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Discussion Starter #1
I made this thread to talk about the good and bad of going Dark side or dbl dark side. No one needs to get butt hurt in this thread. If flaming starts I will have it removed. Everyone is entitled to their opinion.

I run dbl dark on my GW. I do not have any issues cornering. I do not have any issues leaning into the curves. The difference I noticed is when I came back to center it came up a lot quicker than with a MC tire. In the rain the bike does not wiggle like it did with a MC tire. Checking my load rating on the best mc tire I was at its limit with wife and gear on the bike. I had the front and back of the bike weighed. I am well within the C/T I mounted the tire myself on the rear and the bead visually hits where the car rim hits. I was able to get it to mount up with less than 40PSI of pressure. After reading how a CT and MC tire bead is I did put High Tack on it. This is the same stuff we use on the race car rims in the back to stop the rim from spinning inside the tire on launch. I used I keep the tire within the tire specifications for air. The front is of course a rear turned around. I have zero issues in the rain. The rain grooves move the water just fine. Since I put progressive springs in and tapered bearings I do not have the GW front end wobble or abnormal wear. So I cannot judge that from a normal front tire to a back tire. If you are uncomfortable running dark side don't do it. I wanted to do it on my Raider as well, but looking at the low profile of the back tire I do feel it would affect the handling too much for comfort. Since the Raider is set up for a single rider and no luggage I do not have the load capacity need of a car tire and it is not my "Touring" bike so it is possible I will not put the mileage on the tire within the 3 years I set for all my tires to be replaced.

Have fun with this thread. I do not care if it goes left right or sideways. The couch is over there -->>
We have a full bar upstairs and we are serving popcorn at each table.
 

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The biggest unresolved issue that I am aware of is the fact that motorcycle wheels/rims are different from car or truck tire rims. The bead sizes are different and they are not interchangeable. As far as I know, no one is making motorcycle wheels that match the bead dimensions of a car tire, or making a car wheel that will somehow fit on a motorcycle.

I have seen a lot of custom motorcycles, usually with very large engines, that have what clearly looks like a wide and flat profile car tire on the back wheel. The bikes look like they would stand up without a kickstand. Whether these bikes are intended to be trailer queens that get transported from one show to the next, and seldom get ridden - I don't know.

If someone were to address this, either by making MC wheels with the dimensions to match car tire beads, that would resolve what I would perceive to be the primary issue.

Last week I took a road trip from upstate NY to Newport Rhode Island, 850 miles there and back. I was suppose to get a mid size car from the rental company, but they were out of cars, so they gave me a brand new Ford F150 crew cab pickup truck for the same price. The trip is 95% highway miles, and I enjoyed driving a new truck with the cruise control nearly the whole way on the interstate. (The F150 got 22mpg, so I have no complaints).

I did notice that, getting a feel for the truck at 70mph, if I pushed the steering wheel a bit hard to change lanes the truck really really loaded up its suspension and tires, and it had a very mushy over-steering feeling - far more than I expected. Ok I expected it to drive like a truck, its not a sports car, and if I had to swerve suddenly or took a corner too fast I would quickly get in trouble. But its a 5 passenger truck, and would easily carry 2000 pounds of weight in the bed, so it has to be driven accordingly with respect for its limitations.

There are people that ride their motorcycles under similar conditions, fully loaded or overloaded, riding on the interstate highway with all the handling and cornering needs of an 18 wheeler, and riding all day long.

So yeah, I could see someone wanting a heavy highway tire on their bike. I'm surprised no one makes one specifically for a motorcycle, and no one makes or modifies wheels specifically for putting that kind of car tire on a motorcycle. What do they put on custom bikes that have V8 engines?! I have no idea!

People seem to always put car tires on trikes and on side cars, so something is disconnected here.
 

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My only experience with it is my current bike came with a 'darkside' tire on the back. It was probably 30% worn, so clearly had somehow been mounted at least 'good enough'. There was really never a chance I was keeping it, but figured I'd give it a shot before I took the bike over for new shoes. Maybe leave it on for a while and put off paying for new tires. Nope. One ride was all it took. No freakin' way. Felt awful. Scary, in fact.

