GTA Geo and tyre pressures.

As per title, since my big rebuild frankly E200 has never felt as stable at speed as before.
A few things have changed including a total rear end strip and rebuild with new bushes etc, also I've gone from 255/45 Yoko AVS to Toyo T1R's but of course in a 225/50.
Everything including the rear lower shims went back in the same order and quantity.
So what's up?
Approaching 80 it starts to feel nervous....twitchy even, so with an impending motorway run I thought I'd get it on the level and see how it looks, I have new front wishbones to fit ( well one side, still looking for the other ) so I don't want to spend on a pro set up yet, and have no leads on where to take it ( although there is an ex works rally spanner man on our road so I will quiz him next ) so for the time being I thought I'd square it up on a level part of the drive and see if anything glares at me.




It's not a perfect check but by squaring the car and string, I thought I might see if there was any variation in toe.
the distance from each edge is not critical, more the string is square and the car is parallel, it took a while but I am happy it was close enough to give me some indication.

I made the string sections long enough so I could roll the car back and forth and take three readings, and yes there was variations but it was a pattern I was looking for and the results showed whatever position I measured the O/S rear had 5mm of toe in wherever I place the car, the front was slightly toe out in fairly equal amounts and the rear N/S varied between being nigh on parallel to 2-3mm toe in.

A quick check in the manual and it stated the front should be 2mm total toe in for a D500, but 2mm toe out for a D501, perhaps this is to help with the more tail happy Turbo power delivery?
The rear should be 4.5 ( +/- 0.5mm) and I was looking at that on one wheel !
At this point I want to reiterate I was looking for patterns, so with only a few days to go before I am going on a decent distance run I decided to look at what shims I had in the car.
On inspection I found three 1.5mm shims in the O/S and only two in the nearside, so for the ten minutes it takes to whip one out I thought it was worth the effort, a quick run down the bypass and ....Yep better .... not solved but better...defo not worse, next tyre pressures, a check at home showed only 30 in each rear, I'd dropped them down months back to see it if made a difference and forgot about them, so looking at the manual and the bonnet sticker I whacked them up to 45 pound and then bypass...
Nah...! not nice mega twitchy, down to 40 and it feels about as good as it has done for this year, but I still think there is something amiss.
What pressures are people using in 225's, what handling are other people experiencing, what works and what doesn't, the car hasn't done that many miles even allowing for speedo woes ( showing 65k I think?) there is no play in the front anywhere, standard front, rear konis on standard springs...
If you have had a proper Geo set up, what problem did you have before and is it solved ?
A proper four wheel aligment is wise at the very least, but I'd rather wait till the front end gets its shiny things and then go the whole geo set up hog........comments welcomed.

[mettersl]

Ingenious...I had my 610 done at Elite tyres on the A13 on the way to London...a petrol heads wheel and tyre emporium.
They used a USA system -Hunter, it not only measures the car, it tells them how to adjust the car too .and it knows about alipines in the database.
..they have an on-line look up service to tell you who is closest.

http://www.alignmycar.co.uk/

Not everyone that has one is good...I had a not great experience when I used someone more local (even though I avoided the Kwik fits that have them) and I have found the cost is very variable.
Elite is something like £40 to measure and then an hourly charge for adjustment based on how long it takes...stuck bolts etc. The other place was a flat fee.
For my 610 it transformed the car, no pulling at all, more stable and a dramatic reduction in tyre wear.

As you say, change those front wishbones first though or it will have to be done again.

[BIG_MVS]

Genius!

I always had my GTA's on about 34 psi rears and 30 fronts which seemed OK. 40 - 45 sounds a bit much to me.

Thanks for input, Lee, I think the Hunter system is going to my first choice and now remember my father in law's place has one as we had the Clio cup on it after a very light prang, the print out is in the service history somewhere, Clee.
Unfortunately he doesn't hold the high up position he once had and it is a Ford main dealer recently changed hands, so I think that one may not be viable for a 28 year old Renault !

According to the link you posted there are a couple of others very close, one only 3 miles away at a place that rings a bell and another at Ripley ( might suit you Clee ?) so I'll start asking around and try and get some first hand reports and some names, always helps if you can drop someone's name in with a recommendation.

It will be next year though as I think this winters job will be to go all new on the front, well as new as I can so I'm not doing the alignment job twice.

Any more experiences gratefully received?

I've driven past that place in Ripley ...will give them a try with the latest 610 rebuild .They do other stuff as well I think .
http://www.mgautos.uk.com/
610 has Spax coilovers tho and all new running gear so may well turn into a longer process than std ........

How much fuel have you got in it? Also how much windscreen fluid?

Sounds daft I know, but the front is very light with anything less than 6 gallons in the fuel tank and that makes it skittish.

The windscreen washer tank is as far forward as you can get in the car and again is pretty enormous for a car the size of a GTA. Brim that and you have some extra weight ahead of the front axle to counteract the weight of the engine trailing the rear axle. Yes it's still 60+% rear balanced, but you'd be surprised.

Tyre pressures, I wouldn't go beyond about 35 at the rear and 32 at the front. You can probably go 30/32 depending on the tyres. (Yokohamas really needed a bit lower pressure than norm). Toyo's are good though, they're what I run and I've always found them very surefooted.

Rear definitely sounds like you're running too much toe, but from what you said you've cut that down.

Might be worth cutting the front toe down to zero perhaps? With no power going through the front wheels they'll tend to be splayed out as the power comes in - friction pushes them apart. (Front wheel drive cars often have toe out as the power going through the wheels cancels that out - it pulls them inwards to end up closer to zero) Toe out would make it more unstable I think as toe-in is usually added to increase stability - why the GTA runs it to stabilise the rear ... at the expense of the tyres!

