F1: How stiff is stiff?

[phitho]

Hello, this is my first post here and to start myself off I thought I'd ask a pretty straight forward question. I'm wondering just how stiff modern F1 cars are run, in regards to springs, dampers and anti roll bars? I've read some numbers on other forums but nothing concrete, usually in the range of 1000-2000 lbs/in. for the springs. That's rather general and though I doubt anyone would really know any exact settings for any team at any track, what range of setting would be considered stiff and what would be considered soft?

Thanks so much!

Phil

[Monstrobolaxa]

Very interesting question.....

To give you an idea...of stiffness.

- Car part - Stifness - Damping

- Tire carcass - ~50N/mm - 5%
- Tire Pressure - ~200N/mm - 0%
- Spring/Damper - ~175N/mm - 70%
- Bump Stop - 0 to 500N/mm - 0%
- Anti-Roll Bar - 0 to 1000N/mm - 0 to 70%
- Chassis Torsion (at pickup points) - 1500+ N/mm - 0%

Those are typical numbers....but they came in N/mm.....and in Race car terms we use lbs/in....so lets convert

So...

- Tire Carcass - 285,7 lbs/in
- Tire Pressure - 1142,86 lbs/in
- Spring/Damper - 1000 lbs/in (but can goes from 600 to 2200lb/in)
- Bump Stop - 0 to 2860 lbs/in
- ARB - 0 to 5700 lbs/in
- Chassis - 5800 lbs/in (and above)

Please notice that some of the values I'm using are average numbers.....for example in the springs and dampers.

I hope this can give you a general idea of what you wanted....to give you an idea of what lbs/in means....it's the of lbs that have to be applied on something so that it deforms 1 in.

All the information used in the thread was taken from the book Formula 1 Technology, by Peter Wright. Some other info was taken from Competition Car Suspension, by Allan Stanforth. And the conversion factores were taken from Introduction to Fluid Mecanics, by Fox.

If you need anything else....just let me know

[phitho]

Wow, some actual numbers that make sense...cool. Thanks for the reply Monstrobolaxa. I'll have to look into those books you named. I own Carroll Smith's Tune to Win and Drive to Win, but neither of them go into detailed numbers, it's mostly "If it's understeering then stiffen this...", but my problem with that is where do you start? Is stiff a 'stiff' front spring a 300 lb/in window between 1300 lb/in and 1600 lb/in?

Those are the kind of questions I've got, which means I should get my backside into engineering school and try to get a job on an F1 team to really find out.

[Monstrobolaxa]

Well usually if you have under-steer...you have 2/3 aproaches....soften the front springs.......increase front downforce......reduce front ride height....or harden the rear Anti-Roll Bar........ (in Formula 1)

A good book about car dynamics is Chassis Engineering, by Adams......it talks alot about dynamics...and uses easy to understand examples.

[red300zx99]

Soften the front springs or increase roll bar rate, those are 2 different things having oppisite effects. If you increase the roll bar then you increase the roll rate, but if you decrease the springs then you decrease the roll rate. US, soften something up front or increase something in the rear, we'll as far as spring and roll bars are concerned

[Monstrobolaxa]

red300zx99 you're absolutly right....I read your post about an hour ago an came the whole way to university thinking about it and going through the competition car suspension and Chassis Engineering book.....and your completly right.... my mistake!

about hardening the ARB usually you do it to reduce oversteer and not understeer.

I still have a slight doupt about the roll rate....I'll post back if I still can't understand it....