I don't know enough about beads and mounting to know if it's safe or not. Only that plenty of folks seem to do it without tires blowing out all over the place.

It's certainly not for me just from a 'ride feel' standpoint, though I am anything BUT an interstate rider. I'm more a two-lane back-roads cruiser. Not 'twisties' particularly, but also not flat and mostly-straight for miles on end like an interstate.

I'm not gonna blanket condemn (or endorse) it for others. I can simply say I tried it and wouldn't have it.
 

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The problem with assessing the safety of putting a car tire on a motorcycle, is anyone killed by riding that way is not here to tell us.

I doubt most accident investigators would even think to check if a motorcycle had a car tire on the back wheel.
 

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Discussion Starter #5
The problem with assessing the safety of putting a car tire on a motorcycle, is anyone killed by riding that way is not here to tell us.

I doubt most accident investigators would even think to check if a motorcycle had a car tire on the back wheel.
Yes they do. Looking at the tires is a primary in a crash that involved a death. Hell my ex wife was in a very bad crash with injuries and the officer at the scene checked the tires.
 

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well yeah they check the tires, but would they have any reason to even look at the tire size and see if the MC letters are there?

I'm sure they look at the treads and look for a bead that came off.

I tried to goggle accidents caused by car tires on motorcycles, and I could not find any kind of reports of 'wrong tires' being a classification.

Just by shear chance there must have been some people that have crashed with car tires on their bikes. Where is that information?
 

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Discussion Starter #7
well yeah they check the tires, but would they have any reason to even look at the tire size and see if the MC letters are there?

I'm sure they look at the treads and look for a bead that came off.

I tried to goggle accidents caused by car tires on motorcycles, and I could not find any kind of reports of 'wrong tires' being a classification.

Just by shear chance there must have been some people that have crashed with car tires on their bikes. Where is that information?
I could not find that information either. That is another reason I went with a car tire. Also for the tire to come off of the bead there would have to be a big problem with that heavy braided steel cable that runs the whole bead of a tire.
 

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I meant more the bead being pushed in off the wheel, which would make a tubeless tire go flat.

Low pressure, skidding sideways, hit a pot hole... ?! We are talking about people putting 600 lbs or more on their seats and luggage racks....
 

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OK here's my take on going Darkside... oh wait, I already said all that I possibly could say on the matter elsewhere so I'll spare everyone. You're welcome. :wink:
 

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well yeah they check the tires, but would they have any reason to even look at the tire size and see if the MC letters are there?

I'm sure they look at the treads and look for a bead that came off.

I tried to goggle accidents caused by car tires on motorcycles, and I could not find any kind of reports of 'wrong tires' being a classification.

Just by shear chance there must have been some people that have crashed with car tires on their bikes. Where is that information?
I am a retired police officer, spent 13 years in traffic homicide, the reason you don't find information on car tires on motorcycles in crashes is because a normal crash report does not capture that information, even the traffic homicide report while it captures more tire information does not break it down as to if it is a car tire being used.

You were correct in your other post about the beads on car rims and motorcycle rims being different sizes, that was done to discourage the use of car tires on motorcycles, yes it was done on purpose.

This double dark side is where you put a rear motorcycle tire on the front running it in reverse rotation of the arrow, that is not a good idea either because of how the belts in the rear tire are designed, running the tire against the rotation arrow or backwards can result in the belts coming apart.

Again crash reports don't capture that data nor do traffic homicide reports.

A car tire is not designed to roll up onto its shoulder, where a motorcycle tire is designed to do that, that is why a motorcycle tire is curved.

Notice the only bikes you see running car tires outside of custom choppers with huge tires are large cruisers and touring bikes. How many have been involved in crashes, crashes with injuries and fatal crashes is unknown again because that information is not collected and tracked on the crash reports.

