Bump steer spacers opinions

[Bert Poliakoff]

Several members have replied to my bump steer spacers.
Being that I am not an engineer type, it' is beyond me to figure out the size spacers to use. The theory used by a fellow on the e24 forum, is inch of spacer to inch of drop. That sounds pretty aggressive to me so some opinions or even facts please.

 

[E911]

I suspect its less than a 1:1 ratio. I'll ask a couple people in the Porsche world since it's so common. I only know of one size for 911s... I'd guessing .5" per 1" of drop would suffice.

 

[bdigel]

it has nothing to do with how much you dropped the car, it is about correcting the angle of the control arms and tie rods , an inch drop in ride height really isn't that much . Also to give a heads up when you fix bumpsteer with spacers on the outside you loose clearance between the arms and the wheel , an inch spacer more than likely will not clear with normal wheels

you can kinda see the spacer here , The car is dropped as far as I can , forgot what I have the height set at currently , notice the lack of clearance with the wheel , and this a 16 inch wheel with thin barrels

FYI , AKG sells spacers that should fit those spindles

 

[bdigel]

https://www.akgmotorsport.com/product/bump-steer-correction-spacers-bmw-e12-pre-1983-e24/

No affiliation

 

[Bert Poliakoff]

AKG is a well known provider. My reason for getting into this is that AKG only makes the spacers in 1/2" sizes, as does anyone else making them. So the reason for doing this is to offer options no one else does. I can do these in any size you want no matter how small or thick you want. In addition, I provide the domestic shipping costs in my prices.

 

['69 2800cs]

I have the AKG spacers waiting to go in, FWIW, though I like the idea of custom sizes.

My opinion is it's pretty close to a 1:1 ratio, to get the steering parts and A arms back in to the range they were designed to work in. That means spacers of 2 and 3 inches would be useful, given how much some cars are lowered. However, as noted, they will not fit. Below is a look at my strut with 14" wheels, I bet I could use an inch spacer before the ball joint would hit the rim. In the 911 world it's the same, the amount you can "raise the spindles" is driven by your wheel diameter. Larger diameter wheels, the more "spacer" you can use.

Which brings up another point. In the 911 world, the "correct" way to lower the car is to raise the spindle on the strut, then bend or adapt the steering linkage with spacers back to stock geometry. The benefit of doing it this way is getting the steering linkage right, same as these spacers but it also preserves wheel travel. So, if you lower the car a bunch and use large spacers like this, you have better geometry but you are still running the suspension near the bump stops unless you also shorten the strut and use a different insert. That is where I am headed, eventually, now that I have a welder.

All that being said if you can verify an inch spacer would fit 14" wheels that would be a useful size.