Shit Tyres In The Wet Or Crappy Suspension Setup?

[Wacky Dee]

I have a R34 GTT with minimal power mods (185rwkw) and a set of 18" wheel with Maxxis MA-Z1 Victra directional tyres .. they're not cheapies but not top of the line rubber either ($260 per corner or thereabouts)

http://www.maxxis.com/AutomobileLight-Truc...-Z1-Victra.aspx

Now I've had Bilstein shocks installed with my stock springs lowered a couple of cms and in the dry the tyres seem ok except when cornering (at normal/avg speeds) if there're any sort of bumps or an incline ie. not flat road, I lose tracting quite often. But that's not so scary and I usually turn off TCS for this reason.

However in the wet I've noticed taking corners now is almost suicidal ... I've lost traction and fishtailed 3 times now even at lower than normal cornering speed with TCS off.

The tyres are still pretty new (3,000kms or so) and the shitty* wheel alignment they've done at heasman's said my alignment is fine. I said shitty because it was just a mechanical/manual alignment afaik. The car had front left damage because the guard is painted crappily and does not line up to the door properly (it came like that from japan) and when I measured the height PRIOR to bilsteins, that corner appeared 1cm higher (or lower, can't remember exactly) probably because the guard wasn't lined up correctly after the crash in japan.

Anyway, after the Bilstein's were installed all corners appear same height which doesnt make sense and can only mean they didn't take into account the fact that the front left guard was repaired and isn't sitting correctly 100% ie. they adjusted the height on this corner so that the centre of guard to cente of wheel is equal to all othes. I did bring this to their attention when I had the car there for the suspension upgrade but I had a feeling that info was completely ignored.

Anyway, i'm thinking this might have something to do with the loss of traction especially in the wet ..since the front left corner now probably sits 1cm higher or lower than the rest (even though if u measure from guard to centre of wheel it equals everywhere when it shouldn't...)

Or could it just be shitty tyres? or some other suspension setup ?

I'm kinda broke now so don't have hundreds of dollars to blow on a REAL wheel alignment where they weigh each corner etc. So what other options do i have? other than to take corners like a grandma and pray i don't fishtail when its wet?

Edited January 9, 2009 by Delta Force

[jrm]

Did you have a camber kit fitted when the Bilsteins were fitted? Generally speaking putting on lowered suspension means the camber is *way* out which could be affecting your handling ... A wheel alignment place should be able to tell you this ...

[Wacky Dee]

yeah camber kit was installed as was rear subframe alignment kit .. could the rear subframe kit have something to do with this crappy traction issue ?

[zZzDanzZz]

best thing would be to take it to a suspension shop which is known to do good work and get them to check it out. might cost you money but its a hell of a lot better than crashing

the tyres should pretty good so for them to lose it like that even in the dry would point to suspension issues

[Wacky Dee]

just checked my tyre pressure and fronts were about 30 psi and rears 32psi so i've upped the fronts to 32psi as well... could tyre pressure explain the traction issue or is the difference not that big for it to be that ?

[zZzDanzZz]

thats a bit low, but shouldnt cause your traction issues. im running 38psi cold so that after they warm up fully, all 4 are running at 40psi

[Wacky Dee]

I'm pretty sure the tyre place recommended 32psi .. not sure on the exact size of the tyres I'll look them up tommorw and see what everyone else uses but they're 18" aftermarket wheels not the stock 17s.

it could be just my imagination but since I pumped the fronts back to 32psi this arvo the car seems to corner better without traction issue but it could be just my imagination, I'll know for sure in a couple of days I guess as there's some really shitty roads around where I live.

Edit: tyres are 245/40/ZR18 95W ...also made from some rubbery compund and black in colour!

Edited January 10, 2009 by Delta Force

[R32Abuser]

Tyre pressures are always a trade off between the lateral stiffness of the tyre (read sidewall) vs the tyre contact patch on the road

Too higher tyre pressure will ensure your sidewalls are stiff enough to not act like a soft spring in a corner, however you also lose traction and overall grip due to the reduced contact patch on the road.

Too lower tyre pressures will ensure that a larger portion of the tread is in contact with the road, however now your sidewalls will have a reduced stiffness, so effectively they will work like a softer spring than the above situation, resisting less roll caused by weight transfer.

