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  • Darksider Tire Change!

    Well, one of my ongoing projects that's about to get wrapped up goes back to July 2011 when I crossed over to the DARK SIDE and put a car tire on the back. What follows will be the updates, performance notes and progress on this until my next tire.

    7-7-2011
    Well, after eating up four Dunlops at 11000, 8000, 6000(loose spokes), and 10000 miles, I figured it was time to take a trip to the dark side and try a RADIAL car tire on the back. Ordered an Excelsior Stahl 5.50R16 radial tire from Coker Tire, a Metzler tube and a pair of Motion Pro 11" Tire Irons. A couple of big screwdrivers and my old trusty Matco pry bar came in handy, too. Getting that last bead on is a four-limb/full body operation! There are probably some very good reasons why you might want to change a tire yourself without the help of modern machines, but don't let the fact that I can't think of any right now encourage you. Seriously, though, I will say that I'm not so scared at all to do it again. It just takes a couple of extra hours, that's all! Overall, I was done in about six hours, but I wasn't in a hurry. It takes a lot longer to break in a car tire, so I took it real easy on the ride to work this morning. It feels a little squishy right now, but I'm probaby too far under pressure. Most guys are running 29 to 34 PSI in these, but this tire calls for 41 PSI max.

    This is what the Dunlop D401 looks like after about 9000 miles...




    Dunlop still pressured up on the wheel, so the new tire looks much taller in relation than it will actually be. Still, I will probably get a 5.00R16 next time...




    Bead breaking with a 6" vise.




    Better comparison with both tires off.




    Excelsior Stahl 5.50R16 - beads seated at 59psi







    Last edited by Furcifer; 1 week ago.
    "Gunfighting is one part technique and three parts attitude. It is the man, rather than the gun, that matters." -Col. Jeff Cooper, U.S.M.C.(ret.), Founder, IPSC

  • #2
    Now, I'm not "advocating", I'm just relating my experience with an alternative that many riders have had pretty good experiences with. Nobody has all the facts on this - especially not the tire companies who must cover their legal asses even if they had actually done testing, which they HAVE NOT... These are the facts we do have:

    Motorcycle tires are a niche market. Yes, they are made for motorcycles, but that's about all we can say for them. They don't enjoy ANYWHERE NEAR the R&D $$$ that goes into car tire development. That said, while it's true that car tires are not made with motorcycles in mind, they ARE, however, made for a WIDER variety of applications and road conditions, and specifically, to LAST a LOT longer.

    Every decision made in tire construction is a trade-off, and the primary trade-off made in motorcycle tires is to match production costs with market demand, which is nowhere near the demand in the car tire market. Other trade-offs are not under our control - those decisions are being made FOR US. So would we really be surprised to find out that motorcycle tires are designed to wear out around 10,000 miles, specifically to help maintain sales volume, and really for NO other reason? Once compounds and construction are "good enough", the rest is a business decision. This 10,000-mile norm has long been established, so why on earth would they offer a better tire that would necessarily reduce long-term (volume-based) profits, when it's already a low-volume market?

    Consider the evidence we have: Car tires can last THREE TIMES longer, or more, even when they are installed on motorcycles. If motorcycle tires are so great for grip or if this "softer vs. harder" rubber myth had any evidenciary merit (durometer tests say otherwise), then you should be able to put motorcycle tires on a small car and run like you're on rails. But while nobody is doing that (not even a niche racing series), hundreds of bikes ARE running with car tires, and running well? Hmmm. Something tells me that the manufacturers CANNOT have been telling us the whole truth and not just because they don't really know it! On the performance side, we're led to believe that these Metzelers, Avons, Pirellis and Dunlops are about the best in performance and handling that can be had in a street motorcycle tire, but how do we really KNOW, except by seat of the pants (and money out of our pockets)?

    Conclusion: THEY COULD BE BUILDING A MUCH BETTER MOTORCYCLE TIRE, BUT THEY JUST AREN'T DOING IT. They're getting over on us!

    So why don't racers use them? Specifically, I think we can acknowledge a few known facts about the trade-offs there, too, and infer an explanation: A racing tire only needs to last the length of a race, run on flat track (near-perfect) conditions, and accommodate the max lean angles of racing bikes (60 degrees vs. 30 degrees max of a Harley). Now, does somebody want to make the case that Metzeler 880's or Dunlop D401's are the best choice for racing tires?

