Adding Tire temp to AIM system
12-18-2018, 06:02 PM
#16
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I've found displaying tire temps or pressures can be a bit of a mixed bag. I've seen some drivers need that verification to have the confidence that the car will handle the inputs they want to deliver and it improves their performance.
Drive the car to what it can take, not what you think. Use the data for engineering, setup, and evaluation after the fact, but don't let it limit your performance.
Drive the car to what it can take, not what you think. Use the data for engineering, setup, and evaluation after the fact, but don't let it limit your performance.
It's a Catch-22.
To warm the tires, brakes and driver up well, the driver needs to drive with controlled aggression. The better (and quicker) they're coming up to speed, the quicker the platform will stabilize at the optimum values, hence further confidence ensues...
Listening to pro drivers leave the pit lane from my office at VIR, this is reinforced EVERY time.
Now, for carbon brakes on LMP cars, I've found either a page with temps or an alarm LED that goes out above a threshold, especially for Am drivers, to be REALLY helpful...
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12-19-2018, 06:45 PM
#17
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When leaving pits, my procedure is to accelerate in 1st gear, then brake to threshold and repeat several times to warmup tires and brakes. Learned this technique from a procoach.
12-19-2018, 07:07 PM
#18
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That’s good advice!
Ken Payne, Motorsports Technical Director for Michelin North America, explained to me decades ago that rapid and high value LonG deltas were the best way to stabilize temps and pressures in a racing tire.
The cars we raced together long ago didn’t have the juice to do that, so we just slid around until they came up to temp, but the explanation is simple.
The flexion of the cross ply belting in the tire carcass when subjected to abrupt fore-aft acceleration and deceleration causes internal friction, which causes heat internally throughout the carcass of the tire, eventually permeating the tread.
But more than that, internal pressures rise due to heat, causing the tire to stiffen and provide a better platform, sooner. This helps the driver have increasing confidence over the out lap to the point where the tire is functioning nominally by the time the first hot lap starts.
In the class that I race, and the categories he oversees in IMSA for Michelin, this can be a particularly effective competitive advantage. Certainly a quality the very best professional drivers have honed to a high level.
While I do understand the lateral “scrubbing” folks often do on pace laps or out laps, that’s more effective in knocking off particulates and debris off the tread surface than for “conditioning the tire” quickly and effectively.
Ken Payne, Motorsports Technical Director for Michelin North America, explained to me decades ago that rapid and high value LonG deltas were the best way to stabilize temps and pressures in a racing tire.
The cars we raced together long ago didn’t have the juice to do that, so we just slid around until they came up to temp, but the explanation is simple.
The flexion of the cross ply belting in the tire carcass when subjected to abrupt fore-aft acceleration and deceleration causes internal friction, which causes heat internally throughout the carcass of the tire, eventually permeating the tread.
But more than that, internal pressures rise due to heat, causing the tire to stiffen and provide a better platform, sooner. This helps the driver have increasing confidence over the out lap to the point where the tire is functioning nominally by the time the first hot lap starts.
In the class that I race, and the categories he oversees in IMSA for Michelin, this can be a particularly effective competitive advantage. Certainly a quality the very best professional drivers have honed to a high level.
While I do understand the lateral “scrubbing” folks often do on pace laps or out laps, that’s more effective in knocking off particulates and debris off the tread surface than for “conditioning the tire” quickly and effectively.
12-19-2018, 09:18 PM
#19
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That’s good advice!
Ken Payne, Motorsports Technical Director for Michelin North America, explained to me decades ago that rapid and high value LonG deltas were the best way to stabilize temps and pressures in a racing tire.
The cars we raced together long ago didn’t have the juice to do that, so we just slid around until they came up to temp, but the explanation is simple.
The flexion of the cross ply belting in the tire carcass when subjected to abrupt fore-aft acceleration and deceleration causes internal friction, which causes heat internally throughout the carcass of the tire, eventually permeating the tread.
But more than that, internal pressures rise due to heat, causing the tire to stiffen and provide a better platform, sooner. This helps the driver have increasing confidence over the out lap to the point where the tire is functioning nominally by the time the first hot lap starts.
