mx5cartalk.com

I know a few questions have been asked about alignments lately

But I have another one, lol

Ive had the alignment below put on my NB8B (lowered with Tein Coils) and i've found it understeers quite a bit when pushed hard.


Front

Caster: Maximum
Camber: -1.5°
Toe out 1/16" per side (2mm)

Rear

Camber: -2°
Toe in 1/16" per side (2mm)

So can anyone suggest a way to remove the understeer?

Or even a better alignment

Cheers everyone

What spring rates, ARBs f&r and tyres are you using, as all these three items can affect the handling balance..

The spring rates for the Teins are 336lbs front and 252lbs rear.

What are ARB's?

Tyres are (unfortunately) Hero Milanza HZ1's (205/45ZR16)

Cheers

ARB is Anti Roll Bar (also called sway bars)

Spring rates seem ok ratio wise (about 1.5:1 seems best eg 300f, 200r) so yours if anything would lean more towards oversteer than std, not understeer. (336:252 is 1.33)

Front and rear anti roll bar sizes, or incorrect tyre pressures may be the cause, or could simply be carrying too much speed into corners...

Cheers, the sway bars are standard. My tyre pressures are 34psi Front and 36psi Rear, I keep wondering if my approach is too fast, if I slow it down I feel like i'm going to slow, lol. Maybe I need a few tips from you guys, lol

I would say ditch the tyres and get something really really decent

As per JCS + same tyre pressures front/rear and maybe a bit less negative camber on the rear.

Alignment figures look great for a lowered NB that’s set up for both spirited driving and the odd track day every month or two.

I’d agree with JBT on tyre pressures, get them even and down to around 31-32 psi on the road. Next adjust your driving style for corners, slower on the entry, faster on the exit.

You have reached the point that most of us have at sometime where alignment settings can only go so far and the next step is adjustable sways and shocks.
I suspect that you are running the standard shocks and if your car has more than 80K on the clock then there is a good chance that they are on the way out

Thanks guys, I will bring the Tyre pressures down a little and make them the same, plus my shocks are probably finished 120k on the clock. I'll try and adjust my driving style a little, cheerss

Okay, so i've dropped the tyre pressures down to 32psi, and the car seems to be much more neutral, most of the understeer is gone, still a little bit of understeer.

I'm ordering some adjustable signature swaybars next week, so we will see how they go on the car, i've thought about a rear strut brace aswell, suppose it can't hurt to get one, can anybody suggest the best ones to look for and where I can get them?

Cheers

Matty

Hi,

Do you find that your car has good turn in initially, but then at about 1/2 of turn of lock on, the understeer creeps in?

If so, I would suggest losing some of the caster. If the above it true, the understeer will probably be the result of the camber increases as the wheels are turned, ie the caster. I have dríven a few cars with a lot of caster, skyline, AE86, mx5 and nearly always find caster to cause the above characterics.

As with any alignment, the angles working in harmony, so the impact of caster will also depend on the initial camber angle.

Si

Caster angle is very different in a car like an MX5 with double uneven arms compared to a car with struts. The best and common approach for caster is to set the negative camber at maximum and then adjust to keep as much neg camber with a minimum of 4 degrees positive castor. More than 4 is good - less than 4 is not so good. Toe out on the front of an MX5 is not good generally. Toe out is used on the front of a car to help it turn - MX5's don't need help to turn. Toe in on the rear however is good and helps to keep the rear in sync with the front during cornering and braking. Having different camber front to rear on the road is not usually a good setting on an NB and will promote understeer/oversteer depending on the bias. Mostly, zero front toe and 1-2mm total rear toe in is a sensible setup. When lowered, make sure the lower control arms on the front are no less than parallel to the ground when measured through the lower ball joint bolt and the lower control arm bolts. This is common and induces bump steer. As the NB series cars are also stiffer in the chassis than the NA, they do like a larger rear way to compliment a larger front sway. Most NAs appreciate a softer rear sway.

i have + 0.9mm total toe on the rear and - 1.2 total toe on the front. is that bad?

Hi Si.G,

Yeah that's exactly the kind of understeer I'm experiencing. Maybe I will try and reduce the amount of caster, I may also try what CT suggested, I suppose if I just keep playing with the alignment setting I'll find something I like. The car does seem really balanced now though, very little understeer and I can get oversteer if I'm being silly

But once I get the ADJ Swaybars I'll have start all over again I'm guessing? Lol

Cheers

Matty

Si.G wrote:Hi,
If so, I would suggest losing some of the caster. If the above it true, the understeer will probably be the result of the camber increases as the wheels are turned, ie the caster.
Si

???

High caster would give more negative camber as the wheel is turned (dynamic camber) so should give less understeer not more...