If anyone wants more information, or a dissertation if you will, Carol Smith literally wrote the book on this subject. Its deep, its involved, but its darned correct information.
I think it’s also important to note that BMW and Porsche don’t do their McPherson Struts like anyone else. They don’t have the usual one piece solid lower control arm on each side with a pair of bushings (front and back) and one piece of balljoint. On the BMW and Porsche cars there is usually more than one balljoint at the bottom per strut, probably to mitigate one of those disadvantages mentioned in the video. Kinda similar to Honda’s “dual-axis” and Toyota’s “super strut”. The Japanese brands have a brand name for this style of McPherson Strut while for BMW and Porsche it’s just a normal thing.
Two piece lower section. Allows for a sweeping motion on the lower section of the strut. That small sweep is magnified when in compression, counter act to the caster effect on rotational axis.
Maybe I'm missing something here. BMW and Mercedes use a double joint McPherson strut on the front of their smaller cars (E90, W203). But I don't see this on my Carrera or a 991 gt3 (last GT car with McPherson)
It is called multi-link suspension and can be better than double wish bone. Instead of a wishbone they put two links Each link can be designed to alter the performance of the car.
Thank You for the visuals. I learn better with them. Words can only do so much. I’m sure a lot of people will still overly space their wheels on McPherson and not know what bad handling is.
I think the camber curve being a bit worse on the strut is overstated. The elastokinematic camber loss is noticeably higher in all the K&C I've looked at on strut cars vs ML/DWB cars, and that's not dependent on suspension travel, so you're gonna get a noticeable difference in a racecar as well, where the suspension travel is low enough for the camber curve not to matter so much compared to potentially worse elastokinematics that only get worse with more lateral force. The alignment issues are present on a DWB/ML setup as well; changing the arm lengths to align camber into the tire will also change the SAI and a little bit the scrub radius of a DWB/ML geometry. Some geometries do it more independently, but it's quite rare, certainly in racing. If you're not changing arm lengths, you'd be changing joint positions, which will do the same to the SAI anyway. Changing arm lengths will also change the kinematic curves, so it's more complex and you will need to tinker with more arms to maintain good bumpsteer, antis, elastokinematics etc., as opposed to a strut where changing camber via a strut top will typically not influence the other curves very much.
It's interesting to me that my GTI has double wishbones in rear and Mcpherson strut in the front. The struts are almost certainly for "packaging", and the double wishbones guarantee that the car understeers for "safety"?
We raced 911s in the '70s. Wider wheels, coil over McPhersons, bump steer mods, shorter 930 trailing arms, but we still reached a plateau in handling performance. In '75 I took our 911 chassis to a NASCAR shop. Bingo, problems solved. Weight shaved off. Tube chassis welded in. Then super heavy springs and locked diff. Finally the RSR was perfect.
So I'm running coilovers on an S5 with a strut up front, two upper control arms and two lower control arms with slightly stiffer bushings. Is this a double wishbone set up? I believe in the shop literature it's listed as multi link but I'm not sure off the top of my head.
I guess the biggest disadvantage if McPherson struts are the change if the caster in relation to changing the turn if the wheel, it goes so far into positive that Tyre is basically runs on the 1/3 of it's width on the outside wall, and that's why porsche 911 has to have so much of a camber to maintain the caster in desired value while turning, so the contact patch doesn't go off to the outside wall. It fixed in double axis McPherson struts, but its a wonder why porsche engineers remain faithful to the basic design.
Caster on strut and DWB works the same. The strut top is effectively just an upper balljoint. More caster is beneficial for performance, providing negative camber on the outside wheel.
I’d like to see that just to compare. No one ever complained about any 911 steering till the 992 gt3 came out, then all of a sudden it’s a game changer. One TH-camr went on an on about the 992 steering then a few videos later jumped in a 997 gt3 and declared it the best Porsche steering ever 😳…. most of this guys (not Mike) are just parroting what others say
@@frederickcook87 another thing to note is that “better suspension feel” doesn’t make the suspension magically perform better. A lot of the time good suspension for maximum grip doesn’t actually feel good to drive especially for street cars.
Haha... "The Cayenne has a better suspension than my 911..." Yeah. Tell me about it. I have a Guards Red 930... Only tried to kill us both three times. But I forgive her, 'coz she's pretty and I'm a red-blooded man 😉🤣
If anyone wants more information, or a dissertation if you will, Carol Smith literally wrote the book on this subject. Its deep, its involved, but its darned correct information.
Niiiiiice. I will get it, then!
I think it’s also important to note that BMW and Porsche don’t do their McPherson Struts like anyone else. They don’t have the usual one piece solid lower control arm on each side with a pair of bushings (front and back) and one piece of balljoint. On the BMW and Porsche cars there is usually more than one balljoint at the bottom per strut, probably to mitigate one of those disadvantages mentioned in the video. Kinda similar to Honda’s “dual-axis” and Toyota’s “super strut”. The Japanese brands have a brand name for this style of McPherson Strut while for BMW and Porsche it’s just a normal thing.