All they do on a traffic homicide report is document the brand, size and air pressure if not flat and the tread depth. No where on the reports does is ask is it is the proper tire for the vehicle/motorcycle.

The percentage of people running car tires on motorcycles is small so any sample size would be small as well.

One of the claims dark siders push is car tires provide better traction but if that was the case whey don't motorcycle makers install car tires from the factory? They would actually save money on the cost of the bike as car tires are much cheaper than motorcycle tires so that would mean more profit in their pockets yet they don't do that for a reason, one the rim beads are not compatible no matter if people are forcing car tires on motorcycle rims or not. Two the bikes are designed for motorcycle tires because motorcycle tires are designed to lean and still provide traction.

Car tires are not designed to be leaned, the cruiser and touring bike people are getting away with it only because they can't push it to the limit like a sport bike can and you never see car tires on sport bikes.

I know I am wasting my time but installing car tires on motorcycles is not smart.
 

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Discussion Starter #11
The bike does not ride up on the side of a car tire. It rolls to the outside edge. This has been shown time and time again with different cameras and patch swatches. The car tire does better in the rain and uneven surfaces. As for turning the tire backwards and putting it on the front I think it is Avon that has arrows that say front and rear depending on where you are putting the tire. I know you were/are a police officer and spent 13 years in traffic homicide. How many MC crashes did you work that the rear tire failed? How many of those crashes were a car tire. I know you say the report does not ask it, but as a motorcyclist, I would think you would say even if just to yourself "Idiot had a car tire on the bike and it failed just like everyone says it will". Honestly I researched this as much as I could for 2 years before I did it. I found 2 groups of people. Those who are darkside and love it and those who never tried it and hate it.
 

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I hate these kinds of threads because the car tire people are going to do it anyway no matter what evidence you show them that is not a smart thing to do.

Fact, the bead on a car rim and a motorcycle rim are different, they changed the bead on motorcycle rims to discourage the use of car tires on them. Just because people force the bead of a car tire onto a motorcycle rim does not mean it is ok.

There is a ton of information explaining why you should not put a car tire on a motorcycle rim. The Tire and Rubber Manufacture association says don't do it. Tire companies say don't do it. Motorcycle manufactures say don't do it.

If car tires were such a good idea motorcycle manufactures would be all over it but they spend millions of dollars in research and development and that is still not good enough for the dark siders because they think they are smarter than the manufacturer engineers and the tire engineers of the tire companies.

There was a tire store once that advertised putting car tires on motorcycles, but once it was explained to them the difference between the beads and rims they quit advertising car tires on motorcycles.

The truth is it is a very small percentage of people who are actually putting car tires on motorcycles. I guess the bigger question is how much is all your personal possessions worth to you? Do you own a home or business? Are you prepared to have part of your salary garnished for the rest of someone else life if you are at fault in a crash that hurts them and you are running a car tire.

Dark siders all rant about how much better the traction is with a car tire, yet not a single motorcycle racing team uses a car tire with the exception of motorcycle pro class drag racers and their rims have the proper car tire bead on them as they are mounting drag slicks and the bikes only go straight down the 1/4 mile, everything about the bike is built to go straight. Road racing motorcycles all use motorcycle tires.

Put all the car tires you want on your motorcycle, heck put rear tires on the front and risk the belts coming apart because you are running a directional tire backwards at high speeds for all I care, but pray to the almighty above that you never get into an accident with someone from my family because the lawsuits will be coming.

There is one constant from all dark siders and that is I have yet to find one who has not said that it changes the handling of the motorcycle but you will get used to it. What they don't say it is changes the handling for the worse because motorcycles lean into turns and in order to lean a car tire you have to get it up onto the edge. Most dark siders are running their car tires way under inflated which causes sidewall flex which can lead to sidewall failure. I think the reason dark siders have gotten away with the low air pressure is two fold one the motorcycles weight is lighter than a cars and two they are still wearing out the car tire twice as fast to three times as fast as it would wear on a car so the side wall just has not yet had time to come apart from the sidewall plies being over worked from flexing.