    I'm not claiming that a car tire will be the BEST choice for performance in the twisties, but then neither is the bike I'm riding, hmmm? I'll freely admit that the different feel of the car tire takes some getting used to, and I'm committed. I'm testing to see if the handling is comparable to justify the increased mileage, but some major OTHER significant safety and handling advantages have also been identified: Braking and wet road performance is MUCH BETTER!

    At full lean at a track day - you can see that half the tread stays on the road, and the contact patch is actually the same size as a motorcycle tire, and even larger when the bike is straight up. This is probably why braking is so much better... Also, NO sportbikes passed me on that track day, LOL!

    Last edited by Furcifer; 2 weeks ago.
    "Gunfighting is one part technique and three parts attitude. It is the man, rather than the gun, that matters." -Col. Jeff Cooper, U.S.M.C.(ret.), Founder, IPSC

    Comment


    • #3
      The long-awaited and much-anticipated anti-climactic limited-edition director's-cut Darksider Tire Movie!!!!!



      UPDATE 09JAN2012:
      And as you can see and will be able to see if you click on one of the similar films on youtube done with a motorcycle tire, the contact patch of this particular car tire is a bit larger than a motorcycle tire, keeping at least half the tread pattern on the ground at all times (while ALL of it is available for braking!), while a motorcycle tire is designed to only use about a third at a time. The tire doesn't have as much flex as it feels like to me when I'm riding on it, but also, as you can see, the tire DOES NOT roll up on the sidewall. I can testify that I've been riding it for enough miles now that if concrete had been scrubbing on the sidewall any at all, I would be seeing evidence of it on the side of the tire near the edge of the tread, and I'm not. As most who have ridden with me know, I live to scrape my boards off, so rest assured that max lean angle of my bike is regularly achieved, at all speeds. In fact, near the end of the video, I was cornering and hit a bump that compressed the suspension enough to hit the camera, which remains at a slight angle until the end.

      Now, the video is a bit longer than I should have required to make the point, but I've been desperate to get this done for months now, and Hawaii traffic, as I've often complained, makes doing anything like this nearly impossible. I edited out over 15 minutes of sitting at traffic lights behind brain-dead idiots who want to stare at the green light for 10 seconds before they pull their heads out and get the hell on, as it is...

      (I shot this with my new GoPro Hero2 camera and edited with MP4Cam2AVI v2.98 and VirtualDub 1.9.11 to maintain at least 720p.)
      "Gunfighting is one part technique and three parts attitude. It is the man, rather than the gun, that matters." -Col. Jeff Cooper, U.S.M.C.(ret.), Founder, IPSC

      Comment


      • #4
        In the interest of full disclosure, what follows were some responses in 2011 from some of the motorcycle tire manufacturers, and most of it is to be expected from people who have a business interest in people NOT doing this, especially since they haven't actually tested any of this. The bead question you will see mentioned has been argued before on other sites. Some Darksiders have clay-molded their bead seats and compared them to candidate tires to ensure good seating. Basically the fairest answer I can give is YRMV, depending on the tire. A LOT depends on the particular tire, particular wheel and particular bike. That's why there's the Darkside Database, listing hundreds of these combinations. That said, the belt separations, bead slippage or blistering have yet to manifest themselves in the form of any measurable failure trend by actual Darksiders. My beads seated at 59psi and I run a tube as well, so, no problems with bead seating here. On the contrary, I've read elsewhere that most people who have been through a couple of these car tires only changed them out because the tire got OLD! What is really laughable are the claims of a reduced contact patch and poor grip in wet weather conditions, when we have reports from riders and now actual video (above) that clearly demonstrates the exact opposite of these biased and unresearched claims:

        From Avon:

        Great question!

        The 2 major differences is if you are putting a car tire on a bike wheel, the beads are different sizes and the wheels have different rim flanges from a car wheel to a bike wheel, so it may stay on but not safe as it is loose. Also the load belts and the way the tires are wrapped are way different so it could cause long term problems like blistering, separations etc… Hope this helps!

