Zender 'Turbo' Centre Cap Specifications...

Thought I'd start a thread to help anyone on the look out for a set of these and hopefully save you covering the same ground I had to when trying to decipher the confusing / conflicting information out there.

A little of the info. that follows will be basic stuff to those in the know, but it's aimed at someone (as I was) with no prior knowledge of these wheels.

It also refers only to the original Turbos and not the later Turbo 2's.

Turbo's were produced in a mass of different width / PCD and diameter combinations and it wouldn't surprise me that there may be one or two oddities not listed which don't conform to what you're about to read.

I've intentionally limited this post to early VW 4 x 100 applications as it's presumably what interests you and will apply to the vast majority of wheels or caps you'll be looking at.

Apparently over time there were three distinct issues of the original Turbo wheel, sometimes referred to as 'phases'.

The term 'phase' was to me the single biggest cause of confusion and you will probably see Turbo's incorrectly grouped together and referred to in general terms as phase 1's, regardless of which of the three issues they really come from.

This confusion is continued by then wrongly calling the later Turbo 2's, phase 2's when in reality they are a completely separate wheel.

Caps for the phase one wheels were made of thick plastic with 4 x integral metal clips that snapped into a cast groove on the wheel.

Phase one wheels are noticeably heavier that the later phases, and you can see additional strengthening ribs cast into their rear.

Phase two wheels saw the introduction of metal centre caps, secured by a bolt on one side and either a rectangular oblong peg or a circular pin on the other.

This style of cap continued into the third phase.

Phase two and three wheels differ just very slightly and even then it seems to be limited to the width of the outer ring of their face.

To accommodate the securing bolt, the second and third phase wheels have a corresponding lug with threaded hole cast into them. Phase one wheels have no such lug / threaded hole.

Apart from this different fixing method the phase one caps are also slightly bigger in diameter than the phase two and three's meaning in this respect alone they aren't interchangeable.

Caps for phase two and three wheels however are interchangeable but importantly only subject to the following criteria.

Ignore for a moment that I've been concentrating on 4x100 PCD Turbos for VW's which will generally be in 6x14, 6x15 and 7x15 sizes.

All phase two and three 6x14 and 6x15 wheels (regardless of PCD) share the same centre caps both in diameter and in having a rectangular oblong peg that slots into a corresponding hole in the wheel, opposite the securing bolt fixing.

All phase two and three 7x15 wheels have caps of a larger diameter than those of phase two and three 6x14 or 6x15 wheels and a small round pin in place of the rectangular oblong meaning they aren't interchangeable both on grounds of size and fixing method.

Caps for all 7x15 Turbo's are the same as those on 7x16, 8x16 and 9x16 wheels (again regardless of PCD) and are interchangeable.

(There is one exception I can vouch for and this relates to the phase two and three Turbos in 7x15 for the VW-Bus… The catalogues specifically say this cap is unique to that vehicle, even giving it a separate part number but doesn't explain in what way it differs.)

Centre caps for phase 1 wheels…



Caps for phase two and three 6x14 and 6x15 wheels…



Caps for phase two and three 7x15, 7x16, 8x16 and 9x16 wheels…

Sweet baby moses. And I thought I was a wheel geek!

Good job.

Hopefully of use to someone… If I'd had the above info. it would've saved me needlessly spending a lot of time (and money) sourcing caps that weren't suitable for the sets of Turbo's I have.

On the plus side for someone… I've a surplus set of 4 x resin caps made from an original 6x14 / 6x15 one (The smaller type with the oblong peg fitting).

Anyone interested can drop me a line for some pics.

Excellent info and write up ,mine are 7 x 15  et 38  with metal caps and securing bolts and original key .What is the difference between phase 2 and 3?

Mine came from  a zender kitted mk2 that got broken up ( not by me )

Excellent write up.  

Apparently very little other than the outer rim on the face is slightly narrower.

ET38 is an unusual spec. for Turbo's.

The above images were taken from the inter-web. I took my own tonight, but it's difficult to show the differences in diameter clearly.

Phase 1 front and rear to show the method of attachment. (These were refurbished with the wheels, but the writing on the rear is from before. It tallies closely with the later phase 2/3 part numbers you'll see in the last catalogue scan so I'd be comfortable it's accurate.)




A phase 2/3 (15x7 and above) cap sitting atop a phase 1, showing a good 8mm in difference across the face.



Phase 2/3 cap (15x7 and above) front and rear.




Phase 2/3 cap (14x6 and 15/6) - Resin reproduction cast from an original.





Phase 2/3 14x6, 15/6 atop a phase 2/3 15x7 and above - Approx. 18mm difference across the face.



Oblong peg and round pin in close-up




Catalogue scan of spare parts, caps are top left of page.

Another excellent write up - your the zender king  

Far from it I'm afraid… There's a long time poster over on Vortex who has a Turbo fetish judging by the number of sets he's had over the years.

He was more than helpful and put me in the right direction for what I needed, I'm just passing it on.

Ah well fair play for sharing. I love picking up info like this.

bacardincoke said

Hopefully of use to someone… If I'd had the above info. it would've saved me needlessly spending a lot of time (and money) sourcing caps that weren't suitable for the sets of Turbo's I have.

On the plus side for someone… I've a surplus set of 4 x resin caps made from an original 6x14 / 6x15 one (The smaller type with the oblong peg fitting).

Anyone interested can drop me a line for some pics.