GaryC

Just had my car (MY99) set to 'fast road spec' a.k.a. Prodrive settings.

Am amazed at:

1) the difference it has made to the handling

2) how far out it was before.

UK cars are supposed to be better 'set-up', but even so one front wheel dead upright, the other 4 degrees out!, no two measurements were the same!

Now it is done, it's a different car! Turn in is so much sharper, grip improved...everything. Especially with front strut brace fitted too

Had it done at ABP in Crewe. £90 all in. Took two hours. First rate service, kept me fully briefed, even showed me what they were doing etc.

Definite thumbs up!!

HAPPY

found exactly the same on my uk99 car.so very much better now and for only £38.

dave fairhurst

I have been waiting to get my geometry set up properly for a while and although all reports of ABP are good, it's a long way to go. Does anyone know a good place to get it done in the Milton Keynes/ East midlands area?

Cheers
Dave

GaryC

Really only £38? What garage charges £19 per hour? (or £13 given it can take 3 hours!)

I am used to paying £40+ for anyone half decent!!!

DocJock

Gary,

Fit strut brace involves remove and replace four nuts/washers - 10 mins max. DIY

2 hours 50 mins to reset geometry ???

Someones pulling your pl****r mate !!

J

Subarussian

I remember reading on this BBS that Prodrive geometry setting increases tire wear. Is this true?

SecretAgentMan

It's because of the increased camber, leaning the wheel more. The inner part of the contac area will be showing more wear.

Has anyone got the prodrive spec....?

JamesH

Secret Squirrel

Try the SIDC FAQ

Iain P

Just a note regarding tyre settings and tyre wear. I was sure that the settings on my RB5 were out (turn-in wasn't very sharp and understeered a bit too much for my liking)and seemed to be wearing the inside of the fronts too fast, so I got them checked. Bingo........ fronts had 0.5 deg of toe-out and the other settings were all over the place. Got them reset to -1 deg Camber and +10' toe-in (Prodrive recommended) and noticed a big improvement. Now have a more neutral balance with superb lift-off oversteer control. So as far as additional wear goes, the standard settings were more damaging. Got the settings done at Elite in Rainham (01708) 525577. Cost £58 and took about 40 minutes - they have the latest lazer set-up.

GaryC

Doc - strut brace actually only took 5 minutes - geometry relignment took just over 2 hours of solid work at ABP - I watched them do it, maybe they were over meticulous, I'm not complaining? Most places charge between £70 and £120 for Prodrive settings, so I guess most places take 2-3 hours!

Subarussian - the ABP 'fast road' spec, is not quite Prodrive settings, to prevent un-even tyre wear. This setting *won't* cause uneven tyre wear, although the better it drives, the harder you drive it, so wear probably will be greater

GranTurismo

Hello,

I had this done to my MY97 and it transformed the car (much less understeer). However I do beleive that Geometery is just the posh word for tracking and tracking must be done frequently to maintain it. Parking on kerbs and bumpy roads will knock it out easily. every 3-6 months is the usual, but uneven tire ware indicates a problem. I had mine done on a laser jig for about £45 (Camber and toe in as per FAQ).

Bye

Dave.

Stupot

Where is ABP???
Stu

ChrisB

Stu,

ABP is in a small village called Shavington, about equi-distant between Crewe and Stoke-on-Trent. It's actually behind the Esso petrol station.

From J16 of the M16 it's a run of about 10 to 15mins (their advert in Evo reckons about 5 minutes which is pushing it as Shavington is a 40mph limit).

Chris.

PhilBennett

Iain - I'm suprised that you noticed improved turn in with the front tracking toe in.

Are you sure?

SDB

Hi Phil

A touch of front toe-in will surely always help turn-in on a scooby as it compensates for bump steer?

Regards

Simon

PhilBennett

I don't follow your point.

Toe out will always help turn in - even if the Impreza increases toe out in compression then it still doesn't explain.

From the Impreza's I drove at Donington the Impreza doesn't seem to have too much of a problem under braking anyway.

Bob Rawle

Standard Impreza geometry induces understeer, the Prodrive settings are max equal neg camber both sides and 1 mm total toe IN fronts and same for rears. With anti lift kit fitted I run 1.5 deg neg both sides and 1 mm total toe at front with 1.1 neg bothsides and 2 mm total toe IN at rear. Handling is superb, no understeer and the car just bites at the corners with good poise and precision ... I repeat, no understeer and just a touch of rear oversteer in the wet.The anti lift kit transformed it ... evem my passengers at Donnington noticed the difference and on the road its brilliant.

Bob

PhilBennett

Hi Bob - yeah I'm sure it doesn't U/S but that would be more to do with the rear tracking and the increase in negative camber.

I just got confuesd with Iain's post talking of front adjustments.

Fullonloon

Hello

I am going to take visit to my local tyre guru either Wednesday or Thursday, and I would appreciate some advice. The handling doesn't seem to be that brilliant, partly through crap tyres which I will change, but also that the tracking has not been checked since I had the car.

