Wheel size and the new GT6 patch

Discussion in 'GT6 Tuning' started by danlimski, Oct 7, 2015.

  1. danlimski

    danlimski

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    I was wondering if a few people are willing to make this experiment...
    1. Take any stock vehicle and no oil change. Drive it around your favorite track and record your times.
    2. Change the wheel size and drive around again. Record your times.

    Is there a drastic difference in your speed around the track (I'm not talking about a second or 2 change in lap times)?

    Thanks for reading, Dan.
     
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  2. Wydopen

    Wydopen

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    Here is what my testing showed:

    Brand new Corvette Z06 (C5) '04 bone stock

    Midfield Raceway

    First round with stock wheels 1:22.133 trap speed at end of straight 152

    Second round with +2 OZ Racing Botecelli lll wheels 1:21.246 with trap of 154

    Put stock wheels back on 1:21.306 with trap of 153

    Personally I don't see any difference in the times. The car did kind of have a different feel with the wheels, but that could have just been in my head. The numbers don't lie
     
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  3. Cole Brown

    Cole Brown

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    A 1:22.1 to a 1:21.2 is a difference. Then again it could be practice. Have to test it out myself.

    Edit: @trobes29, @Whitetail We may need to investigate just in case.
     
  4. Wydopen

    Wydopen

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    That's why I put the stockers back on and went around again. I got within a tenth and that is easily attributed to the driver.
     
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  5. Cole Brown

    Cole Brown

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    Just in case though. PDI be sketch
     
  6. DolHaus

    DolHaus

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    No difference, purely visual.

    A second or 2 as you describe it would be a huge change, I'd hope to gain that much with a fully tuned car vs. stock setup but changing the wheels isn't going to do it. If you are getting that kind of differential between lap times then you are not familiar enough with the circuit/car to give meaningful results in the first place

    This has been questioned before and no evidence was put forward to suggest a noticeable or definable change
     
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  7. fordlaser

    fordlaser Premium

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    No difference as @DolHaus pointed out.
     
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  8. danlimski

    danlimski

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    Please forgive me if I am beating a dead horse. I did a trial on a Vitz F '99 with reduced window weight.

    Normal tires:
    - Nürburgring 24h: 13:31.097
    - Circuito de la Sierra: 13:53.327

    +2 inch tires:
    - Nürburgring 24h: 13:19.622
    - Circuito de la Sierra: 13:46.127

    I do not question your knowledge at all, I just want a clearer understanding.

    And again, thanks for all the effort and time placed into the testing... Dan.

    edit: I forgot to mention that both tests were on comfort soft tires.
     
    Last edited: Oct 8, 2015
  9. DolHaus

    DolHaus

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    You won't really see a tangible result using such a long course, there are so many places that you could have gained/lost time over the course of a 13 minute lap that even if you had found something you could never isolate or prove it. If I ran a few laps with normals and then jumped in the +2 I'd expect to go faster because I'm more familiar with the course after how ever many laps I put in setting a baseline.
    Pick a shorter course, practice over the course of a week (or more) until you can hot lap within half a second and then rerun the test multiple times and average the results. Ideally you should have someone else fit the rims so you don't know which size you are running to avoid bias.

    The weight of the car doesn't change so the wheels aren't offering gains in that way and the outside circumference of the wheel doesn't change so its not changing the gearing. The tyre side wall height changes but its purely visual, nothing changes except the look, the tyres have no element of flex to affect
     
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  10. rosckolove

    rosckolove

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    I can run well within a second consistently around the ring in my preferred cars. I'll give this a go when boredom strikes.

    I think this will be a good way to perform the test since consistency isn't an issue. And the length of the lap will amplify any actual differences.

    I do want to say, I think it's purely visual.. I'll report back later.
     
  11. danlimski

    danlimski

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    Many thanks for the insightful comments. I will try to make this happen over the weekend. I'll try to get something down over then.
     
