Rear struts rubbing

[Chungus]

Hey everyone,

I recently replaced my rear struts with a pair of Bilstein B6 (24-015974). Upon installation I noticed the spring perches were pretty much sitting on the tire making the vehicle undriveable. After installing 20mm spacers the car is now drivable but still rubs ocassionally around corners or if I have people sitting in the rear.

I'm a bit confused as the current wheels were used with the previous oem struts so it shouldn't be an issue with the offset, and the Bilsteins should be oem replacements.

Does anyone have any experience with this?

 

[garciapiano]

What is the offset and width of your wheels? This is a typical occurrence with aftermarket suspension components unfortunately.

 

[Steve Addy]

Hey everyone,

I recently replaced my rear struts with a pair of Bilstein B6 (24-015974). Upon installation I noticed the spring perches were pretty much sitting on the tire making the vehicle undriveable. After installing 20mm spacers the car is now drivable but still rubs ocassionally around corners or if I have people sitting in the rear.

I'm a bit confused as the current wheels were used with the previous oem struts so it shouldn't be an issue with the offset, and the Bilsteins should be oem replacements.

Does anyone have any experience with this?

What's your tire size too? Are you running a non-stock wheel tire setup, or one that deviates from stock by quite a bit?

Don't Bilstein B6 struts typically have additional channels cut in so you can move the spring perch higher or lower?

Did you compare height of the ones removed with the new Bilstein struts? When you say it's rubbing what exactly is it that's rubbing?

Steve

 

[Chungus]

Not too sure on wheel size, will have to pull off and check width and offset. Tire size is 205 55 16.

Ive checked the struts and there's only one groove for the spring perch. The old oem struts were thrown out a few years back so no chance on comparison.

The bottom of the spring perch is making contact with the inside edge of the tire

 

[ToddA1]

That tire size is definitely not stock.

-Todd

 

[Abacus]

That tire size is definitely not stock.

-Todd

That’s not bad though, I’m running 205/45-16 with great results and the diameter is spot on. The width is the same and mine don’t hint at rubbing with the stock offset.

 

[oilhammer]

A 205-55-16 tire is about 1.5 inches in diameter bigger than a 205-45-16, which means it is about 3/4 inches closer to something at the outer edge.

Tire Size Comparison

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But obviously something changed with the replacement struts, so it is not just the oversize tires' fault with the OP's car.

 

[Abacus]

The struts are parallel to the tires, so it shouldn't make a difference.

 

[oilhammer]

The lower spring perch is right next to the upper part of the tire. The wheel offset may not be the exact same as what stock was, too.

Obviously if the OP posted some pictures, and maybe compared the struts' spring perches, we'd see better what is happening. Some of the replacement struts don't have the exact same shape/size of those perches.

 

[ToddA1]

Something is definitely going on with offset, if a 20mm spacer needs to be used. What’s odd is it previously didn’t rub… I’d trust Bilstein has this figured out.

-Todd

 

[Chungus]

I'll grab some pictures in a bit.

Something is definitely going on with offset, if a 20mm spacer needs to be used. What’s odd is it previously didn’t rub… I’d trust Bilstein has this figured out.

-Todd

Yeah this is what's confusing me also. This tire wheel combo was on the car when I purchased it, along with the stock suspension. I swapped the stock suspension for a set of FK coilovers which were fine also. But when I put the Bilsteins in, there was barely a 1/2 finger gap between the spring perch and inner edge of the tire. Even with the 20mm spacer it still rubs around corners and bumps. I could go 25mm or thicker but I'd rather figure out the issue...

 

[Chungus]

20221120_151805.jpg

• Chungus
• Nov 28, 2022

20221120_151758.jpg

• Chungus
• Nov 28, 2022

Finally got some pictures, this with a 20mm spacer and the rear unloaded. Wheels are 16x7.5

 

[turbodieseldyke]

Wheels are 16x7.5

But what is the offset?

The perch is supposed to have its holes aligned with the shock bushing at the bottom. Possibly that could make a difference, but I doubt it. There must be a slight difference in perch placement, between these B6 and OEM, but that doesn't add up, since they're supposed to have stock ride height.

I dont know. Maybe you can install a perch spacer too, but it wouldn't be an off-the-shelf item.

 

[Chungus]

But what is the offset?

The perch is supposed to have its holes aligned with the shock bushing at the bottom. Possibly that could make a difference, but I doubt it. There must be a slight difference in perch placement, between these B6 and OEM, but that doesn't add up, since they're supposed to have stock ride height.

I dont know. Maybe you can install a perch spacer too, but it wouldn't be an off-the-shelf item.

Sorry forgot to mention, offset is +35.

...yeah I'm super confused also, B6 are supposed to be stock replacements

 

[turbodieseldyke]

35 is real close. 38 is oem, iirc. A 205 tire will only cost you 5mm horizontal clearance vs. a 195 (stock), so it must be a vertical issue.

 

[Steve Addy]

35 is real close. 38 is oem, iirc. A 205 tire will only cost you 5mm horizontal clearance vs. a 195 (stock), so it must be a vertical issue.

Based on the photos there isn't a problem with vertical clearance. The distance between the tire and the spring perch is fixed and won't change no matter what, so if there's rubbing it's coming from somewhere else.

