BMW PS issues - extremely rough ride...installation issue? Help me diagnose please

[Black Gold]

Hey guys,

I recently installed the BMW performance suspension kit on my 135i along with the m3 front suspension parts.

The car handles and drives well, but i have noticed two issues that have gotten very bad.

The car rides extremely rough over even small bumps, way worse than stock even with RFT's. It is also very loud. I do have re-11 tires which are firm, but are in slightly upsized 225/235 sizes, so there is a little more sidewall than stock.

It also has began having a little bit more of a wobbly bouncy ride than initally, and is somewhat severe on its reactions to undulations in the road.

I am hoping something is wrong with the install, but am not sure what it could be. I am planning on bringing the car in to a shop to diagnose whether something is wrong with the parts or installation. I would like to know what type of possible issues with the installation there could be so i am clued in on what to look for.

Also, recommendations on a shop in houston that is very familiar with this suspension, and this kit in general would be great.

I wish i could drive in someone elses car who had this suspension and compare it to mine so i could know for sure.

But the noise and extreme harshness over bumps is pretty excessive....100x harsher and louder than stock with rft.

Thanks for any input

[Dackelone]

So... you are running RFT's (run flats) AND the PS with M3 control arms? ???

Have you tried adjusting your tire pressure? And what are they? I would also ditch the RFT's and go with normal tires.

[Black Gold]

Originally Posted by Dackelone

So... you are running RFT's (run flats) AND the PS with M3 control arms? ???

Have you tried adjusting your tire pressure? And what are they? I would also ditch the RFT's and go with normal tires.

no, i have re-11s in

225/40 and 255/35

on the OEM wheels, no spacers or anything.

yes, i have checked the tire pressure, it is right on spec.

what i was saying is that compared to the stock suspension WITH RFT, this setup with re-11s rides extremely rough. i also had the re-11 on stock suspension and the ride was 100x better.

the noises are very loud over bumps, and makes me think (almost) that the front struts are blown or something...but i dont have enough suspension expereince to diagnose suspension issues

[Dackelone]

I think you should test a 'friend's" tires/wheels (non RFT) and see if the ride changes.

Btw... what are your tire pressures set to?

I run 2.3Bar(front) and 2.9 Bar(rear) and that is on the high side. Only reason I run those high pressures is for better high speed response. IF you ran a little less you would have a better ride. I would also consult with Harold at HPA for teh right setup on your car (parts wise).

[Black Gold]

Originally Posted by Dackelone

I think you should test a 'friend's" tires/wheels (non RFT) and see if the ride changes.

Btw... what are your tire pressures set to?

I run 2.3Bar(front) and 2.9 Bar(rear) and that is on the high side. Only reason I run those high pressures is for better high speed response. IF you ran a little less you would have a better ride. I would also consult with Harold at HPA for teh right setup on your car (parts wise).

re-11's are not RFT's. they are an extreme summer tire from bridgestone. i ran them on my last e90 m3, and even on that car, the ride was nowhere near as loud or rough as this car. thats why i am concerned something is wrong.

tire pressures (i cannot remember off hand) are right on what is recommended for the car on the label inside the driver side door.

i did talk to harold, and this setup is pretty basic. OEM bmw performance shocks / struts and springs and m3 front control arm kit, the exact one harold sells.

thanks for your assistance

[M2 Blur]

Hi Kenny,
Thanks for your feedback on my thread about the BMWPS...

Definitely interested in your findings and the resolution to your rough ride complaints... Hopefully, it's an easy fix or just a tire swap!

Good luck.

[jkoral]

I'm running BMW PS and 225/255 RE-11s (no M3 front bits though). No complaints.

I have thrown on a set of stock 128i all-season RFTs in the spring/fall (before going to full winter) and the difference between the RE-11s and the Pirelli eufori RFT is night and day.

For you to say your setup feels worse than the RFTs is shocking. I don't think it's the tires, but it is the easiest to check. Maybe someone in your area has the same or similar setup?

[Black Gold]

Originally Posted by jkoral

I'm running BMW PS and 225/255 RE-11s (no M3 front bits though). No complaints.

I have thrown on a set of stock 128i all-season RFTs in the spring/fall (before going to full winter) and the difference between the RE-11s and the Pirelli eufori RFT is night and day.

For you to say your setup feels worse than the RFTs is shocking. I don't think it's the tires, but it is the easiest to check. Maybe someone in your area has the same or similar setup?

Right on, that's why I'm worried something is wrong.

How would you compare the ride wrh BMW ps to stock?

[yaymitch]

I just ordered the M3 Control Arms, BMWPS and Bilstein shocks. Going to have all those installed plus M3 Sway Bar and rear subframe bushings next week. I will let you know how it goes. Also, putting Conti DW tires on. I am looking at three shops in houston - Bavarian Machine Specialists, Eurocar Werk and M Performance. I will let you know which one I choose and how that goes as well.

[EFI Logics]

OP, can you describe the sounds you are hearing? Have you gotten the car in the air and inspected the suspension yet? Did everything start occurring immediately after the suspension was installed? Who installed the suspension? Does it feel/sound like it's coming from all 4 corners or just 1 corner in particular? If you suspect a blown damper check for fluid around the strut tube/damper body.

-Josh