So, for the Prodrive geometry settings, what do I need to say to the man (as he will probably not have the info.) What are the measurements for each wheel?

Thanks in advance.

Full > who has looked at the FAQ and has read other posts but can't find a clear answer...

Neil F

GaryC.

I can't beleive it took them so long to adjust these settings!
Toe in front and rear is as easy as any other car you've had (5 minutes?) and the camber adjustment is simple to do; there are 2 bolts holding the damper strut to the front hub assembly, aligned top and bottom.
The top bolt is a cam bolt, so once you release the nut, a small tweak with a spanner will rock the top of the hub assembly over to increase/decrease the camber.
This process should take no more than 10 mins.
Unless they are completely unfamiliar with the process or their equipment I think they have given you some flannel here.
I have had this process done twice by Elites in Rainham Essex and a whole "check and set" took 15 minutes start to finish each time.
They both came with a full geometry printout from their laser equipment.

Regardless of all that though, the handling is transformed by these changes and I suffer from little if any understeer in both the wet and dry (and I'm running crap tyres at the moment).

SDB

Hi Phil

I always understood front toe-OUT to help turn-in. Mainly because it does on go-karts

I was surprised to hear everybody talking about toe-IN to help turn-in when I first started reading this board.

Since then I have driven more scoobies on the limit that all but a small handful of people in the world, and have to say that, in the wet, a touch of toe-IN DOES help the turn-in. Maybe the camber means that toe-IN is more effective than toe-OUT. I'm not sure.

Do you have a detailed explanation as to why Toe-OUT improves turn-in?

Cheers

Simon

MorayMackenzie

Toe out would probably help turn in, if it were toe out on the rear wheels.

Moray
(Who has a little toe in on the front and no toe-out anywhere. )

GaryC

As I said, they, or rather he, was working for 2 hours solid. The rear wheels needed the shock absorber mount drilling to adjust to the proper camber which took 15 minutes in itself.

They are used to doing this, they do between 5 and 10 per week.


Either way - the positive affect it has had is easily worth the £90!

Neil F

This could be the clue to it all:
Prodrive detail the rear camber as "unadjustable" and therefore do not specify a setting. Indeed to adjust the rear camber would involve drilling the rear mounts. This in turn would involve at least partially if not fully removing the rear struts to gain access to the holes and have enough room to "swing" the drill. This would add considerably to the time required.
I would be interested to know what rear camber settings they achieved and where they were specified (I know that MRT in Australia offer slightly different settings to Prodrive?).
As said before though, if you are happy, then it's worth it.

Neil.

PhilBennett

Hi guys - I think I understand the confusion here.

I think you chaps are mis-understanding the phases of the corner and mixing up initial turn in with mid corner.

Your impression of toe in will be its affect at the rear of the car.

Front toe out will assist initial turn in NOT toe in - the misunderstanding here is that during initial turn in very little weight transfer has taken place. Once it has then we are into a different phases - entry, mid then exit.

They probably set the car up with front toe in for stability.

SDB

That's not the case Phil

Firstly the Load on the front of the car is at its maximum at the point of turnin if you are trailbraking heavily and this is when I have noticed the improvements.

I am the first to accept that I may have the wrong end of the stick, my technical knowledge is not the strongest in the world, but...

Front Toe in is not engineered in for stability, quite the reverse. Toe out IS engineered in for stability through bump steer.

I would still be more than willing to accept a new theory but the way I would understand it is...

It is obvious that when you turn right the load moves more the the left.
It is also clear that when the car is going straight, the wheels will be in theory pointing in or out (depending on whether there is toe in or out) by about the same amount. In other words the car is moving in a direction dead in the middle of these two angles??

So...

With Front Toe IN
-----------------
You start to turn right and the weight moves over to the left tyre. This tyre is pointing slightly more right than the angle dead in the middle of the two front wheels. With it's new found weight and therefore grip, it will turn the front of the car to the right slightly more that the initial steering movement might suggest?

If we took this to ridiculous extremes and had say 15 degrees of toe in. If you also had soft suspension, ans turned right suddenly and let go of the steering wheel, I would expect the steering to whip itself round to full right lock in a split second and turn right visciously??

With Front Toe OUT
------------------
The oposite happens, as you turn right the left wheel is turning less than the steering would suggest and therefore lessens the amount of initial turn-in.


Now AFTER turn-in (which we are not talking about), I am not as convinced. I would expect a touch of Toe-out to be necessary due to ackerman angles (only recently learnt that term and wanted to use it ), but I may be getting too deep.


This is only my understanding of it and should not be taken as genuine information. You sound as though you are dead sure so I would love to hear the technical explanation.

The fact DOES remain though, that scoobies exhibiting toe out at the front, also exhibit greatly reduced turn-in efficiency in the wet.

Cheers

Simon
PS. Sorry it's a long one

PhilBennett

Hi Simon :-)

This debate is good stuff.

The only thing is you are giving more detail to your senario.

