Rear Tyres Wearing Out Need Camber Kit?

[Turbz RB-25]

Hi guys,

I've done alot of reading using the search button but I don't really understand what many people are talking about.

Ok, firstly, I am getting alot of inside tyre wear on the rear wheels. My car is not lowered (much) on the back, by that I mean there is still about 2.5 inchs from the rear tyres and the guard.

With that being said, I understand that the inside of my tyres wear out when I plant my foot on the accelorator and my car sqauts.

I have taken my car to the shop to get my HKS GT2835 Pro S fitted, and when it comes out, the car is going to squat even more and the wear will only occur faster.

Now, I understand that I have two options available, bushes and upper arms?

Could someone please explain to me the difference between the two in simple terms, I'm still a noob.

I understand that upper arms arm more expensive and have more room for adjustment.

If I understood correctly, bushes are cheaper, dont have much adjustment and wear out or something?? Does that mean you have to keep replacing them after a while because they wear out?

Do I go for bushes or adjustable arms? and could the gurus out there point out the exact differences and the cost differences including installation?

What's more suitable for my application since my car isn't that low?

I am more into straight line racing rather then track.

I don't race my car ever on a track, I just give it the occasional hit on the road on a straight line.

Even now with 194 rwkw, it doesn't get any traction in 1st when it hits boost, and when I shift into second. I can't imagine what it will be like with 260rwkw!

As I don't really understand the echnical terms, could someone please take the time to explain this to m and what I need for my style of driving? I want to be able to get all the tyre on the road when accelerating, not just the inner 15%.

However, if I do through in more positive camber, does this mean the outside of my tyres will wear faster then my inside?

sorry for all the questions guys.... still learning...

cheerio

[Sydneykid]

Some reading for you;

http://www.skylinesaustralia.com/forums/Wr...tml&hl=arms

http://www.skylinesaustralia.com/forums/in...showtopic=85467

For camber kits, this what is usually needed for each height increment, note that all measurements are centre of wheel to guard;

Standard (new) height is 380 mm front and 370 mm rear

360/350 mm needs only the standard rear camber adjusters

350/340 mm needs 1 front camber kit and 1 rear camber kit

340/330 mm needs I front camber kit and 2 rear camber kits

The standard rear subframe bushes are very soft, silicone filled. They are soft when new and do wear over time until they finally leak. The rear subframe alignment kit supplements the standard bushes, stops the subframe from flopping around and at the same time give some adjustment of the rear squat. This allows for improvement in the rear traction. This is a must have for a drag car.

Some stuff I posted yesterday that you may also find helpful;

You want no more then 3 kg/mm rear springs, around 2.5 kg/, is better. You want rear shocks with very little low frequency bump valving but a large amount of low frequency rebound damping. If the shocks are a decent brand then you can leave the high frequency valving alone. The soft spring rate allows the rear to squat and absorb the torque hit, the large amount of low frequency rebound damping holds the rear down for maximum weight transfer onto the rear tyres. The problem is you get a lot of dynamic negative camber when you get enough squat, so you need to set the static rear camber slightly positive (around 0.5 deggres). A rear subframe alignment kit installed in the "Maximum Traction" positions is also a must.

Around 3.5 to 4.0 kg/mm front springs are OK (hardly "hard"). You want front shocks with a large amount of low frequency bump valving but with very little low frequency rebound damping. Similarly to the rear, if the shocks are a decent brand then you can leave the high frequency valving alone. The limited amount of low frequency rebound damping allows the front suspension to extend therebye reducing the weight over the front and hence more effective weight transfer to the rear. The reasonable front spring rate helps to hold the front tyres onto the track, you may need to steer at some point. The front suspension geometry is pretty much irrelevant, just make sure the wheels are pointed straight ahead (zero toe) so they don't provide too much drag.

In a general sense the average Japanese aftermarket coil over kits are not suitable for drag racing and the standard suspension is better. But (there is always a "but") the problem with the rear standard shocks is that they don't have anywhere near enough rebound damping. That's when they are new, let alone 15 or so years old. So you get bad axle tramp, the kind that breaks drive shafts. The more power the car has, the worse this problem becomes. In a standard'ish Skyline (boost up, FMIC, exhaust etc) you might just get away with it (standard shocks) on street tyres. But drag radials or slicks and decent power don't mix well with poor rebound control. You will spend more money/time replacing drive shafts than you will spending the extra on buying the right shock spring combo.

