Rattie

There's plenty of milage on this one, as you'll see from a search. We bit the bullet and got our Ford/Quaiffe unit replaced recently and we're now happy with the TADTS level of noise that has replaced the angle grinder loose in the boot kind of noise we had before. Truth is that RWD diffs are quite noisy devices, and Ford and BMW wrap them in lots of noise dampening material, rear seats and the like, and move them further from your ears, while also hanging them off much larger bushes than will fit into the back of a Caterham. Old Ford units are often relatively quiet and so are new BMW ones. The worst offenders are some of the pattern parts that had to be fitted before the switch to BMW. It's worth noting that most noisy diffs are noisy on the overrun, when the secondary faces are meshing. I suspect its to do with the design of the gear profiles being optimised for the primary drivefaces meshing because you spen more time applying more force that way. I for one would be interested to know if yours is a Ford or BMW diff. If you get a torch and look through the spokes of one of the rear wheels, and follow the drive shaft back to the diff, the main cast body of the diff will be either silver/grey with lots of webs cast into the side http://www.robcollingridge.com/kitcar/build/2004/03/2004_03_20_cleaned_diff.jpg or Black and a bit smoother, with less webs and partly encased in a welded, sheet metal mounting cage. http://www.caterham-build.co.uk/images/news/img52_1.jpeg Martyn

-1 for cover on a trailer +1 for tonneau It's the grit that'll get you. Even a tight cover will move about enough in the towing vehicle's wake to cause abrasion. We trailer the car to trackdays. If it looks like rain we put the tonneau on before setting out, other wise keep it in the tow car boot.

If you just look from the rear, the back plate is silver on both diffs, though the BMW one has a (7) logo engraved on it. You'll have to look through the spokes of one of the rear wheels to get a good look at the body of the diff. The BMW one is black as mentioned and even has "BMW" cast into the side just in front of the right hand drive shaft. (You can just barely make it out in that photo) Martyn

Just get the Goodridge 600 Colourflex hose rather than the uncoated 600. It's a couple of quid extra over the whole setup. Plus you can have it in clear, black or pretty colours 😬

clonking on transition between power on and power off is slack in the drive shaft UJs. Tripod UJs are like that. Grinding and whining noises are from the crown wheel to pinion mesh quality/alignment/gap. LSD noises, like snapping and a particular type of grumbling/grinding only show up when cornering. When going straight the LSD or open diff is almost a paperweight 😬

Odd, a slack mesh on the pinion to crown wheel with usually make awful whining noises before it makes clonking noises. The biggest source of clonking noises is the tripod UJs on the drive shafts. They're often poor and only get worse with wear. Is there evidence you haven't mentioned that leads you to the conclusion that is defo the pinion?

Out of interest, why are the trumpets wildly different lengths?

Welded up? Are you 100%? The casing is bolted certainly. As for "gears welded to shafts" which was SM25T's original assertion, quoting the famous "I. Heard" 😬, I'm not sure I can think of which gears would be welded to which shafts to make it unservicable. That's not to say it's not true, just that looking at the unit I'm a touch sceptical. I'd be interested to know the source on that one. I suspect it may just be that as a BMW OEM part they are set up so as to not need a change of oil, but the Caterham rear cover plate has a fill/drain port and it's been used, to added oil and LSD additive at CC Mids. Oh and yes, it comes from a 1 series, specifically I. Heard says it's a Coupe. Who am I to argue Superb unit, far better than the late pattern Sierra, even with Quaife CW&P. Martyn

For reference, the shaft is 36 spline, so one spline = 10 degrees. Handy to know when Simon gets the Rapfix bosses welded on 90 degrees out 😬

Steve will definitely be able to sort it. If the engine came from Minister, I can't see why it would have a locked Caterham/Cosworth unit. What does the MBE box say on it? They usually have a laserprinted sticker. A number like YD8083 would be a CC locked unit, while a number like MBE9A4 or MBE967 would be the standard MBE open product.

