+ Reply to Thread
Results 1 to 6 of 6

Thread: New Hoosier tire sizes

  1. #1

    New Hoosier tire sizes

    Hoosier has announced that there will be a new, smaller outside diameter 10 inch tire available this summer. 16 inches outside diameter, 6 and 7.5 inches wide, available in LC0 and R25B compounds. Do we expect to see any teams already running these in Michigan or Lincoln this year? I know Texas A&M is on them already (which is not the biggest change they have made this year), as I'm pretty sure they have been testing them for the last year. How many teams do you think will be switching to them for next season? The TTC will probably be testing them in August, which makes an interesting timeline for North American teams who are considering them. It is a pretty big change, as I image it will be difficult to design a chassis/suspension that will be able to test both an 18 inch and a 16 inch diameter tire due to the size difference.

    Aside from waiting for the tire data, does anyone have any qualitative predictions on how they will behave? Although I don't understand a ton about tires (does anybody?), I would expect that the slimmer sidewall will make them a lot stiffer, whereas the current 18 inch diameter sidewalls seem to roll/thrust over a lot during cornering. I would image this might make them react a lot quicker to steering inputs? What does the smaller sidewall mean for overall levels of grip?

    With all the talk of how inactive the forums have been, just wanted to get some good discussion going here!
    University of Missouri - Mizzou Racing | 2015 - ????

  2. #2
    Besides effects on the actual tire behavior, think also the effects on tire heat capacity, overall unsprung weight and aero.

  3. #3
    Senior Member
    Join Date
    Mar 2008
    Location
    Brighton, MI
    Posts
    677

    TIRF Wars

    Someone should check with TIRF to see if they can 'handle' this size. Because they can incline only 1 way because of spindle head real estate, the test procedure for these small tires needs to include a reverse mount with appropriate rotation so you can merge the data to get a full sweep of slip and inclination. From what I have seen, many of these tires have puzzling camber stiffnesses and their responses confuse attempts to artificially reflect the camber characteristics. I'd sure like to see a camber sweep on any one of these tires in the next round to settle the reflection issue.

    Do you know what the recommended rim width for this new size is ? TIRF will need some alternate wheels too. (Maybe).

    Just got a note from Prof. K about a TTC Round 8 series pending. Time to fetch some of them there new fangled tars...

    Stiffer sidewalls imply faster relaxation 'length's and less Mx migration. Its a haptic thing.

  4. #4
    Senior Member
    Join Date
    Mar 2008
    Location
    Buffalo, NY USA
    Posts
    321
    Small loaded radius tires like these (also the 10" Avons) don't work on the main TIRF spindle, it does not go low enough. Instead, they are tested on an offset adapter that is attached to the main spindle (spindle is locked) and balance--this costs TTC a good buck for the additional setup time. Unfortunately, this means free rolling data only, no drive/brake/combined.

    I've looked at other flat belt rigs and not found any that go lower. More details: The TIRF staff remove a plastic spacer on their column (crash bumper) and can then go slightly lower than the MTS rigs I've seen. Also, the TIRF software does not abort when the bottom stop is reached, while the MTS software I'm aware of aborts immediately. In other words TIRF might not meet all the highest load conditions (for the smallest tires that do work on the main spindle) but the test will run through to the end.

    TTC will probably be buying some more zero-offset rims for Round 8. We plan to test on two rim widths as before.

    Interesting idea to run a camber sweep (assuming you mean at slip angle = zero), although it can't go very far in negative inclination angle with any of these small diameter tires. The limit is parts of the test head crashing with the roadway belt.

  5. #5
    I also agree having a camber sweep would be nice - it has been hard to do much analysis with only the 3 different angles currently tested. Even if they can't go very far with the machine, it would be nice to add another dimension to the data.
    University of Missouri - Mizzou Racing | 2015 - ????

  6. #6
    Senior Member
    Join Date
    Mar 2008
    Location
    Brighton, MI
    Posts
    677

    Chimney Sweep

    A camber sweep is not uncommon. It's for "answering the question". Would not be run at zero slip angle.c_sweep.JPG

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts