Work Boots or Sneakers 2

work-bootsRyan still hasn’t returned from his trip to the states, so I haven’t had time to be de-briefed in detail… but via a short conversation he did present something that may be a problem with his current set up.  It is typical for fast auto-x cars to run stupidly large rubber.  An auto-xer can get away with it more so than another auto racer because auto-x is void of long straights and high speeds where drag is a hindrance.

The downside of running enormous rubber in auto-x however… is WIDTH.  Ryan’s competition is the fastest full interior cars on the continent.  They out power him, usually weigh only marginally more and always have more rubber, so what chance might he have?  He’ll be the first to admit he isn’t out driving anyone.  Against the likes of Vipers, Vettes, and FD’s his advantage should be size, but the currently enormous rubber has nullified that.

I’m a nerd so… I did some math and calculated exactly how much of an advantage being SMALL can be through the cones.

slalomsheetThe math isn’t too complex on the surface.  It’s based on the path traveled by the car through a slalom having the same shape as a SINE curve.  The vehicle travels a constant speed throughout the length of the slalom, and that speed is calculated based on the MAX. achievable lateral G’s.  The current model makes a couple basic assumptions about car attitude, but I believe it to be a good simulation.

On a fairly fast slalom, it indicates that cutting overall width by 4″ can cut split times by about 2-3% and increase overall speed by 2km/h.  Of course… the tighter the slalom, the more the advantage observed.  I still haven’t seen any video from Ryan’s runs in Wendover… but I have seen the course via other video.

See why a couple of tenths in slaloms is not a minor thing? Look for Ryan to be playing with some narrower front rubber in the future.

PS.  The Kiesel Sprite is something else entirely.

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2 thoughts on “Work Boots or Sneakers

  • Van

    Narrower is good. Fortunately, the 275/15’s on a 10″ wheel is marginally wider than a 255/13 on a 10″ wheel.

    That’s good info to know from your math/graph.