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  12. danlimski

    danlimski

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    These are some of my numbers...

    Repurchased standard tires (PP: 314, 805kg, 71HP, 74 ft-lb, carbon (body color) hood, window weight reduction and comfort soft compound)
    • Other conditions
      • Active steering: Off
      • Traction control: 0
      • Active stability management: Off
      • ABS: 1
      • Skid recovery force: Off
      • Number of times around the track: 5
    • Fastest time around:
      • Red Bull Ring Short Track: 1:16.062
      • Brands Hatch Indy Circuit: 1:07.170

    Repurchased +2 inch tires (PP: 314, 805kg, 71HP, 74 ft-lb, carbon (body color) hood, window weight reduction and comfort soft compound)
    • Other conditions
      • Active steering: Off
      • Traction control: 0
      • Active stability management: Off
      • ABS: 1
      • Skid recovery force: Off
      • Number of times around the track: 5
    • Fastest time around:
      • Red Bull Ring Short Track: 1:15.432
      • Brands Hatch Indy Circuit: 1:06.363
    I've only used one type of car. I will be trying other vehicles with different drive trains and different PP's as well.

    Dan.
     
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  13. Otaliema

    Otaliema

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    If the rims affect anything it's maximum G force in a turn due to reduced tire flex.
    Which would mean an oval would show difference in lap times rather well as higher G load allows for high speeds.
    Just saying fewer chances of a mistake
     
  14. fordlaser

    fordlaser Premium

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    These tests that you are doing are you using a DS3 or a wheel, because I am using a wheel I only get a few 100s of a second difference with these wheel sizes with same car.
     
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  15. rosckolove

    rosckolove

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    I think you guys are just running different lap times.... I don't think the rims have anything to do with it.
     
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  16. danlimski

    danlimski

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    I am using a DS3 and thanks for the testing, Dan.

    It could be all in my head, I don't know. But I'd like to find out if its true ... and on that note, have you tried?
    Dan.

    I didn't think about that. I'll pay more attention next time.
     
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  17. cjr3559

    cjr3559 Premium

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    Try purchasing two cars that you can drive consistently and well within your abilities without losing control and crashing. Equip one with custom wheels. Choose the car with the custom wheels FIRST. Pick a SHORT track (preferably one you've already run hundreds of laps, i.e. Tsukuba or Autumn Mini). Seriously run around 20-30 laps without stopping. Record your best lap. Take a break and come back to the game later. Now do the same test on the car with stock rims. Record the best lap. Compare.
     
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  18. danlimski

    danlimski

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    The vehicle that I picked was Suzuki's Alto Lapin. I've attached to this post the MoTec output that GT6 makes.

    The vehicle is completely stock minus the wheels, which are Comfort Hards. I will make another pass on it with Comfort Mediums and post the output in the near future.

    By the way, I only went 14 rounds.

    Thanks for reading and for the input, Dan.
     

    Attached Files:

    Last edited: Oct 25, 2015
  19. danlimski

    danlimski

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    I've upgraded the wheels to +2 inches but kept the Comfort Hards on. There seems to be a difference in gripping power when comparing the 2 rims. I've attached my MoTec output from GT6.

    I would like any constructive input from the faster/better drivers and tuners.

    Thanks for looking, Dan.
     

    Attached Files:

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  20. fordlaser

    fordlaser Premium

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    I have done a number of laps using a stock Suzuki's Alto Lapin at the Red Bull Short Track on Comfort Hard tyres, only changes I made to the car is the rims only.

    Active steering: strong
    Traction control: 0
    Active stability management: Off
    ABS: 1
    Skid recovery force: Off
    Number of laps 10 on +1 Inch & 10 laps on +2 Inch.

    My best lap time for the +1 Inch rim is 1:23.033 for the +2 Inch rim is 1:23.241, so it is not much of a difference between rim sizes, and it all depends on your braking points and your steering and also acceleration as well. This test was done using a G29 wheel.
     
