Going to the Dark Side

garyahouse said:

Run Flat tires? Good grief, absolutely not. One thing i know about run flats is that they ALL have significantly stiffer side walls than regular tires. They're made that way on purpose. Maybe the Wings, with their 950 lbs of vehicle weight aren't as much affected by super stiff sidewalls. However, this is exactly what I DON'T want in a CT. The beauty of the Exalto that many of us run is that the side walls flex as well as they do. It's made to do this and it does it very well. That's why it feels as much like a MT as it does.
One thing about Run Flats that you might not know: when they are actually driven on... while the tire is flat, every reputable tire shop that I know of will refuse to patch, plug, or repair them. Their reason? I was told that once they've been used while "flat," there's a question about the integrity of the tire and it should be discarded. The sidewalls are designed not to flex, and when they are forced to do so because of being run while "flat," they should be replaced rather than repaired. I'm guessing that this has to do with research done by tire companies and/or insurance companies and their endless preoccupation with anything that could cause a lawsuit. Who knows. I don't know what kind of results Wingers are having with them, but from a safety standpoint, I would wonder. From a cornering standpoint, I'd think that they would not be a good choice for the lighter FJR.

Flex is your friend.

Gary

darksider #44

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Flexure of the rubber in the sidewalls is an important aspect of tire design and a tire flexes with each rotation. The flat spot at the bottom contact patch of the tire is deflection of the sidewall, so as the tire rotates, the flat spot and location of max sidewall deflection will change. Real fast!

Rubber molecules essentially slide next to each other, creating heat. The problem is that rubber is also an extremely poor thermal insulator and will retain the heat in the sidewall construction, so overflexing from the designed amount results in heating of the sidewall rubber. Tires with thinner sidewalls (non run flats) have less thickness for the cross section of rubber thickness and so they hold less heat. For the thicker sidewalls, every rotation adds to the heat and it's not hard to exceed the temp where the rubber loses strength.

For example, the hottest part of your tire is normally where the tread contacts the pavement and after a "spirited" twisty ride, you may find two indications of heat. First, the rubber will take on a blue tint in the sin, then little balls of rubber will form at the edges of the tread. Pinch a couple and you can see that they generally are like thickened or resolidified goo.

The fabric plies are the strength of any tire. The rubber not only seals the air in the tire, it also is the "glue" that holds the structural plies together. So if the rubber gets hot enough that the plies aren't held perfectly together a tire will generally fail dramatically, as opposed to the nice slow release of pressure from a small hole.

Example: When this Learjet lost the four main tires in 2008 during takeoff from Columbia, SC, they had no brakes and went off the end of the runway. That's the runway in the background

https://www.baaa-acro.com/Photos-60/N999LJ.jpg



Pieces of the tires also took out circuits needed for the engine throttle/reverser control.

Welp, I've taken the first step for going to the darkside. Got a General G-Max delivered the other day. It's this one



Local Hoda dealer says he'll mount it, no trouble. Why not? They do it all the time for GoldWings, he says.

Actually I guess I took the 2nd step too. Got a piece 3/16"x3/4" Al flat to replace the rear caliper stabilizer tube but I need to measure/cut/polish it a little. I've sill got a few thousand miles left on the m/c tire on the bike now but hopefully I'll be done with buying them for a while.

RadioHowie said:

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Obviously a photoshop :lol:

.....said the Photoshop expert! :finger:

As hard as it is to believe that this thread continues relatively unabated, and also at the risk of being re-subscribed to it (but I do know how to unsubscribe from it (again)), I just wanted to report (and taunt) that it gave me some small amount satisfaction to help another NERD FJR rider out of his square tire misery by pulling the less than half worn Michelin car tire off of CJ's bike (he's sending it up to Maine for Aroostook to try (that boy has never been quite right) and shodding it up anew with some quality (round) motorcycle tires for his upcoming vacation trip. He was so happy to be light-siding again that he gifted me a tasty bottle of bourbon (Knob Creek) for the efforts.

Keep on darksiding, my friends...

Fred W said:

As hard as it is to believe that this thread continues relatively unabated, and also at the risk of being re-subscribed to it (but I do know how to unsubscribe from it (again)), I just wanted to report (and taunt) that it gave me some small amount satisfaction to help another NERD FJR rider out of his square tire misery by pulling the less than half worn Michelin car tire off of CJ's bike (he's sending it up to Maine for Aroostook to try (that boy has never been quite right) and shodding it up anew with some quality (round) motorcycle tires for his upcoming vacation trip. He was so happy to be light-siding again that he gifted me a tasty bottle of bourbon (Knob Creek) for the efforts.
Keep on darksiding, my friends...

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What's CJ's forum handle?

De Oppressor Liber

Thank you. One of the secret Darksiders. We normally use them for tactical work. Aaroostook is #49, so he should appreciate the tire.

Prolly make a swing out of it...

My new Darkside tire, General G-Max pictured above.



And after about 60 miles to scrub it a little



And lastly the minor modification needed for fitment. Removed the tube and replaced it with a piece of 3/4" flat bar. I wire brushed it really well to remove the pickling, cleaned it with alcohol, heated it to about 200*F and applied flat black engine enamel for rust prevention. Used the OEM fasteners on both ends but added a flat and lockwasher.





