ScottR400D

When I first pushed my car to higher speeds, around 100mph, the speedo kept dropping out. I moved the transducer a little closer to the segmented disc and it's been fine since.

It's OK to use PTFE tape as long as you're not relying on the contact of the sensor with the housing to ground the sensor. If you are the tape can stop it earthing. Tape shouldn't be necessary on a tapered thread.

Standard Operating Procedure?

Do you mind saying where you got the sockets from?

On the subject of replacing the Torx + with cap heads or hexagons, does anyone think that would be an issue? From what I've found out Torx heads were originally designed to enable greater torque to be applied to Phillips/Posidrive type screws, because the Torx resists 'cam out' better. They were also used as tamper proof fixings when Torx tools weren't so widely available and that was the original use for the male type Torx bolts. They have no advantage in terms of torque application over a cap head or hex head. So there seems no reason at all why these particular bolts couldn't be replaced by cap heads or hexagons, assuming, of course, the same thread and material spec is used.

A 12.9 is higher tensile strength than 10.9, of course, but unless what you are bolting them into is strong enough to allow you to increase the applied torque there's no point changing. Further, the higher tensile bolt is also more brittle and more susceptible to failure cause by cyclic loads such as seen with repeated heating and cooling. I'd stick with what's specified.

If it was reading low then there WAS a risk of you going too fast, surely?

I've had unsuitable stuff from DT in the last and they've arranged collection. Did you get the tyres off, Glasgow and spin up the wheels?

No fasteners in mine, just pushes into place.

Ahh, the issue is that OE tyres often have more than one spot on them and they don't always mean that's the heavy spot and needs to be near the valve! Some spots indicate a high point as opposed to a heavy point and manufacturers often have other spots for reasons best known to themselves!

Just to give my opinion on some of the points raised! A static balance cancels out imbalances radially, ie across the diameter of the wheel. A dynamic balance cancels out any imbalance across the width of the wheel. I used to have a little rig to demonstrate the difference. It was a small plastic wheel on a bearing on the end of a handle so you could hold the handle in one hand and spin the wheel. Around its circumference where a series of holes, drilled axially. If you pushed a small weight into one of these holes and spun the wheel it would be all over the place. If you put another weight in the same side, directly opposite, the wheel would spin freely and smoothly. if you then moved one of these weights to the other side of the wheel, still diametrically opposite but axially on a different plane you would get a significant wobble. Not as bad as with only one weight, but certainly not good! That element is what a dynamic balance removes. I hope that's understandable! As for the brake caliper thing, that can happen but unless you're using a steel weight the weight would soon wear off. In any case, I haven't seen an issue on the front wheels with Apollos. On the rear of my car the weights need to be about 40mm into the rim (8") to clear the rear calliper. Other than that there shouldn't be an issue. As for the correct way of mounting that should always be trying to mimic the way the wheel is mounted on the car. If it locates on the centre hole then it should be coned. If it locates on the studs, use a flange plate. Many tyre shops will try to use cones because they're quicker and cheaper to use. You need a wide range of flanges and they're not cheap! A few different sized cones costs a lot less and is near enough most of the time. Having said that, and based on my experience with my Apollos, they locate on the machined surface in the rear of the centre hole and that's why I back cone them. Mine are the black/diamond cut, the silver may be different. I would still suggest going back to getting the tyres off, checking the rims and going from there, with all the advice on this thread. Hope it goes well.

I'm not sure about that but I think they know where it will be because it's where the breaker plies overlap at the base of the tread. If you look inside the tyre you'll see the bulge.

