what a difference 10' makes...

[buzzer1955]

I had a couple of tyres fitted to the Trophy last week... The guy at the tyre place offered me a free tracking check so I said go ahead.

He put the lazer alignment gauges on and told me it was out as it was 0.5mm toe in. He offered to adjust it for £17.50 but I declined as I have a set of track gauges myself.


Using a pair of calibrated optical tracking gauges I measured the front track and found it to be parallel, I.E. 0 degrees. Just to be sure I checked with the wheels in 4 different positions to rule out any rim discrepancies.

I note the factory reccomended setting is 5' - 15' toe out so I set it to the middle at 10'

I have been out in it today and what a difference! the car is far less sensitive to tram lining and a lot less "figity" when you give it the beans!

Just goes to show that the equipment used in some garages is not as accurate as they would have you believe... the way he manhandled and banged around the tracking equipment... I can see why its out! I wonder how often their kit gets calibrated!

 

[Gardus]

I'd say never...

are you sure you didn't mean TOE IN? If I remember correctly, both front and rear tyres with oem value are / \ with the car goint "up", if you get what I'm saying.

 

[buzzer1955]

Auto data tells me that the setting is Toe out \ / with the car going up! unless anyone knows different? certainly feels much better to drive.

Anyone like to comment on what the front track should be?

 

[Gardus]

Usually if you set the front tyres toe out the car tends to follow every variation of the road, you can get down the power better out of the corners but it's less stable at speed too.
Toe in the car is more stable at high speed.

At the rear toe out means the car will oversteer and be more agile, but it'll be more unstable, especially in the wet. Toe in and the car wil be more "safe" but it'll understeer.

Usually the oem value for FWD cars are toe in both front and rear. Maybe the trophy has different oem values than other RS?

 

[daddycool]

i've got a hunter alignment on mine booked in for this saturday. settings for the cup should be 0 degrees +/- a 10' (or 0mm +/- 1.2mm). is it worth asking for that extra 10' on the toe in, or leave the hunter to work its magic?

 

[Gardus]

Wait, what's that +/-1.2 mm? Is that tolerance?
Because from -1.2 to +1.2 there's A LOT of difference in the handling of the car!

Next time I'm going to have the front at 0 (instead of -2 mm as it is, it's just too camber sensitive on straight country roads...turn in is very good though!), rear already is...do you have camber bolts?

 

[daddycool]

yeah tolerance i think. half a mm tolerance each side isn't that much though

 

[Gardus]

If it +-1,2 the total difference is 2,4 mm and that's not small...

 

[daddycool]

true, but it will only ever be 1.2mm from zero toe, be it in or out

not my figures mind, taken from renaults own technical document for the cup

 

[Gardus]

Well, 1.2 is not small either, especially if you ave different values between right and left sides or between front and rear.

I think the perfect setup is somewhere between 0 and -1 mm at the front, with as much camber as you can (1,5°~2,5°), and 0 or +1 mm at the rear (not sure about camber, but standard should be ok). On my car this was done with shims at the rear and camber bolt at the front.

 

[daddycool]

different values either side would only affect the angle of the steering wheel, it would still track straight if both sides added up to, for example, +/-1.2mm

standard figures for 172 cup are:
rear toe is -0*32' +/- 10'
front camber -0*32' +/- 30'
rear camber -1*30 +/- 20'

 

[Gardus]

Anyway. the camber is the most limiting factor, 0°30' is not enough!

 

[daddycool]

my knowledge on camber only extends to what i see the touring cars running on the tv but i can see that more negative camber gives you more grip round corners

 

[Gardus]

That's true but the amount of camber is very dependable from the kind of tyre you use, slick tyres can get 4-5°, road tyres 2-3°.
And if you do a lot of motorway is better stay with the oem values, to avoid irregular wear.

On the rear is even harder to understand what's the best.