Changing Thrust Angle

[colgy]

Hey guys, looking for some advice with regards to my 182 FF's dodgy handling! Just had 4 wheel alignment checked which flagged up excessive camber on the left (which you could feel!) and a small steer ahead due to the difference in front toe. I'm looking at get the front camber sorted (camber bolts inbound!), altering the front right toe (to get the steering wheel straight) and leaving the rear right toe (looks ok underneath, can't see any play etc - technically within tolerance).

My question is, what about the thrust angle? The rear wheels are effectively pointing 9 mins to the left so should I ignore it or have the front toe adjusted around the thrust angle; basically set the front left to -21 mins (-12 with 9 mins more toe-out) and the front right to -3 mins (-12 with 9 mins more toe-in) instead of -12 mins each?

Hope thats not too confusing!:S

 

[KevF182]

Like how you have made notes! I agree with you totally on your settings and effects of any changes.

Do you have any clues as to why it's out of alignment? I think your plan is sound but just make sure its not anything worn otherwise you'll just be masking a problem.

It's possible to use shims to adjust rear toe and camber. Personally, I'd rather set front toe to take into account the slight rear thrust angle, like you say.

 

[TheEvilGiraffe]

WTF's the thrust angle ?!

Is your car running regular or aftermarket suspension.. coilies/springs etc..

 

[KevF182]

WTF's the thrust angle ?!

rear wheels should have equal toe. This will make it track straight. If different to each other then it will have a steering affect called thrust angle

 

[colgy]

WTF's the thrust angle ?!

Is your car running regular or aftermarket suspension.. coilies/springs etc..

Just the stock suspension; If you imagine that the rear wheels were both pointed 45 degrees to the left (so left: toe-out, right toe-in) then the thrust angle would be 45 degrees to the left. Similar thing with the front, except that the front is called 'steer ahead' as if both front wheels pointed in the same direction then the car would turn and you'd have to drive with a bit of steering lock on to go straight! My steer ahead isn't zero, so that's why my steering wheel is slightly off centre.

Jengis, cheers for that; my concern for the back is that it's still within tolerance that Renault specify and it might be a pain to get 0.3 degrees with a shim. You think I should go with -21 FL, -3 FR then? Would this not result in a 9 minute steer ahead angle mean that the steering wheel wouldn't be straight in relation to the front of the car?? I've recently fitted 2 new rear dampers but they were a straight bolt on/bolt off job with no adjustment - is there anything in particular I should be looking for as I don't fancy dropping the rear axle!

 

[rich-6]

Somethings either worn out or bent to get that much camber on standard suspension and no camber bolts, even if the toe was a long way out you wouldnt be able to achieve that!

 

[colgy]

Somethings either worn out or bent to get that much camber on standard suspension and no camber bolts, even if the toe was a long way out you wouldnt be able to achieve that!

Yeah that's my worry! Underneath looks ok, just need to check the top mounts next

 

[01chris02]

Do you know anyone near you with a clio with the same suspension? You could try swapping some parts about to see if you can determine which bit is messed up? Just an idea.

 

[Jay Payne]

WTF's the thrust angle ?!
.

A term they use in porno production? :S

 

[Jay Payne]

My question is, what about the thrust angle? The rear wheels are effectively pointing 9 mins to the left so should I ignore it or have the front toe adjusted around the thrust angle; basically set the front left to -21 mins (-12 with 9 mins more toe-out) and the front right to -3 mins (-12 with 9 mins more toe-in) instead of -12 mins each?

Tbh id leave the rear, its not that bad. The rear beams are a bit flimsy and any fiddling with it would be undone when you next hit a pot hole. You can adjust the fronts to get the rear square but personally I dont like it done that way. Ive always got the front setup with the wheel straight. Seen it done so many times where the thrust has been dialed out and its all 'spot on' on the machine only to find the steering wheel miles out when road tested.

To show how s**t the rear beams are, ours was setup and shimmed to give -2deg camber both sides. Did 50 laps of mallory park, end result. Driver side -1deg passenger side -3deg. had to move the shims all to one side of the car to even it back up

 

[colgy]

Tbh id leave the rear, its not that bad. The rear beams are a bit flimsy and any fiddling with it would be undone when you next hit a pot hole. You can adjust the fronts to get the rear square but personally I dont like it done that way. Ive always got the front setup with the wheel straight. Seen it done so many times where the thrust has been dialed out and its all 'spot on' on the machine only to find the steering wheel miles out when road tested.

To show how s**t the rear beams are, ours was setup and shimmed to give -2deg camber both sides. Did 50 laps of mallory park, end result. Driver side -1deg passenger side -3deg. had to move the shims all to one side of the car to even it back up

Yeah I think I will to be honest, steering wheel is probably the most obvious thing when you're driving it. This car is supposed to just be my run-around to keep the miles off of my vx but I can't help getting sucked in and tinkering - I love it!

 

[jack_davey]

2 shims from pure-motorsport would sort the rear toe.

The smallest shim they do is 10 minutes which is about 0.17 degrees.

You want a 10 minute shim on the nearside to increase toe, and a 10 minute shim facing the opposite direction on the offside to decrease the toe.

Got the rear geometry absolutely bang on with both my 182 and my girlfriends, you can feel the difference.

 

[colgy]

2 shims from pure-motorsport would sort the rear toe.

The smallest shim they do is 10 minutes which is about 0.17 degrees.

You want a 10 minute shim on the nearside to increase toe, and a 10 minute shim facing the opposite direction on the offside to decrease the toe.

Got the rear geometry absolutely bang on with both my 182 and my girlfriends, you can feel the difference.

I think it would just be one shim I needed - the RR wheel is within 2 minutes - close enough for semi-independent suspension! I'm concerned that faffing about will change something else or it will wander like Jay mentioned; the Pure Motorsport description seems to imply that the axle might not even be straight anyway! I love my little car, but at the end of the day it's a car with basic rear suspension, not sure it's worth it just for road/motorway use.

Was it easy to fit by the way?