The Dark Side

Phil Tarman

Phil Tarman

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Joined
Dec 12, 2010
Messages
9,381
Age
81
Location
Greeley, CO
Bike
2010 Silver NT700VA (ABS)
I'm on the Long Distance Rider mail-list and a regular topic of conversation is the use of car tires, particularly on the heavier bikes like Goldwings, the big BMWs, and, in this case a Triumph Trophy.

I know the guy who posted this. It's "interesting," to say the least:

After having spent an estimated $3200 on rear tires for my K1200LT I've
decided to give a car tire a shot. Reports indicate that an $80 car tire
can last as long as 30,000 miles on a bike. Big difference compared to
$200 PR4s lasting 12,000 miles

I managed to come up with a spare wheel so going back and forth will not
be a problem.

I've seen lots of videos with car tires but none that showed before and
after. I made one up if anybody is interested.

https://www.youtube.com/watch?v=oZ5U2WDj5ik

It was a challenge making sure a tire would fit. After many measurements
I decided the nearest match was a 205/50. There is plenty of clearance
for a 205 width. A larger diameter size was preferable to replacing the
stock 190/50 but those sizes were not available for a 17" wheel. Some
detail pix here:

https://picasaweb.google.com/107830667926908438954/TriumphTrophySEDarkside02

For my experiment, I was lucky enough to have a spare wheel and to find
a used tire dealer that didn't have a problem mounting the tire on a
motorcycle wheel. Mounted and balanced I was out the door for $30.

I'm riding this to the National Meet this month and if I'm satisfied
with the results I'll get a new tire.?

Having talked with many riders who have gone darkside I was well aware
of the fact that initiating a turn takes more effort. What was
surprising was the drop off when coming out of a turn. Neither items are
bad, just something one will need to adjust to.

If you are a canyon carver, this additional effort will spoil your fun.
But, like most of us, I spend a lot of time on the straight and narrow
and my tires are wearing out in the center. I'll report back in a couple
of weeks.


--
Mike Langford [aka IB Pete]

Dan, since Mike was riding a Trophy in the video, I naturally thought of you! :)
 
Interesting, but something is nagging me deep in my brain...didn't a bike mag....Maybe Rider or Cycle World, do a piece on really good reasons why you shouldn't go to the dark side?
I cant remember if it was riding in the rain or bad things that happened during evasive maneuvering during emergencies...ah...here we go....
http://www.ridermagazine.com/browse...rk-side-putting-car-tires-on-motorcycles.htm/

Biggest consideration for me would be lawyers. If you were to cause death or serious injury to someone or yourself, and had installed non recommended tires, you leave a big hole for the
insurance company and their lawyers. I listen to unbelieveable stories from insurance company lawyers and their clients who I camp out with at Oshkosh....sorry...two thumbs down on this idea.
You have a tricycle, well, maybe that is different....an old Harley with a 10 degree lean angle? Maybe. Not for a sport bike though. But then again, there are those the chose to ride without a helmet.
Its a free country. If your state allows you to use car tires on a bike, then it is on you.
 
[...If you were to cause death or serious injury to someone or yourself, and had installed non recommended tires, you leave a big hole for the insurance company and their lawyers....]

Once there is one big case where a motorcyclist is found at fault in an accident because he/she fitted a car tire, the manufacturers will be forced to add these words to a wheel "Do not mount automotive tires."
 
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Car tires on motorcycles: for me it like riding with no Helmet, do so if you choose. There is not a conspiracy involving motorcycle tires, motorcycle need tires designed for motorcycles. Go to a bicycle shop, they will have 30 different type of tires for different uses. It is the same with a motorcycle, motorcycles need tires design for Motorcycles: okay the cost might be too much. Suck it up and get correct tires designed for motorcycles.
 
THOUSANDS of motorcycles have been ridden MILLIONS of miles with a car tire on the back. If you want a "rounded" tire that will do away with the transition problem going from dtraight up to cornering and back, check out the Austone brand.

For the doubters: Are you aware that scientists and airplane designers have proven that bees CANNOT fly? Never trust an "expert".
 
Just do me a favor, if you have done something like a car tire on your motorcycle don't ride near me. And remember load pipes save life too, bull crap.
It like the practice of not using a tube on a old BMW. I had to more then once tell a shop I don't car if the tire says tubeless use a tube. It the rim that requires you to use a tube. The seat on a car rim is different then a motorcycle. Yep if you choose use a car tire. They really don't investigate motorcycle accidents, so no one will know it was the tire that caused the crash.
 
