Wheel geometry settings - wheelbase?

[Finn]

I'm due to four wheel alignment today after a complete suspension/brake/tyre+wheel rebuild. I will be getting it done according to TRD settings shown in the sticky topic ie.

TRD setup:

toe-in:
ft=1.6mm
rr=3.2mm

castor = 6 deg

camber
ft= 1 neg
rr= 1.5 neg

My question is as follows:

What should the wheelbase be set at?

I mean that by adjusting the forward/rear pointing arms you can move the wheels to some extent fore/aft and I would like to have the wheelbase at factory setting. Now I feel that the wheels are not centered within the wheel opening.

EDIT:

Some source says the wheelbase is 2319 mm. Can you verify if that is correct?

[cartledge_uk]

Adjusting the forward/rear pointing arms adjusts 'castor' (where the wheel sits in the arch). I'm not sure what the factory settings are, but you may have more luck searching for castor.

A lot of the digital places have the settings programmed, so should be abl to adjust them, although a lot of people dont touch the castor.

[elbon50]

Track (side to side) & wheelbase (fore & aft) are just measurements of the car's stance on the ground Finn

You don't need to set them

Toe-in & camber are the main settings to be concerned about

Castor action has to do with the steering's ability to auto centre

If you have stock fore & aft arms with rubber bushes then adjusting them just tends to squash the bushes one way or t'other rather than altering castor very much

Tein pillowball arms are much more adjustable

[Finn]

Thanks guys.

There's no rubber bushings left in the car, everything is urethane now.

So as long as also the castor checks too, then everything including wheel positions should be OKish.

[elbon50]

Thanks guys.

There's no rubber bushings left in the car, everything is urethane now

Yes, urethane squashes too Finn

So as long as also the castor checks too, then everything including wheel positions should be OKish.

What I would do, as a final check is to see if wheelbase (hubcentre to hubcentre) is same at both sides

[Finn]

Yes, urethane squashes too Finn

Yes, but just fractions compared to the original rubber thingys.

Urethane in suspension bushings is good - I took urethane motor mount bushings off after two days and installed brand new factory mounts instead. Could not stand the vibration and resonance.

What I would do, as a final check is to see if wheelbase (hubcentre to hubcentre) is same at both sides

Good idea, we'll do that.

[elbon50]

Urethane in suspension bushings is good - I took urethane motor mount bushings off after two days and installed brand new factory mounts instead. Could not stand the vibration and resonance

Yes, probably depends on the specific formulation of the urethane Finn

The bushes I had from Peter G squashed quite a lot (although a big improvement on rubber)

I have some Tein pillowball arms to put on now

[Finn]

Mine are black Prothane kit from Twos R Us and they seem fairly solid.

Cannot wait to get the car on the road all aligned and with new wheels and tyres.

[IanParkhouse]

Just remember that mm setting will change with wheel diameter so if you're not on 14 inch wheels the mm setting swill be out. The alignment place I use requires measurements in degrees

[Finn]

Right. We got the setting to following:

toe-in:
ft=1.6 mm
rr=3.2 mm

castor = 6 deg

camber
ft= 0.5 deg neg
rr= 1.5 deg neg

I would have wanted a full degree negative camber but the offset adjustment thingys were at max. Are there adjustable camber plates available for MK1?

Anyway, as soon as I backed off from the lift I noticed how easily and lightly car moves now. On the highway it goes straight effortlessly and there's no need to steer much if at all to keep the line.

In the twisties it's now like a go-kart.

These Hankook Ventus V12 Evo K110 tyres in 195/50-15 size feel great.

[trunks_mk1]

how does the stance look? how it drive now with the TRD setup?

[Finn]

how does the stance look? how it drive now with the TRD setup?

Stance is pretty much the same as before alignment ie. as in the photo below



It has Koni adjustable kit SSK234 with -30 mm Lesjofors springs. I now have one full turn rebound up front and 1.5 turns in the back and it is nice, really nice. Not hard with 195/50-15 tyres by no means. Needs maybe a quarter to half a turn more rebound but that's something to test.

I have stock 19/13 mm ARBs on the car and I 'feel' they could be stiffer. On the other hand this serves as a daily driver in the summer so better it's not too stiff.

[Adam W]

That's exactly the same as my old setup. I then added a whiteline rear ARB and it really improved things, got rid of a lot of understeer and made the car feel really "pointy" as it turned in. Adding the ARB didn't affect the ride quality as far as I can recall.

[elbon50]

That's exactly the same as my old setup. I then added a whiteline rear ARB and it really improved things, got rid of a lot of understeer and made the car feel really "pointy" as it turned in. Adding the ARB didn't affect the ride quality as far as I can recall.

Yes, I'd definately recommend a Whiteline on the rear Finn for the reasons Adam mentions

[Finn]

Thanks guys.

So the Whiteline rear ARB is this 18 mm one, right?

http://www.camskill.co.uk/m5b346s2378p1 ... 1_MR2_AW11

Price is fairly reasonable.

[stenky]

http://www.camskill.co.uk/m5b346s2378p1 ... 1_MR2_AW11

Price is fairly reasonable.

it looks like there's no better place to get whiteline ARB from in europe i will get mine from camskill as well