Corner Weighting?

[_Nathan_]

BMSport.com is Bexley's site, quite near you I think.

Agree it is worth doing as part of a geo on any car that is used on track.

[Thorney]

I'm not saying we're not interested, I'm trying to be helpful?

Corner weighting is a great deal different from setting up adjustable suspension, which of course is absolutely essential.

Corner weighting is the process where you try to get the car balanced in terms of equal weight distribution on the wheels. This is of course impossible as the engines in the front so you will always have more weight on the front axle, thats natural but what you're trying to achieve is a 50:50 displacement of weight from corner to corner (ie front left to rear right and rear left to front right).

You do this via small changes in the cars ride height on the suspension, sounds simple enough but once you change one corner you change all the other 3 as well, by different proportions so its a time consuming exercise of adjusting each corner then going back over again until its right. The E46 is very easy to get 50:50 (its normally shown in percentage terms, 50%) as the chassis is so balanced anyway but a proper corner weighted set up is worth decent time on track.

However (and this is where I'm trying to save people money) the process is very specific, the driver, wearing the exact clothes he wears on track, complete with helmet needs to be in the car for the entire process (when we dont have the driver we fill the seat with sacks of spuds, weight etc to match the drivers weight), so plan for a few hours sitting there reading a book. On a race car we know exactly what weight of fuel we run, each litre is 1kg approx so we corner weight the car for race fuel weight, we re-corner weight for success ballast (60kg win penalty in CSL Cup) as these make dramatic differences to corner weighting.

Apply this to a road car, add a tank of fuel and you've got 60kg added, if you've corner weighted it with half a tank you're now 30kg out and you've wasted your time. Run with a passenger? Again, waste of time, 80kg sat next to you will throw it out massively.

My point is that corner weighting is a racing thing or at absolute best a track day car where you are trying to get the last nth degree out of a laptime, for a road car its a nice way to spend a couple of hundred quid and make you feel better, if you have the money and want to be quicker buy a set of new tyres, or instruction make use of it rather than spending it on something that you dont need or can make any real use of.

I'll happily do it, charge you the labour anything you want, but I'd rather educate people on what to spend their money on rather than just take it, sorry.

[Thorney]

It is a completely different process to setting up suspension and geo, dont mix the two up.

[Dan]

Very good post that makes much sense there John!

[DuncanR]

Originally Posted by Dan

Very good post that makes much sense there John!

+1 there JT, dont think I will bother now ! ... beer and curry solutions will forever be throwing my corner weighting out of kilter , besides, would costs too much in bags of spuds to ballast me !

[cantfind1]

Have to say John I disagree! You don t need to explain to me the process or what it achieves that's not what I am asking.

I am asking where to get it done, I have had it done many time in Australia and America and only once over here but was not quite happy with it. So I am looking for another place, quite simple really.

Corner weighting is essential if you fit coilovers to a car that is going to be used on track, even if you can't get it spot on, which in a right hand drive M3 is virtually impossible (they were designed as a left hand drive car afterall) it will be miles better than if you had not performed the simple corner weighting.

You can t just fit coilovers measure the ride height and be done with it if you are going to do any serious driving. End of!

This is one of the reasons many people don't use Thorneys anymore, wrong information in my opinion.

[_Nathan_]

Originally Posted by Thorney

It is a completely different process to setting up suspension and geo, dont mix the two up.

Done as part of setting up and geo not saying it is the same thing.

As with all these things you can find a compromise that works well for a trackday car, sure it might be a little out when you have differing passenger sizes or with different fuel loads but still better than not having it done at all (and arguably no different to a race car where your corner weighting is compromised on fuel load between beginning and end of a race \ fuel stint).

As an example Plans did my Noble with 40kg in the passenger seat as it was a halfway house between passenger and none, in a car as heavy as a road going M3 the weight of the drivers clothes is neither here nor there!

PS. Fuel is approx 0.75 kg per litre

[Thorney]

Originally Posted by cantfind1

Have to say John I disagree! You don t need to explain to me the process or what it achieves that's not what I am asking.

Simply trying to be informative

Originally Posted by cantfind1

Corner weighting is essential if you fit coilovers to a car that is going to be used on track, even if you can't get it spot on, which in a right hand drive M3 is virtually impossible (they were designed as a left hand drive car afterall) it will be miles better than if you had not performed the simple corner weighting.

Fair enough, you're entitled to your opinion, however getting it 'spot on' as you say will change as you change weight in the car, hence its a pointless exercise unless you maintain that as a constant, for most people even on track day cars thats important to know.

Originally Posted by cantfind1

You can t just fit coilovers measure the ride height and be done with it if you are going to do any serious driving. End of!

I believe I said that quite clearly, I even made a seperate post about it, the process of geo is abour camber, toe, castor, trail, height, tyre pressure, dampers, spring settings, spring types etc

Originally Posted by cantfind1

This is one of the reasons many people don't use Thorneys anymore, wrong information in my opinion.

As you say in your opinion, which of course you are entitled to. However, having founded the CSL Cup, won multiple races in it myself (14 seconds last Donington round is still the largest margin of any win this season or last) and running multiple cars both race race winning I'll rely on our credentials.

Take a look at last year, at Donington Park I ran my car on 6 degrees of negative camber, Dan Stringfellow and the others all took the piss in the paddock saying it looked silly, fast forward to now and the whole grid is running 5-6 degrees from last years 3-4 degrees. Dan was having major issues in handling and set up last season, even considering changing suspension, I did three laps of Brands Hatch and suggested stiffer springs and softer damping (which was the exact opposit to what he'd been told by all the self appointed 'experts'). Fast forward to now, he's stuck with Nitron who have redeveloped his suspension with guess what? Stiffer springs and softer damping and hes winning straight away (end of last season he didn't beat me once in last 4 races).

I think I have a rough idea what to do.

My point is that corner weighting on a car where the actual chassis weight displacement will not meaningfully change over the course of its use is very much worth doing, but for 99.99% of all track day cars the range of weight variance that the car will undergo even during an average track day makes the process excessive and there are better things to spend money on to get ultimate track times. If you disagree with that then fine, vive la difference but please dont say I'm wrong, we simply dont agree, thats fair enough.

[Thorney]

Originally Posted by _Nathan_

Done as part of setting up and geo not saying it is the same thing.

As with all these things you can find a compromise that works well for a trackday car, sure it might be a little out when you have differing passenger sizes or with different fuel loads but still better than not having it done at all (and arguably no different to a race car where your corner weighting is compromised on fuel load between beginning and end of a race \ fuel stint).

As an example Plans did my Noble with 40kg in the passenger seat as it was a halfway house between passenger and none, in a car as heavy as a road going M3 the weight of the drivers clothes is neither here nor there!

PS. Fuel is approx 0.75 kg per litre

Nathan this is my point, there is no such thing as a compromise corner weight - its all compromise as its a dynamic. If that dynamic is minimised then corner weighting has a positive effect but this positive effect is minimised for each change in that dynamic.

Think of it this way, if you're 2 feet from the dartboard you're accuracy is pretty good, paying for glasses so you can see the board better makes sense. If you're 40 feet from the board being able to see a bit better isn't like to make much difference!

[Thorney]

Originally Posted by _Nathan_

As an example Plans did my Noble with 40kg in the passenger seat as it was a halfway house between passenger and none

You see this makes no sense at all, so unless you had a 40kg passenger in the car the car wasn't corner weighted at all, in other words the car was deliberately out? Weird.

Tell me this, do you weigh your passengers? Do you re-corner weight your cars each time you fill/refill with fuel? If yes then corner weight away, if not then.......