Superlight R wheel centre caps

[Nick Bassett]

Just got some Superlight R wheels but missing the centre caps... anymore have any spare gathering dust for sale?

Thanks

Nick

 

 

[Nick Bassett]

Bttt - I wonder if any of the other wheel centres might do the job as well - Prisoner, HPC etc?

[SLR No.77]

Prisoner and HPC centre caps are a bigger diameter but as far as I can tell they appear to have been made from the "same" tooling, the centre badge section appears to be the same and the location of the puzzle bolt hole relative to the centre is the same. If you're able to get hold of some Prisoner/HPC centres they will need the overall diameter reducing to suit, but are then effectively the same. Obviously they'll need painting. This does not apply to the alloy HPC caps which are thicker.

I have 4 full sets of SLR wheels but only 2 sets had SLR centres, I've recently managed to source the extra (Prisoner) centres I needed to have full sets, although I've yet to trim these down to the correct size.

Stu.

[Nick Bassett]

Thanks Stu - very informative.

Can you recall by how many mm the Prisoner/HPC centres need reducing by to fit a SLR wheel?

[TomB]

How would you reduce the diameter of them in a uniform way?  Mount the plastic discs in a lathe and turn them down with a knife blade or file?  

Id be interested in a spare set, as I can hear the plastic creaking when I fasten up the puzzle bolt and one day I expect the attachment moulding to fatigue.

[SLR No.77]

Nick, I'll need to measure them.

Tom, my intention is to make up a "buck" to mount them in the lathe and add some strength to the rear, then carefully lathe off the outer section.

[SLR No.77]

Id be interested in a spare set, as I can hear the plastic creaking when I fasten up the puzzle bolt and one day I expect the attachment moulding to fatigue.

I have thought about adding a thick neoprene washer to the rear where the puzzle bolt locates, some of them do flex a long way if tightened down and a washer would maybe add some security without the need to over tighten the puzzle bolts.

[garybee]

These look like a pretty simple design and something that I could put together without too much difficulty. 

Is originality/genuine Caterham part a must or would you be interested in a part that is machined from thick sheet aluminium with a 3D printed centre or entirely 3D printed?

[Nick Bassett]

Hi Gary,

I had thought of 3D printing, but have no practical experience of it so wouldn't know where to start really.

Originality isn't a must, so if you could help that would be fantastic - thank you.

I have learnt that where the SLR wheel was used as a racing wheel, the wheel centres weren't supplied, which probably explains why they are so rare! This could even develop into a bulk buy...

I have approached Caterham Cars to see if they would consider another production run... well that was a waste of time!

Cheers

Nick

[garybee]

No problem Nick.  Centre caps for these wheels is one of the parts I've been meaning to get to for a while anyway.  

Now, the more dimensions and pictures I can get the more accurate a CAD model I can make.  If anyone who has access to an original set is able to send me some good pictures from various angles and some accurate measurements it shouldn't take me too long to put these together.

By the looks of what's been written above we could get this from HPC or prisoner centre caps (maybe others too) and the dimensions of the relief in your current wheels but it would be best to start with SLR if possible.  I'll get round to doing the others at some point (if people are interested).

Cheers

Gary

 

[TomB]

Probably best if you can borrow one Id have thought.  My car is off the road and the covers are off the wheels pending removal so I don't mind sending you one, just don't loose or break it!! .    ;-) 

[Nick Bassett]

Great work chaps - is the location lock & key going to be an issue?

A close up of the wheel can be found here:

https://www.pistonheads.com/classifieds/used-cars/caterham/all-models/caterham-superlight-r/7369665#&gid=1&pid=8

@Gary - can you pm me your email address please?

Thanks

Nick

[SLR No.77]

If you want to save yourself a load of trouble doing a 3D printed centre badge, they're available from Caterham, they just need painting black.

Also the Prisoner outer centre cap is definitely from the same tooling, I have both types on my desk and they came out of the same tool, I suspect the SLR version was simply turned down. Look at the numbers on the back.

