saj is half right but at the same time very wrong.
I think the lecturer was either stuck in the theory or was trying to deliberatly wind you up.
Without writing a lecture myself. Roll bars connect the two sides of your suspension so when oneside dips under cornering, the opposite side lifts it back up. This means you get less grip on the outside cornering wheel... Saj is right :shock: ...... but by raising the outside wheel you also push the weight back over the inside and increase its grip.....saj is wrong
For a given wheel size, the amount of static grip a wheel has is a function of the weight pushing down on it.
Analogy: If you get an eraser and push it around the table its easy. If you put some weight on it it becomes more difficult.
Now if you put a huge ARB on the front, the weight distribution L & R would be balanced with nice level cornering and equal levels of grip. BUT the total level of grip at the front doesn't significantly change as you still have the same weight pushing down on the tyres. (There are still some subtleties but in simple terms that's it)
Throw in some water though and you need the weight pushing the tyre down or you get the same effect as moving an eraser around on a slippery surface. The car will tend to drift a lot as the tyres can't key into the tarmac the same through the film of water.
Take your ARB's of in the wet and the outside tyre will have its weight increased a lot as the car rolls over and will push the tyre through the water into the road Saj is right again
BUT :!: if you take the ARB off you increase the instability of the car as the weight loaded up in the car flips to the other side on exit. The alternative would be to have really stiff suspension but that has its own inherent problems.
This is still quite a simple look at the reason for ARB's and ther are lots of other subtleties in balancing the size of the ARN with the rest of the suspension setup.
The other key point which is the reason for a smaller front whitelineARB:
If your car has perfect weight distribution, you would probably opt for equal ARB's front and back to maintain the Front to back balance during cornering. The gtir doesn't so the front arb is already bigger than the back.
Now if the car is rolling more at the back than at the front, it will cause more weight to be transfered to the back and increase its grip and the car will understeer. If you decrease the size of the roll bar at the front, it will roll more and hopefully give a more neutral weight distribution front to back and stop the understeer
Alternativley you could stiffen up the back so it rolled less. (Amongst 101 other things)
IMO, leave the front bar as is and buy the whiteline rear adjustable ARB to save yourself some money. Adjust it until you are happy with the handling and leave it.
This really is the noddy guide to handling though and doesn't touch on suspension interactions, handling through a corner or maintianing a contact pacth on bumpy roads.
Suspension setup is a subjective art as well as a science.
I think the lecturer was either stuck in the theory or was trying to deliberatly wind you up.
Without writing a lecture myself. Roll bars connect the two sides of your suspension so when oneside dips under cornering, the opposite side lifts it back up. This means you get less grip on the outside cornering wheel... Saj is right :shock: ...... but by raising the outside wheel you also push the weight back over the inside and increase its grip.....saj is wrong
For a given wheel size, the amount of static grip a wheel has is a function of the weight pushing down on it.
Analogy: If you get an eraser and push it around the table its easy. If you put some weight on it it becomes more difficult.
Now if you put a huge ARB on the front, the weight distribution L & R would be balanced with nice level cornering and equal levels of grip. BUT the total level of grip at the front doesn't significantly change as you still have the same weight pushing down on the tyres. (There are still some subtleties but in simple terms that's it)
Throw in some water though and you need the weight pushing the tyre down or you get the same effect as moving an eraser around on a slippery surface. The car will tend to drift a lot as the tyres can't key into the tarmac the same through the film of water.
Take your ARB's of in the wet and the outside tyre will have its weight increased a lot as the car rolls over and will push the tyre through the water into the road Saj is right again
BUT :!: if you take the ARB off you increase the instability of the car as the weight loaded up in the car flips to the other side on exit. The alternative would be to have really stiff suspension but that has its own inherent problems.
This is still quite a simple look at the reason for ARB's and ther are lots of other subtleties in balancing the size of the ARN with the rest of the suspension setup.
The other key point which is the reason for a smaller front whitelineARB:
If your car has perfect weight distribution, you would probably opt for equal ARB's front and back to maintain the Front to back balance during cornering. The gtir doesn't so the front arb is already bigger than the back.
Now if the car is rolling more at the back than at the front, it will cause more weight to be transfered to the back and increase its grip and the car will understeer. If you decrease the size of the roll bar at the front, it will roll more and hopefully give a more neutral weight distribution front to back and stop the understeer
Alternativley you could stiffen up the back so it rolled less. (Amongst 101 other things)
IMO, leave the front bar as is and buy the whiteline rear adjustable ARB to save yourself some money. Adjust it until you are happy with the handling and leave it.
This really is the noddy guide to handling though and doesn't touch on suspension interactions, handling through a corner or maintianing a contact pacth on bumpy roads.
Suspension setup is a subjective art as well as a science.
ki_saj_ng
New Member
mmm, i dunno, u could fight either side of the arguement but i will always lose
nah i think ur right but the theory on my side is right too, its just one of them things u could look at from different angles.
once my lil r is back on the road, imma try it out tho wanna feel how the car works without and then il update u guys but i must say, it wont be for a while
one thing, campbellju, in ur essay, i scored 2 n u guys 1 so i WIN!!!
nah i think ur right but the theory on my side is right too, its just one of them things u could look at from different angles.
once my lil r is back on the road, imma try it out tho
wanna feel how the car works without and then il update u guys but i must say, it wont be for a while one thing, campbellju, in ur essay, i scored 2 n u guys 1 so i WIN!!!
L
lead
Guest
Not a problemki_saj_ng said:
Great advice guys, thanks!
K
KRS
Guest
Just to add, I recently fitted a Strutbrace Front and Rear and am amazed how much more secure my car feels through the bends.
I wouldnt take the ARB off, Its designed into the cars setup, my guess would be a very undesirable wobble on all corners. :lol:
I wouldnt take the ARB off, Its designed into the cars setup, my guess would be a very undesirable wobble on all corners. :lol:
The world loves a trier :lol:ki_saj_ng said:one thing, campbellju, in ur essay, i scored 2 n u guys 1 so i WIN!!!
Jim
Lead/Saj,
look here at my post in the sticky.
Saj, consider buying your lecturer the book its taken from to put him right
Cheers,
Jim
look here at my post in the sticky.
Saj, consider buying your lecturer the book its taken from to put him right
Cheers,
Jim
skiddusmarkus
Active Member
It was me who said about it being better in the wet with no ARB so 2-1 to the club Ki Saj Ng .
.
I
Innovate Performance
Guest
Saj,
the other thing you need to take into account is on all motorsport cars they have a fook off roll cage which will totaly change the way the cars handle and the way that the weight is tranfered when cournering.
campbellju you are pretty spot on with the explination.
The thing we have found is no matter what car you have the only way you will get spot on handling is by trying stuff and seeing what works. Or sitting down with a calulator and a pencil and pad and working it all out.
1st way is more fun
the other thing you need to take into account is on all motorsport cars they have a fook off roll cage which will totaly change the way the cars handle and the way that the weight is tranfered when cournering.
campbellju you are pretty spot on with the explination.
The thing we have found is no matter what car you have the only way you will get spot on handling is by trying stuff and seeing what works. Or sitting down with a calulator and a pencil and pad and working it all out.
1st way is more fun