Weird geometry... reasons?

[AdamR]

Evening all,

I bought some camber bolts for my 172 Cup to dial in some negative camber as the car has been eating outsides edges of the front tyres on track (29-30psi with Federal 595 RSR).

Before going ahead, I decided to check the geo - however, it wasn't quite what I expected, especially after comparing with what is listed in the document in the guides section...

Front camber:
NS -1.3
OS -1.5

Front toe in 25 minutes (0.42 degrees)

The suspension has been changed to AVO GTX coilovers by a previous owner - which I believe were custom made for the car.

Is it possible they have had 1.5 deg of camber 'built in'? The bolts at the moment are standard.

Toe in - fine with that, but may try straight or toe out to see which I prefer.


Rear camber:
NS -0.6
OS -2.9 (!!)

I fitted 1 degree camber shims recently. Looks like I have a been a complete spacker and fitted one of them upside down? :quiet:

Do the rear stub axles sometimes bend? Standard is 1.5 deg each side so that would make the OS 'out' by 0.4 deg...

Any help appreciated ('you are a dunce and did it wrong' doesn't count - I know that!).

Cheers,
Adam

 

[AdamR]

Right, checked the shim and it IS fitted correctly. So that means the stub axle is either the wrong one for the car, or bent DOWN by 2 degrees?

The Torx heads on the bolts on that side were pretty f**ked when I got the car, so is it possible someone has changed the stub axle in the past for the wrong model? I read that the Cup one is different to standard...?

Seems that a new stub axle is bloody expensive - so, next question is, am I safe to add another 2 deg of camber shims, or is 3 too much on one side?

Cheers!

 

[AdamR]

Got some quotes from breakers for a replacement stub axle - £80 sound about right?

 

[Fred@BTM]

nearly £300 for a new one!

 

[AdamR]

Kin ell, rape! £80 isn't sounding too bad then... Cheers Fred!

 

[Cupman29]

The breakers one might be worse than yours so its all relative.

I bought one second hand but never needed to use it yet. Cant remember which side it is but you can have that if it is the correct side for £40 if you like?

If interested I'll get you some photos up.

 

[AdamR]

True - however I think the one I've got on is actually the wrong one (non-Cup model), there's no way it's bent 2 degrees downwards (towards +ve camber)...

I'm in need of the OS/passenger side, if yours fits the bill then more than happy to take it off your hands for £40

Cheers!

 

[Cupman29]

I'll check when i get home tonight and let you know.

 

[AdamR]

Cheers dude!

Edit: Mong - it's the NS/passenger I need... (not the OS I said before).

 

[Cupman29]

Managed to get pics of the stub shaft and I'm pretty sure its the NS I have. Its been in the garage for a year or so and Ive never fitted but looks in good nick other than some surface rust which will rub up ok.

Before you buy any you should take yours apart as the stub can come out the housing. You may be able to see where it is bent and get it straightened?

Anyway, here is the pics:

Let me know if you're still interested.

 

[AdamR]

Thanks dude, I'll whip it off asap and let you know Last time I had it off (a few months ago to fit camber shims) it was still in one piece, but you never know...

 

[Cupman29]

It is one piece but only as the stub shaft part is pressed it to the carrier part. I think the bolts are where its strength comes from.

You can let me know if you need it or not.

 

[AdamR]

Just had a check - not had chance to get the caliper/disc off yet but I think that one looks like a drivers/OS side, given the position of the axle compared with the caliper mount and also the large (non countersunk) hole being at the bottom rather than the top. Thanks though!

 

[Cupman29]

I've checked mate next to mine and it is definitely the passenger side. The stub axle is free to be put in either side, I may have just put it in the wrong way in the pic.

 

[AdamR]

Now that might explain it! I'll whip the old one off and have a check Cheers!

 

[jack_davey]

IIRC the stub axles arent handed, however the part it is pictured with above (that secures the brake caliper) is handed (left and right).

Stub axles were £180 ish last time I checked at my local dealer and the cups do not have different ones as far as I know

What was the geometry checked on? It is possible the gauges werent fitted correctly. You would be able to see that much of a difference in camber on the rear without putting it on a alignment machine.

Oh and 25 minutes of toe on the front could well be the cause as that is twice as much as the cars were setup with as standard even for two wheels!
They run 12 minutes in total as standard (between 5 and 6 on each wheel)

 

[AdamR]

Yeah, the bits that secure the caliper are definitely left and right, wasn't aware the stub came out though, so will tap it out and check it over, cheers.

Hmm, conflicting info then - have read on here (Fred@BTM) that the Cup uses a different stub axle... Whether that is the carrier or the axle itself I'm not sure.

Geo was checked by myself on a home-made tool, the NS is visibly different to the OS of the car though, I am confident the readings are correct.

Sorry - I don't follow... 25 mins of toe on the front could be the cause of the rear camber being weird? Is that what you meant? That can't be right...

All the geo has been setup differently from standard (apart from the rear toe which is set by the stub axles as far as I can make out). I have tweaked the front toe now so it's out a little, and added some more camber to the front. Rear is the same though. Guess I just need to get the stub axle off and take it from there... Cheers!

 

[jack_davey]

Sorry - I don't follow... 25 mins of toe on the front could be the cause of the rear camber being weird? Is that what you meant? That can't be right...

I meant that could be the cause for the uneven wear you mentioned on the front tyres.

