URO Strut Mount hole ID larger than factory hole??

[85RedCarrera]

I received a pair of URO HD Rubber Strut Mounts, and the ID of the URO inner bushing is approx 0.34mm mm larger than the factory part.... I placed it on top of my stock BOGE strut, and it is loose/wobbles. Same thing with the Bilstein strut. Both BOGE & Bilstein struts have a nice, snug fit in the factory strut mount.

URO bushing ID: 18.23
Factory bushing ID: 17.89mm

I double checked the part number and it is the part specified for my '85 Carrera.

Part Numbers on the box: URO-013504 / 911 341 018 00HD

I am guessing that some struts have a slightly larger top diameter? The Bilstein insert and the BOGE insert both have the same OD at the top. Or is the URO part just not made to factory spec?

Any idea what's going on here? Searched the forum and I don't see any posts complaining of this problem.

Thanks,

Dave

[Ian Comerford]

Have you given URO an opportunity to comment?

[85RedCarrera]

Originally Posted by Ian Comerford

Have you given URO an opportunity to comment?

I have not contacted them. I just looked them up now- I didn't realize that they were local to me. I'll call on Monday.

The thing is- you could install your strut into this mount, torque it up, and you would probably never know that it could potentially be moving around in it, due to the excessive clearance.

I'll see what they say.

[Ian Comerford]

If you search in this forum you will find a URO guy who regularly posts and replies to comments, seems keen to help.

[Ian Comerford]

This one is reasonably current
https://forums.pelicanparts.com/porsche-911-technical-forum/998122-re-designed-new-uro-windshield-seal-review-9.html

[SiliconSurfer]

I'm interested to see how you go with these, as I was going to order a pair.

I suspect that the clearance may not be much of a problem, because when the nut is tightened down, the sleeve is clamped solidly between the top of the strut body and the large washer on the top.

Let us know how you go.

[85RedCarrera]

Originally Posted by Ian Comerford

This one is reasonably current
https://forums.pelicanparts.com/porsche-911-technical-forum/998122-re-designed-new-uro-windshield-seal-review-9.html

Thanks. I sent him a PM

[nickelplated5s]

85Red, why don't you start a dedicated thread? I get the 'chipping' away with a project, time and such. Slow down and take a breath. I'm not sure why you are worried about the strut bushings when you haven't done the others. How about a prioritized list? Better people than myself can help you with answers but I've been through this too.

[85RedCarrera]

Originally Posted by nickelplated5s

85Red, why don't you start a dedicated thread? I get the 'chipping' away with a project, time and such. Slow down and take a breath. I'm not sure why you are worried about the strut bushings when you haven't done the others. How about a prioritized list? Better people than myself can help you with answers but I've been through this too.

Oh, you poked the bear with that one. Hmmm... you could look at this a couple of different ways:

1. Separate threads help others to quickly locate threads that are relevant to their search, if the thread is separate and specific to the particular issue at-hand. For instance: when a common suspension part (strut mount) that is often replaced or upgraded is found to be dimensionally incorrect. My intent here was twofold- to alert others that they are installing a part that does not fit together correctly with other parts, and to try to get an answer from someone who has already discovered this problem, but perhaps did not post about it.

2. A single thread regarding the same, ongoing project create a better experience (continuity) for those who would like to follow a project, and results in less "clutter" in the forum. Perhaps I will start a dedicated thread next time- not sure yet.

As far as why I am concerned about my strut mounts right now- Should I wait until I am in the middle of re-assembling the front end to look at the part and discover that it potentially has an issue? I really don't need to be doing things that will lengthen the time required for this restoration.... my front end is completely disassembled and some parts are headed to the powder coating shop. I'll be assembling the front end sometime next week, IF I have the correct parts, in-hand.

I want the car to be done. I find little joy in caressing or admiring this car in the garage- I'll leave that to the others who worry about putting miles on their collectable precious. I cannot really relate to those owners. Drive the heck out of the car and let the next guy/gal restore it again- don't rob yourself of the "Ultimate Driving Experience", and don't rob the next owner of the "joys" of restoration

Additionally, the cost of parts is only going UP- the sooner I am done, the less this restoration is going to cost me. Parts supply issues are also getting worse- and we haven't seen the worst of it, yet.

If I have been inconsiderate to the forum users by posting on each issue separately, I will certainly stop this practice immediately.

[nickelplated5s]

Continuity for myself and thanks for the answer. I and others would like real world impressions when it's back together. Mines sitting in my shop until the motor comes back so can't give you mine yet. Then we have the rain here. Probably two months if I get a dry day.

[UROParts]

Hi guys, we've sold a LOT of these mounts so far with only one pair returned with the "defective" box checked on the paperwork, no details or complaints.

Originally Posted by SiliconSurfer

I suspect that the clearance may not be much of a problem, because when the nut is tightened down, the sleeve is clamped solidly between the top of the strut body and the large washer on the top.

Agreed, once the hardware is tightened there probably isn't any movement. Our engineers are still evaluating the tolerances though, and may snug up the sleeve a bit on the next production run. The 0.17mm difference in radius is slightly more than the 0.11mm wall thickness of an aluminum can, and shouldn't affect camber or caster if the strut isn't exactly centered in the sleeve when the hardware is tightened. It's also unlikely that the metal sleeve (surrounded by rubber) is exactly parallel with the strut, so the strut would self-center in the sleeve.

If anyone has any additional details or feedback, please let us know at https://apaindustries.com/contact, thanks!

[85RedCarrera]

Originally Posted by UROParts

Hi guys, we've sold about a thousand of these mounts so far with only one pair returned with the "defective" box checked on the paperwork, no details or complaints.



Agreed, once the hardware is tightened there probably isn't any movement. Our engineers are still evaluating the tolerances though, and may snug up the sleeve a bit on the next production run. The 0.17mm difference in radius is slightly more than the 0.11mm wall thickness of an aluminum can, and shouldn't affect camber or caster if the strut isn't exactly centered in the sleeve when the hardware is tightened. It's also unlikely that the metal sleeve (surrounded by rubber) is exactly parallel with the strut, so the strut would self-center in the sleeve.

If anyone has any additional details or feedback, please let us know at https://apaindustries.com/contact, thanks!

Thank you for your reply. My concerns were the axial loads that are transferred to the strut mount bushing during heavy braking, and that the clamping force provided by the strut top nut was never intended to limit axial movement of the strut within the bushing- that job was done through the factory bushing ID spec that provided a slip-fit with the strut.

[UROParts]

^ That is certainly logical. Has anyone ever removed the pressure plate / big washer from a mount and found evidence of the plate rubbing against or scuffing the rubber? Or is the rubber bushing clamped too tightly under the plate?

[85RedCarrera]

Update: I returned the URO strut mount and received the "German" version of this part.
The German version also has more clearance in the bushing than the factory part, with perceivable "play" prior to torquing the assembly (nearly equivalent to the URO part)

So, I am not seeing any difference between the "German" and URO part, aside from the price of each. I am still curious why this dimensional change was made from the factory spec. I wonder if the ER inserts are any different?