren't made for a bike? A car tire wouldn't roll over like a mc tire.
Kris, car tires have flexible side walls and operate (in the correct 30-35 psi air pressure range) as they are designed to do when installed on the steering (front) tires on a car. In any normal or sane person's turns the tread stays mostly flat to the pavement and the sidewall flexes to set up the turn while keeping the tread flat to the pavement.
(mostly, unless you are doing the insane sharp mountain turns like we do up at the dragon).
In doing so a car tire keeps a much larger & flatter oblong contact patch in contact with the pavement, and it grips on a Savage at the same level or better that the much smaller motorcycle "round oval" contact patch does.
Folks tell me at a full dragging lean I only use the inside half of my rear tire, but that "half of a MUCH wider thread width" much flatter oblong patch is still 3x-4x larger than the round-oval contact profile zone that a bike rear tire gets at the same lean angle.
The rubber used on the bike tire HAS be a lot stickier (softer) to work in a mountain turn, the car tire rubber can be a more durable tougher rubber and because of the larger contact patch still work just as well as the bike tire -- remember, contact gripping formula is "coefficient of friction times the contact area".
This is part and parcel of the low life you get out of a bike rear tire (generally 1-2 years) vs the well over 6 years of use you can get out of a car tire (with miles being the same on each type of tire).
I have run both car and motorcycle rear tires up at the Dragon, as has MM. Dave has seen both of us in front of him, as has Lancer and others.
A car tire on the rear of a Savage can perform as well in the mountains as far as handling, grip, wet traction, etc. etc. goes. It does it every year, in extremes of braking and cornering that make the front rotor turn deep black purple from the heat generated.
The biggest downside of running a car tire is MOUNTING the sumbitch. Mounting a car tire is troublesome and dangerous, and you have to use MM's trick of greasing the section that does not want to pop with axle grease to get it to pop up on the bead without using excessive air pressure.
This works because the entire ungreased side and the ungreased part of the side that was greased keeps the tire nice and stable and stationary until the rubber in the bead itself can absorb the thin coat of grease that you used. Oils and waxes and soaps are a natural part of rubber, so the little bit of grease you added just "goes into solution" over time and becomes part of the rubber just like the rest of the oils, soaps and waxes used in making the rubber.
Last issue is this, unless you have a bike shop that does a lot of darksider tires for the long distance touring crowd (Goldwings and big Kawasaki bikes) you will have no one local to you with the skills and experience to put a car tire your bike safely.
I still have an inch and a quarter long scar on my left wrist from a Firestone bead that broke on me before I started using MM's grease trick
Too much air pressure CAN break a bead you know, especially if it is kinked over the bead like it is before it seats. The actual mounting of the car tire and the popping of the bead is when your maximum risk takes place ......Where a car tire shines is in touring mode though, as the tire contact area is 5x-6x wider and a bit longer than a bike tire's contact patch, even after you have worn that hideous flat spot into your softer motorcycle rear tire's profile. And if you are riding upright, why you get to use ALL of the BIG flat contact zone and that makes for very little braking/acceleration wear compared to what a softer rubber smaller rounded contact zone bike tire will see.
Pages: 1 