I refuse to give up the handling of my motorcycle to save sixty dollars if that on a tire that might last me 5,000 miles longer than a proper motorcycle tire, and that is not even getting into the bead difference between a motorcycle rim and a car rim.
 

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Discussion Starter #13
I hate these kinds of threads because the car tire people are going to do it anyway no matter what evidence you show them that is not a smart thing to do.

Fact, the bead on a car rim and a motorcycle rim are different, they changed the bead on motorcycle rims to discourage the use of car tires on them. Just because people force the bead of a car tire onto a motorcycle rim does not mean it is ok.

There is a ton of information explaining why you should not put a car tire on a motorcycle rim. The Tire and Rubber Manufacture association says don't do it. Tire companies say don't do it. Motorcycle manufactures say don't do it.

If car tires were such a good idea motorcycle manufactures would be all over it but they spend millions of dollars in research and development and that is still not good enough for the dark siders because they think they are smarter than the manufacturer engineers and the tire engineers of the tire companies.

There was a tire store once that advertised putting car tires on motorcycles, but once it was explained to them the difference between the beads and rims they quit advertising car tires on motorcycles.

The truth is it is a very small percentage of people who are actually putting car tires on motorcycles. I guess the bigger question is how much is all your personal possessions worth to you? Do you own a home or business? Are you prepared to have part of your salary garnished for the rest of someone else life if you are at fault in a crash that hurts them and you are running a car tire.

Dark siders all rant about how much better the traction is with a car tire, yet not a single motorcycle racing team uses a car tire with the exception of motorcycle pro class drag racers and their rims have the proper car tire bead on them as they are mounting drag slicks and the bikes only go straight down the 1/4 mile, everything about the bike is built to go straight. Road racing motorcycles all use motorcycle tires.

Put all the car tires you want on your motorcycle, heck put rear tires on the front and risk the belts coming apart because you are running a directional tire backwards at high speeds for all I care, but pray to the almighty above that you never get into an accident with someone from my family because the lawsuits will be coming.

There is one constant from all dark siders and that is I have yet to find one who has not said that it changes the handling of the motorcycle but you will get used to it. What they don't say it is changes the handling for the worse because motorcycles lean into turns and in order to lean a car tire you have to get it up onto the edge. Most dark siders are running their car tires way under inflated which causes sidewall flex which can lead to sidewall failure. I think the reason dark siders have gotten away with the low air pressure is two fold one the motorcycles weight is lighter than a cars and two they are still wearing out the car tire twice as fast to three times as fast as it would wear on a car so the side wall just has not yet had time to come apart from the sidewall plies being over worked from flexing.

I refuse to give up the handling of my motorcycle to save sixty dollars if that on a tire that might last me 5,000 miles longer than a proper motorcycle tire, and that is not even getting into the bead difference between a motorcycle rim and a car rim.
You should know by now when I say something on the forum I am speaking from experience and am willing to prove it. I run dbl dark on my Goldwing. If I can find a tire to fit the Venture when I get it I will run dbl dark on it too. I mounted my tires myself on my rims. The car tire hits the rim and visa versa the same as a MC tire does. The MC rim takes the whole bead of the tire and does NOT leave any hanging out like is shown in all the cartoon pictures of MC rims and car tires. There is a steel band that goes around the bead of the tire and as long as the tire has air in it it cannot come off of the rim. IT is impossible. With the heavy bike, 2 up and gear the MC tire is getting pushed to its limit. This is a known fact, not someone just saying it. The MC tire also is pushed to the limit on heat. A car tire runs cooler and can handle the heavy load of all that with ease. When I first got the GW I took it home in the rain. I had to hold on for dear life several times with a brand new MC tire on the back. Since I have had the CT on the back that issue is GONE. I take it in the mountains with no issues whatsoever. I kept up with a group of bikes with a lot more riding experience than I have. I do like that it stands up faster. I stop in a shorter distance. I get better wet traction. I am not going into cost savings because I use a high end tire so I will only get about 25k out of it and it cost me through the shop 150 dollars. As far as the tire coming apart in the front running it backwards that won't happen either. There are MC tire makers that have arrows on the tires that say front one way and rear another.. On the SAME tire. It is your bike you run what you want. I will not ever make fun or discourage you from doing what you want with YOUR bike. All I ask is for others to do the same. I researched it for years and talked to several vehicle homicide investigators. I can not find one shred of evidence of a car tire that failed on a MC. I have found the opposite in fact. I talked to people who got something in the tire and instead of wrecking they were able to bring the bike to a safe stop, even fully loaded. https://www.roadandtrack.com/car-culture/a8606/why-so-called-darksiders-prefer-auto-tires-on-their-motorcycles/ an interesting article. Here is a quote from a GW FB page Jerry Craig was actually refering to Michael Hansen about never hearing of a darksider blowing out one lol but i did hit something in the road and like i said it rode like a dream even flat as a flitter with two up which is normally a death sentence on a mc tire.
 