As for the stub axles being different on cups, I'm not 100% (that's why I said AFAIK)
I was thinking with regards to cup packed 182s and just realised you have a 172 cup, so they may well be different as I've never checked those and I seem to remember the 172cup has increased TOE over the regular 172.

I would get the alignment checked on a Hunter or similar 4 wheel alignment computer

 

[Cupman29]

When I bought this stub axle the seller said it was off a 172 cup that he was breaking.

 

[Cupman29]

I would get the alignment checked on a Hunter or similar 4 wheel alignment computer

Agree with this too!

 

[AdamR]

I meant that could be the cause for the uneven wear you mentioned on the front tyres.

Aah - no that was from track use. Road wheels have always had even wear

4 wheel alignment... I will probably get flamed for this, but I'd rather get it somewhere close first before taking it anywhere (if at all). They will just tell me the rear NS is miles out and charge me £100odd for the privilege, which I already know. Pretty confident I'm within 0.2 degrees (probably 0.1) on the camber and a couple of minutes on the toe.

 

[jack_davey]

Fair enough.

A few things to check with regards to the rear camber:

-What do the rear axle bushes look like?
-Swap the stub axles side to side and see what the geometry does
-Check tyre pressures and rotate the wheels to see if the geometry changes

Once it's closer to being where you want it, I highly recommend pure motorsport's shims. They are super accurate, I used them to correct both the Toe and Camber on both my car and my girlfriend's.

 

[AdamR]

Good tips - thanks dude, I shall have a crack at that. Rear axle bushings, where exactly are these?

I did the '180ing the wheels' trick (was listed in the manual for the tracking gauge I have) and they seem to be pretty straight and true, no difference.

Thanks - will look into those

 

[jack_davey]

No worries, report back with your findings

 

[AdamR]

Got part way through then remembered what a mess one of the stub axle bolts was (not me officer!) - decided to re-assemble and fight it again another non-rainy evening, and order some new bolts...



This is what I've got though (yours is a NS then Cupman - sorry for the confusion there):



And here's the spacer that sits between the bearing and the stub.



Looks to me like the stub axle should have a matching taper to the washer..? It doesn't sit at all well with the taper facing the bearing, so surely the taper has to face in towards the beam... If the beam had a matching taper that would help keep the hub nut tight too.

Edit: Can't quite tell from your pic Cupman, but that axle doesn't look quite the same as the (almost certainly) incorrect one I have on the car at the moment. There also appears to be a very small gap around the base of the one on my car, whereas the one in your pic fits well. Looks like changing the stub might be the way to go, if I can get that fecked bolt out.

Jack - whereabouts are the rear axle bushes you mentioned? Edit again: Found what they look like, but not sure where they are located... trying to find exploded diagrams of the rear end now: http://cgi.ebay.co.uk/RENAULT-CLIO-MK2-1998-2005-REAR-AXLE-MOUNTING-BUSH-X-2-/230510025776

Cheers guys!

 

[bmh.01]

All of those bolts have been out before with a cheap torx bit by the looks of them.

 

[AdamR]

Indeed - pretty sure the stub has been changed for an incorrect one in the past, in the process raping the bolts. 2 are fine, 1 is 'ok', but the M8 one is buggered. Trying to hunt a replacement at the mo but proving tricky - time to get bummed by the local Renault stealers methinks!

 

[dave_rudabar]

Haven't you got a local hardware store that you can pickup the right bolt from? It wouldn't have to be Torx afterall, just the same size.

 

[turbo tom]

http://www.cliosport.net/forum/attachment.php?attachmentid=61294&d=1313086488

called deflectors iirc and i think the do sit flat to the bearing, mine shattered on fitting my rear discs so bought new 1s

 

[AdamR]

http://www.cliosport.net/forum/attachment.php?attachmentid=61294&d=1313086488

called deflectors iirc and i think the do sit flat to the bearing, mine shattered on fitting my rear discs so bought new 1s

Nice one!

Haven't you got a local hardware store that you can pickup the right bolt from? It wouldn't have to be Torx afterall, just the same size.

Possibly - I guess allen key head would do the job! Torx would be nice though...

 

[jack_davey]

The deflectors are meant to have the tapered side facing inwards, they shatter if you try and do up the hub nut with them the wrong way round.

You'll find the rear axle bushes where the beam joins to the underside of the car.

 

[AdamR]

Thanking you - so your thinking behind checking them, is that if one has collapsed the whole rear beam will be on the piss, thus giving the dodgy camber readings. I getcha now! Guess I should also check the ride height at each side and the position of the spring platforms relative to each other.

 

[jack_davey]

That's right mate

 

[AdamR]

Wicked - thanks again! Will report back...

 

[NorthloopCup]

Front camber at 1.5 degrees negative is the cause of your tyre wear on the outer edges mate i would say. For track you need to be at least 2.5 degrees negative - if not more, but if you use it on the road as well its more of a compromised setup you'd need.

Regards the rear geometry i have a few questions: Are you measuring it on a flat level surface? Are the tyre pressures the same on both sides? And lastly, is the rear beam bent? Any of these would cause your alignment readings to be incorrect.

The beam will normally give way before the stub axle does from what i've seen in the past.

Hope this helps.

 

[BrianB]

is the rear beam bent? Any of these would cause your alignment readings to be incorrect.

The beam will normally give way before the stub axle does from what i've seen in the past.

Hope this helps.

I had a similar problem, try'd everything as I was convinced the beam was straight, swaped the beam and everything was better

The old beam must have only been 2mm out at the most on the flat part where the stub/calliper carrier bolts on but that was enough to throw the geometry out