Jaguar XJ-S. Manual - part 102

 
 

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Modern spoke wheels normally have stainless steel spokes, which is a big improvement over earlier designs.  However, 
spoke wheels generally still have chrome-plated steel rims and centers, leading to rust problems, flaking chrome, and 
associated air leakage at the tire/rim seal. 

By the way, if it’s a weight reduction you expect, forget it.  There is nothing lightweight about spoke wheels. 

It should also be noted that since the spoke wheels are more flexible than alloy, the handling will suffer somewhat.  
With a car this heavy, the difference in the way the car corners is noticeable.  You may even get sounds, as the spokes 
strain and creak with the load. 

Note that older Dayton wire wheels had 60 spokes while later designs have 70 spokes, with the 70-spoke versions 
reportedly better.  John Tompane says, “The 70-spoke wheels weren't available until I think '89.  I have 70-spoke 
Daytons on my wife's XJ6 and they have been trouble-free for years.  When I got the new XJS it came with the same 
wires already on the car.  Since I sometimes drive harder than my bride, I had planned to replace them with sport lattice 
wheels like I had my '88.  But frankly, so far they have been great.  I've pushed them pretty hard and they have stayed 
in balance.  I think I'm going to keep them at this point. If I were going to race, autocross or really push the car hard for 
long periods it would be stupid to use them.  They aren't designed for that. But for everyday driving and little spirited 
driving they're pretty damn good.  Not great, but not nearly as bad as advertised.  The 60-spokes were true nightmares 
(or is it untrue nightmares?) and should be avoided at all cost.” 

Peyton Gill counters:  “The Daytons which failed on my '86 XJ-S were 70-spoke.  The point of failure was the wheel.  
Cracks formed between the spokes.  In some cases the cracks meet from one spoke to another.  The car had not been 
subjected to any abusive or aggressive driving.” 

“I bought my XJ-S from my sister who bought it new.  She had one wheel self-destruct when a car pulled in front of 
her.  She did not hit the car but the action of hard braking caused one wheel to collapse.” 

There are (or were at one time) also 50-spoke wire wheels made by TrueSpoke.  Brett Kelien says, “I have had enough 
problems out of 60-spoke Daytons and TrueSpokes to say they will never be on a car of mine.  I have broken them 
going down the highway.  On the good side Dayton did make me a good deal on the 70-spoke wheels which I really 
like.” 

Actually, it appears that Dayton will make anyone with their 60-spoke wheels a good deal.  Steve Gallant says, “I called 
Dayton Wire Wheels and found that they would not repair the wheels under any circumstances.  However, they would 
replace them with new ones for a very low price.  And these new ones had both a larger spoke diameter and more 
spokes.  Dayton was trying to get these wheels out of circulation by offering good replacement deals.  I'm sure they 
could see the liability issue coming to bite them in the ass sooner or later with wheels not sufficently strong for the 
intended application.” 

For more info, surf to 

 

 

http://www.daytonwirewheels.com

 

and drop them a line.  Or contact their warehouse distributor, Floristar, at 1-800-782-7050. 

So, if spoke wheels are so much trouble, why did Jaguar fit the car with them?  The answer: they didn’t.  If you have 
wire wheels, they were either installed by the dealer or by an owner.  Jaguar wouldn’t wish those things on you, and 
won’t accept responsibility for problems you have with them. 

Now, despite the problems mentioned above, many XJ-S owners will use wire wheels anyway.  They came with the car 
and you don’t feel like paying for a good set of alloys; you bought them before you read this book; or you just like the 
looks regardless of the problems.  Whatever, I provide the following tips for those who insist on driving around on 
wires. 

Dayton wheels apparently come with stainless steel lug nuts.  These sound like a really good idea, but for some reason 
they tend to gall the threads on the Jaguar studs.  The problem may be avoidable by the use of anti-seize compound 
and/or chasing the threads in the lug nuts with a tap before use, but if you don’t want to take the chance you can 
purchase generic 1/2” fine thread chrome-plated steel acorn nuts at just about any auto parts store.  You will usually 
have a choice of shoulder length, so you need to check the thickness of the flange on the wire wheel before buying.  

 
 

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The chrome-plated nuts match the chrome-plated center of the wire wheels better than the stainless steel nuts!  
Remember to make sure that you have an emergency tire wrench in the boot that will fit your lug nuts, since the 
aftermarket nuts are likely to have a different hex size than the Jaguar OEM nuts. 

If you need to buy replacement center caps for wire wheels, note that the center caps may be something that looks like a 
big domed nut or it may look like a 3-bladed knock-off.  The item used on the TrueSpokes looks like an 8-sided nut.  
Regarding Daytons, Gallant says, “The 60-spoke wheels came with the hex caps, the 3-spoke knock-off spinner was 
optional and could be purchased separately from Dayton.”  Note that the knock-off style caps seem to get lost regularly, 
so if you have this type you might want to check the attachment scheme.  If they attach with a bolt, use Loctite or some 
such, or even better figure out how to apply locking wire. 

Note that there are at least two configurations of Dayton knock-off; Michael Mongelli explains:  “I have, if you can 
believe it, two different types of spinners on my wheels.  The one that fits best is 2 1/2 inches in center diameter; the 
blades are 2 inches.  The other type is about 3 inches in center diameter with a shoulder; this one fits but it requires a 
round shim that fits over the wheel center to make it tight..the blades are 2 1/8".” 