"if you are trailbraking heavily and this is when I have noticed the improvements"

However this most certainly isn't the only way you turn in! You can turn in under power - as in Craner curves at Donington or Bridge at Silverstone.

You can have a neutral or balance throttle - as in McLeans (Donington) or Copse (Silverstone).

And so on..

Whilst your weight transfer theory would stand up - it will give instability so that what you feel is worse - I guess a good word would be darting. Such as having extreme toe OUT at the rear - yeah for sure it will turn in - but HOW!!

There is no way you could be consistant like this.

So I'm saying yeah your theory works but just re-enforces my point about not improving the turn in.

At the end of the day the job of suspension is to keep the tyre in contact with the road as efficiently as possible. I believe you set up a car for two reasons - one to maximise the above and two to give the driver confidence to drive to the limit.

For me too much front toe IN makes the car dart during corner entry then U/S like hell.

Too much toe OUT and the car may get into the corner but won't settle.

Maf

I read (can't remember where) that the toe-in on the Prodrive settings was aid stability (in a straight line I imagine) under braking i.e. to counteract the wheels' natural tendancy to "splay", i.e. toe-out, under braking.

Maf

AndyMc

Hi all

I have never liked the Impreza's soft inital turn in ever since I've had the car and have tried many different settings using the prodrive geometry as a starting point.I also have an ALK fitted.

To be honest I have not noticed that the front toe setting has that much effect on inital turn in, but it does once the car is settled into the corner.(I have used +20mins to -20mins)
A lot of front toe in makes it understeer very badly in my experiance (the tyres squeal at low speeds)
Toe out makes it twitchy and it wanders on the motorway and weaves under braking.(and makes the steering lighter)

I run as little front toe in as possible consistent with not to much weaving under braking(about 5 mins).

The prodrive settings made NO differance to the turn in IMHO ,but did give the front a lot more grip once the car was settled into the bend,it also gave a lot more lift off oversteer.

Rear toe out is no good because the car turns in great but then wants to keep on going in to a spin.This also gives more lift off oversteer.

Again rear toe in makes it understeer and kills lift off oversteer.(I run the rear with zero toe)

I have not read the above in a book but have learned it by trial and error on my car.

I would also be interested to know if ABP increase or reduce the rear camber when they modify the rear struts.In my opinion if the rear camber is reduced from the standard 1 deg neg the car might be a bit too front endy at high speed if the front has neg camber set.

With respect to tyre wear I am wearing the outsides of the fronts even with 1deg neg camber and the ALK although I do like roundabouts.

Hope this helps

Andy

SDB

hehe (I'm in way over my head!!! )

Half the problem is the word 'better' or 'improved'.

These are subjective things, not measurable constants. This is demonstrated in AndyMc's excellent post. Some people prefer a car to understeer mid bend, some to oversteer. One persons thresh-hold(sp?) for tollerence (sp? ) lift-off oversteer is later than others, etc.

Therefore, when we say 'Improved' what do we really mean? Well...

When we were talkig about turn-in, I would have thought we merely meant the *amount* the car turns in??

I know there are other aspects to the set-up other than the sheer power of everything. When we talk about having better brakes, we probably *mostly* mean 'they are more powerful', but if they locked all four wheels as soon as you touched the peddle, they would be useless.

Phil
If we now agree that having a touch of toe-in will *increase* the initial turn-in efficiency, then surely it is only a case of optimising how much toe-in you have (ie very small amounts) to chose the actual set-up. This would then allow you to take into account the balance and smoothness aspect you want.

The other part of this which leads me to think that toe-out creates stability rather than the other way round is:-

Almost all manufacturers engineer IN bump steer to force the front wheels to toe-out during load. As we are well aware, the front suspension is under load when braking and this is also when the car is at it's most unstable. Manufacturers tune in the bump steer to save us from ourselves.

Taking things to extremes again (the opposite of the extreme toe-in example in my last post)..
With Toe OUT, if you turned the wheel right quickly and then let go, the weight would go onto the left wheel which would be pointing more to the left than the steering would suggest. This would force the steering wheel to the left, which would throw weight onto the right wheel, making the oposite happen. Although, this example would almost certanily result in a very wobbly and comical looking car, it is almost impossible to think of the car spinning or even turning very much. This sounds like stability to me?

I totally accept that mid-bend is a trade-off, but isn't just about everything in set-ups?

In my mind, the best way to have a perfect set-up is to have the tyres held at the perfect slip angle for whatever steering angle / suspension load you throw at it.

Like I say, I have driven countless scoobies on the limit and have absolutely NO reservations in saying that IMHO the best 2 scoobies I have ever driven were BOTH set-up by Powerstation, to remove bump-steer altogether. Be careful though, if you have this done, the car will handle much more like a competition car and will start to act on your exact instructions rather than pad them out with a safety blanket of bump steer. But if you know what you're doing behind the wheel, there is no question in my mind what to do with the geometry. The second I pick my car up, I'm driving straight there!!

Cheers

Simon

PS Sorry again!