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someone cut a motorcycle wheel with a motorcycle tire on it, and a motorcycle wheel with a car tire on it.










the following is why i will never go to a CT on a motorcycle - i would never trust it as much in a lean as i would a MT. a MT uses different rubber compounds engineered to flex and grip the road for turns and leans and its shape is designed for this. a CT is designed and engineered to stay flat always. the top photo is with a CT and the bottom is with a MT.



 

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Discussion Starter #15 (Edited)
LOL @ That post. So you show a 2 up bike leaning so hard that they are scraping the frame then a 1 up bike with all the clearance in the world because the rider is leaning with the bike. Also the 2 up is hugging the inside of the curve better than the solo rider Bevo.. Those pics make my point. The car tire is being abused so much harder by them leaning against the turn and yet it still has as much or more contact with the road. Here are pics from my bike and a car in the shop with SIMILAR tires. I do not have one in with the exact brand. Note the bead on the MC rim is more covered with NO gap where the Car tire on the CAR rim has a gap. I feel safer on the bike. .LOL So I showed the closeup pics to my wife who does not know the difference between my MC wheel and that car wheel up close. She picked out the MC rim with the CT looking safer.
 

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in both MC photos the riders have their heads leaning to the outside of the curve

the 2nd photo the rider has his shoulders slightly to the outside of the curve. In both cases that would make the bike lean more, not less.

If you want the bike to stand up more (not scrape) you have to shift your body weight to the inside of the curve, the center of mass of bike and rider stays over the center of the tire, and the bike leans less, because the rider is putting his body weight into the curve.

I have to agree that with the steel wires in the bead of the tires, neither tire is going to come off the wheel unless it goes flat.

Whether or not the beads are designed to match the wheels or not, they either stay on or they dont.

I have ridden my MC tires down to where there is a flat spot in the center of the back tire. It happens gradually over the life of the tire, so you dont really notice the difference

but when I put a new tire on the back wheel, I can feel the response and the nimble-lean return - its very pronounced. I cant imagine riding a motorcycle with a tire that is designed to be flat in the center.

I think that would suck the life out of the way the bike handles: just my 2¢
 

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Discussion Starter #17
in both MC photos the riders have their heads leaning to the outside of the curve

the 2nd photo the rider has his shoulders slightly to the outside of the curve. In both cases that would make the bike lean more, not less.

If you want the bike to stand up more (not scrape) you have to shift your body weight to the inside of the curve, the center of mass of bike and rider stays over the center of the tire, and the bike leans less, because the rider is putting his body weight into the curve.

I have to agree that with the steel wires in the bead of the tires, neither tire is going to come off the wheel unless it goes flat.

Whether or not the beads are designed to match the wheels or not, they either stay on or they dont.