Keep this in mind

Edited January 10, 2009 by R32Abuser

[nisskid]

im gonna go with shit driver sorry not to say there might not be setup flaws, but the way u describe it makes it sound like u cant keep the thing straight, even with baldies and stock suspension i didnt have my car stepping out on me through the hills unless i wanted it to, skylines really arent that violent, in fact they are pretty tame relatively speaking.

get a basic alignment, anything that cant be seen in a basic alignment wont affect ur car as much as ur talking about, my advice is to maybe go some carbon fibre shoes or something and lighten up that foot on the accelerator.

[Ultimategtr]

I kinda had a similar issue when i bought my car. It has Potenza lowered suspension. In the wet, it would go hairy everywhere, even in 3rd gear turning right at the lights at 30k. At first it was fun but got scary when it happened everytime i turned.

BUT it no longer happens. I changed to Goodyear Eagle F1's and boy it sticks like shit!!!! even in the dry giving it heat in 1st, it hardly squeals.

[GTR-N1]

Options are

i) susp'n set up & camber/castor/toe

ii) tyres (which Powerplay Imports use Maxxis for compliancing only and they're aware of what they do in the wet) OR... OR...

iii) optometrist

[vidospace]

East coast suspension has a laser aligner. They are doing my install in a few weeks. Speak to David.

[Wacky Dee]

I'll try a bit higher tyre pressure .. 34psi at the front and 33psi at the back and see how I go. If I still notice traction issues I'll take it to eastcoast ..

How does the laser alignment stuff work? does that just measure the distance from centre of wheel guards to centre of wheel or ? because that's useless for my front left as that guard doesn't sit correctly due to prior damage

I thought the best way to align it was by placing the car on that big scale thingy where it actually weighs each corner ?

Edited January 11, 2009 by Delta Force

[MBS206]

For a set of 235/45/18s, get those pressures up near 38PSi.

34PSi is way under inflated for those tyres, and will be causing the tyre to wander around.

It's a great pressure for drag racing, (Not really, I'd be going for alower pressure when dragging) but it's absolutely shit for cornering.

[nuffsaid]

Pretty sure laser aligners dont use guard in measuring height. They have lasers that shoot underneath the car from left to right to calculate alignment specs.

I run my fronts at 36psi so maybe try that

Corner balancing the car might be hard, especially with suspension that you cant adjust mm by mm. Circlip grooves might be enough, not sure.

How was the car in similar driving conditions with the rims+tyres but stock suspension?

[Wacky Dee]

not sure if the traction issue started when i got the aftermarket wheel+tyres or after suspension/lowering .. it all happened within a space of 3-4 months and I don't drive that much as I work from home. I know this doesn't help in determining anything, just saying...

Matt, you mentioned 38psi on 235/45/18s but mine are 245/40/18's ... ?? I'll try 36psi front and 35 psi back see how I go.

[dori34]

32 is definately too low so bump it up higher. i got 235/40/18 and theyre on 36psi all round.

for a place as good & reputable as heasemens, i thought they would at least do a proper alignment for you.

[MBS206]

not sure if the traction issue started when i got the aftermarket wheel+tyres or after suspension/lowering .. it all happened within a space of 3-4 months and I don't drive that much as I work from home. I know this doesn't help in determining anything, just saying...

Matt, you mentioned 38psi on 235/45/18s but mine are 245/40/18's ... ?? I'll try 36psi front and 35 psi back see how I go.

Same thing man, 245/40/18... I couldn't quite remember the size you siad.

On a low profile, really, 36PSi is the LOWEST you want to go.

I HAD to run a set of Falkens at 32PSi before as I had severe straight line grip issues... Spoke to a person I know at a tyre shop, and they said they'd normally put them at 38PSi, if there's issues with wheel spin in a straight line under moderate throttle, they'd drop them to as low as 36PSi... Thye were a touch shocked when we had to get mine to run at 32PSi... Made cornering bullshit though...

From memory I went back to 36... And it was purely that the tyres, even though low profile, just rolled around too much...

[zZzDanzZz]

tyre shops usually say 32psi so that they can't be liable for damages caused by people who over inflate their tyres as they told them to use 32psi.

[Wacky Dee]

Ok I've upped it to 36 fronts and 35 rears .. cornering felt better but hard to say as I've only driven it for a couple of hours since. However ride is noticably harsher .. bugger it, if I wanted a comfy ride I woulda kept the vitara