Yamaha XC155 (SMax) thread

Discussion in 'Battle Scooters' started by Chillis, Aug 28, 2014.

  1. aguim

    aguim Been here awhile

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    Sorry, pushed the wrong button...but came back.
  2. Nick113

    Nick113 Adventurer

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    What brand of tire was that? Enough clearance on sides, to clear a swing arm and stuff? In other words you did like it and 250 RPM drop was icing on a cake?
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  3. klaviator

    klaviator Long timer

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    For the most part I agree with what you said about adapting to different bikes and/or tires but I have had some tires that just didn't work that well. They were never so bad that I didn't ride them until they wore out but then I replaced them with something different.

    I will be watching to see how the larger size tire works out for others. The biggest plus of a larger tire for me would be more cornering clearance and therefore higher speeds in the curves. The first thing to drag on the Smax is the swingarm which is fairly far back so a taller rear tire would definitely help.
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  4. Nick113

    Nick113 Adventurer

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    Interesting Mathematics...
    130/70 tire including robber has 512 mm in outer diameter total. 512mm X 3.14 (pi) = 1,608 mm distance traveled on each revolution.
    150/70 tire including robber has 540 mm in outer diameter total. 540mm X 3.14 (pi) = 1.696 mm distance traveled on each revolution.
    Interesting enough, for 130 tire to cover distance of 1 mile it takes 1000 revolutions. Or 100,000 rev. to travel 100 miles.
    For 150 tire, to travel 1 mile it takes 943 revolutions. Or 95,300 rev. to travel 100 miles.
    It's just funny mechanics, but to complete 5K on tire, the 130 tire needs to revolve 5,000,000 times. While 150 tire will need to revolve 4,715,000 times.
    Lol, 285,000 revolution saving! Cool... LOL!
  5. aguim

    aguim Been here awhile

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    Well, that was 2 years ago, so I can't quite remember the numbers...but was very pleased with the RPM drop. I now have a Forza, also with a slightly bigger rear -- slightly screwing the speedo readings THUS rev drop estimations !.
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  6. Nick113

    Nick113 Adventurer

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    Great, thanks. Do you recall by any chance any clearances problems? Has anything gotten your attention? Especially on sides, due to wider tire, you know... Anything?
    Thanks for your advice...
  7. Nick113

    Nick113 Adventurer

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    Maybe the brand name?
  8. aguim

    aguim Been here awhile

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    I'm 25% absolutely sure it was a Metzeler...see, I don't really pay attention to 'tyres' (I'd
    use anything that fits/ looks good --yet not cheap).

    In 40+ years of riding bikes, never even scratched a peg...
  9. aguim

    aguim Been here awhile

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    I'm also fascinated with maths :

    Somebody calculated that, given the quantities of rubber dust left on roads since tires
    exist, we should be covered miles deep with the stuff. Yet, this hasn't happened. What was wrong with the maths !
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  10. minimac

    minimac Been here awhile

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    I don't recall anyone saying anything about a 150 front tire. If there's room for it to fit on the rear, the effect will be exactly as I stated earlier, unless the front tire is also increased in size. It acts almost as though it "overpowers" the front slightly. It's not as dramatic as it sounds, though , and the change in handling is easily and quickly adapted to. I would guess that most riders won't notice it. If there's room for a 130 front, go for it. Just be mindful of clearance at full suspension travel.
    Without going into the full darkside thing, a car tire on the rear is actually a softer compound(because of the silicates) than almost all bike tires. That's why darksiders rave about the better handling-wet and dry-even though it gets at least twice the mileage and puts down a bigger footprint. Using the tire calculator I posted earlier, you can get a good idea of the various sized tires. Using a car tire for the rear also gives you the option of 60,65,70, and 75 series tires.
    Because I wanted to slightly drop my rpms on my Majesty(mainly interstate travel),I went to a slightly taller car tire on the rear. I also changed my rollers to lighter ones, so my performance from a stop remained pretty much the same. The handling changes I described are based on my own experience. I now have almost 20K miles on the rear tire and it still has between 1/2-3/4 thread left.
    If your happy with stock sized tires that's fine. I changed mine to fine tune for the way I ride.
    DISCLAIMER: I'm not trying to convince anyone to darkside. I post only to show there are other options and my results.
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  11. Nick113

    Nick113 Adventurer

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    Going FULL DARK SIDE? This seems to be good option. A car tire 155/70-13 ... There is also 155/80 ... I'm wondering if it fits...

    Here is the compare chart of our tire 130/70-13 to 155/70-13 Nice numbers!

    Tire Size Comparison(2).png
  12. Nick113

    Nick113 Adventurer

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    Here is the option that has been already successfully tried by a few inmates, worked great for them! I'll go 150 rear my next tire change!

    Chart shows it will cure the speedo issue nicely! Great. Compare chart 130/70-13 to 150/70-13 ... It gives about 4 MPH more at same RPM! Sweet.

    Tire Size Comparison(1).png
  13. minimac

    minimac Been here awhile

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    My Majesty came with a 150/70/13 rear tire. I'm currently running a 165/65/13 car tire which is very close to the 150, much closer than the tire you show. The tire you chose is probably way to tall to consider. One other 'benefit', if you will, is a much greater loading capacity compared to a bike tire. I've run this on the Tail of the Dragon, and the Back of the Dragon without any issues. You don't 'fall off the edge' of the tire, you'll scrape everything first- besides,if you look at a worn bike tire-it's almost flat across. You don't want a car tire on the front, though.
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  14. Nick113

    Nick113 Adventurer

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    You're right, 150/70 rubber is 105mm tall, 165/65 rubber is 107.25mm tall. Not much of a difference in terms of changing RPM much. Just bigger contact patch.
    BTW, I wish I knew if 155/80-13 car tire would fit, I swear I'd try it just for the sake of it! I like trying new things...
  15. minimac

    minimac Been here awhile

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  16. Nick113

    Nick113 Adventurer

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  17. minimac

    minimac Been here awhile

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    Look carefully! That's the price for four tires. Thirty seven and forty three is hardly going to break the bank! :)
  18. Nick113

    Nick113 Adventurer

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    Oops, my bad, that was price for 4. They're not expensive at all. Now how do I find out if they fit ... 64K question.
  19. minimac

    minimac Been here awhile

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    Lets take this to a conversation......I'll start.
  20. Nick113

    Nick113 Adventurer

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    Any info on "dark side" tires air pressure differences? Smax is obviously much lighter than a car. So, tire pressure must be adjusted accordingly. Any info on that?