imported post
Darksiders: I apologize in advance if you find this posting offensive. Safety is a stickler issue with me. If there is one scientific study by a car tire manufacturer stating that his car tire is approved for use on a motorcycle please post it!
Unfortunately, people do put car tires on motorcycles. And because they didn't have an accident today they think hey, it's safe! But the only evidence they have to support their view is anecdotal in nature. (Websters 2nd definition defines anecdotal as: "based on or consisting of reports or observations of usually unscientific observers - anecdotal evidence") I've read where 'darksiders' say it's a "personal choice" and "we're not suggesting that it's right for you...bla bla" Riding the darkside is like playing russian roulette the only difference is, if a darksider goes down in a group, he is going to take his passenger and possibly others with him! This is an example of where a 'darkside' choice effects others - directly.
I submitted the question to Stu Oltman, the well known and respected technical editor of GWRRA's Wingworld magazine and in his response he states that he is opposed to using car tires for safety reasons, plus there is the liability issue of financial responsibility if there is a failure in a tire carcass when it was used in a manner not contemplated by the manufacturer.
It is useful for one to take the trouble to understand why a motorcycle tire has a rounded tread area and a car tire has a flat one. It's because of the tread contact zone. A car tire has maximum contact when it is placed at 90 degrees to the road surface(straight up and down to the road). Where do you think the motorcycle tire's maximum contact zone is? It's on it's rounded tread area's side. A motorcycle's tire grabs better in a lean angle than upright. Also, many tire manufacturers use a stickier rubber compound on the sides of the tread to further improve traction. The more you lean, the more contact area you get, and the more traction. This is completely the opposite of a car tire.
Here is a video on Youtube that shows a car tire on the back of a goldwing. Check out the decreased contact area when the tire is in a lean angle.
http://www.youtube.com/watch?v=xaIj1XrmvLM&feature=related
Here is an example of how the contact area on a motorcycle rear tire looks:
So running a car tire on a motorcycle comes down to this.
Honda says its not safe to do it. (see below)
and
It hasn't been tested or approved by the tire manufacturers or the Motorcycle manufacturers.
and
Professionals in the field say it's not safe to do it.
From the Honda Owners Manual 1800.
From the Honda 1500 Shop manual:
Why would one be willing to risk their life, to go against all the warnings, just because it hasn't killed/hurt him or others today? Is saving money on tires that important? Isn't riding a bike dangerous enough? In my judgment, using untested and non-approved tires is either incredibly arrogant or just plain stupid and puts all of us at greater risk. I sincerely hope that laws are passed outlawing the practice .
It's all about safety.
Daveo
Darksiders: I apologize in advance if you find this posting offensive. Safety is a stickler issue with me. If there is one scientific study by a car tire manufacturer stating that his car tire is approved for use on a motorcycle please post it!
Unfortunately, people do put car tires on motorcycles. And because they didn't have an accident today they think hey, it's safe! But the only evidence they have to support their view is anecdotal in nature. (Websters 2nd definition defines anecdotal as: "based on or consisting of reports or observations of usually unscientific observers - anecdotal evidence") I've read where 'darksiders' say it's a "personal choice" and "we're not suggesting that it's right for you...bla bla" Riding the darkside is like playing russian roulette the only difference is, if a darksider goes down in a group, he is going to take his passenger and possibly others with him! This is an example of where a 'darkside' choice effects others - directly.
I submitted the question to Stu Oltman, the well known and respected technical editor of GWRRA's Wingworld magazine and in his response he states that he is opposed to using car tires for safety reasons, plus there is the liability issue of financial responsibility if there is a failure in a tire carcass when it was used in a manner not contemplated by the manufacturer.
It is useful for one to take the trouble to understand why a motorcycle tire has a rounded tread area and a car tire has a flat one. It's because of the tread contact zone. A car tire has maximum contact when it is placed at 90 degrees to the road surface(straight up and down to the road). Where do you think the motorcycle tire's maximum contact zone is? It's on it's rounded tread area's side. A motorcycle's tire grabs better in a lean angle than upright. Also, many tire manufacturers use a stickier rubber compound on the sides of the tread to further improve traction. The more you lean, the more contact area you get, and the more traction. This is completely the opposite of a car tire.
Here is a video on Youtube that shows a car tire on the back of a goldwing. Check out the decreased contact area when the tire is in a lean angle.
http://www.youtube.com/watch?v=xaIj1XrmvLM&feature=related
Here is an example of how the contact area on a motorcycle rear tire looks:
So running a car tire on a motorcycle comes down to this.
Honda says its not safe to do it. (see below)
and
It hasn't been tested or approved by the tire manufacturers or the Motorcycle manufacturers.
and
Professionals in the field say it's not safe to do it.
From the Honda Owners Manual 1800.
From the Honda 1500 Shop manual:
Why would one be willing to risk their life, to go against all the warnings, just because it hasn't killed/hurt him or others today? Is saving money on tires that important? Isn't riding a bike dangerous enough? In my judgment, using untested and non-approved tires is either incredibly arrogant or just plain stupid and puts all of us at greater risk. I sincerely hope that laws are passed outlawing the practice .
It's all about safety.
Daveo