Car Tires - Debate

Tombstone

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I have waaaaaay over 100,000 miles on DS tires on 2 cruisers and 1 V-Strom. If the current test works on the S-10 I'll be putting one on that as well.

Carry on.
 
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ericv, the urge to tell others that what their doing is wrong is not any different than the darksiders preaching car tires are the way to go..... and I'm not really saying its wrong as much as I'm saying its unsafe .... and I don't have to experience jumping off a "cliff" to know that jumping off a "cliff" is dangerous ..... people do that too and most of the time most get away with it ..... some don't. I believe you and I believe your experience on the subject , doesn't make it safe ..... that you and your fellow darksiders are good at it also doesn't mean others will be... I wished we lived closer , I would buy you a cup of coffee , it could be interesting .... have two son in laws who are structural engineers.... I work for a construction company , I'm around engineers all the time.... time to get ready for work , got to save money for a new set of tires don't you know...... bought shienkos last go round saved a ton of money , pretty good tire.... if your ever in Austin or Buda area let me know , I will buy you a BBQ lunch .
 

Checkswrecks

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Tombstone said:
I have waaaaaay over 100,000 miles on DS tires on 2 cruisers and 1 V-Strom. If the current test works on the S-10 I'll be putting one on that as well.

Carry on.

Tombstone -
The Tenere and Strom have the same spec rim profile, which also is shared by others. With all those miles you may already be aware that there is a very slight difference between the bead area of the bike and car rims, with the bike rim having (iirc) something like 5 millimeters less contact. For that reason, the car tire is not recommended (I personally have no experience doing it on a Tenere). At the same time, there are many years of experience like yours on the Strom and folks here with the Tenere, and I'm sure you are aware of the depth of Iron Butt experience.




Eric and Madhatter - Thanks for keeping it civil.
 

Tombstone

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Madhatter said:
ericv, the urge to tell others that what their doing is wrong is not any different than the darksiders preaching car tires are the way to go.....
The only threads I've seen where DS v MT merits has been 'discussed' is when folks start saying DS won't work. Personally I've not seen a thread where a DSer has been preaching, but only defending.

Checkswrecks said:
With all those miles you may already be aware that there is a very slight difference between the bead area of the bike and car rims, with the bike rim having (iirc) something like a millimeter less contact.
I'm aware that "it won't work" has been repeatedly said by numerous experts... But it works just fine.
 

Checkswrecks

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Found where I'd dumped the data and it's in Post # 75 of this very thread! You can go there to see the profiles of the respective wheel flanges and some data. As related by EricV, Tombstone, and others (includes me) handling is not an issue. http://www.yamahasupertenere.com/index.php?topic=16401.75

The technical reason why car tires will work is that the bead dimensions of the wheels are only 5mm different. The 5mm missing from the MC rim is from a dimension which assures a car tire will not unseat the bead when pressure is lost. A LOT of testing is involved in getting products to meet NHTSA and international standards. This is not to say that a car tire WILL unseat on a MC with low pressure, just that there are no known test results which show how the missing 5mm will affect the bead's ability to either retain or prevent unseating.

So the two bottom lines that I see are:
(1) Using a CT involves an assumed risk, which everybody running CTs is already extremely aware of.
(2) If using a CT on a MC wheel, then do not to let the air pressure get low.
 
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I've had a MC tire (Shinko 805 rear big block) pop the bead on my Tenere when air psi got low. On a twisty mountain road nonetheless, definitely a pucker up moment. Very hot day and the sidewalls are too soft to begin with.

Maybe I should go darkside as MC tires are unsafe. Lol but didn't crash so doesn't count.

Seriously though, if a CT could handle rough off pavement I would definitely have already tried one. Not skeered.

Regardless I'm interested in what mileage sallydog gets from that 175 CT.

Sent from my SM-G860P using Tapatalk
 

cjclint

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Yelloewolf said he could ride the dragon faster WITH a car tire. I have used run flat car tires (195-55-16) on my goldwings for 160,000 miles. Twice rode home with a flat on a rear tire, once for 20 miles without problem. Removed tire, patched it inside and continued to ride on it another 500 miles over weekend until new tire came in on Monday. Also use a run flat on a harley ultra. The correct run flat darkside tires are a good choice for heavy goldwings and harleys.
 

