DSCF2501

Comments

Add a comment
  • Elmo Zoneball on 2012-Apr-22 16:53:02 Elmo Zoneball said

    Are modern Xootrs really THAT slow?

    CIA C came off Hill #2 two seconds BEHIND Rubicon v.2.0, which is equipped with Xootrs, and obviously blew past Rubicon before the corner.

    My best estimate is Rubicon was about 6 seconds slower in FR than it was on pneumatics a year ago. Can stock Xootrs be blamed for that, or is there something else wrong?
  • Jerry on 2012-Apr-22 20:37:35 Jerry said

    Short answer: Basically.

    Long answer: Apparently (coming second-hand, as my team has never touched xootrs) the stock compound on the wheels has degraded *substantially* in performance since the early 2000's. Whether or not a team has a stockpile of old xootrs (as Apex did from the Pioneers era, and SAE likely didn't) has actually had a large effect on how they end up rolling

    Ackermann steering is also notoriously difficult to get perfectly aligned (as Mr. Zoneball probably knows) which can cause a buggy to scrub energy all the way around the course. Freyja has been rolling substantially faster after we angrily tore out her Ackermann and retrofitted it with a simple wagon.

    In this heat, Freyja attempted to pass Rubicon on the inside of the corner and hit against the curb (and potentially also Rubicon). We got DQ'd for interference but I couldn't easily tell if SAE's driver braked or not.
  • Elmo Zoneball on 2012-Apr-22 21:09:58 Elmo Zoneball said

    Interesting.

    Watching the video, it looks like Rubicon did not accelerate well coming off of Hill #2, (which obviously is before the pass took place.) Reinforcing this impression is the fact that CIA C made up the two second deficit as rapidly as they did.

    This is another reason why I wondered if it's just the tires, or something more that's slowing things down. If there was contact, I suppose that could chew up some energy, but 6 seconds worth of FR?
  • Jmohin on 2012-Apr-22 21:30:46 Jmohin said

    It has to be the steering alignment. Non-original xootrs are NOT that slow, you can trust me on that.
    When a buggy is that slow off the hill 2 push on the first part of the free roll, it's not wheels, it's alignment. It's the hardest part of moving to ackermann.
  • chayes on 2012-Apr-22 21:42:30 chayes said

    Even rolling on the same era xootrs as insite did originally, our free roll time was a decent amount slower than that last time it ran. It seems that wheel prep makes a huge difference to how these buggies roll. Our alignment was probably a bit off too, but the new xootrs behave much differently than the old ones in many ways (most of them bad).
  • shafeeq on 2012-Apr-23 02:31:03 shafeeq said

    If you had been able to borrow Fringe B's Hill 2, I'd bet the freeroll times would've been a lot closer to Insite's old times. Speed into the freeroll has a huge effect on the time, though not so big an effect on the final speed. SigNu A's race shows the effect of excellent wheels making up for a not-so-great Hill 2 - it takes them longer to reach the stop sign, but by the time they get there, they're moving as fast as anyone.
  • Elmo Zoneball on 2012-Apr-23 16:40:41 Elmo Zoneball said

    shafeeq's points are well taken.

    Note the Hill #2 push-off for Rubicon. If you watch the video:

    http://new.livestream.com/cmuTVlive/Buggy2012Day1

    (start at approximately 2h 59m) you'll see what I mean.

    Note the SDC push off (pretty good), then watch the SAE push-off by the Hill #2 pusher -- it has what can only be described as a "good-enough-for-government-work" quality about it. Immediately following that, you can see Rubicon coming off of Hill #2 from the next camera angle, and it sure looks slow and doesn't seem to be accelerating very well at all.

    "Flaccid" push-off and acceleration are a deadly combination.
  • mccue on 2012-Apr-23 20:15:20 mccue said

    I wonder how many wheels Apex came into from Pioneers old stash. I don't think it's many, and I think they might be used/degraded.

    I disagree big time with Mohin. New Xootrs are so much slower than old Xootrs it's unreal. I can't believe they're *only* 6 seconds different from the old Panaracers SAE was rolling on. I have a hilarious email exchange between me and one of the guys at Xootr when they changed the formula asking for my money back, where I provided a lot of data to this effect but in which no fucks were given by the Xootr guy.

    Don't get down about Insite. Alignment, wheel prep, etc. are just some of a zillion factors that are hard to get just right for raceday.

Download Photo

Photo info

View more information