Shock absorber question

[Lagonda]

I went to the vehicle inspection this morning (MOT). Now it appears that I have to come back because my rear suspension isn't ok. I had the same thing happen 2 years ago. I had to dealer put in new shock absorbers and it was ok. Now my question is, is it normal that shocks go out after 2 years and 30.000 km ? I've never changed the front shocks and they perform great. The guy that did the inspection was trying to blame it on the 16" wheels (standard wheels are 14") which is a load of crap if you ask me since the front suspension performs great and the rear suspension performed great last year when they checked it.

[hightower99]

What do you mean by "not ok"?

Do you drive in such a way that loads/stresses the rear suspension more than the front? (like when driving over a speed bump do you slowly drive the front wheels over then accelerate quickly before the rear wheels have passed the bump?

2 years and 30K is not much at all for shocks.

[Lagonda]

Well, they test the shocks by putting the wheels on two rubber pads who vibrate. You can see the test results on a monitor. The front ones had a rigidity number of around 270-280 and the rears as well. But there is another number that was in the double digits for the front and the single digits for the rear. It's called an Eusama reading. And the rear wheels gave a 3 (left) and 4 (right) as a result. It should read somewhere between 20 and 40 for a small car (like the Clio).

I always accelerate after passing a speedbump. Speedbumps are pretty high here, accelerating when still on the bump will make you slam your rear end on the speedbump. So I don't do that.

It's a front wheel drive car if it matters (renault Clio).

[drakkie]

The guy that did the inspection was trying to blame it on the 16" wheels (standard wheels are 14") which is a load of crap if you ask me since the front suspension performs great and the rear suspension performed great last year when they checked it.

He might be partly right, mate. I am not sure about everything, but what I do know is that putting other rims onto a car can cause serious problems.

As you might know, the entire suspension dynamics are influenced by making a single change, how tiny it might be. The bigger rims and flatter tires offcourse increase vibration of the suspension. If Renault designed the standard shock absorbers to cope with force X, you changed these forces to X+Y, which proved too much..

Offcourse we will never know for sure without complicated simulations, but to me anyway this seems plausible.

If you replace the shocks anyway, look if Koni makes FSD shocks for your Clio. Believe me, the difference is enormous and it might improve the lifetime also. Handling will increase a lot too ! You'll be amazed, believe me

[macoran]

http://www.patentstorm.us/patents/47...scription.html

You'll find everything on the Eusama test here.

Question, when you fitted the 16" rims, were any adjustments made to the suspension ?
Did you have your suspension lowered ?

[Lagonda]

Method of and equipment for qualifying shock absorbers of a motor vehicle - US Patent 4703645

You'll find everything on the Eusama test here.

Question, when you fitted the 16" rims, were any adjustments made to the suspension ?
Did you have your suspension lowered ?

I never fitted the 16" wheels. They came with the car when I bought it. I don't think that anything was changed.

[2ndclasscitizen]

The bigger wheels shouldn't wreck your shocks. What specifically did they say was wrong with your rear suspension? I mightn't have been the shocks, it could have been the springs, or damage to the suspension arms or the axle. It's definately not normal for shocks to go after 30,000km.

[Lagonda]

He didn't say. I asked him if I needed to replace the shocks and he told me "maybe, depends. You'll have to come back, that's for sure". Pretty rude.

Suspension arms or axle, that sounds pretty expensive, no ? I already had 600 euros is repairs done last week (new brakes and rear brake cilinder, basically an entire new brake system for the rear) so this problem isn't really welcome.

The car feels absolutely normal fwiw.

Those Koni FSDs look awesome Drakkie, but they are €550 for a set of 4. I really can't afford that right now and it seems that they don't make them for Renaults yet. (EDIT: they do make them for Renault but only for the Clio 3, not the Clio 2).

Maybe I need other shocks for my low profile tyres ? What I don't want is an even firmer ride nor do I want to lower the car. Maybe some red Koni's ? They make red and yellow Koni's for my Clio.

