That's it. Doesn't matter whether the tank is full or empty, or who is or isn't sitting in the car, this still holds true
I've lost the link I had which gave a good explaination, anyone got one?
Thanks
Alex
Ps I tried a search but without any luck
My method? Dead simple: Initially rough adjust for required ride height, then using cornerweight scales, fine adjust so that each diagonal pair of
wheels is carrying an equal amount of weight.
That's it. Doesn't matter whether the tank is full or empty, or who is or isn't sitting in the car, this still holds true
When you say weight on diagonal wheels: do you mean equalising the weight on the opposite side of the same axle, ie, front wheels OR say, the front
right wheel equalised with the left rear?
Mal.
When you say weight on diagonal wheels: do you mean equalising the weight on the opposite side of the same axle, ie, front wheels OR say, the front
right wheel equalised with the left rear?
Mal.
Reminder to me!
Don't press the post reply button twice.
I think* it is the sum of the front left + rear right is equal to front right + rear left.
Alex
* I'm not 100%, hence the quesion
Sorry, my explanation was a bit ambiguous - it's as sevensport has just clarified.
Thanks Geoff, found this between replies: Spreadsheet
corner weights should be done with the driver in the car or at least ballast to the drivers weight otherwise your altering everything youve done when
you sit in it .11stone driver or 70ish kilos completley mucks everything up
unless you have a similiar weight passenger in the car
[Edited on 10/4/07 by higgsti]
quote:
corner weights should be done with the driver in the car or at least ballast to the drivers weight otherwise your altering everything youve done when you sit in it .11stone driver or 70ish kilos completley mucks everything up unless you have a similiar weight passenger in the car
how can a vehicle with more weight on one corner ie driver be balanced .race teams spend hrs moving things around there cars to achieve a balanced car like batteries fuel tanks .why do raceline make a special bell housing adapter for a duratec to type nine in order to fit the engine closer to the back .everybody i know who has had a car corner weighted has always been asked there weight so the car can be balanced accordingly.if all this doesnt matter how come i can notice adifference in a corner when i have a passenger in
In cornerweight terms, the only thing you can really adjust with spring platforms is that the two diagonals carry their equal share of the weight.
Adding weight in one corner will obviously increase the weight on that wheel, but the sum weights of the two diagonals will still be the same...
http://www.ybapublications.co.uk/shortcircuit/Features/sc_story_weight_distribution.htm
quote
Taking readings accurately is a two-man job as the driver will be in the car when it is on the track, he needs to be in the car to get the proper
readings, plus anything else as if the car was on track ready for the race.
http://www.northamptonmotorsport.com/default.asp?id=20
quote
your car has adjustable spring platform shock absorbers, the platforms can be adjusted up or down to optimise the distribution of weight around the
car, this allows us to take into account the manufacturing tolerances in the suspension and chassis and also to compensate for driver weight. Corner
weighting can also be useful during the build of a car as once the major items whose position is fixed have been fitted other items such as batteries,
fire extinguishers etc can be placed to optimise the weight distribution as much as possible.
another quote
We adjust the cornerweights to give the best balance between cornering and braking taking into account fuel load and driver weight. A properly
adjusted car will corner harder, have more steering feel and be more stable under braking with a reduction in the tendency to lock one wheel under
hard braking.
http://www.stockcarcentral.co.uk/tech_tips/corner_weights.htm
thats 4 websites which say your talking rubbish
In cornerweight terms, the only thing you can really adjust with spring platforms is that the two diagonals carry their equal share of the weight.
Adding weight in one corner will obviously increase the weight on that wheel, but the sum weights of the two diagonals will still be the same...
how can they be as soon as you sit in the drivers seat youve altered one of your diagonals and also your rear end balance left to right.why bother
cornerweight the car if what your saying you might as well just weigh front axle get these the same then do the same at back axle and front to back
not bother with the diagonals
Anti roll bar(s) if fitted should be disconnected and reconnected and adjusted after adjustment of corner heights
Driver MUST be in car.
The aim is to get each corner bearing the weight it should according to the fore-aft and left-right weight distribution.
Setting both front corners to equal weights is the wrong way to do it, it will cost dearly in terms of traction.
