Formula Student Tires

[matty641R]

im currently a final year BSc student studying at Huddersfield university. basically as part of a final year project im in charge of the area of tire analysis and performance. i haven't as yet had a detailed meeting to discuss the different routes that the team has allready explored. i have a very basic knowledge in this area and was wondering if anyone knows of any good articles, advice and any potential software that would be extremely usefull. thanks guys.

[KeithYoung]

I don't have the details but for very cheap you can join the FSAE Tire Data group. I don't know that's the exact name but you'll get the data you some of the popular FSAE tire options.

If you're still having trouble let me know.

[krisfx]

I'm a year below you at the same uni! Just onto placement. Aren't the FSAE tyres quite similar regardless of what you go for?

I did read something online, though that had a comparison between them (I think).

I did find this, though so I hope it helps: http://www.engr.colostate.edu/pts/Job/U ... deling.pdf

[Lycoming]

Tire Test Consortium, it's called. If your team isn't already in it and you plan to do anything objective regarding tires, get it. And if you do, don't forget to display the Calspan sticker; it's a bit depressing how many teams don't do that.

Also, you'd probably by far better off asking these kinds of questions on the FSAE forums.

[KeithYoung]

That's what the name was. Go with what Lycoming said.

[flmkane]

I'm a year below you at the same uni! Just onto placement. Aren't the FSAE tyres quite similar regardless of what you go for?

I did read something online, though that had a comparison between them (I think).

I did find this, though so I hope it helps: http://www.engr.colostate.edu/pts/Job/U ... deling.pdf

Afraid they are not. The Tyres available for FSAE cars are very dissimilar in pretty much every parameter. They vary significantly in weight, cornering stiffness, coefficient of friction, operating temperature etc. They must be investigated very minutely and the resultant difference will impact the design of your whole car, especially suspension (and aero if you have it)

[Greg Locock]

Well I'm glad to hear that. Has anyone run these oh so different tires on a car optimised for one particular design and measured the effect? That'd be a project report worth a few points in the design judging. Actually I'm being sarcastic, I suspect the difference might be well within the noise in the measurements. Still worth doing though. Knowing that something isn't worth agonising over is just as useful as knowing that something is important. Bear in mind if you don't like this answer that I haven't seen the F&M data from the various tires.

[Jersey Tom]

They're not that fundamentally unique. Typical stuff, no surprises.

In any event I'd say you'd get the biggest performance gain by just bolting on the right product rather than "optimizing" one setup to the n-th degree. When I was still involved in developing these things (the tires), you could make a few good design changes, bolt on something new, and drop seconds of lap time without touching a spring or bar.

[Lycoming]

Did you also at the end of the day go back and bolt the original back on and see if it was still seconds slower? With the typical skill level of drivers in this series, sometimes it can be hard to tell. To say nothing of various other environmental factors...

Of course, these days, one of the biggest decisions is 10" or 13" (or 8" if you're feeling lucky) and it's rather difficult to test those back to back...

[flmkane]

Well I'm glad to hear that. Has anyone run these oh so different tires on a car optimised for one particular design and measured the effect? That'd be a project report worth a few points in the design judging. Actually I'm being sarcastic, I suspect the difference might be well within the noise in the measurements. Still worth doing though. Knowing that something isn't worth agonising over is just as useful as knowing that something is important. Bear in mind if you don't like this answer that I haven't seen the F&M data from the various tires.

I"ll ignore your sarcasm.

Yes they have.

If you have not seen the data then dont try to tell me it's not worth agonizing over. That is simple misinformation.

[flmkane]

They're not that fundamentally unique. Typical stuff, no surprises.

In any event I'd say you'd get the biggest performance gain by just bolting on the right product rather than "optimizing" one setup to the n-th degree. When I was still involved in developing these things (the tires), you could make a few good design changes, bolt on something new, and drop seconds of lap time without touching a spring or bar.

You are correct. But which is the right product? As I said they are fundamentally different. It depends on the design philosophy of your car.

In Formula Student you'd probably have an easier time dropping time with a better driver, than with one magic upgrade, unless your car is a new design.

[flmkane]

Did you also at the end of the day go back and bolt the original back on and see if it was still seconds slower? With the typical skill level of drivers in this series, sometimes it can be hard to tell. To say nothing of various other environmental factors...