As is prolly usual for first time Darksiders I thought, "oooh! T'is weird!!" But I quickly got used to the differences:
1) requires a little more effort for turn in. No big deal.

2) tire wants to ride in the middle of the tire rut when present. My only concerns here:
- that's where water collects when raining
- feels like "wandering" but it's really like stabilizing itself position-wise.

3) different slow speed characteristics- much less leaning and more turning the bars. Not a bad thing at all.

I started with 28 psi but it felt a little mushy so I went to 32 psi. Feels fine, actually confidence inspiring. Rock solid at 110 mph on the interstate. Scraping pegs and perfect line tracking in the country. I think all is going to just fine riding and wallet-wise.

Welcome to the Darkside rbentnail. You have been added to the FAQ as Darksider # 64.

The tracking in ruts is one of those things you simply learn to try and stay out of the ruts when possible. It can be especially unpleasant on a deeply rutted dirt road, and the studded tire grooves on some highways. I got into the habit of making sure I was crossing the tire groove at some angle so it wouldn't 'drop in' to the groove.

The wandering calms down after 1000 miles or so as the tire settles into how it's being used. Turn in usually gets easier as well, though you will always notice the difference riding back to back with moto Vs CT.

I hope it meets your needs well and you can ride more with the money saved on tires.

It's a real change going from the Wing with a CT to the FJR with PR2's. Thw Wing reeaallly follows the studded tire ruts. When I go to the darkside with the FJR it won't be such a shock

OCfjr said:

Welcome to the Darkside rbentnail. You have been added to the FAQ as Darksider # 64.
The tracking in ruts is one of those things you simply learn to try and stay out of the ruts when possible. It can be especially unpleasant on a deeply rutted dirt road, and the studded tire grooves on some highways. I got into the habit of making sure I was crossing the tire groove at some angle so it wouldn't 'drop in' to the groove.

The wandering calms down after 1000 miles or so as the tire settles into how it's being used. Turn in usually gets easier as well, though you will always notice the difference riding back to back with moto Vs CT.

I hope it meets your needs well and you can ride more with the money saved on tires.

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FJRay said:

It's a real change going from the Wing with a CT to the FJR with PR2's. Thw Wing reeaallly follows the studded tire ruts. When I go to the darkside with the FJR it won't be such a shock

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Eric hit the "downside of the Darkside" very nicely, and FJRay's comment was spot on.

So far, only my Wing is shod with a CT. I'm on my second (got about 19k miles on my first) and love it. The adjustment only took me about 50 miles and, like Eric said, you learn to anticipate those "special circumstances" and they are no problem.

When I go from the Hondapotamus to the FJR, the first thing I notice is the difference in weight just standing it from the side stand! Once I get moving, memory kicks in and I never have any 'oops' moments.

We got back from a 6 week trip abroad and I was SO ready for a ride. I hopped on the Wingabago first and giggled at how fun it was - it seemed nimble and quick. Then I came back and climbed aboard Lucille... And remembered why Rose spends so much time on the battery tender, and it ain't the difference in tires!

Enjoy!

Ordered a Michelin Pilot Exalto A/S at my lunch hour today. I'm headed to Alaska in less than 2 weeks and don't want to be fuxoring around with tires on the trip.

So I'm going to be giving the CT another try, this time with the recommended tire instead of that POS Cooper I had on the first time in 2010. I won't be doing much twisties on this trip so I can live with the handling. But I'll be taking it off when I return a spooning on a fresh PR3. It only remains to be seen whether I keep it for these long trips, or send it off to find it's mate out on the wilds of our local landfill.

Good thing I left the modified brake stay on the bike

That General G-Max should be good in the snow..

lnewlf said:

That General G-Max should be good in the snow..

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I was thinking the wet . Down our way we're quickly moving into the summer heat so it rains a little nearly every evening. I work the graveyard shift so very often I miss the rain but the roads are still wet.

rbentnail said:

lnewlf said:

That General G-Max should be good in the snow..

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I was thinking the wet

. Down our way we're quickly moving into the summer heat so it rains a little nearly every evening. I work the graveyard shift so very often I miss the rain but the roads are still wet.

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You'll love the Darkside in the wet. You have a metric butt load of traction, it's nearly impossible to hydroplane, and it throws a rooster tail so big NO ONE will tailgate you.

Bungie said:

Ordered a Michelin Pilot Exalto A/S at my lunch hour today. I'm headed to Alaska in less than 2 weeks and don't want to be fuxoring around with tires on the trip.
So I'm going to be giving the CT another try, this time with the recommended tire instead of that POS Cooper I had on the first time in 2010. I won't be doing much twisties on this trip so I can live with the handling. But I'll be taking it off when I return a spooning on a fresh PR3. It only remains to be seen whether I keep it for these long trips, or send it off to find it's mate out on the wilds of our local landfill.

Good thing I left the modified brake stay on the bike

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Good for ya Steve.. It's gonna save you 2 or 3 changes I bet. I know you had issues with the first tire and i hope the "correct" tire works for ya.

Glad to see you at least were willing to give it one more try. Best of luck and times on your latest adventure.

166 pages to discuss a rear tire - wow.