EricV

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Checkswrecks said:
Found where I'd dumped the data and it's in Post # 75 of this very thread! You can go there to see the profiles of the respective wheel flanges and some data. As related by EricV, Tombstone, and others (includes me) handling is not an issue. http://www.yamahasupertenere.com/index.php?topic=16401.75

The technical reason why car tires will work is that the bead dimensions of the wheels are only 5mm different. The 5mm missing from the MC rim is from a dimension which assures a car tire will not unseat the bead when pressure is lost. A LOT of testing is involved in getting products to meet NHTSA and international standards. This is not to say that a car tire WILL unseat on a MC with low pressure, just that there are no known test results which show how the missing 5mm will affect the bead's ability to either retain or prevent unseating.

So the two bottom lines that I see are:
(1) Using a CT involves an assumed risk, which everybody running CTs is already extremely aware of.
(2) If using a CT on a MC wheel, then do not to let the air pressure get low.
I've seen that before, from the engineer friend of mine that wrote it all up. {side note, he was running a CT on his Wing because of concerns over the load limits and heat. He later changed back to a moto tire when he stopped running two up loaded for rally riding and was just poking around more.}

What's not really discussed is that rubber molds to the shape of the rim and that the CT sits deeper on the bead area on a moto wheel. I have personally experienced a flat, (non-run flat), CT on the bike at various speeds a few times. You need to pay a bit more attention to the symptoms of low pressure/no pressure, but it becomes apparent as a weave. Not severe and there was no danger of the tire coming off the wheel in my personal experiences. Or any loss of control. I know of several others in the FJR Darksider group that have experienced flats and none felt things were scary, just slowed down, dealt with the flat or in one case, rode on the flat tire until they got home. That tire was toast, having inside side wall damage from the extended running w/o pressure.

My personal option in mounting a CT to a moto wheel, with the 205/50-17 size used on the FJR, is that it's simply not coming off unless you take it off. It's a good bit of effort to get it on in the first place, though seasoned tire changers argue it's no worse than heavy sidewall cruiser tires.

Worth mentioning here is the dynamic that occurs when you lean the bike with a CT mounted. At lower lean levels the tire deforms into an eliptical shape, with all of the tread staying on the ground. When you lean far enough over to exceed the ability of the carcass to deform, a couple of things happen simultaneously: The tire goes back to a round shape, the outside of the tread lifts up and this raises the back of the bike. This is important to understand because at this exact moment, you would expect to feel resistance to turn in. You don't, because as the bike rear lifts, that steepens the rake and quickens turn in, in actual effect, canceling out the increased resistance to turn in when the tire transitions from elliptical to round. None of this is felt by the rider. Just smooth turn in all the way over.

It's still possible to drag pegs, but most riders that go DS aren't riders that drag pegs to begin with. Nothing dramatic occurs when you ride the bike hard, aside from accelerated wear to the edge of the tread. More normal, or shall we say, less aggressive riding results in typically very even tread wear accros the tire. I was getting 40k from CTs running all season tires with tread wear ratings in the 400 range.

I look forward to seeing what kind of tread wear sallydog gets. Too bad there isn't a broader selection in this size. I have already investigated the possibility of running a 205/50-17 tire, but it's not possible to do this on a wheel wide enough for that tire and I personally am not comfortable running the tire on a narrower rim than it's rated for. This new tire is rated to fit the rim width of the Super Ten. Hope it wears well.
 
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EricV said:
I look forward to seeing what kind of tread wear sallydog gets. Too bad there isn't a broader selection in this size. I have already investigated the possibility of running a 205/50-17 tire, but it's not possible to do this on a wheel wide enough for that tire and I personally am not comfortable running the tire on a narrower rim than it's rated for. This new tire is rated to fit the rim width of the Super Ten. Hope it wears well.
Are you talking about the Achilles Economist 175/55r17
 

EricV

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ace50 said:
Are you talking about the Achilles Economist 175/55r17
Yes. Its rated for a 4.5" wheel, as I recall. The 205 width was rated down to a 5.5" wide wheel.
 
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I used a 205/50/17 on my 2011 FZ1 for 30,000 miles without any issues. It was nice having rear tires last longer than fronts. It did miles of burnouts over all types of off-road terrain, and handled just fine well above posted speed limits on Pocono Mountain twisty roads.

If anyone has a genuine interest in trying a car tire and has questions please shoot me a PM. My results are anecdotal, and I don't recommend or advise this practice.


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