What is your wheelbase?

[Lyn Labahn UW-Madison]

Since we already had a weight discussion, how about another interesting figure, what is your wheelbase?

Us: 2001-66in 2002-64in 2003-62in

2002/2003 Team Leader

[Lyn Labahn UW-Madison]

Since we already had a weight discussion, how about another interesting figure, what is your wheelbase?

Us: 2001-66in 2002-64in 2003-62in

2002/2003 Team Leader

[ben]

At Birmingham we've got a 1675mm wheelbase - I don't know what an inch is :-)

Ben

[Andy K]

167.5 mm = 65.94 in

Andris Kanins
McGill Racing Team - Body Design

[Richard Lewis]

2002 - 72in (too big!)
2003 - 68in

-------------------------
UVIC Formula SAE Team
http://members.shaw.ca/drax77/UVICFSAEcar.jpg
http://uvic.fsae.ca

[EliseS2]

Exactly 60in.

[Dominic Venieri]

wow our car is huge.

www.formularpi.com (http://www.formularpi.com)

[Lyn Labahn UW-Madison]

How long his huge? http://fsae.com/groupee_common/emoticons/icon_wink.gif

2002/2003 Team Leader
Best overall average finish of the new millenium http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Nam Tran]

2001 - 72 inches [Left], 71.5 inches [Right]
2002 - 73 inches [Symmetric http://fsae.com/groupee_common/emoticons/icon_smile.gif]
2003 - 68 inches [Still Praying]

[Charlie]

Everyone's going shorter. But what was UTA's wheelbase last year (winner in AutoX)? It was fairly long wasn't it?

-Charlie Ping
Auburn University FSAE 1999-present

[Lyn Labahn UW-Madison]

Charlie,

Yes it was, if you go to google and type in "Road and Track formula sae", you should be able to bring up the car specs that competed in the event last year, UTA was one of them.

2002/2003 Team Leader
Best overall average finish of the new millenium http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Ben Beacock]

66in wheelbase. fits in a 99 dodge pickup with the tailgate up and no body. (it was a large pickup)

Ben Beacock
Chassis Design and Technical Coordinator
Gryphon Racing - University of Guelph

[Nigel Lavers]

Right on 60 inches.

[Dominic Venieri]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Charlie:
Everyone's going shorter. But what was UTA's wheelbase last year (winner in AutoX)? It was fairly long wasn't it?

-Charlie Ping
Auburn University FSAE 1999-present
<HR></BLOCKQUOTE>

From the R&T page:

UTA wheelbase - 68.897... inches (1750mm)

www.formularpi.com (http://www.formularpi.com)

[stscxr]

2000 - 70 in
2001 - 70 in
2002 - 70 in
2003 - 70 in

I got lots of other stuff to deal with than screwing around with the wheelbase. And besides the last thing I want to do move the front wheels any closer to the steering wheel, let alone sit on the header or file the engine case with the sprocket. You guys with the 60 in wheelbase's must have even more fun with packaging than we have.

Ian

[Alan]

Ours is 68 in. this year. I am curious how everybody comes up with what they want their wheelbase to be. We base it off of what we want our weight distribution to be, with weight transfer and turning radius being secondary considerations.

Kettering University FSAE

[Dominic Venieri]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Lyn Labahn UW-Madison:
How long his huge? http://fsae.com/groupee_common/emoticons/icon_wink.gif

2002/2003 Team Leader
Best overall average finish of the new millenium http://fsae.com/groupee_common/emoticons/icon_smile.gif<HR></BLOCKQUOTE>

How's 76" sound? http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

www.formularpi.com (http://www.formularpi.com)

[-Gabriel]

2002: 71 in (1803mm)
2003: 66 in (1676mm)

The main reason to go smaller is the smaller turn radius. Considering the same sprung mass distribution and the front unsprung mass moved 5 in back, it changes the weight distribution about 1% toward the front. Well, need to confirm it on scales... http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif

Gabriel Denoury
Ecole Polytechnique de Montréal FSAE
www.fsae.polymtl.ca (http://www.fsae.polymtl.ca)

[Charlie]

Wow, at 68in, UTA is shorter than I remembered. Auburn finished 7th in the 2002 autocross with a 72in wheelbase. We are going shorter for 2003.

