Front lower control arm of Subaru Impreza and Brz

[ysyy88]

why they reverse the triangle arm？
because no drive force on the front wheel of brz？

[marcush.]

reverse in what ? putting one leg paralell to the axle line and and the other forward is not reversing in my view .
It may be package constraints , production demands and of course cost that lead to solutions like this.

I think it is something owed to FWD layouts ,the Mcpherson strut seems very front wheel drive as well...so maybe they borrowed the whole front suspension from another car or produce the car on a FWD assembly line..

[ysyy88]

reverse in what ? putting one leg paralell to the axle line and and the other forward is not reversing in my view .
It may be package constraints , production demands and of course cost that lead to solutions like this.

I think it is something owed to FWD layouts ,the Mcpherson strut seems very front wheel drive as well...so maybe they borrowed the whole front suspension from another car or produce the car on a FWD assembly line..

the hypotenuse at the front of arm or back of the arm

[ysyy88]

reverse in what ? putting one leg paralell to the axle line and and the other forward is not reversing in my view .
It may be package constraints , production demands and of course cost that lead to solutions like this.

I think it is something owed to FWD layouts ,the Mcpherson strut seems very front wheel drive as well...so maybe they borrowed the whole front suspension from another car or produce the car on a FWD assembly line..

these bmws

E90 325xi and 325i

[marcush.]

even the two pics you posted show one similar to the subaru ,no? The E90 325i angles the forward leg of the wishbone far to the front of the car and has the rear leg paralell to the axle line ...

[Greg Locock]

For some reason i can't see any of your pictures.

In a conventional modern MacP it is always advantageous to have one link directly in line with the wheel centre, as this provides your lateral compliance and is part of the steering parallelogram.

The choice is then where to locate the other inboard bush.

It can go forward or behind the wheel centre.

Often it is driven by the rack location - there ar e compliance advantages in having the rack and the bush on the same side.

Rack location is usually fixed by the engine packaging.

However if we ignore that - Forward is worse for crash, and tends to be worse for impact harshness.

However I would guess in 90% of cases it is driven by packaging and nothing else.

[Tim.Wright]

I'd agree about the packaging being the main constraint.

What's the effect of the rack position on impact harshness? Can't get my head around that one.

[Greg Locock]

Body is stiffer further back, therefore the impedance mismatch between the bush and body is greater.

[olefud]

I can’t get your illustrations either. But as I picture it, the forward arm would load in tension under braking. Generally, it’s better to load in compression, but expect either is sufficiently strong. But this may be what looks odd.
The design may well have come from front-wheel drive. The drive loading on the A-arm isn’t as high with FWD but the steering feedback from lash is more noticeable.