camber bolts required?

[envy2]

Okay so I order a set of Bilstein PSS. I will be leaving it at the highest height setting so I will only be getting the estimated 30 mm drop so the question is do I need to get camber bolts? I heard some says no if the drop under 1.5 inch while other says yes if lower more than 1 inch (30 mm = 1.18"). I just don't want to be at the alignment shop only to find out I need them. Thanks.

 

[DrWebster]

My understanding is that the rear alignment is set at the factory and is not adjustable, so if you change the suspension geometry then you'll be out of alignment with no stock way to set it straight. Personally I'd go for the camber bolts, but others here should be able to chime in as to how out of alignment you'll end up without them.

 

[Mistersix]

You will be running a good bit of negative camber in the rear without adjustment.

So there are no after market alignment solutions for this chassis?

 

[flatlander937]

You will be running a good bit of negative camber in the rear without adjustment.

So there are no after market alignment solutions for this chassis?

It's a solid trailing beam rear axle... it does not camber in or out with bump/droop. The only toe change in the rear is minimal due to whatever flex is in the beam assembly under cornering loads(and maybe a minute amount due to the arc it goes in assuming it's not level). For our intents and purposes: the rear is completely non-adjustable without putting angled alignment shims between the rear wheel bearing and trailing beam mounting surfaces(assuming they're available).

The front does not need to be adjusted with camber bolts, it's a strut suspension, so your camber change will be essentially moot if you don't get camber bolts. That said if you find one side is just slightly off from the other, you can try slotting the bolt holes in the strut to get both sides even.

For the $30 or whatever it costs, I'd get them because camber in the front is the difference between taking corners kinda fast and making your passengers leave a poop stain on the seat because it grips so well... assuming you're into auto-x.

FWIW here's a thread with specs after lowering, no other changes... front camber is fine and in spec, but if he had camber bolts(or slotted one of the struts) then it would be possible to at least even the camber out left vs right. It wouldn't be necessary for a daily driver, but if you auto-x it's something that would be good to do.

http://www.mazdas247.com/forum/showthread.php?123813958-FYI-Lowered-2-and-no-alignment

 

[zps2004]

Camber bolts would only be needed in the front. The main question is what do you want to do with the car. If you want better performance than the camber bolts will help get you more negative camber which will help the front end turn.

Also the rear does have camber and tow change with ride height. Camber not to much, but the toe does change a good bit. I have the toe documented in my build thread. Either way there is no simple/cheap way to adjust it. Shouldn't be an issue with the ride height you are going for though.

 

[flatlander937]

The whole beam might flex/bushings flex, but the toe doesn't change in relation left vs right from any built in geometry(aside from the tiny amount I mentioned due to it swinging in an arc). It DOES change as a whole which is what you're experiencing. You are seeing the change in toe from a big change in the angle that the whole beam is at.


Vision this:

Beam is perfectly level front to back.

Toe in is 0.5 degrees total. Camber is 0.

angle the beam front upwards(or rear downwards. This simulates lifting the rear body end just like you did)... until the beam is at a 45 degree angle. Now you have 0.25 degree toe and 0.25 degree negative camber.

It's not completely independent like an IRS, if you gain toe on one side, you gain it on both as the car jounces... not toe in one one side and toe out on the other like just about every other car.

I do agree that limiting the toe in the back with the rear beam brace deal/"sway bar" will help though with your rotation problem.

(Nice build by the way... I went there to look for the toe change thing and ended up reading the whole damn thing about. You've got similar goals as I do with my 2... mine is black as well, hope to start fiddling with it in a few months)

 

[zps2004]

but the toe doesn't change in relation left vs right from any built in geometry(aside from the tiny amount I mentioned due to it swinging in an arc)

It does in roll. Also the position of the mounting points of the twist beam does effect the toe and camber changes of the suspension as it moves, so you can design it in just like any other suspension design. It just takes a different analysis to see what it is doing.

not toe in one one side and toe out on the other like just about every other car.

Umm when you lift the rear of any car the toe will change in the same direction on both sides(either in or out). Now when a car rolls you can get one side to do something different than the other, but the twist beam in the rear of our car does the same thing.

Thanks for the comments on my build thread. I will have a number of new things to put on there later this month hopefully.

 

[flatlander937]

It does in roll. Also the position of the mounting points of the twist beam does effect the toe and camber changes of the suspension as it moves, so you can design it in just like any other suspension design. It just takes a different analysis to see what it is doing.

You know what you're right, was visualizing it as only a beam, not thinking about beam in relation to vehicle centerline. Oops!(whistle)

Umm when you lift the rear of any car the toe will change in the same direction on both sides(either in or out). Now when a car rolls you can get one side to do something different than the other, but the twist beam in the rear of our car does the same thing.

Thanks for the comments on my build thread. I will have a number of new things to put on there later this month hopefully.

Yes I was talking about in roll, same as above wasn't thinking of the whole picture.

Doh.

Edit: a good way to test might be to pull a rear spring while its on the alignment rack(knowing the actual alignment before hand), and maybe provide some additional persuasion with straps to see just how much change is going on(not counting bushing slop and beam flex under lateral loads).

 

[envy2]

I guess its better to buy it and install it and not need it then need it later on and having to install it. Anyone done their own alignment? I've been researching the quicktrick alignment kit and it's looks pretty solid + straight forward. Since with this I can drop it and align it for autox and then set it back to the normal setting for street use. There is only 10 autox event for the season spread across 6 months.

 

[DanR]

I am new to front wheel drive and learning after driving a miatas for 12 years. On the highest setting, my car dropped about 1 1/4'' in the front. I haven't had the car aligned yet, but it visually looks like it has more camber both front and rear. Other than adjusting the toe, I don't think there is much to adjust if you don't have the camber bolts or slot the car. I plan on getting them when I have the car aligned.

 

[zps2004]

I use these for doing my alignment.

http://www.longacreracing.com/products.aspx?pagename=Product Details&itemid=1709&prodid=7236

For camber I use a digital angle guage.

 

[envy2]

Where you get your digital angle gauge since the Quick Trick kit is kind of pricey. Then again the longacre complete kit is about the same also. It would be nice to piece one together at a lower cost.

 

[zps2004]

I would just go on ebay and look for digital protractor. Should be able to find a good high quality one at a cheaper price because it is used. As long as you always use the same one your readings should be good and consistent.