[The Ru]

Is there a difference in springs and ride height on xdrive cars vs rwd?

I have a 435i xDrive m sport with EDC. Front fender gap is huge, was wondering if stock rwd front springs would bring it down a bit.

I don't really want to lower the car all around, thought maybe just these front springs would be a compromise.

thanks

ian

[Jvac]

Yes, rwd is lower. You can't lower too much on x drive cars because it strains the axles to the point of failure, but oem springs don't lower substantially, so you should be fine on them. I have a set of rwd, m- sport springs that just came off my '15 335i. I was planning to list them for sale when I got back home in a couple of weeks. The x drive car is a bit heavier than RWD, so these might not be ideal, and I can't personally guarantee they would fit your car, but someone else might be able to chime in here to confirm.

[The Ru]

Originally Posted by Jvac

Yes, rwd is lower. You can't lower too much on x drive cars because it strains the axles to the point of failure, but oem springs don't lower substantially, so you should be fine on them. I have a set of rwd, m- sport springs that just came off my '15 335i. I was planning to list them for sale when I got back home in a couple of weeks. The x drive car is a bit heavier than RWD, so these might not be ideal, and I can't personally guarantee they would fit your car, but someone else might be able to chime in here to confirm.

I think i would be interested, depending on some further responses. The rear isnt bad, but the front is higher, and i'd like it to come down a bit. But i dont want lowering springs and that big drop.

Thanks

Ian

[Ennoch]

The problem with only installing shorter springs at the front is that spring rate will likely be different (due to the reduced travel in which to control the mass of the vehicle) which will alter flat ride and might not give the ride characteristics you're after. From what I've seen most of the spring packs provided aftermarket keep a similar F/R height relationship so if you're looking to drop the front, and in doing so increase the rake angle which will move the roll centre forwards and improve turn in, you can only do this via coilovers which is likely not the route you'd want to go down!

[The Ru]

Originally Posted by Ennoch

The problem with only installing shorter springs at the front is that spring rate will likely be different (due to the reduced travel in which to control the mass of the vehicle) which will alter flat ride and might not give the ride characteristics you're after. From what I've seen most of the spring packs provided aftermarket keep a similar F/R height relationship so if you're looking to drop the front, and in doing so increase the rake angle which will move the roll centre forwards and improve turn in, you can only do this via coilovers which is likely not the route you'd want to go down!

Yeah good point. I was just trying to reduce that front gap a bit without going crazy. The right move is probably the correct eibach springs, but my car has 75k. Struts are okay as if now, but are edc and will be costly to replace. I also dont really want a harsher ride if at all possible.

If i was to just try some m sport rwd car front springs, i wonder how much drop thst would accomplish.

[cfm56d7b]

OP, do you prefer to retain EDC functionality or non EDC coilovers are an option?

[The Ru]

Originally Posted by cfm56d7b

OP, do you prefer to retain EDC functionality or non EDC coilovers are an option?

Retain EDC. I was just hoping the rwd msport front springs might lower my front a bit on the cheap ...

Thanks

[Ennoch]

Originally Posted by The Ru

Yeah good point. I was just trying to reduce that front gap a bit without going crazy. The right move is probably the correct eibach springs, but my car has 75k. Struts are okay as if now, but are edc and will be costly to replace. I also dont really want a harsher ride if at all possible.

If i was to just try some m sport rwd car front springs, i wonder how much drop thst would accomplish.

M Sport springs are 10mm lower, allegedly, assuming they fit on the strut spring seats and top mounts in the same way - I don't know how long each spring is but you can end up in situations where a lower spring is longer because the spring perch is in a different position. Also, the additional weight of the transfer case and extra driveshafts (a portion of which is sprung weight) could have the effect of increasing any drop, assuming the aforementioned point about spring perches doesn't come into play. I had a set of struts on the Impreza that I cut the perches off and dropped down by 10mm to get the rake angle I wanted without going to coilovers, but I did a lot of research on spring rates and lengths and ride heights to get to that point.

I've also driven cars which have mismatched springs before which have worked well, but only because the rates and ride frequencies have been worked out. I've been in a lot more that drive terribly. The issue with mis-matched spring rates is that you end up with ride frequencies that can be at odds with each other. At best this can give head bobbling over uneven roads (bad enough to make you feel a little queasy), or at worst it can completely destroy the handling balance of the car. If someone has the data on what rate the standard RWD front springs are vs the AWD items then that will allow you to decide whether it's going to work. I suspect they're going to be too stiff to match to the rears.

[The Ru]

Originally Posted by Ennoch

M Sport springs are 10mm lower, allegedly, assuming they fit on the strut spring seats and top mounts in the same way - I don't know how long each spring is but you can end up in situations where a lower spring is longer because the spring perch is in a different position. Also, the additional weight of the transfer case and extra driveshafts (a portion of which is sprung weight) could have the effect of increasing any drop, assuming the aforementioned point about spring perches doesn't come into play. I had a set of struts on the Impreza that I cut the perches off and dropped down by 10mm to get the rake angle I wanted without going to coilovers, but I did a lot of research on spring rates and lengths and ride heights to get to that point.

I've also driven cars which have mismatched springs before which have worked well, but only because the rates and ride frequencies have been worked out. I've been in a lot more that drive terribly. The issue with mis-matched spring rates is that you end up with ride frequencies that can be at odds with each other. At best this can give head bobbling over uneven roads (bad enough to make you feel a little queasy), or at worst it can completely destroy the handling balance of the car. If someone has the data on what rate the standard RWD front springs are vs the AWD items then that will allow you to decide whether it's going to work. I suspect they're going to be too stiff to match to the rears.

I could see that all being an issue. I might just leave well enough alone i guess. thought i could get a lil 10mm of front drop cheaply without affecting too much.

thanks

Ian

[The Ru]

For reference, this is my wheel gap:

[alohasurftoad]

just do it "right", with Eibach 5-22 and F80 bump stops.

https://f30.bimmerpost.com/forums/sh...1901058&page=2

[The Ru]

Originally Posted by alohasurftoad

just do it "right", with Eibach 5-22 and F80 bump stops.

https://f30.bimmerpost.com/forums/sh...1901058&page=2

I gotcha. Not ready for full suspension replacement at this point though.

I had read through that thread before. Good info in there.

[alohasurftoad]

with the adaptive dampers you currently have...

like @psyki
https://f30.bimmerpost.com/forums/sh...0&postcount=35
https://f30.bimmerpost.com/forums/sh....php?t=1765870
.

[dmanb2b]

Originally Posted by The Ru

I gotcha. Not ready for full suspension replacement at this point though.

I had read through that thread before. Good info in there.

You don't necessarily have to replace the whole suspension as I did. The springs are maybe $250 and then just get f80 bump stops.