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Ha! I remember that story from my first day in aero engineering at the U of Ill. Yes, the state of science is always improving and will continue to do so. But for better or worse, we DO put our lives in the hands of experts every day. Whether we are taking medicine or taking a trip on an airliner...or riding an NT. I shudder every time I remember those dangerous crappy tires that came on the 1960s bikes...but things continue to improve on the tire front....I will stick with my Michelins. And wear a helmet.

suvcw04 said:
THOUSANDS of motorcycles have been ridden MILLIONS of miles with a car tire on the back. If you want a "rounded" tire that will do away with the transition problem going from dtraight up to cornering and back, check out the Austone brand.

For the doubters: Are you aware that scientists and airplane designers have proven that bees CANNOT fly? Never trust an "expert".
Click to expand...
 
Chris, my dad was a (civilian) primary flight instructor for the USAF from '50-'57. He came home from the base one day to get us all so we could see a C-124 on the flightline at Greenville (MS) AFB. I remember the size of the tires more than anything. We even got to walk in and climb up to the cockpit. It didn't seem like anything bigger than that could ever possibly fly.
 
There was a reason they called the C-124 "Old shakey." We loaded a lot of them at the Pisa airport in Itlay during the Cuban missle crisis.
 
For this discussion to be practical for those that only ride an NT is there a car tire size that will fit on the NT rim?
 
I don't know and I don't really care. I'll keep running MC tires.
 
NT is not one of the heavy tourers, GW and H-D are using the 'wrong' tires. One reason darksiders say the can use car tires is because they don't lean to far as they scrape before too much of a lean. The NT you can really lean it over (if you not, you not having too much fun), so the theory of car tires would not work.
Don't use CAR tires, wear a helmet, gear, and pay attention.
 
I will say this , IF you have not personally tried a CT you have no business knocking it. I have about 50, 000 on CT with my GL1800 and If I were to find a size compatible CT for NT it would be on it. As far as sprt tourers go, There are more than one FJR owners with many miles of hard riding on CTires. When I first went dark on the Wing everyone in Wing chaper were NAY SAYERS, :O: now there are 6 or 7 darksiders there, some of them the same ones who were the mouthiest in a negative manner. As far as canyon carving acouple good riders one on CT and one on mc tire of choice , the mc tire bike will not run away from the CT, and if the CT bike is in lead the MC tired bike will maybe be able to stay withteh CT. BEEN there done that , speaking from experience.

eldon
 
LOL. Folks are funny about this topic.

My RF car tires take about 30 psi to seat. The same as the OEM motorcycle tire. Most seating issues occur with folks putting CTs on 15" rims. There appears to be greater differences in car and moto rims in that size making seating more difficult. I won't mount any tire that takes more than 40psi to seat.

My first 3 motorcycle tires failed on me (heat related failures). I run TWO TPMS systems so I know I was running at the correct pressure (which was the max allowed by the sidewall stamp). The main problem is I was running the bike at or very near the max load limit for the tire. These tires are just not up to being stressed at the maximum. So I switched not for the $$ but because tire manufactures don't seem capable of building a moto tire that will not fail on me. The RF tire cost about the same (if not a bit more) than the moto AND it run 40% cooler and doesn't fail.

I would suggest folks to be a little less quick to judge and a little more quick to understand the why's behind the decisions being made. We aren't all unsafe idiots. :)
 
It is hard to understand when a car tire will work on a bike and when it won't. But, there are circumstances when it will.

Given the bike I have and the way I ride I will stick to MC tires. But, if I had a land barge I'd definitely make the switch. And, yes, we engineers can be a picky bunch :)
 
Rmcapozzi said:
The main problem is I was running the bike at or very near the max load limit for the tire.
Click to expand...

I don't care what other people do with their bikes. They're adults; they can make their own decisions.

I am curious about those 3 failures. What tires were they? And what were the load limits of the tires?

I agree that it is umm ... sub-optimal to run things at their limits.
 
Tattoo Paul said:
One other thing to consider about a car tire on a motorcycle - traction.

One of the reasons a car tire lasts so long on a bike is the rubber compound. Harder rubber = longer wear, but harder rubber = less grip as well. Remember, on a car, you have more weight per square inch of contact pattern with the road, and you have four contact patches.

For me, if I had to 'cheap out' on something on the bike, I know it wouldn't be the only thing that connects the machine to the road.
Click to expand...

Just a note: With my Prius (not exactly known as a muscle car) I can spin a tire easily starting on wet pavement. Take it for what it's worth.
 
FWIW your Prius has a bunch of torque at 0rpm. Electric motor. I'm surprised you can't spin a tire on dry pavement.

The biggest difference would be in hydroplaning so slowing down when in rain would be prudent.
 
Rich said:
With my Prius (not exactly known as a muscle car) I can spin a tire easily starting on wet pavement.
Click to expand...

Betcha' a nickel that Prius tires are designed for low rolling resistance rather than high traction. Just guessin'.
 
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