How can teams resolve tyre issues?

[Jersey Tom]

I have spent immense amount of time using these tire test machines.. and going through gigabytes of test data every year.

The bottom line, as Ben alludes to, is that you're never testing absolutes. You never will. There are huge limitations in what kind of data you can collect, or what you can do with it, regardless of the source. Big limitations with flat track testing.. with force hub testing (the Kistler WFT's posted earlier), etc. There's no one solution that does it all. I'm not even sure there's a combination of solutions that does it all. I'm not going to get into specifics.. as it would be (a) way beyond most of this audience (b) too time consuming (c) confidential.

Point being, while flat track and other testing has a lot of value.. it's not absolute or 100% real. It's also very easy to get crap data if you aren't very careful about how you test.

Has a profound impact on what you do with it (simulation or otherwise).

[ubrben]

Dave: The spool in a DSSV is that purely an orifice or is there any spring loaded poppet or shim of any sort?

Ben

[DaveW]

Dave: The spool in a DSSV is that purely an orifice or is there any spring loaded poppet or shim of any sort?

Spools are driven by pressure, balanced by deflecting springs. Flow is controlled by a port that is revealed as the spool moves. Flow is at 90 degrees to the spool motion, thereby minimizing pressure/flow interactions. Spool natural frequencies are in the range 300-600 Hz. The shape of the ports can be designed to yield any required pressure (force) - flow (velocity) relationship. Port shapes are computed using physics, rather than the more usual trial & error process. Controlled flow is almost entirely turbulent, so damper characteristics don't vary significantly with temperature (I ran a test once, replacing normal damper fluid with water - damping coefficient changed by <2 %).

In standard form, anyway, they provide consistent damping control, as do several others. I happen to think, however, that DSSV's offer unsurpassed flow control. There are also several novel derivatives. They are used widely, from F3 through to F1. I'm not a Multimatic employee, BTW, & am happy to deliver grief when it is deserved.

[DaveW]

Point being, while flat track and other testing has a lot of value.. it's not absolute or 100% real. It's also very easy to get crap data if you aren't very careful about how you test.

I was given the opportunity to examine "flat trac" results once, for a pair of Champ car tyres. I was a little confused at first but, after demonstrating that tyre vertical stiffness could become negative under high loads, I decided that the results were telling me more about the facility & its procedures than they were about the tyres. My conclusions were fed back, which resulted in another (free) test day. The new results were different, but still didn't make complete sense to me. Hence I wish you well in your work, JT.

[Jersey Tom]

Yep. The more data you get, the more confusing it is.

Plus, many engineers are only exposed to the fitted model data for tires without seeing the raw data behind it.

For that matter, the whole method of turning the raw data into a model that can be used in a sim - is half science, half art. You could take the same set of tire test data and give it to two people to fit and run in a sim, and get entirely different results.

IMO if you don't have the raw test data itself, or know the person fitting your data and how good they typically are.. you have no information as to whether your tire data (and ALL OF YOUR SIM RESULTS) are reasonable or complete crap.

[ubrben]

Yep. The more data you get, the more confusing it is.

Plus, many engineers are only exposed to the fitted model data for tires without seeing the raw data behind it.

For that matter, the whole method of turning the raw data into a model that can be used in a sim - is half science, half art. You could take the same set of tire test data and give it to two people to fit and run in a sim, and get entirely different results.

IMO if you don't have the raw test data itself, or know the person fitting your data and how good they typically are.. you have no information as to whether your tire data (and ALL OF YOUR SIM RESULTS) are reasonable or complete crap.

Scary, but true

A fitted Pacejka model might have a 3% error relative to a filtered set of the raw data. The error could be higher for the combined lateral model or the Mz model. You then run a sim with some +-2% aero data. Come Saturday the percentage difference in lap time might be 0.5% from 1st to 10th...

Ben

[autogyro]

So the best piece of equipment for setting up a car for tyres would be a Ouija board then.

[ubrben]

So the best piece of equipment for setting up a car for tyres would be a Ouija board then.

The best (and most ignored advice) in racing is to listen to your tyre technician.

Interesting example is the recent LMS race at Portimao. All the reports talk about punctures (seemingly implying they were unlucky) befalling some Ferraris. Also there were reports of other Ferraris struggling with setup and front end performance.

Actual story: They were left front tyre failures not punctures - same left front tyre failure the SEATs were getting in the Portimao WTCC race earlier in the month. The teams were asked to remove front negative camber due to tyre safety concerns. One team listened to the advice, hurt the balance a little to save the tyres and got 1-2 in the race. Another team didn't.

Overall I wouldn't say a Ouija board is necessary, just a healthy dose of pragmatism about what you can and can't know for sure about any race tyre let alone the race tyres you have.