Cheers

Gary

[Turbz RB-25]

Some reading for you;

http://www.skylinesaustralia.com/forums/Wr...tml&hl=arms

http://www.skylinesaustralia.com/forums/in...showtopic=85467

For camber kits, this what is usually needed for each height increment, note that all measurements are centre of wheel to guard;

Standard (new) height is 380 mm front and 370 mm rear

360/350 mm needs only the standard rear camber adjusters

350/340 mm needs 1 front camber kit and 1 rear camber kit

340/330 mm needs I front camber kit and 2 rear camber kits

The standard rear subframe bushes are very soft, silicone filled. They are soft when new and do wear over time until they finally leak. The rear subframe alignment kit supplements the standard bushes, stops the subframe from flopping around and at the same time give some adjustment of the rear squat. This allows for improvement in the rear traction. This is a must have for a drag car.

Some stuff I posted yesterday that you may also find helpful;

You want no more then 3 kg/mm rear springs, around 2.5 kg/, is better. You want rear shocks with very little low frequency bump valving but a large amount of low frequency rebound damping. If the shocks are a decent brand then you can leave the high frequency valving alone. The soft spring rate allows the rear to squat and absorb the torque hit, the large amount of low frequency rebound damping holds the rear down for maximum weight transfer onto the rear tyres. The problem is you get a lot of dynamic negative camber when you get enough squat, so you need to set the static rear camber slightly positive (around 0.5 deggres). A rear subframe alignment kit installed in the "Maximum Traction" positions is also a must.

Around 3.5 to 4.0 kg/mm front springs are OK (hardly "hard"). You want front shocks with a large amount of low frequency bump valving but with very little low frequency rebound damping. Similarly to the rear, if the shocks are a decent brand then you can leave the high frequency valving alone. The limited amount of low frequency rebound damping allows the front suspension to extend therebye reducing the weight over the front and hence more effective weight transfer to the rear. The reasonable front spring rate helps to hold the front tyres onto the track, you may need to steer at some point. The front suspension geometry is pretty much irrelevant, just make sure the wheels are pointed straight ahead (zero toe) so they don't provide too much drag.

In a general sense the average Japanese aftermarket coil over kits are not suitable for drag racing and the standard suspension is better. But (there is always a "but") the problem with the rear standard shocks is that they don't have anywhere near enough rebound damping. That's when they are new, let alone 15 or so years old. So you get bad axle tramp, the kind that breaks drive shafts. The more power the car has, the worse this problem becomes. In a standard'ish Skyline (boost up, FMIC, exhaust etc) you might just get away with it (standard shocks) on street tyres. But drag radials or slicks and decent power don't mix well with poor rebound control. You will spend more money/time replacing drive shafts than you will spending the extra on buying the right shock spring combo.

Cheers

Gary

Hi Gary,

Thanks for tyring to explain all this stuff but I'm still finding alot of words too technical.

Could you please tell me in simple terms what I need, shocks, camber kit etc to stop this inside rear tyre wear and get maximum traction when I plant my foot on the floor. and also, the price for install (genreally how many hours would it take to install?)

Do I need:

New springs

New shocks

Camber kit?

Many thanks for your help.

[Turbz RB-25]

Can you get something other than those spherical bushes? they dont sound too good, you mentioned in a post that they feel horrible and hard and that they wear out very quickly.(how quickly, months, weeks?)

Is there an alternative?

[Sydneykid]

How long spherical bearings last depends on many things;

How rough are the roads that you normal drive on?

How dirty are the roads that you normally drive on?

What size sphericals has the maker has used? Some are very small and last weeks, some are more sensible size and last months.

Do the sphericals have dust covers? If not, the crap gets in and shortens their life even further.

If they don't have dust covers, do the sphericals have grease nipples? At least you can grease them and prolong their life a bit.

How low is the ride height? If there isn't enough suspension travel then the impact loads are passed into the sphericals as there is no spring or shock travel left to take the hits.

How often do you degrease the car? It washes off the lubricant, if there is any.

To fix the rear camber with bushes, you need a rear camber kit, they are $125 each. If the car is low (refer to the previous post) then you may need 2 kits to remove the excessive negative camber. Fitting is usually around $150 or so, plus a wheel alignment of course. Check with your local suspension workshop (there is a list of recommended shops in the Group Buy thread).

In a couple of weeks I will have a Group Buy up for exchange control arms with Noltec camber kits already fitted, if you can wait that long.

Cheers

Gary

[Turbz RB-25]

Hi guys,

So do I need this:

https://www.whiteline.com.au/store/default.asp?part=KCA348

or this; in order to fix my inner rear tyre wear when my car squats down from the torque:

https://www.whiteline.com.au/store/default.asp?part=KCA331

Sorry about all the questions but I seriously don't know what to get, I'm stupid when it comes to suspension.

Cheers