Two piece lower section. Allows for a sweeping motion on the lower section of the strut. That small sweep is magnified when in compression, counter act to the caster effect on rotational axis.
Thank you. There we go. Many live by the books and argue double wishbone > struts blindly lol
Maybe I'm missing something here. BMW and Mercedes use a double joint McPherson strut on the front of their smaller cars (E90, W203). But I don't see this on my Carrera or a 991 gt3 (last GT car with McPherson)
It is called multi-link suspension and can be better than double wish bone. Instead of a wishbone they put two links Each link can be designed to alter the performance of the car.
@@cognition26 I’m taking about the McPherson strut on the front. Technically it’s kinda “multi-link” but still a McPherson Strut.
Thank You for the visuals. I learn better with them. Words can only do so much. I’m sure a lot of people will still overly space their wheels on McPherson and not know what bad handling is.
I think the camber curve being a bit worse on the strut is overstated. The elastokinematic camber loss is noticeably higher in all the K&C I've looked at on strut cars vs ML/DWB cars, and that's not dependent on suspension travel, so you're gonna get a noticeable difference in a racecar as well, where the suspension travel is low enough for the camber curve not to matter so much compared to potentially worse elastokinematics that only get worse with more lateral force.
The alignment issues are present on a DWB/ML setup as well; changing the arm lengths to align camber into the tire will also change the SAI and a little bit the scrub radius of a DWB/ML geometry. Some geometries do it more independently, but it's quite rare, certainly in racing. If you're not changing arm lengths, you'd be changing joint positions, which will do the same to the SAI anyway. Changing arm lengths will also change the kinematic curves, so it's more complex and you will need to tinker with more arms to maintain good bumpsteer, antis, elastokinematics etc., as opposed to a strut where changing camber via a strut top will typically not influence the other curves very much.
Thank you for this. This conversation is gold.
Glad you liked it! More to come!
*Sees Mike Kojima in the thumbnail*
*Liked the video*
*Subscribed*
*Finally, watching*
I used to work for mcs, I've built some of yalls dampers
Super informative!!! Where can I find your allignment recommendations for a 911 GT3?
Those aren’t published but available from us with our suspension arm packages or with MCS packages…
Ah yes the Dave point. I miss the SCC days
It's interesting to me that my GTI has double wishbones in rear and Mcpherson strut in the front. The struts are almost certainly for "packaging", and the double wishbones guarantee that the car understeers for "safety"?
I'm sitting here with a rear twist beam, I guess the tarnished silver lining is thats its a fwd.
We raced 911s in the '70s. Wider wheels, coil over McPhersons, bump steer mods, shorter 930 trailing arms, but we still reached a plateau in handling performance. In '75 I took our 911 chassis to a NASCAR shop. Bingo, problems solved. Weight shaved off. Tube chassis welded in. Then super heavy springs and locked diff. Finally the RSR was perfect.
AMG runs decent negative camber and toe out. Makes those heavy cars handle but chews up tires.
So I'm running coilovers on an S5 with a strut up front, two upper control arms and two lower control arms with slightly stiffer bushings. Is this a double wishbone set up? I believe in the shop literature it's listed as multi link but I'm not sure off the top of my head.
I guess the biggest disadvantage if McPherson struts are the change if the caster in relation to changing the turn if the wheel, it goes so far into positive that Tyre is basically runs on the 1/3 of it's width on the outside wall, and that's why porsche 911 has to have so much of a camber to maintain the caster in desired value while turning, so the contact patch doesn't go off to the outside wall.
It fixed in double axis McPherson struts, but its a wonder why porsche engineers remain faithful to the basic design.
Caster on strut and DWB works the same. The strut top is effectively just an upper balljoint.
More caster is beneficial for performance, providing negative camber on the outside wheel.
Yes, In off-road you will almost always see double wishbone due to the amount of travel.
@@jasgap Well, DWB is typically used in offroad applications because there's more, stronger elements to absorb impacts.
The miata is very simple car that handles great and its not very expensive
yup....yup yup..... yup
How many times this guy said yep, sure?
How about adapting the 992 GT3 RS front suspension to the Cayman GT4 RS?
Can't slap double wishbones on a chassis that only has strut mounting points
Hope someone can come up with a option to take front strut to double wishbone say for a 992 Carrera T or 991, 997, and 996 models...
I’d like to see that just to compare. No one ever complained about any 911 steering till the 992 gt3 came out, then all of a sudden it’s a game changer. One TH-camr went on an on about the 992 steering then a few videos later jumped in a 997 gt3 and declared it the best Porsche steering ever 😳…. most of this guys (not Mike) are just parroting what others say
@@frederickcook87 another thing to note is that “better suspension feel” doesn’t make the suspension magically perform better. A lot of the time good suspension for maximum grip doesn’t actually feel good to drive especially for street cars.
I don’t think you understand what’s involved
Haha... "The Cayenne has a better suspension than my 911..." Yeah. Tell me about it. I have a Guards Red 930... Only tried to kill us both three times. But I forgive her, 'coz she's pretty and I'm a red-blooded man 😉🤣