IVA fail 1

[blueyedbiker]

Afternoon all,

Well no surprises, it failed its IVA but what do you expect when you put a X Flow and a pile of old bits that had been hanging around the garage for years into a 2000 chassis?  It is, in reality a remarkably positive result in that the majority of the installation is fine and most of the twenty odd fail points are relatively easy to fix - wiring faults, the odd cover here or cap there.

There are however a few points that will need some creative solutions and to make it easier to keep track I’ll do them as separate posts, so, beginning with the trickiest;

The wheels are secured to the hubs with studs and tapered nuts as per usual.  The requirement however,  is that the wheels should be “self-centring” on the hubs and the wheel/hub interface should be “load bearing”, this being achieved by the holes in the wheel centres locating over raised lips round the centres of the hubs, the studs and nuts being there just to hold it all together.  There are indeed raised lips on the hubs - uprated front, standard de dion rear but these are somewhat smaller in outside diameter than the holes in the wheels (Minilites) and interestingly enough they are smaller diameter on the front hubs than the rear hubs so clearly CCC are not using these lips for wheel centring otherwise they’d need different wheels front and back.  Initial contact with CCC reveals that this has not come to light previously so they’re doing an internal investigation.

The holes in the Minilites are around 55mm on the outside face of the wheel but rather larger on the inside face so my initial thoughts on a solution would be to have “rings” fabricated to be a snug fit on the hub lips and an outside diameter to match the hole diameter on the inside of the wheel.  I’d need to run it past the DVSA technical people beforehand but any other solutions will be welcome.

The inference of course is that this applies to all 7’s going through an IVA so if you have one booked already I suggest you get in touch with CCC pronto. 

My test was done at the Gillingham centre where they’re no strangers to 7’s.

[Jim 123]

Is your test being conducted based on "rebuilt" criteria or as an "amateur build" ? 

[ScottR400D]

You should be able to use centring rings, they’re common enough. You might even be able to buy the sizes you’ll need. Search “hub centric rings”

As I understand it, having the wheel centre locate on a spigot is more for a secondary location in case the nuts come loose. 

The nuts centre and clamp the wheel to the hub. There’s no load taken on the spigot in normal use. 

[aerobod - near CYYC]

The standard Caterham 15" and 13" wheels on my 2012 R400D are certainly not hubcentric from the factory. I'm pretty sure that unless things have changed over the past couple of years, Caterham doesn't  use the hub boss for wheel location. Wheel centre bore is about 10mm larger diameter than the hub boss.

The other issue is that the hub boss is quite shallow, compared with for example VW or BMW hub bosses, only about half the depth. This means that the bevel that many centring adapter rings have may be too pronounced for the ring to sit on the hub boss anyway.

[Jim 123]

It is possible that the tester is being over zealous in my opinion, as the "load bearing" issue and "self-centering" design is what the hub mounted studs and dished wheel nuts achieve. (You would never be able to drive without the wheel being out of balance if the nut and stud did not self - centre) Also I'd venture that he solution they are asking for is not likely to be feasible on a car with pressed steel wheels either.  Have they referred to what section of the Test Manual they have applied as interpretation may give some clues to other fixes? This is probably all academic as the Gillingham centre will just find other issues to fail you on if you appeal.

[PeterM]

It is possible that the tester is being over zealous in my opinion ​- agree this.

Take it to another test station (like Southampton where I did mine) as the relationship between Gillingham and Caterham is probably getting a bit edgy by now - as in familiarity breeds contempt!

[blueyedbiker]

Evening all,

Been in a wifi deadspot for a few days so not had chance to respond.

Jim, thanks for your thoughts, it was done as an "Amateur build" and I did wonder about the zealousness of the inspector but he wasn't sure and brought over another guy for a second opinion, guy#2 thought that there was a CCC part that would fit but CCC parts dept haven't heard of it.

The hub centric rings may do the trick but if they're not deep enough they'll fall off the lips which in practice wouldn't be a problem, the potential difficulty would be getting it through the retest.

Now I'm back I'll see what CCC can come up with and report back.

[blueyedbiker]

Heard back from Caterham that this is the first time this has happened.  Great.  Meanwhile I've been on to the DVSA approvals team for their suggestions.

[Jonathan Kay]

Can't see anything relevant in the Manual...

Jonathan

[aerobod - near CYYC]

I checked every instance of the word "wheel" in the manual, no hint of any requirement relating to wheel mounting or location that would require the wheel to be hubcentric. It does specify not to use wing nuts to attach the wheel, though.

[Jim 123]

Ebay have hub centric spigot rings.  Might not be perfect for your car, but maybe a good starting point to tweak in a lathe?

[blueyedbiker]

Thanks for the replies chaps, this weeks tasks are visits to the local engineers to investigate bespoke hub centric rings and to the Hayes depot for an opinion.

Shame about the wing nuts!