    Last edited: Oct 26, 2015
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  21. danlimski

    danlimski

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    So the difference may lie in the standard sizes and the rims (either +1 or +2).

    And I wonder what the difference in sensitivity may be with the DS3 pad and the wheel... more testing is required for it.

    My 2 cents, Dan.
     
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  22. fordlaser

    fordlaser Premium

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    I will test between standard rims and the 1 inch rims and see, but I can not see a big time difference in a lap when trying different rim sizes when using a G29 wheel. As I said in my last post it all depends on your braking and your steering and also your acceleration, and to have +1 inch and +2 inch just over 200 of a second difference I am very close to be putting this one to bed.

    Edit: I have done 10 laps on the standard size rims and my best time is 1:23.409, and I have found that driving the 10 laps within a couple 100s of a second of that time, so between the standard, +1 inch and the +2 inch rims there is no big difference in lap time, and the grip level appears to be the same so my conclusion in this test, there is no big difference in lap times between rims sizes.
     
    Last edited: Oct 27, 2015
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  23. Otaliema

    Otaliema

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    But there is a difference and if you're building a TT tune that 100th of a second could be the difference between 150th and 250th in the rankings. If such things matter to you.
     
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  24. fordlaser

    fordlaser Premium

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    Also depends on your braking and your turning and also your acceleration comes into to play as well.
     
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  25. DolHaus

    DolHaus

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    It is too small of a difference to be considered anything but a margin of error. Unless you've got a driver who can consistently run flat out laps (as fast as the car can go, not the driver) with only thousandths of a second difference then you're not going to get a dependable result
     
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  26. Burned_Rubber

    Burned_Rubber

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    In that case, adjusting the transmission to never come out of last gear would cut out a few variables. Full throttle around an entire track would eliminate acceleration and braking all together. Also using no aides and abs0 would rear the head of consistency. Lap times would be significantly slower but, if handling/cornering speed on a certain rim size is the test, a consistent line is more important. Just my 2 cents. BTW, well done @hall90 on some great lap averages
     
  27. fordlaser

    fordlaser Premium

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    I done this test driving Auto, manual I did not do, and I tried to get a consistent line on every lap, and if I was getting lap times that were a few seconds apart with different sizes rims then I can say there is a difference but there is not, and with a few hundreds of a second a lap time between the different size rims is nothing, as @DolHaus pointed out in his post it could be a margin of error.
     
  28. danlimski

    danlimski

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    I hear you there Otaliema. And I agree with you 100%.


    Thanks for your testing ... its much appreciated. And with my current driving skills, there's a lot of margin of error.

    I will be trying out other vehicles and other tuning types. More to follow.
     
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  29. jblackrevo9

    jblackrevo9

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    Bigger wheel Diameter means more handling and you can cover more ground.

    Tire radius. I read about it. And that's why I always increase tire size
     
  30. DolHaus

    DolHaus

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    Changing wheel diameter doesn't do anything to the handling even in real life, it only changes the gearing and the linear grip (acceleration/braking) slightly. The increase in diameter gives the tyre a longer contact patch allowing it to potentially handle more load but the increase is slight unless taken to the extremes of tall walled drag tyres. However, changing the wheels in GT does not make the outside diameter of the wheel any different (rim changes diameter/tire remains the same) so that effect will not be seen.
    What does change is the size of the tire side-wall, as you fit larger rims this shrinks which in real life would have the effect of stiffening the side-wall and allowing it to potentially handle more lateral load before distorting. The downside of this is that the tire will absorb less shock when driving over uneven surfaces so the ride and handling may be compromised in these circumstances.

    Tire simulation is basic at best in GT, you can't alter tire dimension or even pressure, they warm up and wear as a single unit rather than in bands, camber doesn't work and toe is overly effective, the chances they modelled side-wall flex (which is something not a lot of PC Sims do) are a million to one.
     
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