Higgsti,
If you look under the "crossweight" section of the first link in your post, you'll find precisely the concept I've been
discussing - albeit maybe a little better explained.......
quote:
Originally posted by GeoffT
Sorry, but I disagree - the weight of the driver (or passenger, it doesn't matter) will always be distributed around the four wheels in a manner that maintains the diagonal equilibrium. It's a concept that I can picture in my head, but don't know how to express mathematically, any takers...?
from same website in the how to section it states
quote
Taking readings accurately is a two-man job as the driver will be in the car when it is on the track, he needs to be in the car to get the proper
readings, plus anything else as if the car was on track ready for the race.
the driver must be in the car or ballast of his weight
[Edited on 10/4/07 by higgsti]
.....but I maintain you'll end up with the same crossweight adjustment whether the driver is in the car or not. To quote from further down the
section you mention :-
"......and most importantly the crossweight. This is the combined percentage of the outside front wheel and the inner rear wheel."
I can accept that in something like small oval racing where cars only corner in one direction, then crossweight maladjustment may have some advantage,
but I can't see any advantage in it for road vehicles
your car has adjustable spring platform shock absorbers, the platforms can be adjusted up or down to optimise the distribution of weight around the
car, this allows us to take into account the manufacturing tolerances in the suspension and chassis and also to compensate for driver weight. Corner
weighting can also be useful during the build of a car as once the major items whose position is fixed have been fitted other items such as batteries,
fire extinguishers etc can be placed to optimise the weight distribution as much as possible.
from northhampton motorsport .it matters more on cars which are driven in different directions if its important to move a battery round a car and fire
extinguiser im sure an 11 stone plus drivers weight is
[Edited on 10/4/07 by higgsti]
....ok, we'll obviously have to agree to disagree....., interesting discussion though.
....but next time you get a chance to set up corner weights calculate and set up equal crossweights with an empty car, put somebody in the
driver's seat and recalculate the crossweights. You may get a surprise and find that you don't need to readjust......
ATB, Geoff.
and why dont you try putting ballast in your car to your weight on your side and post up your findings on here
i think geoff is right mathmatically, after all if a 100kgs driver sits over the back right wheel, he would add roughly 50 kgs to that wheel and 25kgs to each of the wheels on the other diagonal. So, totals would be unchanged. However, you are also totally correct that the driver should be in, as the ride height would end up uneven.
http://7faq.com/owbase/ow.asp?FlatFloorSetup
another one for you geoff in the set up it says and relevent to our cars
Second all weights should be taken with the driver in the car and with an average load of fuel.
all these people cant be wrong unless its a conspiracy theory.you can learn something every day
maybee the maths is right but were talking about the correct way to corner weight a car
quote:
Originally posted by higgsti
maybee the maths is right but were talking about the correct way to corner weight a car
I did mine recently with bathroom scales & a big propane tank pretending to be me.
I agree with the diagonals concept. However you cannot argue with the fact that if the 2 rear wheels have different weights on 'em, the
differential will make sure that there's always one wheel that breaks traction first & acceleration will be lower because of it. So initial
weight distribution IS an important factor that adjustable spring seats can't completely compensate for. Aside from that, make the diagonals
share the load and get the ride height right. I was surprised how easy and quick the job was. The bathroom scales were 20kg or so above full scale
(when doing the back axle) but seemed to cope alright (went back to zero, results plausible and repeatable)
Bob
PS pre adjustment I had nearly 40kg difference L/R on the back, afterwards 12. And I now get better traction in spite of the quaife ATB diff!
My argument has always been the mathematical one, the diagonal sum weights will still be the same, driver in or not. As JoelP alludes, the car will
"squat down" on the rear offside corner with this setup. Ok with the driver in the car the squat would be adjusted out, but it would sit
high on this corner when unloaded. Not really a problem, but what happens when you drive it with a passenger? Would you want to readjust the setup
every time? Ok if you only drive it without a passenger, then agreed, setting up crossweights with the driver in the car will set the car level, BUT
if you regularly drive with a passenger, then setting crossweights with the car unloaded (or with both people in the car, same result) would give the
best setup to cover all eventualities.
All these things only affect ride height though, the original statement of the need for diagonal (crossweight) equality still stands.
OK I'm gonna add to this debate!
I have the opinion that the corners weighting benefits most:-
1) Straight Line Braking.
I want the same weight on my two front wheels (with me in the car and petrol etc) when braking in a straight line. This is to allow me to get the
most out of my brakes before locking up one wheel. Ideally both should lock at about the same time.
2) Rear traction.
With an open diff I'd like the weight on the two back wheels to be the same to they break traction as late as possible allowing me to get off the
line ASAP. If this is one properly it will also help minimise the inside wheel spinning up exiting a corner (I've normally only had this problem
in the wet).
Now if both these are met then the diagonals being equal are met OK.
I was told by a world champion hot rod builder that corner weights are not as important to cornering as some folks would have you believe since as
soon as you touch the steering wheel, brake or accelerator you are radically altering the weight pressing down on the four wheels of the car
anyhow.