Of course, these days, one of the biggest decisions is 10" or 13" (or 8" if you're feeling lucky) and it's rather difficult to test those back to back...

Yes it has been done in the past by numerous teams. Even accounting for the drivers, you can definitely tell if one kind of tire gives 0.2 Gs over another.

But the 10 vs 13 debate must be settled by each individual team for their own cars. They are just different tyres, but there is enough data available to make an informed choice between the two. Not mention pretty good simulation tools.

[Lycoming]

If you have not seen the data then dont try to tell me it's not worth agonizing over. That is simple misinformation.

In Formula Student you'd probably have an easier time dropping time with a better driver, than with one magic upgrade, unless your car is a new design.

Sounds like you agree that it's not worth agonizing over...

Afraid they are not. The Tyres available for FSAE cars are very dissimilar in pretty much every parameter. They vary significantly in weight, cornering stiffness, coefficient of friction, operating temperature etc. They must be investigated very minutely and the resultant difference will impact the design of your whole car, especially suspension (and aero if you have it)

I agree with JT... at least within the same size of tire, they're not exactly identical, but they aren't light years away from each other in terms of performance or behavior. Also, knowing the limitations of the testing machine, there's a limit on how minutely you can investigate these parameters. It's a bit like measuring bolt hole diameters with a meterstick.

Actually, question for you: you say it impacts the design of the whole car. Ok, reasonable statement. What design parameters in the suspension system do you design in (ie. cannot be adjusted later) based on the tire choice? There are obvious changes that must be made to accommodate 13" vs 10" tires obviously but for a given rim and tire diameter, where the forces don't vary enough to cause significant changes to structure, which of the parameters that you must lock in does tire really affect? It's not at all unreasonable to build a car where the location of the suspension mounts can be changed, allowing adjustments to camber curves, roll center height, anti dive/squat, etc. For things that you must lock in, like wheelbase or track, are those decisions driven by the differences between, say, the 13" tires available, or would they be the same no matter what tire you chose?

[Jersey Tom]

Did you also at the end of the day go back and bolt the original back on and see if it was still seconds slower? With the typical skill level of drivers in this series, sometimes it can be hard to tell. To say nothing of various other environmental factors...

This was with a professional rather than student driver, and yes with a good test plan. Absolutely seconds a lap difference by putting on the right tread compound and construction combinations.

In any event I'd say bolting the right tires can / does make a bigger impact than weeks of kinematics design or hours / days of tuning springs bars and dampers. But yes, with extremely varied driver talent that is just as big a performance modifier.

[flmkane]

If you have not seen the data then dont try to tell me it's not worth agonizing over. That is simple misinformation.

In Formula Student you'd probably have an easier time dropping time with a better driver, than with one magic upgrade, unless your car is a new design.

Sounds like you agree that it's not worth agonizing over...

Afraid they are not. The Tyres available for FSAE cars are very dissimilar in pretty much every parameter. They vary significantly in weight, cornering stiffness, coefficient of friction, operating temperature etc. They must be investigated very minutely and the resultant difference will impact the design of your whole car, especially suspension (and aero if you have it)

I agree with JT... at least within the same size of tire, they're not exactly identical, but they aren't light years away from each other in terms of performance or behavior. Also, knowing the limitations of the testing machine, there's a limit on how minutely you can investigate these parameters. It's a bit like measuring bolt hole diameters with a meterstick.

Actually, question for you: you say it impacts the design of the whole car. Ok, reasonable statement. What design parameters in the suspension system do you design in (ie. cannot be adjusted later) based on the tire choice? There are obvious changes that must be made to accommodate 13" vs 10" tires obviously but for a given rim and tire diameter, where the forces don't vary enough to cause significant changes to structure, which of the parameters that you must lock in does tire really affect? It's not at all unreasonable to build a car where the location of the suspension mounts can be changed, allowing adjustments to camber curves, roll center height, anti dive/squat, etc. For things that you must lock in, like wheelbase or track, are those decisions driven by the differences between, say, the 13" tires available, or would they be the same no matter what tire you chose?

I did not contradict myself. Both driver training and suspension design are critical for performance. Compromising either with lose you seconds per lap.

And I aint writing a 100 page thesis just for your sake. Other people have already done that. Here you go:

http://www.mate.tue.nl/mate/pdfs/9288.pdf

If you dont understand that then I'll just PM you a pdf link for the Milliken book.