In the class that I race, and the categories he oversees in IMSA for Michelin, this can be a particularly effective competitive advantage. Certainly a quality the very best professional drivers have honed to a high level.
While I do understand the lateral “scrubbing” folks often do on pace laps or out laps, that’s more effective in knocking off particulates and debris off the tread surface than for “conditioning the tire” quickly and effectively.
Do you still run bias ply tires in vintage S2000? The radials in IMSA have some pretty cool qualities.
12-19-2018, 09:52 PM
#20
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My data review (temps and pressures) has shown different and has been validated by a set of engineers (tire company and high end professional). Belt structures and rubber compounds make a very large difference in how the tire heats up, both in time and rate, and how it sheds heat.
Bruce Foss at Hoosier and Ken Payne at Michelin aren't directors of their company's programs for nothing. I learned a great deal testing tires for magazines at Michelin's Laurens Proving Grounds, but that was fifteen plus years ago. They were radials though!
I was speaking from a driver's perspective.
Regardless of the construction method of the tire, either bias-ply (which I use on my own car) and radials (on every current car), the importance of the driver quickly and effectively stressing the tire in the fore-aft axis to gain quick and evenly distributed heat and pressure is the same, and extremely important.
Paul Haney's book is one of the bibles, really. Great discussion on temps, pressures and construction.
Claude Rouelle's OptimumG Vehicle Dynamics seminars are the best on understanding how tires "switch on," how to measure that and make changes to the platform to improve that.
12-19-2018, 10:06 PM
#21
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I'll add that most purpose built racing slicks that are not designed for specific series use (like your Trans Am Pirellis) generally have a broader range of compounds, which do affect warm-up characteristics substantially.
The Hoosier R25B/R35B/R45B bias and R35B/R55A/S75/S80/S100 radial range, the Goodyear R160/R250/R255/R430/R470 range (available in both bias and radial) and the Avon A49/A11/A56 all show very different warm-up characteristics.
But in the end, it's up to the driver to nudge up against and slightly over the limit on the out lap and on the first race lap to get them to temp, especially during the moving target it takes to get there...
The Hoosier R25B/R35B/R45B bias and R35B/R55A/S75/S80/S100 radial range, the Goodyear R160/R250/R255/R430/R470 range (available in both bias and radial) and the Avon A49/A11/A56 all show very different warm-up characteristics.
But in the end, it's up to the driver to nudge up against and slightly over the limit on the out lap and on the first race lap to get them to temp, especially during the moving target it takes to get there...
12-19-2018, 10:48 PM
#22
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I'll agree that the driver is the most important variable. The tire data I have is across multiple manufacturers, compounds, and sizes. It's not just compound that changes the temp characteristics. Even in one style of tire, different layups can have substantial effects on tire temp and feel.
Dunlop has released some really good data from the European work.
I'll see what I can pull together from data I can share. I should be able to show temps and possibly pressure versus lateral G for how they warm up. I'm pretty straight out through the end of the year. Maybe you have some data you can share too?
Dunlop has released some really good data from the European work.
I'll see what I can pull together from data I can share. I should be able to show temps and possibly pressure versus lateral G for how they warm up. I'm pretty straight out through the end of the year. Maybe you have some data you can share too?
12-20-2018, 02:56 PM
#23
Sorry - I misunderstood. I thought you were going with the AIM single sensor system. FYI - My front sensors are at the top of the tire built into the wheel well cover so they still work with the wheels turned. My rears are in front of the tire to minimize debris impact. In one season I have lost several sensors already due to debris. The real time display is cool as it gives you reliable information in terms of the best techniques to get temps into the tires.
Lots of good info on the pros and cons of an in car tire temperature display. My original plan was to provide info after the fact that could be used to aid in car set up and for my coach to look at as an additional data point. Now, maybe some kind of indicator to confirm the tire temp is where it “feels”, might be a good thing.
Last edited by dogger15; 12-23-2018 at 12:35 PM.