-Charlie Ping
Auburn University FSAE 1999-present

[MercerFSAE C. Burch]

on what your wheelbase is? For our first car I want to try a 1700mm wheelbase, as it is right in the middle of what the more successfull teams run. But then again, Cornell and several other teams keep going smaller? Also, why do teams usually go with 13" wheels instead of 10" wheels with less rotational inertia and a lower Cg? Would one of the benefits of a shorter wheelbase be a lower overall rotational inertia for the car with the relatively heavy wheels, tires, brakes, uprights et al. being closer to the car's Cg?

I'd appreciate some insight into the thoughts behind your decisions.

-Chris
Mercer University - Drive!
Coming to an Auto-X track near you! May 2004.

[Nam Tran]

This has probably been one of the biggest setbacks for us in previous years. With relatively little information to go from, we had a lot of trouble trying to squeeze parts into whatever space was left in the chassis.

[ANDONI]

70 --- 2001
66 --- 2002

Andoni Mazeika
www.formulasaeusb.com (http://www.formulasaeusb.com)

[loose_nut]

Yeah packaging isn't easy. We're at 72 inches because of the extra space required for our Bombardier CVT. I always have to compromise between CG height and wheelbase.

[Michael Jones]

We've gone from 71" to 64" in the last two years...

---
Cornell Racing
http://fsae.mae.cornell.edu

[Schumi_Jr]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>why do teams usually go with 13" wheels instead of 10" wheels with less rotational inertia and a lower Cg? <HR></BLOCKQUOTE>

Each wheel/tire combination has its benefits. I personally believe that a car with 10" wheels done properly will be faster. The most obvious advantage with 13" wheels is the additional room for packaging brakes suspension geometries.

Cornell and Wisconsin, what was your rationale for going even shorter? Did this compromise your transient stability much? For those who care:

Waterloo
2002: 1727mm (68in)
2003: 1700mm (67in)

Aaron Johnston
University of Waterloo FSAE

www.eng.uwaterloo.ca/~fsae (http://www.eng.uwaterloo.ca/~fsae)

[This message was edited by Schumi_Jr on March 24, 2003 at 01:06 PM.]

[Richard Lewis]

47 in wheelbase? You've got to be joking! Holy smokes that is short.

-------------------------
UVIC Formula SAE Team
http://members.shaw.ca/drax77/Formula%20UVic%20Sig.jpg
http://uvic.fsae.ca

[Schumi_Jr]

yikes! I changed my post to the correct values.

Aaron Johnston
University of Waterloo FSAE

www.eng.uwaterloo.ca/~fsae (http://www.eng.uwaterloo.ca/~fsae)

[MercerFSAE C. Burch]

With regard to the 13" vs 10" wheels - I went to GA Tech's presentation of their car and asked them the same question, figuring that they had probably tested both. Their conclusion was that the 13" tires give much better feedback to the driver, as the 10" ones don't offer much at the limit. This was backed up in Race Car Vehicle Dynamics as the author states that a longer narrower tread will give better feedback at the limit. Since driveability is key to winning this competition, the 13" tires are a better way to go.

-Chris
Mercer University - Drive!
Coming to a Auto-X track near you, May 2004

[Lyn Labahn UW-Madison]

Schumi,


Rationale for going shorter? Shoot man, we just do whatever Cornell does...

2002/2003 Team Leader
Best overall average finish of the new millenium http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Garbo]

We keep going shorter each year, 66... 64... 63. As far as I understand, the shorter wheelbase car will handle quicker with a smaller turning radius but be a little less predictable and less easy to correct when it does start to spin.

We had some oversteer problems last year initially but they were due to the shock setup, rather than geometry. When that was worked out, the car was still very longitudinally stable (and a bit big for getting around those little turns).

I don't really know, I do what the suspension guys say but my back is starting to get a bit warm.

www.formulamun.com (http://www.formulamun.com)

[Marc Jaxa-Rozen]

74 inches, all of 'em.

Too big, I know, but it was necessary due to various legacy SNAFU's (i.e very messed up rear packaging).

[Doggyollie]

"Also, why do teams usually go with 13" wheels instead of 10" wheels with less rotational inertia and a lower Cg?"

The reason that makes the most sense to me. More room. This allows for taller uprights, which means less stress on A-arms. Also you get more room for brakes. For me, these reasons are more important than low rotational inertia or cg.

My 2cents

Also
University Of Arizona
70 2002
68 2004

[This message was edited by Doggyollie on May 08, 2003 at 11:15 PM.]

[woollymoof]

Plus the larger contact patch.