        Thanks,
        Shaun Sparks
        Mickey Thompson Tires & Wheels
        Avon Motorcycle Tires North America
        Technical Support
        PH: (800)-222-9092
        Local: (330)-928-9092


        From Dunlop:

        Good morning
        Thank you for taking the time to contact us with your motorcycle tire questions.
        While we don't have a reference for a book that contrasts the two different constructions, this is considered a bad practice.
        The geometry of a passenger car radial (PCR) rim is different from that of a motorcycle (M/C) rim. Mounting a PCR tire on a M/C wheel would increase the chances of bead dislodgement. Typically, a PCR tire would use three or four compounds while a M/C tire would contain seven or eight. The M/C tire requires these specialized compounds for its unique application. Most certainly, the rider would sacrifice wet weather performance. The biggest risk would be performance at camber. The relatively flat PCR profile would exhibit poor handling compared to a M/C tire. The M/C tire profile is specifically designed to provide a large foot print at all camber angles. Again, the reduced foot print of a PCR tire at camber will reduce the size of the contact patch and result in reduced grip. This reduced footprint would be quite dangerous, especially in wet conditions. There are also a multitude of other performance criteria that have never been evaluated as it is just too dangerous to conduct a actual vehicle test. Chances are there would see a substantial degradation in high speed stability both in straight line and camber with a PCR tire.

        Unfortunately, we don't have a specific book or web site that you can consult for additional information.

        Should you need further information or assistance, please call Dunlop Consumer Affairs @ 800-845-8378

        regards,
        Virginia Gallant
        Consumer Affairs Representative
        Consumer Affairs
        Dunlop Motorcycle & ATV Tire Division

        Goodyear/Dunlop Tires N.A., Ltd
        PO Box 1109
        Buffalo, NY 14240
        Ph: (800) 845-8378 Fax: (716) 879-8425

        from Shinko Tires:

        I know of many people that have run car tires on their bikes, I don't think the risks are worth the extra mileage.
        Car tires are much harder than motorcycle tires; a motorcycle needs a softer compound tire for good traction (much less weight on a motorcycle tire, so they need to be much softer/stickier).
        The other main issue is cornering. A car tire has a very flat/square profile and will corner horribly compared to a rounder profiled motorcycle tire. If you were only going in a straight line I could make a little bit of a case for a car tire.

        Our purchasing manager put a car tire on the back of his Valkyrie, he took it back off within a few hundred miles. He hated the unsure feeling in the corners. He rides a lot and has put about 85,000 miles on his bike since he bought it.
        I hope this helps with your decision.

        Thanks,
        Scott Casper
        Western Power Sports
        Street Product Manager
        Shinko Tire Tech and Development
        601 E. Gowen Rd
        Boise, Idaho 83716
        Phone (208)376-8400 ext. 3404
        Fax (208)375-8901
        "Gunfighting is one part technique and three parts attitude. It is the man, rather than the gun, that matters." -Col. Jeff Cooper, U.S.M.C.(ret.), Founder, IPSC

        Comment


        • #5
          UPDATE, Date of post 26AUG2015:

          The tire is now officially below the tread markers on the tire. Performance feels at least as good as a motorcycle tire, although not as great as it was when the tire was new. Current mileage on the tire is 15,000 miles. Previous 4 Dunlop 401 motorcycle tires (OEM application) averaged 8875 miles each. 15K is less than I was hoping for with a car tire, HOWEVER, I discovered that loose spokes had been a contributing factor for wear, for at least 2500 miles - maybe more. The car tire was transferred over to a new aftermarket spoked wheel at 8300 miles. I know from experience that loose spokes will scrub off a tire quickly and reduce overall tread life by almost half, so I can't be sure how much I lost, but I would guess at least 3K or so.

          It has been suggested that the bike's performance mods combined with additional tire height and better traction (reduced slippage on acceleration) may be contributing to the loosening of spokes. I'm sure the CRAP HAWAII ROADS also have a tendency to beat the spokes out of ANY bike... The former factors, anyway, is why a lot of high performance bikes use solid wheels on the rear. Since a somewhat shorter (but still taller than the Dunlop 401 150B16) tire size is now available, I intend to replace the tire with the shorter, fatter size, and possibly change to a solid wheel on the rear if I can find one I like... But I'm not doing that until I move to Texas! Even running on less than 1/32" tread in the center, the tire hooks up great, and is still better in the wet than a motorcycle tire. Given the wear trend, I could easily go another 1000 miles and it still won't look like the Dunlop posted at the top of this thread!
          "Gunfighting is one part technique and three parts attitude. It is the man, rather than the gun, that matters." -Col. Jeff Cooper, U.S.M.C.(ret.), Founder, IPSC

          Comment


          • #6
            Tire wear.


