Tyre Choice

[Flying_Marshie]

Hi All

This is my first year in FS and infact my teams first year. I have been tasked with the job of finding tyres to use on our car.
I've looked at Hoosier, Goodyear and Dunlop. Without much information on these tyres I cant make an educated choice and I have to justify spending that much cash on tyres.
Can anyone help out on which tyre would be best to use. Let me know about any good/bad experiences you've had with certain tyres or any relevant information you think will help.

Thanks!!

[FStotal.com]

Hallo Flying_Marshie,

If your team is a first year competitor then look what tyres you can get for a good price inclusive shipping costs.

When you are finished your car building then test as much as possible and you will get good results.

For a first car the timefaktor is the one you should beat.

If you got enough money you can also buy data from the Tire Test Concortium (http://fsae.com/eve/forums/a/tpc/f/125607348). Most teams use them for their second or third cars when they more understand these data and use them for simulations.

Literature Tires: (http://fsae.com/eve/forums/a/tpc/f/125607348/m/1956095883)

Clark, Samuel K. (Editor), Mechanics of Pneumatic Tires, 2nd Ed. U.S. Dept. of Transportation, National Highway Traffic Safety Administration, 1981. U.S. Govt. Reference #: 050-003-00377-8.

Hays, D.F. & Browne, A.L., The Physics of Tire Traction. Plenum, 1973. ISBN 0-306-30806-1.

Kummer, H.W. & Mayer, W.E., Unified Theory of Rubber and Tire Friction. University Park, PA.: Pennsylvania State University, 1966

Moore, D.F., The Friction of Pneumatic Tyres. Elsevier, 1975. ISBN 0-444-41323-5

Pacejka, Hans B. Tire and Vehicle Dynamics, Second Edition

THE RACING & HIGH-PERFORMANCE TIRE, Using the Tires to Tune for Grip and Balance (R-351) by Paul Haney

[exFSAE]

Tires are arguably the biggest bolt-on performance modifier in this series. Don't take them lightly.

Hoosier and Goodyear are both competitive to each other with their latest tires. Don't have experience with the Dunlop.

Don't go by what other teams use. Raise the money, buy a set of each, and have an internal shootout. Find out what works best for YOUR car and YOUR drivers at YOUR venue.

[Bazanaius]

The problem with a first year car is that really the car should be designed to the tyres, not the tyres selected afterwards. Pretty much every discussion you have about designing a system on the car will come down to the tyres, and this makes it a nightmare for a team who need to get a car out but don't have the data.

Buying a set of each and just testing each of them on a car you've built from scratch would not only depend massively on the car you've built and how it uses each tyre, but I'd also ask the question - how did you design your suspension geometry? Or your weight distribution, or final drive, or brakes etc. etc.

I'd say, whilst it needs to be taken with a pinch of salt regarding actual numbers (and I'm sure exFSAE will agree!) the TTC data is useful for a young team who don't have testing time with a car, and particularly the later tests are slightly more reliable. Take into account the cost of your tyres, and your budget, and the ease of getting hold of them, and invest in the TTC data (just be aware of the conditions under which the tyres are tested and the equipment used) - it's a whole lot cheaper than 4-5 sets of tyres and will let you select and get designing without having to build a car first.

B

[ben]

With the TTC data available I'd pick one of those tyres - please note that doesn't include our offering. I fully appreciate the need for tyre data and we should have some pure Fy flat track data generated in-house within the next two months.

If you have data available you can design the car to suit the tyre. As a design judge logistics and cost are good enough reasons for selecting a tyre given that funding a comparitive test is beyond the means of most first year teams and flat track data gives unrealistic friction levels making compound comparison difficult to meaningless.

Ben

[exFSAE]

Originally posted by Bazanaius:
The problem with a first year car is that really the car should be designed to the tyres, not the tyres selected afterwards. [...]

Buying a set of each and just testing each of them on a car you've built from scratch would not only depend massively on the car you've built and how it uses each tyre, but I'd also ask the question - how did you design your suspension geometry? Or your weight distribution, or final drive, or brakes etc. etc.

[...] Take into account the cost of your tyres, and your budget, and the ease of getting hold of them, and invest in the TTC data (just be aware of the conditions under which the tyres are tested and the equipment used) - it's a whole lot cheaper than 4-5 sets of tyres and will let you select and get designing without having to build a car first.

B

In a professional race series, I would agree... and evaluating set A vs B vs C I'd want to look through F&M data beforehand to set static camber and pressure accordingly. Here, not as much.

A big item is a lot of the events in FSAE are very short duration and are dominated by cold compound grip. This does not show up in the current F&M testing. Can have a real grippy tire, but if it doesn't heat up until 6 laps into endurance you're kinda hosed.

In all practicality, if you're evaluating crossply G vs crossply H vs crossply A, you'll be just fine using the same static settings across the board and running a few laps on each. Cold and hot grip levels will be very apparent between them, as will more subjective stuff like steering response, load sensitivity, and how violently or smoothly the tires break away. I'd make my race rec on those alone.

The TTC data is cool and all, and can give you a general direction on how to design your suspension, but for comp I think you have to back-to-back test at LEAST two different manufacturers. Ideally, 3 or better.

The money is out there.

Conversely, if time and/or money are running out, just buy a set of anything and start driving. The seat time can't be replaced.

[Bazanaius]

Conversely, if time and/or money are running out, just buy a set of anything and start driving. The seat time can't be replaced.


Agreed :-)

[Flying_Marshie]

Thanks for all the responses.

Looks like I need to do more research into this, a LOT more involved than I origionally thought.

As a first year team we only started Feb this year so we still tying to get funding from the faculty and external sources. We are going through a lot of teething problems and funding for software, computers and books is being a problem.

As far as testing tyres on a head to head basis with a ready built car.... I dont think the costs involved will justy the end result (in the eyes of the funding parties).

I would just like to get everyones opinions on the following tyres

Hoosier
20.5 x 6.0-13 R25B
21.0 x 6.5-13 WET

also the Goodyear FSAE tyre in similar sizes

P.S the car will be raced at FS Germany in 2010

Cheers

[Tommo]

Yeah, research is key

You'd love to test 7 different tyres but it ain't gunna happen

The TTC will be incredibly useful when designing suspension around a tyre, it wont really help you make the choice?

If I was back in a first year team, i would choose the tyre which would make life easiest (driver or engineer).
Which means you're not necessarily looking for the best tyre.
In my opinion the easiest tyre (most balloon like) is made by someone thats starts with H (but its not the best tyre).

[Zac]

Goodyear starts with H?

From all of the drivers I've talked to, the Goodyear D2692 is easier to drive consistently than the comparable Hoosier (ie. smoother traction transitions). The D2691 would be a handful to drive in the second half of endurance though, particularly if the sun is out.

Then again, I have my own bias and preferences. So take everything I say with a grain of salt.