Steve

 

[turbodieseldyke]

Based on the photos there isn't a problem with vertical clearance. The distance between the tire and the spring perch is fixed and won't change no matter what, so if there's rubbing it's coming from somewhere else.

That's what i thought from the pic, but then he also said "the rear is unloaded", meaning maybe it's been jacked up? I dont know. Shouldn't have that much visible clearance in the wheel well if it's not jacked.

 

[Chungus]

It was on jackstands yes. Without the spacer the perch is pretty much sitting on the tire, so there is a problem somewhere, where the solution shouldn't be to use a 20mm spacer.

 

[Steve Addy]

That's what i thought from the pic, but then he also said "the rear is unloaded", meaning maybe it's been jacked up? I dont know. Shouldn't have that much visible clearance in the wheel well if it's not jacked.

Yes...but my point was that unless there's something else going on with damaged, worn or broken parts the distances between the tire and the spring perch will not change. The strut in the rear is bolted at almost exactly the same position as the stub axles that hold the rotor / wheel. That is a solid fixing, there shouldn't be any movement in any of the parts that would bring those two closer together unless, as I said before, there's a failed bearing, badly mounted stub axle, loose stub axle bolts etc.

All of that stuff associated with the rear beam axle should be rigid. The only floater in there is the strut piston and coil, that's it, so if there's rubbing it's due to something else that's not right. It shouldn't matter if loaded or unloaded in the rear, all those rear beam components move in tandem.

I still haven't seen a post up about what size tire is being run here.

Steve

 

[turbodieseldyke]

I still haven't seen a post up about what size tire is being run here.

Tire size is 205 55 16.

All of that stuff associated with the rear beam axle should be rigid. The only floater in there is the strut piston and coil, that's it, so if there's rubbing it's due to something else that's not right. It shouldn't matter if loaded or unloaded in the rear, all those rear beam components move in tandem.

You're right. It's hard to get the full picture from a jpg, and not being able to see it in person.

 

[Chungus]

Revisiting this...I think I've concluded that the struts are installed properly and its more of an issue with the wheel tire combo. Bilstein B6s are meant for stock applications, which would mean NOT a 16x7.5 +38. Although the spring perch is slightly different than stock, my 15x6.5 +35 winter wheels cleared without the need for any spacers.

 

[volksguy]

You can get Spendel Spacers in.5mm 10mm 15mm 20mm and 25mm
And stack them even.
Like add 5mm and 15
Wide tires on back of a B4.
Is not a easy fix
Coilovers on mine with 17 x 8 wheels
Tires were with in 3/8 of the adjusters.

 

[Abacus]

Stacking spacers is not something you want to do. Get the proper one in the first place. I bought 20mm spacers but wish I’d have gone 25mm, but the car looks so much better.

 

[volksguy]

The stacking spacers was told to me from the (Manufacturer) of them.
So if some one needed a 30mm and a 5mm and 25mm stacking was a (Design) made into them from the (Manufacturer)
There is times when there out of one size for months so.
In my case i just purchased all of them.

 

[Steve Addy]

The best option is to get stub axle spacers. They don't cause any additional tension on the wheel bearings whereas wheel spacers can depending on the offset.

The rear spring perch for Mk3 doesn't need to be as large as the one always seen installed on struts, is the tire rubbing on the side or bottom of the perch now? You might be able to cut away the portion of the perch that's causing the trouble and avoid doing any spacer work at all.

It used to be that Bilstein included a small perch that was only as large as the last coil, which was up against the strut body pretty tight, do they not provide those anymore?

Steve

 

[Chungus]

The best option is to get stub axle spacers. They don't cause any additional tension on the wheel bearings whereas wheel spacers can depending on the offset.

The rear spring perch for Mk3 doesn't need to be as large as the one always seen installed on struts, is the tire rubbing on the side or bottom of the perch now? You might be able to cut away the portion of the perch that's causing the trouble and avoid doing any spacer work at all.

It used to be that Bilstein included a small perch that was only as large as the last coil, which was up against the strut body pretty tight, do they not provide those anymore?

Steve

Hm I've never thought of modifying the spring perch, will have to look into that.

No I don't believe they did, maybe ill contact them and ask.

I'm currently running 20mm spacers which clear ok on flat roads but over large bumps and dips I'm contacting the dog leg portion of the fender. I'm running LESJÖFORS 4295041 HD springs from rockauto and H&R sport springs in the front. I wonder if switching to the H&R in the rear as well would make it slightly stiffer and less prone to sagging over bumps?

 

[Steve Addy]

Maybe a few photos of your car (in profile) would help with this.

Steve

 

[Chungus]

Maybe a few photos of your car (in profile) would help with this.

Steve

I'll get a few pictures when I tear the rear end apart for wheel bearing replacement in a few days.

I've also been looking into tire size as well. Stock is 195 60 14....205 55 16 is almost 1.7" larger in diameter. Maybe switching to a 204 45 16 would solve the issue?

 

[Abacus]

I run 205/45-16's for my summer tires.

 

[Chungus]

I run 205/45-16's for my summer tires.

What offset are you running? I'm at +38 which should be fine I think?