I have ridden my MC tires down to where there is a flat spot in the center of the back tire. It happens gradually over the life of the tire, so you dont really notice the difference

but when I put a new tire on the back wheel, I can feel the response and the nimble-lean return - its very pronounced. I cant imagine riding a motorcycle with a tire that is designed to be flat in the center.

I think that would suck the life out of the way the bike handles: just my 2¢
My wife and I have 6 bikes. I honestly barely notice the difference with the CT on the Wing. I let the local dealer change the oil. They have general guys who do that, then a tech takes it for a test ride. The tech did not even notice the car tire on the bike. He was shocked when I asked how that CT handled.
 

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LOL @ That post. So you show a 2 up bike leaning so hard that they are scraping the frame then a 1 up bike with all the clearance in the world because the rider is leaning with the bike. Also the 2 up is hugging the inside of the curve better than the solo rider Bevo.. Those pics make my point. The car tire is being abused so much harder by them leaning against the turn and yet it still has as much or more contact with the road...I feel safer on the bike. .LOL So I showed the closeup pics to my wife who does not know the difference between my MC wheel and that car wheel up close. She picked out the MC rim with the CT looking safer.
you're focusing on all the wrong things. those were just the first 2 photos i found that shows an example of a MT and CT in a lean. doesn't matter if one is scraping or clearance or anything else you mentioned. it doesn't matter what the riders are doing (even though they both appear to have almost equal lean positions with respect to the bike). those have nothing to do with what i was saying or the topic. if you think the first biker photo shows an anomaly of what a CT on a motorcycle does in a lean, i can post a bunch more that show the exact same thing.

just look at the tires making contact with the road. look closer. both bikes have a nearly identical lean angle- just lay a flat object across your screen under one fender and then scroll to the next photo to prove it. the CT has a smaller percentage of contact on the road than the MT. if you can't see this then zoom in your browser. you only have about 1/4 of the bottom of the CT in contact with the road and it doesn't flex nearly as much as the MT either. the MT has about 1/2 the entire bottom making contact with the road. and it's difficult to tell from these 2 photos, but the MT looks to have a greater overall contact patch versus the CT.

that's fine if you feel safer on your bike. i wasn't knocking your decision at all, only explaining mine, and pointing out the physical differences between the 2 options. and i have no idea the extent of your wife's expertise and knowledge of motorcycles and physics and wheels and tires so i don't know how bringing her very scientific approach to this helps back up anything you're saying. so you can "LOL" at my post for whatever reasons, but it doesn't seem to be in the same spirit as what you just previously said:

I will not ever make fun or discourage you from doing what you want with YOUR bike. All I ask is for others to do the same.
 

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This is why a car tire should never be mounted on a motorcycle rim, the drawing below shows the difference in the bead seat area of the two rims and yes a car tire could very well loose it bead seat on a motorcycle rim.

My life and my wife life is worth more to me than running a car tire on a motorcycle rim.

If that first one does not convince you try this one that shows just how each tire would seat on a motorcycle rim and a car rim, if this does not convince you then hey you take your chances and at some point you may pay the price.

Notice how the car tire sits in the bead area of a motorcycle rim, starting to see how a car tire can very well slip off the bead seat area of said motorcycle rim?
 

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One more drawing that shows how a car tire sits in the bead area of a motorcycle rim and how if can very easily slip off the bead area resulting in sudden air loss and if it happens it will likely be in a curve where you are assured of hopefully a low side crash but could just as well be a high side crash. Either way it will be a crash if the bead slips off.

The following is right from Dunlap:


Can I use a car tire on the back of my motorcycle?

No. The design of automotive tires and motorcycle tires are very different. The profile of automotive and motorcycle rims are different with a different bead seating area. An automotive tire will not seat properly on a motorcycle rim, making it more susceptible to problems such as rim slip, which can cause balance problems.

Motorcycles are designed specifically with a unique tread profile for leaning over when cornering. Under emergency or extreme maneuvering conditions, an automotive tire on a motorcycle may not allow the bike to handle as it was intended, which can lead to accident, injury or death.
 

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