[ripper46]

I have sympathy for your situation. The people that work in those stations are idiots, they once damaged a control arm on my mothers car because the car wasn't set up properly on the shaky-bench thingy, still , we had to pay for their idiocy. I took my driving test twice in Deurne. When you wait there in the centre, untill the examinator arrives, you can see these monkeys at work (it's a bit like the zoo). First time I went they had to test a an classic jaguar mk2 3.8 , when the guy stepped in the car he stalled it twice, then he couldn't get it into first , and finaly after deffening everybody with raped-gearbox noise he nearly hit the car behind him besause he snatched reverse. Second time I went they scraped an e21 bmw's oil pan when they drove it in to the brake tester. They don't treat your car with any respect at all.
I've heard many more horror stories. But when they have to test your car if you want to sell or buy one, (i.e checking the mechanical state of things), for which they inspect the underside of the car and everyting, they mis the most obvious oil leaks, rust, ....
They also dare to charge you for tuning bits for no good reason : a friend of mine went with an E 30 bmw 318i with an m-sport pack=> they wanted to charge him 20 EUR for having the tiny OEM wing on the back
From what I've learned there are big differences between the stations.
The rules in Belgium are retarded if you look at it: you can pass a car with a body that is basically rotten , but if you want to change anything such as: suspension, coilovers, sometimes even wheels you won't get away with it.
This can be particularly anoying if you import a car. my german professor told me that his friend wanted to import a merc cl65 amg from Germany, when he got to the station they said it was to low, (this car was completely original and in tiptop condition with al the neccesairy papers). My mechanic was stopped by the police and they wanted to take him to a testing station because he was to low ( stock nissan sunny gtr) It took him an hour to persuade these idiots that the car was standard even when he had the homologation paper with him.
These stations are also one of the big reasons why I don't lower my car.
quiggs wouldn't survive belgium
The only way you can play around with cars here is when you get an oldtimer, you can get away with motor- swaps, coilovers, the lot....
thats why I like the idea of getting a mk1 golf

back ontopic again : which station did you go to?

[ripper46]

and btw , IMHO 2 years and 30000 kilometres is worryingly fast,
I suppose you don't drive like a hooligan, Or could it be that the factory shocks are really rubbish

[Lagonda]

I don't drive like a nut. I never take speedbumps quickly because I know that it hurts my back with those low profile tyres. I'm always very carfull and try to avoid bumps and potholes.

CAN you change the stock shocks, without lowering the car, to something like Koni's in belgium ? I'm not too familiar with the laws. I guess that getting non-renault shocks is considerd "tuning" and I was under the impression that there is a separate regulation for "tuning". Not sure.

I went to Brasschaat. It's one of the most lenient stations, according to my parents. Two years ago they didn't let me pass with the same problem. That guy really tried his best to let me pass. He even sat in the trunk while doing the test. You really need to get lucky with who you get. And AFAIK Deurne is horrible.

I've been pondering about this problem all day long and I know that my rear suspension does tend to bottom out when I go more than 50km/h on really bad roads (kinderkopjes), like the one next to the ATV building (and Nanno) next to the Schelde. Maybe the standard Renault shocks really aren't designed for the firmness that's added by the low profile tyres.

[ripper46]

If you get some new suspension , (aftermarket that is) you need an "attest" from the place where they mount the setup. When you go to a place where they sell and install the setup you will pay "the price " I know this is the case for coilovers (schroefkit) but if you only change the shocks you might get away with it without an attest(I don't know a lot about this legal matter), because perhaps they don't notice it. I think my car hasn't got OEM shocks but this hasn't caused problems until now. But I have a sneaking suspicion that the shocks abnormal wear and tear is caused by something else, perhaps your bushings are worn out?

You could ask it on the cleaned. be forums these guys will probably know more about it, because they are the main enenmies for the GOCA. Somewhere on that site I found some documents about the legislation ..

I specialy avoid the stretch of road next to hangar 26 and NANO, its horrible

[Matra et Alpine]

Hmm, it sounds as if you are quite probably blowing the valves in the damper With no tyre wall the damper valves are seeing a very high initial force and in "cheap" shocks likely they are giving up
THe other alternative is you may be bottoming the shock. Do you have bump stops fitted and are the actually hitting first ?
Wow, seldom do I say I'm glad to be in the UK owning a car, but I woudln't accept the restrictions they place on you guys !!!

[Lagonda]

I don't have bump stops fitted, well not that I know of...

How would I best fix the bottoming or the valves blowing ? Getting stiffer shocks ? Shock that offer more resistance, somethink like red Koni's ? The yellow ones are too expensive at the moment. The OEM shocks are probably cheapish and crappy, I think they are €50-60 Monroes.

[ripper46]

I'm gonna take advantage of this thread to ask a little question myself: when I drive with the window down, and I go over a speedbump, I hear the shocks making a little noise as there are compressed/ decompressed. Is this normal?