Does anyone know the diameter of B3 strut tubes? are they same front and rear?
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If memory serves "all" Audi strut tubes on small-chassied Audis....
running McPherson struts are 55mm/2.168" O.D.
Later strut tubes got swaged under-size, to 50mm/1.969" O.D. and 50mm/1.969" down from their threaded top ends. This swaging process is what many people mistakenly refer to as "2-piece" or "welded" strut tubes and/or other terms. There is none of that in Audi's strut tubes as they are "all" one-piece-top-to-bottom. Then the I.D at the strut top is turned on a lathe so extra wall-thickness and internal deformity that occurs during swaging is removed when external threads are added for the strut caps. The reason for this swaging the tubes is simple... to accept smaller piston/smaller diameter strut bodies (read "lower cost") less performance-oriented strut inserts from the factory. Also it precludes "re-tooling" costs to make smaller diameter strut tubes and hub-mounting jigs/fixtures as well as smaller bore steering arms and lower spring perch ID's.
But the area where all coilover threaded sleeves sit for our cars is 55mm O.D. Thats why the Ground Control C/O kit (58mm I.D.) is such a poor/sloppy fit on our strut tubes, being most likely made specifically for a car, or cars, that use 58mm (or more likely 2 1/4") O.D. strut tubes then being sold as "useable" for the 4kQ (and others) vintage Audi chassis.
Later strut tubes got swaged under-size, to 50mm/1.969" O.D. and 50mm/1.969" down from their threaded top ends. This swaging process is what many people mistakenly refer to as "2-piece" or "welded" strut tubes and/or other terms. There is none of that in Audi's strut tubes as they are "all" one-piece-top-to-bottom. Then the I.D at the strut top is turned on a lathe so extra wall-thickness and internal deformity that occurs during swaging is removed when external threads are added for the strut caps. The reason for this swaging the tubes is simple... to accept smaller piston/smaller diameter strut bodies (read "lower cost") less performance-oriented strut inserts from the factory. Also it precludes "re-tooling" costs to make smaller diameter strut tubes and hub-mounting jigs/fixtures as well as smaller bore steering arms and lower spring perch ID's.
But the area where all coilover threaded sleeves sit for our cars is 55mm O.D. Thats why the Ground Control C/O kit (58mm I.D.) is such a poor/sloppy fit on our strut tubes, being most likely made specifically for a car, or cars, that use 58mm (or more likely 2 1/4") O.D. strut tubes then being sold as "useable" for the 4kQ (and others) vintage Audi chassis.
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2nd that... 55mm (55.4mm when I measured)... although 4kq had smaller dia. front strut tubes...
hence the need to split a GC coilover kit for 2 sets of rear tubes to fit the 90q suspension. IIRC, the 4kq front tube fits a 2" coilover sleeve.
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My front/rear kit is GC's kit made for 4kQ and they're 58mm/2.285" I.D...
thats whay I say they're a "poor/sloppy" fit for "every" small-chassis Audi. They'd almost be unuseable (too large) if 4kQ front struts were 2" O.D. as the 4kQ threaded sleeve GC sells is already over 2 1/4" inside diameter. Only way I'd use GC sleeves if that is the case would be to do an aluminum "wrap" of the strut tubes with a piece of 3" O.D. .065" wall aluminum tubing thats been split and then pressed in and siliconed under the GC threaded sleeve.
I dont specifically remember ordering 2 rear kits but I must've if what you're saying about the 4kQ fronts is true. The way GC does business with "over-sizing" threaded sleeves to us the fronts may have been even closer to a good, snug fit for the 55mm strut tubes if they are as over-sized for a 2" strut tube as the rears are over-sized for a 55mm/2.166" strut tube.
What "may" be happening here is GC is buying schedule "xx" T6 tubing with specific SAE ID's like 2", 2.125" and 2.250" and making all their kits from that as it would severely cut down on machining costs.
I dont specifically remember ordering 2 rear kits but I must've if what you're saying about the 4kQ fronts is true. The way GC does business with "over-sizing" threaded sleeves to us the fronts may have been even closer to a good, snug fit for the 55mm strut tubes if they are as over-sized for a 2" strut tube as the rears are over-sized for a 55mm/2.166" strut tube.
What "may" be happening here is GC is buying schedule "xx" T6 tubing with specific SAE ID's like 2", 2.125" and 2.250" and making all their kits from that as it would severely cut down on machining costs.
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Thanks thats exactly what I needed. That being the case.....
Would I then be able to us these tubes with a better fit? do you think I would have to get the strut tubes turned/sanded down to fit these or is .002" big enough?<ul><li><a href="http://www.a1racing.com/index.asp?PageAction=VIEWPROD&ProdID=1734">htt p://www.a1racing.com/index.asp?PageAction=VIEWPROD&ProdID=1734</a</li></ul>
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Looks like a great fit to me. "Might" have to sand tubes lightly to remove some weld spatter...
that gets on the tubes from welding the lower spring perch to the strut tubes. And you'll likely have to cut an inch or so off the the sleeve's overall length to keep their length below the strut tubes threaded ends. But would appear to be a significantly better fit to strut tubes when finished than the GC kit is known to be.
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Yes and there's no cost to you as I provide them free to all Mance-Mount...
original purchasers. As with all my parts, "membership has its privelages." However I'll need to know info on who's upper spring perches you'll be using and what brand struts. I have all that info for GC perches with Bilsteins and/or Konis but may need to get one of your upper perches in here to make adapters if its made by someone else or for shocks other than Bilstein/Koni.
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