@Grubbster: indeed, the carbon effect vinyl is pretty nice. The 3M DI-NOC stuff looks like real CF. I was refering to Charles mentioning that the ABS wing manufacturer does them in CF effect, which I suspect will the chavvy screen printed grey squares that the occasional numpty might think looked a bit like CF, if they had never seen any. 😬

OOh, if the carbon effect is anything like the Westy carbon effect , you'd be better off with plain ABS... or the rather fetching wood finish wraps from MDP 😬

Yeah, sounds like we've had very similar experiences. I also got the guys at Caterham Mids to do it. As for price, yes it's far from cheap. If it was a cheaper car I would have decided against it, and I certainly wish I hadn't missed out on the trade out option, having given the Quaife replacement the benefit of the doubt. Still, we now have a car transformed from something only viable for trackdays with plenty of ear protection to a car we actually can enjoy, even on long journeys. Couldn't have imagined touring in it before. I do wonder why they've gone for the old school tripod joints when the diff comes with flanges for the much quieter Rzeppa joints like most other folks use. I suppose they could be lower drag and they do give a lot of plunge depth. Hey ho.

...and we can now actually drive the car! 😬 The improvement in noise level is truly amazing. I now understand why so many of the old guard gave us the the TADTS story. They just hadn't driven a Caterham with a diff as noisy as a late Sierra pattern part in a metric chassis with poorly aligned metalastic bushes. GRR is now normal noisy, rather Satan's Angle Grinder noisy. We also seem to have been switched over to carbon plated clutch LSD rather than ATB. Does anyone know if there IS an ATB for this particular BMW part? Anyway, that doesn't bother me greatly, though I did love the smooth feel of the ATB. Martyn

Guys (charlie and penn) I suspect you are indeed fighting to agree. I'm not convinced by the "equal front weights" theory, but I know my knowledge of the effect of not having a truly independent rear end is limited, so I'm not making a call on that either way. However lets say we are setting up for equal front weights, and as per Penn's worked example, the driver's side has more weight on it, mostly due to the driver weight. Of course we have to dial that out by transferring weight between the diagonals. Put simply if we go to either the front right or rear left and increase the length of the damper body beyond the spring (by adjusting the perches so as to apparently compress the spring), that will cause that diagonal (FR-RL) to bear more of the weight, in the same way as if you put a floor tile under either of those tyres. Once you have done that enough to equalise the front weights, you will have: a) the two front springs at equal compressed lengths b) the right (drivers) damper with more body showing under the perch than on the left damper. Obviously you pick how you share these adjustments to give you the rake you want, and you may lengthen one side while shortening the other. Talk of preload always seems to end up in bit of confusion, when you generally only do it to avoid the springs becoming loose over large decompressions like the mountain at Cadwell. So unless I missed something I think you were both saying basically that, but with different words and maybe slightly different points of view Help? Martyn

Mine had a pair for third brake light there. So I added a Hella LED strip to one of the diagonals of the rollbar and hooked it up. I can check the colours if you like.

We just put a Longacre wide mirror on instead of the standard bouncer. Does a much better job. I've left the mount point for the CBS demountable mirror so that come MOT time (in a year or so) I can switch back to that if there's a problem. With it being a convex mirror there will be a bit a dazzle at might but not as bad as a non dip plain mirror.

It takes two usually. that one and this one for the wide end of the takeoff.

Hi Egil That would be superb! Pictures would really help. Looking at the schematics I do wonder if the caliper handbrake lever could actually be modified or replaced to suit the stock cables.

😬Maybe, but I do find it helps with the corners! As a largely track oriented car I think ours could do with more wear parity at the back.

Hi guys Further to my other thread, does anyone have these fitted yet? they seem a particularly nice design, running the handbrake on a separate pad. Plus the mountings appear direcltly compatible. I'm prepared to roll the dice and take my chances with HiSpec support etc, but would ideally like to hear from anyone who has gone before me with this exact product... This one here LINKY

OK, sounds about right. I think I may go for a hispec rear pair - seems the least messing about option. Having to change rear pads so often is a pain. Trackdays eat them like cookies.

Oh OK, how many rear pads do you get through for a set of big fronts? Our rears were spent while the fronts have got almost 10pm left per pad!

Cheers Mav, it's kind of good to know that ours isn't "out of spec". I reckon we'll just be watching the rear pad wear like a hawk, maybe replacing twice a year. Either that or replace the calipers with something better matched to the front without these Megacheese pads. Wilwood powerlite maybe?

mic, yes they have. I just checked that before posting. I wonder if some calipers are slightly larger than others at the back causing this interference near max wear. The nasty thing is that it causes the inner pad to bind and wear faster - hence the scoring.