Stu.

 

[TomB]

So whilst the smaller centre cap is available from CC albeit in silver, I presume the larger outer cap is not, whether in silver, larger Prisoner, or smaller black SLR.  IS that the issue here?  

 

[SLR No.77]

Yes Tom correct. I've just bought the last 5 Prisoner outer centres (s/h) that Redline had which when trimmed down I'll have centre caps for all my wheels.

For info Prisoner centres are 6 1/4" diameter, SLR centres are 5 3/4" diameter.

Stu.

[Nick Bassett]

Thanks Stu - disregard the last part of my pm to you!

Nick

[SLR No.77]

Ha ha, i just have!

[garybee]

Wrote a massive reply with loads of info earlier then my internet went down .

Trying again, give me 5...

[garybee]

Probably best if you can borrow one Id have thought.  My car is off the road and the covers are off the wheels pending removal so I don't mind sending you one, just don't loose or break it!! .    ;-) 

If you are happy to do that it would speed things along a lot, happy to pay for any postage of course.  Will send you some details this evening.

Great work chaps - is the location lock & key going to be an issue?

A close up of the wheel can be found here:

https://www.pistonheads.com/classifieds/used-cars/caterham/all-models/caterham-superlight-r/7369665#&gid=1&pid=8

@Gary - can you pm me your email address please?

I could make locking keys that matched the originals either by modifying a bolt on the lathe or turning from new stock.  However, it would be a slow process because of the number of operations which would make it an unrealistic price. 

I think the best solution would be either:-

1) a slight redesign to accept an off-the-shelf (probably allen headed) bolt.  I've added a moulding to the back to support the part from distorting when tightening.

2) removing the locking screw and making it interference fit with the centrre bore in the wheel.  This could be made secure by incorporating an o-ring in the joint.

Interested to know what people would prefer.

If you want to save yourself a load of trouble doing a 3D printed centre badge, they're available from Caterham, they just need painting black.

That's so cheap I think that is a better option than faffing with designing them!  That could make things a lot easier.

 

[Nick Bassett]

I'm not sure which option would be best at this stage Gary - very happy to discuss at a later stage and taking your lead from an engineering perspective.

I'm definitely 'in' though & very grateful for your offer to engineer a solution.

I just purchased 4 of the logo centres from Caterham!

[SLR No.77]

IMHO the best option would be to simply replicate the original outer centre cap including the puzzle bolt "socket".

Stu.

[TomB]

I've ditched the puzzle bolt and just use an appropriate (M6?) zinc coated caphead bolt. Agree with Stu, just the larger outer cap. Will you be able do them in black or standard plastic for us to spray?

[SLR No.77]

There's plenty of options from Pro Bolt that would work fine, just not security bolts.

[Hampshire West AR]

Interested in a set.

[garybee]

Ok it looks like everyone prefers the idea of a copy of the original (outer only) with the bolt recess to the same dimensions.  That makes me happy as that would be the easiest to make and I don't need to spend hours on the lathe making puzzle bolts. 

It's also easy enough to make two versions of this...one as original and one with an extended section on the back that gives the retaining bolt something to clamp down on (will make them a lot stronger and effectively protect them from cracking if overtorqued).

On the subject of colour, I've just ordered some silver filament which will hopefully be a close match to the (minator?) produced wheels and can make them in either this or black.  I can make them in pretty much any colour if anyone wants something different but for now I presume silver or black will do.

Please PM me if you are interested in a set.  Obviously those in this thread who have got the ball rolling have dibs on the first sets.  

Gary

 

Edit: The Caterham 21 wheels I have in my garage (which appear to need the same centres) are retained with an 8mm (8 x 1.25mm) thread.  I'm assuming that this is the same for other versions.  The top of the threaded section is 18 mm from the face of the wheel.  If anyone is able to confirm these dimensions for the other applications it could speed things up a lot.  Thanks in advance.