New struts on McP's, ride height changed...?
Discussion
I just got round to fitting my new shocks to my Peugeot 306.
The car now rides around 15-18mm higher at the front, noted mainly by the fact before I could *just* get my spoiler over the kerb at Sainsburys with audible scraping and now I can see a fair gap there.
So, I'm confused how that has happened. The springs are the same. The new dampers had some 'return' when they were compressed, but a few kg weight ontop would easily have offset that.
They have alot of pre-compression, maybe nearly 40cm uncompressed free from the strut, 30cm on strut, and maybe down to 20cm once on the car and the full weight upon them.
I'm mainly wondering what the mechanics of this are. I'm guessing that the change is the strut top to spring seat distance has changed, so the pre-compression is less. However, the total load on the spring at rest once fitted must be the same, so surely the total spring compression must now be the same?
Any ideas/help much appreciated...
Dave
The car now rides around 15-18mm higher at the front, noted mainly by the fact before I could *just* get my spoiler over the kerb at Sainsburys with audible scraping and now I can see a fair gap there.
So, I'm confused how that has happened. The springs are the same. The new dampers had some 'return' when they were compressed, but a few kg weight ontop would easily have offset that.
They have alot of pre-compression, maybe nearly 40cm uncompressed free from the strut, 30cm on strut, and maybe down to 20cm once on the car and the full weight upon them.
I'm mainly wondering what the mechanics of this are. I'm guessing that the change is the strut top to spring seat distance has changed, so the pre-compression is less. However, the total load on the spring at rest once fitted must be the same, so surely the total spring compression must now be the same?
Any ideas/help much appreciated...
Dave
I didn't check the seat heights. They are the Euro Car Parts 10% uprated OEM Bilstein ones...
Thats a bit crap if the seat is further up and so sitting the car higher than it was on it's OEM dampers.
I'm still a tad confused though. Under full load compression, the spring will always be the same length, I'm pretty sure. So the strut top to spring seat distance will always be the same. If we raise the spring seat we in theory raise the car as the spring then has to move up, and so does the strut top, even though the hub stays in the same place. And then if we lower the spring seat then the spring will drop to meet it, so the strut top does too, and now the strut top is closer to the hub, so a lower ride height!?
I think that makes sense now. Just a bit annoying really as it sat perfectly before.
Pain in the arse. I totally DON'T recommend the Bilsteins from ECP. Get OEM's (real OEM, not pretend, clearly), from Peugeot and make sure it sits nicely!
Dave
Thats a bit crap if the seat is further up and so sitting the car higher than it was on it's OEM dampers.
I'm still a tad confused though. Under full load compression, the spring will always be the same length, I'm pretty sure. So the strut top to spring seat distance will always be the same. If we raise the spring seat we in theory raise the car as the spring then has to move up, and so does the strut top, even though the hub stays in the same place. And then if we lower the spring seat then the spring will drop to meet it, so the strut top does too, and now the strut top is closer to the hub, so a lower ride height!?
I think that makes sense now. Just a bit annoying really as it sat perfectly before.
Pain in the arse. I totally DON'T recommend the Bilsteins from ECP. Get OEM's (real OEM, not pretend, clearly), from Peugeot and make sure it sits nicely!
Dave
http://www.pistonheads.com/xforums/topic.asp?h=0&a...
or just look further down the page in suspension & brakes - it lokks like philip has had the same issue as yourself.
or just look further down the page in suspension & brakes - it lokks like philip has had the same issue as yourself.
I thought it might have been that, but I could easily press in and hold the shaft with a pair of fingers, so no more than maybe 4kg load would keep the shaft in.
The change in ride height is fairly significant. I'd like it lower just because thats how it was, but finding decent lowering springs that come with a full specification is like finding hens teeth.
It might be just a case of getting some made to OEM spec but starting 25mm shorter (almost tempted to chock the car where I want it to sit then just wave an oxyacetelene torch over the spring windings for a while, then when it moves to it's new position spray some water on them
)
Complete and utter PITA. It's things like this that make me wonder how companies like Bilstein actually stay in business. Can they not even get the most simple of bloody calculations correct. I'll be sure to not recommend them to anyone in the future
Dave
The change in ride height is fairly significant. I'd like it lower just because thats how it was, but finding decent lowering springs that come with a full specification is like finding hens teeth.
It might be just a case of getting some made to OEM spec but starting 25mm shorter (almost tempted to chock the car where I want it to sit then just wave an oxyacetelene torch over the spring windings for a while, then when it moves to it's new position spray some water on them
)Complete and utter PITA. It's things like this that make me wonder how companies like Bilstein actually stay in business. Can they not even get the most simple of bloody calculations correct. I'll be sure to not recommend them to anyone in the future
Dave
If you're using the original springs then the length will be unchanged just as you say. If the ride height is different then the spring seat positions must be different. Are you certain the bottom of the strut is fully engaged in the hub? Assuming you still have the old parts it would be useful to see where the lower spring seat was relative to the hub and see if the new one is similar.
GreenV8S said:
If you're using the original springs then the length will be unchanged just as you say. If the ride height is different then the spring seat positions must be different. Are you certain the bottom of the strut is fully engaged in the hub? Assuming you still have the old parts it would be useful to see where the lower spring seat was relative to the hub and see if the new one is similar.
Yep old springs.I'll be checking the strut is sat right down in the hub, and also measuring from the hub to the spring seat to check there too!
I'll get to the bottom of it anyway, and report back
Thanks all!
Dave
Mr2Mike said:
Drive the car for a few hundred miles before doing anything drastic, you may well find it settles down to original height.
Yeah, it had new bushes too, and the springs didn't look 100% seated the way they do when you take them off (into the groove, but not like perfect)...I guess there is a bit of settling to go
Well, I won't be doing anything else from this point anyway, can't really afford it at the moment. I'll certainly measure it all up though just out of interest.
Some nice fully adjustable coilovers/dampers may well be on the cards in the future just so I get some flexibility back... but again it's a minefield knowing what you will get. Hard or really hard etc
Dave
PhillipM said:
Just check the spring ends are right up against the stops on the top and bottom spring pans - they can sometimes stick short if you didn't grease the spring seats which would raise the ride height some.
Will do, gonna be doing the arb drop links and front discs/pads this weekend, and the rear sub bushes soon after... everything seems to have gone at once Dave
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