            I was talking to a Dunlop sales rep about the mileage I was getting on the rear tire on my 03 Sportster or 07 Heritage. (8,000 to 11,000). He asked me what PSI I was running and I told him exactly what the Harley manual states. He said they state a lower PSI for a better ride,run the PSI rating on the sidewall ,that is where the tire was designed for. He said Dunop doesn't make motorcycles and Harley doesn't tires. The lower the PSI ,the hotter the compound gets and the faster It wears. I picked up 4,000 miles per tire.

            Comment


            • #7
              Okay now.

              This might be one of the most interesting threads on tires on the internet.

              Practical experience outweighs theory any day of the week. Thanks for sharing.

              I always was under the impression that the round shoulders of motorcycle tires was for traction in leans an turns. The sharp corners of car tires would cause less traction in leans and "falling off" of the shoulders was a real possibility.

              I know a couple of riders who went to the dark side and came back fairly quickly. Perhaps they chose the wrong tire for their application?

              Fast forward to today:

              I added a sidecar to my Ultra and I will switch to a car tire when this Elite 3 wears out. With no real lean issue anymore, on my rig, just the promise of the extra mileage is very attractive. Braking surface and wet road stability are obviously pluses as well.

              I ride 12 months out of the year and on all types of road surfaces. Some of my "trips" are 10-20 miles and some are 4,000 +. When you are on the road much at all you run into all types of scenarios and I can see the benefits in my application.

              Thanks for the info.

              Comment


              • #8
                Originally posted by Dinero View Post
                Okay now.

                This might be one of the most interesting threads on tires on the internet.

                Practical experience outweighs theory any day of the week. Thanks for sharing.

                I always was under the impression that the round shoulders of motorcycle tires was for traction in leans an turns. The sharp corners of car tires would cause less traction in leans and "falling off" of the shoulders was a real possibility.

                I know a couple of riders who went to the dark side and came back fairly quickly. Perhaps they chose the wrong tire for their application?

                Fast forward to today:

                I added a sidecar to my Ultra and I will switch to a car tire when this Elite 3 wears out. With no real lean issue anymore, on my rig, just the promise of the extra mileage is very attractive. Braking surface and wet road stability are obviously pluses as well.

                I ride 12 months out of the year and on all types of road surfaces. Some of my "trips" are 10-20 miles and some are 4,000 +. When you are on the road much at all you run into all types of scenarios and I can see the benefits in my application.

                Thanks for the info.
                Awesome! And you're welcome! YES, one of the main, up-front points I must stress is that results can vary as widely as the variety of car tire/motorcycle combinations, which is probably a hundred times more varied. I must also say that the feel is quite a bit different, and I was not real happy with it at first - it took some getting used to, but now that I have ridden this way for almost 4 years now, I have tested the limits of the bike and tire combo and found greater capability than I had with a motorcycle tire. I would speculate that a different car tire would also feel quite a bit different from what I have. BLUF: You will pretty much get guaranteed results with a motorcycle tire; this endeavor is for people willing to try for something more and accept the risk of just not liking how it feels.

                The only thing I have not fully tested - being in Hawaii - is long-term highway stability at speeds over 85MPH. Since I never get much over 70MPH in Hawaii and the roads are crap, the car tire has been perfect for me here. I only got to ride in Florida with it for a brief period early on, and there were issues with loose spokes that were unknown to me at the time, causing a wobble, so I have to throw out that data. I would guess that the RIGHT car tire/motorcycle combo would be GREAT on the superslab.

                The sidewalls flex a lot on a car tire, unlike a motorcycle tire. The squarish tread design flexes well enough as a result. Now, sportbikes leaning over 60 degrees in the corners might have some concerns, but 2006 - 2016 Harleys have even less SAE max lean angle than my 2005, which is just over 30 degrees.