One final sobering dose of reality: There isn't a radial racing tyre in existence that you can't cause to fail given the right (or wrong) choice of camber and pressure - I don't care who makes the tyre or who designed or setup the car it failed on.

[marcush.]

the real interesting question would be how close will the well seasoned trucky tire guy be with his guestimates together with a raceengineer with a good gut feeling listening to the tire techs as well and when they roll the dice for Qualy and race settings ..

[DaveW]

So the best piece of equipment for setting up a car for tyres would be a Ouija board then.

Possibly, but the real problem faced by F1 is lack of track testing, I think. This has forced teams to take the simulation & simulator route without first putting in place the tools required to make that a sensible alternative. It's not much different in many junior series...just that F1 has now joined them.....

I wonder what the incremental cost would be of appending, say, a test day to 4 or 5 selected race weekends through the calendar.

[Jersey Tom]

Actual story: They were left front tyre failures not punctures - same left front tyre failure the SEATs were getting in the Portimao WTCC race earlier in the month. The teams were asked to remove front negative camber due to tyre safety concerns. One team listened to the advice, hurt the balance a little to save the tyres and got 1-2 in the race. Another team didn't.

Story every week in NASCAR. With camber values most sportscar setup guys probably wouldn't believe...

[marcush.]

So the best piece of equipment for setting up a car for tyres would be a Ouija board then.

Possibly, but the real problem faced by F1 is lack of track testing, I think. This has forced teams to take the simulation & simulator route without first putting in place the tools required to make that a sensible alternative. It's not much different in many junior series...just that F1 has now joined them.....

I wonder what the incremental cost would be of appending, say, a test day to 4 or 5 selected race weekends through the calendar.

Dave,as long as the teams stay in the pits instead of collecting data in FP1-3 I don´t see this really .
Mercedes got so much distracted by introducing their blown difusser they did not even manage to get their normal work done in Valencia..but I do not remember them driving all the time..so arre they still in the change only 1 item at a time frame of mind? can´t believe this.

Maybe teams would all do better concentrating on maximising their package instead of introducing new variables to the equation week after week.It seems fairly obvious that introducing parts too early will do more harm than help your case...
Mclaren are late with their introoduction of parts but are hauling points like crazy lately..

[DaveW]

Dave,as long as the teams stay in the pits instead of collecting data in FP1-3 I don´t see this really .

True, Marcus. Perhaps the limited tyre allocation is a problem.

[marcush.]

Sporting regulations, tire useage FP1-3
25.4


a) Each nominated driver will be allocated three sets of dry-weather tyres for use during P1 and P2, two of “prime” specification and one of “option” specification. These are the only dry-weather tyres which may be used during these sessions.
One set of “prime” specification must be returned to the tyre supplier before the start of P2 and one further set of “prime” specification and one set of "option" specification before the start of P3.

You are right there ...with only one set of option tire there is not really much scope for experimenting and no chance to have real back to back testing....apart from a split between your two drivers ....

thinking of it it is more of a wonder that teams do not drop the ball more often...

also:
b) Each nominated driver will be allocated eight further sets of dry-weather tyres, four of each specification, for use during the remainder of the Event. However, one set of each specification must be returned to the tyre supplier before the start of the qualifying practice session and may not be used during the remainder of the Event.

So they bring 8 sets for each driver of these ttwo sets are not to be used on the event... so will these just stored for the next event with these tire type? so in
a bad situation you may get 2 or 3 older sets of option tires or even just 1 older option tire ?
JT: any info about shelf degradation of new Racing tires? I heard about as much as 5%
raise in springrate and compound shore hardness increase in 6weeks ...

[myurr]

Sporting regulations, tire useage FP1-3
25.4


a) Each nominated driver will be allocated three sets of dry-weather tyres for use during P1 and P2, two of “prime” specification and one of “option” specification. These are the only dry-weather tyres which may be used during these sessions.
One set of “prime” specification must be returned to the tyre supplier before the start of P2 and one further set of “prime” specification and one set of "option" specification before the start of P3.

You are right there ...with only one set of option tire there is not really much scope for experimenting and no chance to have real back to back testing....apart from a split between your two drivers ....

thinking of it it is more of a wonder that teams do not drop the ball more often...

also:
b) Each nominated driver will be allocated eight further sets of dry-weather tyres, four of each specification, for use during the remainder of the Event. However, one set of each specification must be returned to the tyre supplier before the start of the qualifying practice session and may not be used during the remainder of the Event.

So they bring 8 sets for each driver of these ttwo sets are not to be used on the event... so will these just stored for the next event with these tire type? so in
a bad situation you may get 2 or 3 older sets of option tires or even just 1 older option tire ?
JT: any info about shelf degradation of new Racing tires? I heard about as much as 5%
raise in springrate and compound shore hardness increase in 6weeks ...

Those two sets are used in FP3.