Audi A4 B9 front strut 48.5mm vs 53mm

[Pandemic]

Hey is there a consensus on what the strut diameter should be for pre-July 2016 cars? I've seen people say it should be 53mm as well as 48.5mm for cars with pre-July 2016 build dates.

[Smac770]

The only change in strut fork for the type 8W was the move of 1BE (sport) from using the "all other suspension codes" fork (8W0 413 037 G) to using the 1BD (S sport, ie S4) fork (8W0 413 037 H) starting July 11, 2016. As expected, the 1BE strut damper also changed on this date, since it would have to change diameter to match.

So whatever size the A4 1BA uses, that's what pre-July 11 '16 A4 1BE uses. Whatever size the S4 1BD uses, that's what post-July 11 '16 A4 1BE uses. And I imagine the rev G and rev H are certainly different sizes or this whole issue would never have come up. But which is the smaller diameter and which is the larger diameter, that's not directly referenced in the catalog and I don't have them in hand to measure.

[deviantspeed]

Or so the manufacturers say....

By all their accounts I should have 49.5. I have 53mm. So really, the only way to be 100% sure is to measure them. It's not hard to identify them either.

Good luck finding stock, too :) Struts come in every now and then to the big box stores, but usually sell out quickly. More than often, new struts are out of stock. Again, good luck and hope it goes well!

[deviantspeed]

Here you go, grabbed this from an ebay auction months ago:
s-l1600.jpg

Mine is 10/2018 build...

IMG_20210810_112429.jpg

[Smac770]

You have 1BA (thus the 031 AA part number), which you seem to be presenting as a 53mm barrel bottom (it seems odd that they bothered to have two different parts just to have this lip on the lower barrel). So that would imply the 1BD barrel is the ~49mm one. And 1BE switched from the 53mm to ~49mm in Jul '16. So all if this is exactly in line with what the catalog said.

https://www.deutsche-parts.co.uk/8w0...uine-part.html
There's the AK, the 1BE front damper to Jul '16, note by Monroe. Has the lip. So confirmation that the 1BA fork is the 53mm.
https://www.ecstuning.com/b-genuine-...s/8w0413031bg/
And there's the BG, replaced the BA, the 1BE front damper fr Jul '16, note by Sachs. No lip. So ~49mm.

So everything is as I posted originally.

[deviantspeed]

Nothing to do with mine. Even bidded on 49's.

but I think we can all agree to measure first, buy after. Really annoying on this car and I thin most peeps are just doing springs anyway... bounce bounce bounce,

[Ruxn7]

You have 1BA (thus the 031 AA part number), which you seem to be presenting as a 53mm barrel bottom (it seems odd that they bothered to have two different parts just to have this lip on the lower barrel). So that would imply the 1BD barrel is the ~49mm one. And 1BE switched from the 53mm to ~49mm in Jul '16. So all if this is exactly in line with what the catalog said.

https://www.deutsche-parts.co.uk/8w0...uine-part.html
There's the AK, the 1BE front damper to Jul '16, note by Monroe. Has the lip. So confirmation that the 1BA fork is the 53mm.
https://www.ecstuning.com/b-genuine-...s/8w0413031bg/
And there's the BG, replaced the BA, the 1BE front damper fr Jul '16, note by Sachs. No lip. So ~49mm.

So everything is as I posted originally.

You just saved my life, this is great info! Thanks bud.

[deviantspeed]

You just saved my life, this is great info! Thanks bud.

Did you get the right ones?

I'm even more confused after Smac's post. I did have IBA, with the struts p/n ending in AA.


partsvin:
Shock absorption/suspension system
1BA
Standard suspension/shock absorption

I posted, maybe not in this thread, where I used calipers on the lower strut, but you can see they are the fat mount ones in the pics above, which were 53mm when I put calipers on them before ordering new bilstein b8's.

He's right in the catalog, but the catalog was wrong with mine. But this is the Audi way, really have to reference by vin, but the same part number is quite an oddity. There are other "sub" part numbers on the monroe sticker, that might be the trick.

You can't really see the digital part but you can see the analog lines:

IMG_20210804_185103.jpg

Best of luck all!

[deviantspeed]

One more of the iba strut:

IMG_20210729_094554.jpg

[Smac770]

Yes, the 1BA (that's one-BA, not eye-BA) uses 53mm, the 1BD uses 49mm, and the 1BE switched from using 53mm to using 49mm.

At no time ever did the Audi materials imply you should have a 49mm for a 1BA. Whatever third-party companies might have claimed, they aren't Audi parts catalog, so their errors are on them.

So I'm not sure where any confusion is coming from, as it all seems very specified to me.

[deviantspeed]

There's a lot to digest there. Again, all the aftermarket catalogs say I should have 49. I don't, as you then just stated, but I think implied not that previously unpossible with a monroe catalog, which is also "pre-market AND post-market". When I say aftermarket, Bilstein, H&R, etc...

I think it's as clear as mud now :) :)

[lijbu]

My car has the sport package option($400).
I believe sport suspension package models have 48.5mm; everything else has 53mm for the front struts.
Anyone else able to confirm?

[V0Nzipper]

My non-sport package (BA) 2017 build date had 53mm struts.

Best advice is to measure and confirm. The measurement is at the knuckle, so if you have a lip/shoulder at the lower section of the strut, they are 53mm. I'd suggest buying a cheap caliper measuring tool on Amazon.

Sent from my Pixel 5 using Audizine Forum mobile app

[Smac770]

My car has the sport package option($400).
I believe sport suspension package models have 48.5mm; everything else has 53mm for the front struts.
Anyone else able to confirm?

Already covered in this thread.
If you are 1BD (S sport), you're always 48/49mm.
If you are 1BA (A standard), you're always 53mm.
If you are 1BE (A sport), you are 53mm until Jul '16 and then 48/49mm after that.

So without your build month/year from your vehicle, all we can speculate is that almost no US B9 A4 1BE were likely built before Jul '16.

[Daphnerides]

So I'm not understanding any of this. I have a 2016 Audi A3 2.0T AWD. What diameter is my suspension. I'm so confused.

[Smac770]

You have an A3 ... so not relevant to your vehicle?

[blubusdrvr]

What a total clusterfuck. Why Audi wouldn't source Sport dampers in 53mm body tubes (or BA dampers in 48.5ish tubes) for the same model build years so they use the same fork?? I was literally in the middle of this swap trying to figure out WTF when I found this thread. I guess I'll be putting this back together and looking for some "H" strut forks now...

[Smac770]

I always figured the smaller strut barrel meant a thicker collar on the fork holding the strut barrel. But when you get the alternative set in hand, you'd be able to confirm that. Also, the standard dampers are often by Monroe and the sport ones by Sachs. But we'll probably never really know the why of the dual sizes.

[Pandemic]

lol nice bump on this old thread. it ended up being 53mm, got bilstein B8s and it was smooth sailing from there, great damps