                For those cruiser riders that have "tried it" and gone back, I would submit that they have more likely just not tried quite enough, because there are just so many more different tires/combos to try and there is a significantly longer break-in period as well.
                "Gunfighting is one part technique and three parts attitude. It is the man, rather than the gun, that matters." -Col. Jeff Cooper, U.S.M.C.(ret.), Founder, IPSC

                Comment


                • #9
                  How's that car tire work, driving up a ramp, into the back of a pickup truck?
                  "Blue skies hangin' over my head, I got 500 miles to ride." - RVZ

                  Comment


                  • #10
                    Wow, seems like trial and error has been tested again. Great review and summary. Thanks for sharing.
                    sigpic
                    Semper Fidelis!!!

                    Ride Free - Ride Safe!!!

                    "AKA" - Terry

                    Comment


                    • #11
                      Originally posted by Wanna Ride View Post
                      How's that car tire work, driving up a ramp, into the back of a pickup truck?
                      Better than a motorcycle tire, but I don't perform those kinds of stunts anymore, LOL!

                      Not doing either one of these anymore, if I don't absolutely have to!





                      Last edited by Furcifer; 2 weeks ago.
                      "Gunfighting is one part technique and three parts attitude. It is the man, rather than the gun, that matters." -Col. Jeff Cooper, U.S.M.C.(ret.), Founder, IPSC

                      Comment


                      • #12
                        Furc, just pulling your chain.
                        "Blue skies hangin' over my head, I got 500 miles to ride." - RVZ

                        Comment


                        • #13
                          UPDATE: Well, one thing leads to another, and I never got around to changing that tire. Anyway, I've got the replacement standing by now, and need to get it over to the shop next week. I fixed all the broken pic links on this thread, so hopefully everybody can see them. For the sake of experimentation and hopefully even better results, I'm replacing the 5.50R16 with a 5.00R16. The 5.50 was, as you can see, quite a bit taller than the original Dunflop. All my "online research" indicates that the 5.00R16 will be a bit shorter, but given that that 5.50 turned out to be a bit taller than the online specs indicated, I'm banking on the 5.00R16 being a closer match and maybe even a smidgen taller than the original tire. The 5.50R16 does have a few scrapes on the sides from minor clearance issues, so I'm hoping I can fully remedy that concern as well. I'll be posting back here with my impressions and results as they come in.

                          I'm also looking at maybe upgrading cams and such things as might help that TC88B keep up with the big-bore bikes that have come out in the last 12 years! It wasn't such a thing on little islands where I couldn't get much over 60 anyway, but the TEXAS superslabs are inevitable and often unavoidable if I decide to go just about anywhere over 30min away. Still it's hard for me to believe she's gonna be a teenager next year!

                          I sure hope some of the old Cycle Chat folks are still checking in here. Maybe it's time to jump-start things around here, and start posting up some RIDES again! I'm working on getting one of these newfangled vid cams that will loop everything, and some other upgraded ride-photography options. Jill and I are also upgrading our comm systems, so stand by for that report as well. (Yes, she still thinks I'm supposed to listen to her, even when I'm riding...)
                          "Gunfighting is one part technique and three parts attitude. It is the man, rather than the gun, that matters." -Col. Jeff Cooper, U.S.M.C.(ret.), Founder, IPSC

                          Comment


                          • #14
                            OK, so, finally got it done. Officially 15,000 miles out of the first darkside tire, however, that was on TWO different wheels due to loose spoke/worn-out original hub. I've already seen loose spokes scrub off a tire and cut the tread life by 40% on a motorcycle tire. So, there's no way to know how much MORE mileage I would have gotten without having the loose spoke problem again and finally having to change wheels. We checked the spokes on the aftermarket wheel before the new tire went on, but I'll still have to keep a close eye on spokes. If I have to change another wheel, I'm looking at going with a solid rear wheel next time!



                            Here's the new 5.00Rx16 vs. the old 5.50R-16. The aspect ratio indicates the new shorter tire might be just a smidge wider. I did have just a little rub mark from some bolts inside the fender on the old tire. This shorter tire may well eliminate all the rub. It's still a bit taller than the 150/80B-16 original motorcycle tire, which is what I was hoping for. Going by online conversion charts, etc., it might have been a bit shorter, which is why I went with the 5.50R-16 the first time around.



                            Since we're here, I figured I'd also compare it to the new Shinko tire I'm gonna try on the front.





                            All Done!






                            "Gunfighting is one part technique and three parts attitude. It is the man, rather than the gun, that matters." -Col. Jeff Cooper, U.S.M.C.(ret.), Founder, IPSC

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