Darren, 10 gallons of go go juice and a full tank of fly spray.

I think I'll drop the rears to 35 and try that for now, the front will be getting a good lump of tools, fluids and spares, so that should also lower the front and well as weight it, giving more data to mull over.

When I first built the 4cv it was terrifying to drive so I bought Des Hammils Sportscar & Kitcar suspension book in an effort to understand what was happening and this helped enormously, identifying a bent stub axle giving me mega neg on one of the fronts, and more toe out than a camels foot. All just with string, a tape measure and a level.

But the GTA requires a higher level of accuracy, and the biggy is having a large bang level surface to work on, look at the pictures in custards tracking post where you can see the fella is using the hunter kit, the floor is tiled and the stands that the wheels are sitting on have adjustable feet !

But it doesn't stop me wanting to play around, I've looked at Gunsons trackrite which you roll on and it gives you the toe readings, there's the trackace as well that uses lasers, I've even thought about playing around with some box section and laser levels for the hell of it, ........but you always come to the same thing .....the need for a level bed to set up on and mark out on.

Bearing in mind how many of our cars don't even go anywhere, what do the ones that do, handle like?
By going down to 225's I've lost 60mm of contact patch and 30mm of track at the rear, largish amounts of toe in on the rear may be tolerable with 255's, adding stability and/or helping power oversteer, but with 225's you lose the stability............imagine extremes, steam rollers on the rear against pram wheels on the rear, but both with 5mm of toe in?
Just thinking aloud...........

Good stuff re the fluids - I always used to find it made a big difference, mostly on the bends though.

Yep the Hunter is top end stuff. When I had the M3 aligned they insist on a full fuel tank!

Were you on 255s before all the work was done? I do need to get my geo tested when I get it back on the road again after the water pipe issue, so I'll see then if I can get some numbers. But that all depends on seeing whether I can work out where the pipe's failed

Reading all this with great interest. Surprised to hear the D501 came with toe out at the front as standard. I don't really have the benefit of a before and after comparison but I would say your description, Ryan, pretty much matches my experiences at the moment. I can live with the light front end which is certainly helped by fuel and spare wheel weight but get a very unnerving twitch from the rear, especially as the near side rear hits a rut or pothole. Too much toe, worn bushes, worn dampers? Not clear but something not quite correct.

I remember completely transforming the handling of a car with a 4 wheel hunter alignment years ago so this is definitely on my agenda. Would crack on now but seems a bit silly to do this before getting the suspension swapped out for a set of coil overs. Would be good to have a definitive set of geo numbers to take to alignment people before going down that route. too.

BTW, I have a Gunson trakrite but can't get on with it at all..... just doesn't seem repeatable enough that I can trust the readings... wish I'd bought a laser system instead...

[Alpineandy]

The A310s run something like 18 in the front (can't remember exactly and manual not to hand).
Do GTAs really run over 30 in the front? I know there's more weight and more up front but... I'm shocked...

I got one of those Trakrite thingies, but results could best be described as "patchy".

I have one of these bad boys now, and so far, so good, easy to use, and easy to get right straight away, rather than all the fiddling around with the Trakrite.
Shop around, some places sell them cheaper than others...............

http://www.ebay.co.uk/itm/Compact-2-Whe ... SwVupTqJDt

Yep, Andy pretty big pressures in the manual/bonnet sticker 1.8 to 2.4 bar front 2.5 to 3.6 for 225 on the rear! .....lower for 255 depending on brand, but would think as others are saying 35ish rear 30ish front, although I'm currently down to 26 on the front.

Looking back over my squaring data I can see the front N/S toe out gains slightly when the car was rolled forward, which would point to some play there, which is also the gutter/kerb side and therefore the side you see most wear.

If I assume I am running slight toe out then a bit of slack would increase the toe at speed giving me the high speed bottom nipping, although doing a full stop from 70+ the car pulls up true and doesn't wander or lunge about.

I'm re-reading the suspension book to refresh myself as I know a little about a lot, which can be dangerous! It'll be interesting playing around with toe just a little at the end of this year to see what happens.
What I find interesting is the slight differences in settings Turbo V Atmo, front toe in on the D500 points to adding stability, but toe out on the Turbo points to low speed snappiness....................................

Bob, looking at thingies like that.......in the interests of research, mmmmm,.........garage toys!

[mettersl]

The elite folks measured the ride before work on mine and had weights to hand to load the car up properly if wrong. Tyre pressures also need to be correct...and were checked.
The hunter system not only measures tracking...and you set the front then the rear, it will tell you if you have bent or incorrect bits at the front and rear for camber and caster.
There is a little adjustment for caster at the front of the GTA by shims but camber out means something is bent.
If you have lowered the car, the camber will be out of spec. There is a threaded bar and dire warnings in the workshop manual about playing with it, but I have heard of alpine people getting the angles closer after adjusting that.
Tracking is of course critical but you won't spot the bent parts without all the measurements...however depressing they are in repair terms.
Just measuring tracking at one end isn't enough, both ends need to be aligned togther if the line of thrust of the car is to be correct. This is what you feel as pulling off the line. Again the Hunter system does all this and guides the operator, even on our cars.
If you find the right machine and operator, it's well worth it.
Not only made my Alp work well, it fixed my Audi allroad and Smart roadster too.

Looking forward to hear how people get on.

Well I'll be putting the 610 in soon,probably next week so can report back .

Metters is right my 610 had been lowered and mucked about with over the years and drove like a dog. However I found a guy near me Who has got a megamachine and specialises in setting up racing cars it took us a whole afternoon to get it right now it is superb for a 610. Make sure before you go in all the relevant bolts are easily adjusted and that you have Pack of different size shims. Otherwise You might not even be able to get it finished.