The dynamics and the point of fitting a strut brace?
Discussion
On a car with strut suspension (as opposed to double wish-bones) the camber of the wheel is controlled by the angle between the hub and the top of the suspension strut (where the damper unit is mounted to the monocoque). As the load on the suspension increases (for example when cornering hard), the force on the strut will increase and it will try to flex away from the wheel, which usually means inwards towards the other suspension strut. This allows uncontrolled changes of camber, which is generally bad for handling.
A strut brace attaches the two struts together meaning that in order for one to flex, they both have, to effectively doubling the rigidity of the mounts without adding much weight.
A strut brace attaches the two struts together meaning that in order for one to flex, they both have, to effectively doubling the rigidity of the mounts without adding much weight.
Roughly speaking...Ties the struts together so that they maintain position during hard cornering so that the designed suspension geometry is also maintained. Effectively makes the bodyshell stiffer than it would otherwise be.
ETA..Kambites reply is a bit more detailed than mine
ETA..Kambites reply is a bit more detailed than mine
Edited by mark.c on Monday 30th March 11:14
kambites said:
On a car with strut suspension (as opposed to double wish-bones) the camber of the wheel is controlled by the angle between the hub and the top of the suspension strut (where the damper unit is mounted to the monocoque). As the load on the suspension increases (for example when cornering hard), the force on the strut will increase and it will try to flex away from the wheel, which usually means inwards towards the other suspension strut. This allows uncontrolled changes of camber, which is generally bad for handling.
A strut brace attaches the two struts together meaning that in order for one to flex, they both have, to effectively doubling the rigidity of the mounts without adding much weight.
I hate to be a pedantic tA strut brace attaches the two struts together meaning that in order for one to flex, they both have, to effectively doubling the rigidity of the mounts without adding much weight.
t, but isn't that back to front?The lower balljoint should try to roll over the tyre contact patch on the loaded wheels levering the top of the MacPherson strut outwards away from the other?
Anyway the effect would be the same. Tieing the strut tops together means you can borrow stiffness from the unloaded tower.
jamieduff1981 said:
The lower balljoint should try to roll over the tyre contact patch on the loaded wheels levering the top of the MacPherson strut outwards away from the other?
Hmm, good point. You're probably right. I started off thinking about raw suspension compression then reworded it to relate to cornering forces without taking into account the lateral load. Edited by kambites on Monday 30th March 11:47
jamieduff1981 said:
kambites said:
On a car with strut suspension (as opposed to double wish-bones) the camber of the wheel is controlled by the angle between the hub and the top of the suspension strut (where the damper unit is mounted to the monocoque). As the load on the suspension increases (for example when cornering hard), the force on the strut will increase and it will try to flex away from the wheel, which usually means inwards towards the other suspension strut. This allows uncontrolled changes of camber, which is generally bad for handling.
A strut brace attaches the two struts together meaning that in order for one to flex, they both have, to effectively doubling the rigidity of the mounts without adding much weight.
I hate to be a pedantic tA strut brace attaches the two struts together meaning that in order for one to flex, they both have, to effectively doubling the rigidity of the mounts without adding much weight.
t, but isn't that back to front?The lower balljoint should try to roll over the tyre contact patch on the loaded wheels levering the top of the MacPherson strut outwards away from the other?
Anyway the effect would be the same. Tieing the strut tops together means you can borrow stiffness from the unloaded tower.
Lateral loading on the strut top is minimal though. I simply don't believe people that say they've fitted a strut brace to a road car and felt an immediate difference - either their car was literally falling apart or they have an active imagination. A proper brace on a track car may be useful.
An awful lot of strut braces are also just decorative trinkets. Anything with a bend in it is immediately compromised, and the alloy ones with a thin oval section are just a joke.
Braces on the lower arm attachment points can be useful on some cars, this is where the real loading takes place.
An awful lot of strut braces are also just decorative trinkets. Anything with a bend in it is immediately compromised, and the alloy ones with a thin oval section are just a joke.
Braces on the lower arm attachment points can be useful on some cars, this is where the real loading takes place.
An awful lot of braces, especially front ones, are clearly nowhere near rigid enough to actually do anything. You're talking about trying to stop a few mm of movement with a bar over a meter long, it has to be either completely straight so it can't extend by bending when it's under tension (which is usually impossible at the front due to the engine being in the way) or extremely rigid. I suspect rear strut braces on hatch backs probably help because they can be perfectly straight and that area of the car is usually severely lacking in triangulation.
Edited by kambites on Monday 30th March 12:20
Mr2Mike said:
I simply don't believe people that say they've fitted a strut brace to a road car and felt an immediate difference - either their car was literally falling apart or they have an active imagination. A proper brace on a track car may be useful.
An awful lot of strut braces are also just decorative trinkets.
This, with bells on.An awful lot of strut braces are also just decorative trinkets.
The one that really makes me laugh, though, is the uprated door latches (oops, "door stabilizers") that you can get for GT86s - a friend fitted them and swore blind that he could feel the difference commuting to work...
Mr2Mike said:
Lateral loading on the strut top is minimal though. I simply don't believe people that say they've fitted a strut brace to a road car and felt an immediate difference - either their car was literally falling apart or they have an active imagination. A proper brace on a track car may be useful.
An awful lot of strut braces are also just decorative trinkets. Anything with a bend in it is immediately compromised, and the alloy ones with a thin oval section are just a joke.
Braces on the lower arm attachment points can be useful on some cars, this is where the real loading takes place.
I've had them on my Cappuccino, which made an immediate, marked difference to the turn-in, and on my MR2 Roadster, which was noticeable but far more subtle.An awful lot of strut braces are also just decorative trinkets. Anything with a bend in it is immediately compromised, and the alloy ones with a thin oval section are just a joke.
Braces on the lower arm attachment points can be useful on some cars, this is where the real loading takes place.
Mr2Mike said:
Lateral loading on the strut top is minimal though. I simply don't believe people that say they've fitted a strut brace to a road car and felt an immediate difference - either their car was literally falling apart or they have an active imagination. A proper brace on a track car may be useful.
An awful lot of strut braces are also just decorative trinkets. Anything with a bend in it is immediately compromised, and the alloy ones with a thin oval section are just a joke.
Braces on the lower arm attachment points can be useful on some cars, this is where the real loading takes place.
The only one I believed was a chap who fitted a chassis strengthening kit to his Pantwetter. Something you could see the chassis flexing on at ide before An awful lot of strut braces are also just decorative trinkets. Anything with a bend in it is immediately compromised, and the alloy ones with a thin oval section are just a joke.
Braces on the lower arm attachment points can be useful on some cars, this is where the real loading takes place.
kambites said:
An awful lot of braces, especially front ones, are clearly nowhere near rigid enough to actually do anything. 
That strut brace is a work of art!
I have one in the Volvo as standard. I can't decide if it's because it improves the handling above that of a normal saloon car or because Volvo thought the handling was st on the S60 that they had to throw one in. I suppose I could remove it to see what would happen.
I have one in the Volvo as standard. I can't decide if it's because it improves the handling above that of a normal saloon car or because Volvo thought the handling was s
t on the S60 that they had to throw one in. I suppose I could remove it to see what would happen.kambites said:
An awful lot of braces, especially front ones, are clearly nowhere near rigid enough to actually do anything....
/snip good stuff/
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