Can anyone answer me this, since most tracks in the UK are clockwise why don't we set our cars up with more weight on the inside? (Maybe they do
and no-one's told me!!)
Cheers
Ali
I find with my car that if the diagonals are equal the car is something like 15kg heavier on the nearside, due mainly I suppose to the battery and
exhaust being on that side, plus the engine is canted that way. Problem I found was that if you maladjust the diagonals to say, equalise the weight
across the rear wheels, you end up by pushing the front end even further out of balance, probably compromising front brake balance. I suppose the only
real answer if you need this degree of accuracy is to physically move stuff around in the car, not sure this is really necessary on a road car
though
I would get the front wheels equal first, I've only ever seen the traction problem come in to play on a stinking wet day at Aghadowy with the poorest road tyres on you can imagine!!
joel the link on blatchat does tell you how to cornerweight your car the adjustment of the corner weights does alter ride heights they are both linked
.but you should start with your front bottom wishbones paralell with the ground for best results.
geoff i drive mainly on my own and my prevous car was a megabusa which has the engine placed to they passenger side which affects the corner weights
far more than a cec so the weight in the car is on the same diagonal
Dosen't matter if one front wheel locks up very slightly before the other under extreme braking -- what matters is the car stays straight under heavy braking.
Hi One question. How many people in this topic have acctually played with corner weights on a real car on a track and experimented.
And how many have only worked it out mathamaticly.
cheers matt
never felt the need to alter at the track only played with tyre pressures and damper settings.i have a corner weight guage also and finding flat floor at a track is nigh on impossible.if i had scales those are easier to use and get more accurate reading
quote:
Originally posted by britishtrident
Dosen't matter if one front wheel locks up very slightly before the other under extreme braking -- what matters is the car stays straight under heavy braking.
I used to race Imps the worst case scenario for corner weight distribution, the weight bias towards the right side of the car was huge. The left front corner carried sweet f-a weight on the standard car.
quote:
Originally posted by alister667
snip snip snip
Once they lock you loose about 30% of the grip on that wheel, and , of course, you'll have trouble turning in until you release.
snip snip
Thanks
Ali
[Edited on 11/4/07 by alister667]
Yes of course you're right, neat and tidy is quickest, the point I was making was that if you lock up the fronts you have no steering, at least
turning in under controlled braking (usually done only when I've made a mess of the braking) you can turn in, even if the back becomes very
light.
There are a couple of corners I know where you have no choice but to brake while cornering so it can be done, but with some care to avoid swapping
ends.
I was hoping for more input from procomp who sets up cars professionally and would know a lot about this - I'd be interested to hear his thoughts
on corner weights.
Hi this topic could run as long as the old bec v cec.
But the answer will be simallar in that there is no real difinitive answer each has it's merits in certain applications and differing types of
car. Even with our verry simalar cars there is a difference between live axle and irs setups .
But at the end of the day if you have a driver who truley belives that it should be done this or that way then if that is what he wants as he belives
that will make him quicker round a circuit then so be it . If he has the confidence to drive with the setting he has and knows what to expect in a
given situation and can drive the car accordingley it might not be the text book setup but it could well be that for that driver it works out
quicker.
The point of my post above was to see if anyone had acctually driven a car set one way and then readjusted to be the set the other way as a back to
back test situation and conclucivly proved to himself that one way was better than the other.
It is somthing that if driving/sprinting /racing on a regular basis could be off intrest to see what suits you your setup and the most important part
your driving style as it is relativly easy to alter a cars setup but it is a hard thing to try and change a drivers complete driving style .
I also think that if you as a driver are getting down to the technicalities of differing corner weight setup on cars as light as our type there are
many other things that should also be taken into account before comming to any given conclusion such as dampers and the general geo setup on the car
.
cheers matt
So Matt,
When you set my corner weights and ride height, will I be sitting in the car
I will be down soon for the setting up but want to make sure it will be plain sailing. I have freed the rears ready for adjustment but the front
platforms are seized and I broke a torx bit in while trying to remove the seized grub screw. I will have another go this weekend unless the sun
stays out.
I wouldn't disagree with you. Very interesting, thanks for the response.
Ali
geoff ive tried to corner weight your way but my pace guage doesnt work on the rims that are on .have you tried it with driver in the car?
quote:
geoff ive tried to corner weight your way but my pace guage doesnt work on the rims that are on .have you tried it with driver in the car?
its actually an adr guage it lifts one wheel off the ground on a lever principal the car has to be on a level surface and has to be lifted the same
height for each wheel.you are weighing on a level surface arnt you?
[Edited on 15/4/07 by higgsti]