OK, I've updated the registered teams spreadsheet, and we're now past the voting deadline. We're at 29 teams now, but we'll only count the votes of those whose payment was received (or maybe postmarked...) by 4/30/05.

I mixed up UWA's votes, they're corrected now.

The tires that obviously come out on top are the Hoosier 20x6-13, 20x7-13, 18x6-10, and Goodyear 20x6.5-13. Down at the next level are the Goodyear 20x8-13, 18x6.5-10, and Hoosier 20x7.5-13.

Thanks for joining, everyone!
-Denny

thanks for doing this denny. its really cool to see this go from an internet discussion to reality. hopefully now FSAE will more closely resemble "real" racing.

Hi all,

We'll be updating the financial spreadsheet in a day or two--we're going to wait a few days for those "the check is in the mail" to come in. Looks like we'll have just under $15000 to spend at TIRF, which should go pretty far.

Of course, schools can still sign-up. Voting on tires will be capped at this point so we can start finalizing our test plan and other discussions with TIRF.

Thanks to everyone who joined. See you in Detroit.

Edward

A quick update on money received recently, more to follow later this week.

Dude, you got like 3 feet of air that time!

quote:

Originally posted by Denny Trimble:
A quick update on money received recently, more to follow later this week.

Dude, you got like 3 feet of air that time!

yesssssssssssssssssssssss!

Denny-

A suggestion: Can you weigh all the tires you test? Advertised weights seem to be pretty unreliable, and even tire to tire variation can be big. if you could weigh the tires this would be easy to do and good information for comparison.

Sorry if this was already the plan....

If you're really keen, moment inertias would would be pretty damn cool too... Perhaps easiest using the Claude method by strapping a weight to the tyre and timing the oscillation period when it's all mounted up on the rig ... then do one without a tyre and subtract the rig's inertia. As I said, you'd have to be keen.

Charlie,

When the tire test is run, it starts with the tire suspended above the belt (the "roadway"). As such, the balance should be weighing the tire/wheel assembly at this point. I haven't looked for weight data before, but as long as we start recording before the tire contacts the belt we should be able to extract tire/wheel weights from the data stream. We can weigh the wheels separately to determine the tire weights.

I've got a note to make sure this gets into the test plan. It's a worthwhile addition.

Thanks,
Edward

Nick,

Moments of inertia are good to know, too, but as you suggested you don't need TIRF to do this. Hanging the tire at the end of a long rod is the way to go. I'm not sure the machine can give us this info. Of course, the reason to suggest it is that we'll have a nice collection of tires which any individual team won't have. I made (another) note to myself--maybe TIRF can do this for us? Hmmm...I'll look into it.

Edward

Weight and inertia of tires only would be great.

The TTC page lists "Overturning Moments" as one of the test outputs. Is there a difference between Overturning Moments and Moment Inertias.

quote:

Originally posted by Charlie:
Denny-

A suggestion: Can you weigh all the tires you test? Advertised weights seem to be pretty unreliable, and even tire to tire variation can be big. if you could weigh the tires this would be easy to do and good information for comparison.

Sorry if this was already the plan....

i have found over .25lbs difference between two goodyear 6.5x10, (same compound) tires.

James,

Overturning Moment is one of the six forces and moments on a tire. The forces are Longitudinal Force (X), Lateral Force (Y) and Normal Load (Z). The moments are Overturning Moment (about X-axis), Spin Axis Torque (about Y-axis) and Aligning Torque (aobut Z-axis).

The overturning moment exists because the center of the pressure distribution in the footprint does not typically coincide with the center of the print. There is usually some lateral offset (which can become very large with high camber). Since the SAE tire axis system's origin is located at the center of the footprint, specifying the normal load at this location necessitates the use of overturning moment.

The moments of inertia are the ones used, for example, in Newton's second law: F=ma for linear motion and T=I(alpha) for rotational motion. They're the "I" in this equation.

For what it's worth, definitions of standard vehicle dynamics terms are given in SAE J670E "Vehicle Dynamics Terminology". It's not exactly thrilling to read but it's definitely a good resource to have within reach....

Edward

Maybe one for Edward, but is the testing of the same tyre on different rim widths being considered? I'd be interested to see the relative effects on cornering stiffness of pressure and rim width.

Probably a bit late in the day but just a thought.

Ben

Ben,

I met with Dave at TIRF yesterday to start running some hard numbers for our test. We talked about looking at the effect of rim width as an additional test. I know it's of interest, and it's an outside possibility that we'll run a test or two to gauge the effect. Of course, it all comes down to finances. We've got a nice group of teams already signed-up. We'll see how much more interest I can raise in Detroit today and tomorrow. More teams = more $ = more testing = more value for everyone.

Say, Dunlop wouldn't want to invest $500 to get a whole bunch of tire data, would they? It's the best deal going--we welcome anyone who pays the registration fee (FSAE team or not). Compared to an FSAE budget, $500 out of Dunlop's budget would be positively insignificant

Edward

Maybe, it's got to be quicker than FE methods :-)

Ben

mostly a bump, but what is the current state of this now that we are all home from Detroit?

Sorry for the delay in updates since before Detroit, but I'm busy getting things done at the end of the quarter. I'll have an update early next week, and I'll reply to all the teams who've sent me emails.

OK, I've updated the registered teams spreadsheet:
http://students.washington.edu/dennyt/fsae/tiretesting/TTC_Reg.htm (make sure to "refresh" your browser or it will look a little funny)

Of note, the tire voting deadline has passed, so I've placed "x" marks where teams numerical votes once were, if those teams didn't submit payment by the 4/30 deadline.

Also, as some of you may know, Goodyear has a new tire out, the 20x7.0-13 R065, which some teams were running (Wisconsin-Madison did very well with them). The teams that run this tire suggest it is much better than the previous 6.5 width, due to a new construction.

Does anyone object to substitution of the 7.0 for the 6.5 in our testing?

Edward has met with the CALSPAN folks and they are working on a date and financial agreement. It's looking like late June or July for the testing, but I'll let Edward update us when the official word comes in.

Do any teams have 10" wheels we can use for the testing? I remember Jack from WWU offered some 10's, but I think there was a question as to whether we could actually use them for the testing.

-Denny

Hi all,

Here's an update:

1. We're waiting on Calspan upper management to finalize our agreement. We're trying for Tier 1 testing of the 7 most popular tires with the funds available.

2. The testing has been moved from the week of 6/20 to the week of 7/18. Expect this new date to be the final date.

3. Dr. Bob Woods has got the tire-supply end lined-up. We are in need of 10" rims if anyone has a set we can borrow for the testing. The University at Buffalo is supplying 13" rims.

I'll keep you posted on further developments.

Edward

Cal Poly Pomona may have an extra set of kaizers. Splined, and direct mount. Its finals week but I'll try and get more info by the end of the week.