The wheels should be pretty straight yes. I put one of my spares on the balancer last night, it spins reasonably true. I have a video of it but not sure if I can post it. Not sure what you mean by 'static (ie only on the inside)'. a static balance is carried out with the weight on the centre line. As implied it does not dynamically balance the wheel, ie across the width and if that imbalance is still there you'll get a lot of vibration/wobble/shimmy coming through especially on a Caterham. These wheels should only have weights on the inside in any case, see below. This is a front but needed a 45g and a 20g. The other front had 2 x 20g. Incidentally, when I spun this front it was showing about 15g imbalance. Since I balanced to zero when new, I've done a trackday on them and there is pick up and wear so that's well within an acceptable level and confirms that using a back cone on the centre hole is the correct way to mount. So, in answer to your original question, this isn't typical of the Apollo wheel IMO and you shouldn't live with it. I would suggest you get the tyres off and spin the wheels to see how balanced and true they are. If they aren't then they are at fault, if they are it's the tyres or something to do with the fitment. They are all seated on the rims well aren't they

My business used to involve the sale of tyre changers and wheel balancers amongst other things. Retired now but still have a modern changer and balancer in my garage. That's just background. When I built my R400 last year, I rebalanced the 4 Apollo wheels (CR500) and the spare set of the same that are fitted with ZZRs. All 8 wheels had significant imbalance as received. I back coned them in the centre hole because that's how they appear to be located on the hub, not by the nuts with loose seats. After balancing, I slackened the clamp, rotated the wheel 1/2 a turn and clamped again. No significant change, which indicates an accurate mounting on the centre hole They're all fine on the car, no trace of vibration. There was a little run out on the rim but nothing significant. From memory there were a couple of biggish weights (50gish) but some were very small. In conclusion, I would say they need to be back coned, not reverse mounted or flange plate but need to be very clean on the back of the wheel centre, as does the face of the balancer spindle. I won't criticise KF but my balancer is better than most of the ones they have, unless things have changed recently, and in better condition, though to be fair they use theirs more than I do mine! I would suggest you seek out an independent with a good machine that he knows how to use.

I calculated 22mm drop in ride height and 7.5% speedo overread from those figures. Seems a lot but, of course, a 7 should run on those tyres.

Yes it does, as said earlier. The point is to get the bottom of each tyre at exactly the same height, more correctly the platform of each scale at the same height. IME garage floors often have a slight fall towards the door so I would carefully check that it's level in both directions before I just went ahead and set corner weights that way. As an example, if your garage floor sloped by 10mm across the wheelbase of your 7 you could end up with perhaps twice the rake that is recommended and too much weight on the front. If you don't have a perfectly flat floor, corner weighting will be a waste of time.

Except that if you don't have the car on a flat floor, the corner weighting is pointless. The term flat floor simply refers to what the car is sat on, but covers anything from a flat, horizontal floor to 4 separate scale mounts, set to exactly the same height as each other.

No problem Martyn. I was talking about the squealing but I'm quite intrigued by this thread and I've just had a look at my car, which has the newest 4 pots. The top pin doesn't come out because the stay is in the way. I thought it might wriggle past but I tried and it won't. As you say it's easier to move the caliper than remove the stay. I see what you mean but in my case the caliper is bolted on radially, not from the side so it would probably need both bolts removing and the caliper pulling straight out until the pin could be removed. In answer to the earlier question, with these brakes the pins can't be put in from the other side, they are held in by a split ring mechanism and will only go one way.

My R400 doesn't do it, never has. Is this thread more to do with the standard brakes, as opposed to the 4 pots?

Does this vary model to model? On my car it looks like the top pin will just clear the wing stay.

Just to finish this off, if anyone's interested, the replacement pcb, which solved the problem but suffered some cosmetic damage in shipping, was replaced again by CC. I fitted it on anti-vibration mounts, instead of it being fixed solidly to the bulkhead, so hopefully it will now be more resistant to road shocks. It now has the added advantage of being quickly removable from inside the car, as opposed to having to move the heater. Credit to CC, the response once the failure happened has been excellent, plenty of advice and replacement parts shipped overnight each time.

Does this help?

I guess you could take it back to the dealer but what Ian suggests often works. Which is easiest?

Which wire was at fault?

What condition are they in and how much would you want for them? I have an SV with composites and am thinking of buying some leather seats for road use.