Can dead shocks screw up the tyres??

[Ru$kI]

Hi guys....have a bit of a problem. The other day wen i was doin bout 100km in my EK sedan...the car seemd to vibrate a bit. Later that week i noticed one of the wheel balancing weights lying round on the floor of my garage.

I figured i need 2 get my wheels re-balanced...so called up the place where i got my rims and tyres done and they said 2 come in and theyll do it.

As I get there....the guy goes...mate if i rebalance ur wheels it wont help as your front tyres arent worn evenly (ie its not a smooth curve of the wheel...it's like up n down in some places). So upon asking him what caused this....he replied that my shocks are dead and need replacing, and only after i get that done i shud get my wheels re-balanced and probably re-aligned also (swap the diagonal wheels, putting the rears on the front, since they are still fine).

Is this a load of bulls**t or is it actually true that dead shocks can do that to your tyres??

Mind you I got my new rims and tyres like 2-3 months ago

[CTR Coupe]

how many Kms on your car? lowered?
i don't know if its true but if your car is lowerd that can reduce shock life.
I'll ask some people about it next week for you.

[liberx]

It is possible, but shocks would have to be in a really bad state to wear tyres unevenly.

Tyres can be out of round, due to manufacture defect or flatspotting from a big lockup. It could also be caused by bad shocks with the wheel constantly bouncing on the tyre, setting up a harmonic such that part of the tyre gets a lot of load/friction applied to it compared to other parts around its circumfrance.

I've seen cars with stuffed shocks, and the wheel is constantly doing this - even on relatively smooth roads. However I would hope you would notice worn shocks well before this by the way your car also bounces or floats over bumps, and generally feel unresponsive. Good shocks are always worthwhile, it's one of the first modifications I always make. Shocks older than 80-100k km will always need replacing.

I Suggest:
1. Do a basic test of your shocks by trying to bounce the car while it is parked. Once you stop pushing on it, the car should also stop moving within 1 cycle/bounce. If it continues to bounce any more than this, then you are in dire need of new shocks, and it COULD have caused the problem.

2. Balance the wheels in question, and rotate, so fronts are now on the back. If you still get vibration, but now from the back - tyres are definately out of round. If shocks are not the cause, I'd suggest a warranty claim as defective manufacture.

Hope this helps.

[BlitZ]

very rarly would shocks cause tyre wear..
maybe if you lose tractions alot of pot hole and spin/lock it a alittle..

[Ru$kI]

My car has done something like 83,000km...and to my recollection it seems the shocks have never been changed. It's not lowered, if anything its actually raised a little due to putting on 17x7 rims with 205/40/17 rubber with offset either 38 or 40, cant remember.

While driving the car and going over speedbumps it does seem a bit bouncy tho. I do recall hitting some rather nasty potholes, but i've never spun or locked wheels on the new tyres. I'll do the bouncing check today and report on how it goes.

I have already ordered Tein SS coilovers 2 weeks ago...so they should arrive in a week, after which i'll probably come back to the guy 4 re-balancing, and rotation, and get them re-aligned also

[aozora]

Alignment.

[bennjamin]

suspension changes dynamically so if its less held via shitty shocks id think premature wear would result. Also , looseness would slowly pull out the alignment settings and thus wear rates as said above :)

[Zimp13]

get 2nd opinion....

[Domokun SPL]

I am in agreement with bennjamin.

Suspension is set up statically, but you need to think of it dynamically. Just because you get an alignment of -1deg, around a corner with shitty shocks it will increase far beyond that with good shocks.

I am see the shock letting you down mid corner and then causing the tyre to produce "lowered" type wear, even if the car isnt lowered.

Dont forget though, that spring rate is a spring rate is a spring rate. Just because the car has a poor shock doesnt mean it will compress the spring much more during a corner as the spring rate is a constant regardless of the shock, rather it will be that the spring wont be controlled and the car will bounce rather than absorb energy.

[Ru$kI]

Hmmm....i see...thanks for the input guys. Hopefully getting my coilover this week...cant wait :D...so i'll keep you posted on how the car will feel afterwards.

One thing that i did over the weekend was pump up my tyres...set them to 38psi (since im running 40 profile rubber)...that seemed to reduce the vibration a little and i gained a little more control over the car :)...so pleased with that.

[ErazeR]

will prolly need to balance ur tyres but u cannot actualy screw them up

[aozora]

Domokun, can you explain how such tyre wear would be affected by poor shocks? You say (for example camber, toe etc I'm guessing) values of 1 degree will increase alot more in comparison to good shocks... but aren't bound settings relatively soft to absorb bumps? So wouldn't the spring rate be the main factor in this? As when you compress the whole strut, it will dynamically camber in... the shock won't resist that much (unless you've set them up poorly with too much bound in relation to the spring rate), the shocks main resistance will be against the spring's kinetic energy which will come in on rebound right? So mid corner... lowered effect... then about spring rate almost what I just said... I don't get it >_<
Do you mean by the "hopping" of the tyres as a result of the bouncing/poor shocks causing odd wear?? Please explain! Or anybody really :p

While suspension changes dynamically, ultimately it is the spring that holds the car up and unless you go off road 4WDing regularly I can't see poor shocks being the only reason behind inconsistent tyre wear, atleast initially? Unless Domokun or somebody else proves me wrong which will probably happen :)

But with a decent alignment, they should also be able to tell you if there are any abnormalities in the suspension arms, bushes etc. anyway. And check your ride height too just incase your springs are sagged. :p
If you stick to your coil-over idea, make sure you get an alignment once you put them in or make any changes to the setup (besides damper adjustments obviously).

[Ru$kI]

im pretty sure its not only that my shocks are dead....but my springs are saggy az and have become very soft...i reached this conclusion myself when i saw my 50kg mate get in the back of the car...and the whole rear just dropped 2cm EASY!!!

So it could be the fact that my whole sussy is just ancient thats screwin up my tyres...but then again...thats y i posted the question 2 begin with

[Civic Si]

In some cases if ur shocks are worn, then it may cause patche's of wear from the tyre leaveing the road as ur car would bounce alot losing contact.

I've experienced this wit my old EM1 that had been lowered, but had standard shocks. I ended changing to Bilstein Shocks and got new tyres, then got a wheel alignment.

[aozora]

In some cases if ur shocks are worn, then it may cause patche's of wear from the tyre leaveing the road as ur car would bounce alot losing contact.

I've experienced this wit my old EM1 that had been lowered, but had standard shocks. I ended changing to Bilstein Shocks and got new tyres, then got a wheel alignment.
Funny that you should offer discounted shocks too ;)

That said, go to Pedders (or any suspension place) for that whatever point safety check and get them to test your shocks out too. Most likely they'll be gone I'm guessing, but atleast they can identify any other problems in your suspension too.
The best thing is that there's no commitment cause Pedders sark :p

Basically check shocks, springs, bushes, suspension arms, alignment... etc.