Upgrading the rear shocks only?

soybmw · 02-27-2017, 08:38 AM

I'm replacing the rear shocks on my e91 this weekend. I initially bought Bilstein B4's, but now I'm wondering if B6's might be a better upgrade. My concern is that the front struts are still OEM and I don't plan on replacing them until they go.

Is having mismatched struts/shocks (OEM in the front, B6 in the rear) going to cause any problems down the road? Do issues occur when stiffness differs between front and rear suspension?

matteblue3er · 02-27-2017, 09:20 AM

It's not ideal. It will work but the car may feel a bit weird

feuer · 02-27-2017, 01:11 PM

Are your front struts original factory equipment from 2007? Maybe you don't feel it but most definitely they are underperforming (if not completely gone) and is better to replace them too.

soybmw · 02-27-2017, 04:01 PM

Yes. The front struts are original, but I don't drive the car very often and it has relatively low miles. The reason I am replacing the rears is because I recently inspected the suspension after hitting a pothole and noticed one of the rear shocks was leaking.

feuer · 02-27-2017, 04:17 PM

They are 10y old so even at low miles chances are that they aren't good. Is up to you. Also, when replacing the rears make sure you replace the upper shock mounts as well. Either with OEM or aftermarket.

soybmw · 02-27-2017, 06:52 PM

Yeah I figured they may be bad so I ordered new upper and lower mounts as well as bump stops/protection tubes. Thanks of the advice. I'll let you know how the install goes.

soybmw · 03-04-2017, 05:50 PM

So I just spent the day changing the rear shocks. Decided to go with B4's. For anyone looking to do it yourself, its a pretty straight-forward DIY. The hardest part was disassembling the trunk interior. It took much longer than I thought. Once the interior was off though, everything else took about 30 minutes per side.

The car feels more planted and a little tighter around corners, but I'm sure that's because the old shocks were totally gone. I'm going to look into DIY'ing the front struts. If it seems reasonable, I'll get those changed next time I have a free weekend.

02-27-2017, 08:38 AM	#1
soybmw Enlisted Member 3 Rep 48 Posts Drives: 2007 e91 328xi; 2013 e70 3.5x Join Date: Jan 2016 Location: D.C. iTrader: (0)	Upgrading the rear shocks only? I'm replacing the rear shocks on my e91 this weekend. I initially bought Bilstein B4's, but now I'm wondering if B6's might be a better upgrade. My concern is that the front struts are still OEM and I don't plan on replacing them until they go. Is having mismatched struts/shocks (OEM in the front, B6 in the rear) going to cause any problems down the road? Do issues occur when stiffness differs between front and rear suspension?
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02-27-2017, 09:20 AM	#2
matteblue3er Captain 238 Rep 947 Posts Drives: Racecar Join Date: Jul 2015 Location: Philly iTrader: (0)	It's not ideal. It will work but the car may feel a bit weird
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02-27-2017, 01:11 PM	#3
feuer Major General 4277 Rep 9,209 Posts Drives: wife crazy! Join Date: Apr 2015 Location: Chicago, IL iTrader: (5)	Are your front struts original factory equipment from 2007? Maybe you don't feel it but most definitely they are underperforming (if not completely gone) and is better to replace them too.
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02-27-2017, 04:01 PM	#4
soybmw Enlisted Member 3 Rep 48 Posts Drives: 2007 e91 328xi; 2013 e70 3.5x Join Date: Jan 2016 Location: D.C. iTrader: (0)	Yes. The front struts are original, but I don't drive the car very often and it has relatively low miles. The reason I am replacing the rears is because I recently inspected the suspension after hitting a pothole and noticed one of the rear shocks was leaking.
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02-27-2017, 04:17 PM	#5
feuer Major General 4277 Rep 9,209 Posts Drives: wife crazy! Join Date: Apr 2015 Location: Chicago, IL iTrader: (5)	They are 10y old so even at low miles chances are that they aren't good. Is up to you. Also, when replacing the rears make sure you replace the upper shock mounts as well. Either with OEM or aftermarket.
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02-27-2017, 06:52 PM	#6
soybmw Enlisted Member 3 Rep 48 Posts Drives: 2007 e91 328xi; 2013 e70 3.5x Join Date: Jan 2016 Location: D.C. iTrader: (0)	Yeah I figured they may be bad so I ordered new upper and lower mounts as well as bump stops/protection tubes. Thanks of the advice. I'll let you know how the install goes.
	Appreciate 0 Quote

03-04-2017, 05:50 PM	#7
soybmw Enlisted Member 3 Rep 48 Posts Drives: 2007 e91 328xi; 2013 e70 3.5x Join Date: Jan 2016 Location: D.C. iTrader: (0)	So I just spent the day changing the rear shocks. Decided to go with B4's. For anyone looking to do it yourself, its a pretty straight-forward DIY. The hardest part was disassembling the trunk interior. It took much longer than I thought. Once the interior was off though, everything else took about 30 minutes per side. The car feels more planted and a little tighter around corners, but I'm sure that's because the old shocks were totally gone. I'm going to look into DIY'ing the front struts. If it seems reasonable, I'll get those changed next time I have a free weekend.
	Appreciate 0 Quote