 

CHROME PLATED ALLOY WHEELS:  Nope, these didn’t come from Jaguar!  Chrome plated alloy wheels, like 
spoked wheels, are trouble; Jaguar would never provide them from the factory and won’t warrant them.  The dealers, 
on the other hand, are only too happy to take the wheels off the brand new cars in their showroom, send them off to 
some disreputable plating shop, and pass the costs on to the new Jaguar buyer.  If your chrome-plated wheels are more 
than a few years old, you will probably note flaking chrome.  Mark Stoner says, “My XJ-S has the chromed starfish 
wheels and they are nothing but trouble.  The chroming was done by the dealer and all chroming is not done with equal 
quality.  My problem is that the chrome starts to peel (mainly on the inside of the tire) and causes bad corrosion.  I 
couldn't get one wheel to hold air so I had the chrome turned off of the bead with a lathe.  It still leaked so I put a nice 
bead of silicone on the beads and it seems to be working as a temporary fix.” 

Rod Fleming, who worked with chrome-plated alloy on motorbikes, says, “When you chrome a piece of steel, the first 
layer you apply is copper, which sticks well to steel.  This is very thin, and serves only as a bed for the next layer, in 
order to make it bond well.  This next layer is nickel, which is black until polished.  This layer is quite thick and it is 
this which actually protects the underlying steel.  The nickel needs the copper layer; it won't stick to steel, but it sticks 
like the proverbial to copper. 

“In the early days of the car industry, the nickel was then polished to give a lovely silver sheen.  However, nickel is 
very soft, will wear through easily, and goes black with oxidation.  So in the 1930's people started putting a layer of 
chrome on top.  Chrome is very hard and durable and will stay bright, but, and it's a big but, it's porous.  It offers no 
weather protection at all, and the layer that is applied is very thin.  So "chrome plate" is actually a complex interaction 
of the properties of several metals applied in very thin layers. 

“Now the trouble is that you can't, try as you like, get that all-important copper layer to stick to aluminium alloy.  So 
you have to get the nickel to plate directly onto the alloy.  This it is not very happy to do.  The bond is okay for say, 
engine components or interior applications, but leave it out in the salt and rain, not to mention the gritblast of road use, 
and it will come off in short order. As soon as it is penetrated, the underlying alloy starts to swell and oxidise, popping 
off more plate, and pretty soon you've got the shameful mess we all recognise. 

“In addition, the thickness of the nickel layer is important; if it is not thick enough, then it will fail.  Nickel is expensive, 
and platers have been known to cheapskate...this is why you can leave a '74 Norton Commando out in the rain for years 
and still have decent chrome, yet a '74 Moto Guzzi's chrome would have turned to brown lizard-skin after two weeks. 
(Not that any you see today will be wearing the original stuff.) 

“I doubt if the effect has much to do with differing thermal expansion rates; we are only talking about a few microns 
thickness here.  At least, no one ever mentioned it, and I would expect it to be more of a problem on engine parts -- but 
these, as I said, seem to suffer less. 

“As for rechroming/chroming, old chrome (and the nickel, etc.) is removed the same way it goes on:  just by reversing 
the electroplating current.  The electroplater uses it again.  Not really a problem. 

 
 

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“The real issue with any kind of chrome plating, by the way, (leaving aside the specific issues above) is polishing the 
metal to be plated.  The slightest blemish will show; indeed it will be greatly magnified by the plate.  Also, a smooth 
surface is important to the long term integrity of the plate as it is very difficult to build up a decent thickness on high 
points.  Frankly the thought of  polishing a lattice wheel properly fills me with dread! 

“It's hard to find a plater whose work is good enough for restoration use, largely because of the polishing; it's all man-
hours, and they cost.  Most platers are used to doing new bath taps and the like, not polishing the pits out of already 
well used components. 

“Stripping and lacquering wheels is definitely a better idea than chroming; in the UK at least there are many firms who 
will do this very cheaply and who turn out a very high quality finish.” 

 

WHEEL SIZES:  Over the decades that the XJ-S was offered, tires were gradually becoming lower profile -- wider 
and/or not standing as far above the rim (which requires a larger diameter wheel to maintain overall diameter).  This is a 
good thing; shorter and wider is more stable than taller and skinnier.  Basically, Jaguar cars came fitted with the best 
arrangement of tires and wheels commonly available at the time -- but as the best arrangement available kept changing 
over the years, the tires and wheels fitted to Jaguars changed to keep up.  In general, owners of older cars can improve 
their cars considerably by moving to the later tire and wheel configurations. 

The wheels used on the pre-H.E. XJ-S are 6” wide.  The wheels used on the H.E., both the “domed starfish” pre-ABS 
and the “lattice” on ABS cars, are 6½” wide.  Owners of pre-H.E.’s, therefore, might consider installing later wheels 
onto their cars.  While ½” may not sound like much, a wider wheel provides the casing of a tire more stability.  The 
difference is noticeable, even if you reinstall the same tires. 

The wheels on some late-80’s/early 90’s XJ6 (XJ40) models are 7” wide, and will bolt onto the XJ-S.  This gives 
owners of all XJ-S’s with 15” wheels an option for wider wheels yet.  The 7” wheels work very well with the 235/60 
tires. 

D. C. Cook (see page 712) offers some snazzy 7.5x16” and 8x16” wheels for Jaguars, and you can also get 16” wheels 
directly from Jaguar; 90’s XJ-S’s and XJ12’s came from the factory with 16” wheels.  In fact, if you go shopping for 
aftermarket wheels, you may find that 16” is the way to go; the aftermarket shops seem to offer more in 16” than 15”.  
But besides the wheel availability, it also may be easier -- and cheaper! -- to find speed-rated tires in 16” sizes to fit the 
Jaguar.  Specifically, the 255/50R-16 size is suitable, and is widely available for less money than V-rated 15” tires.  
John C. Palm reports that “Corvettes used 255/50-16’s from ’83 to ’87.  Camaros & Firebirds have long used 245/50-
16’s.” 

And, yes, you can go beyond 16” and install 17” or even 18” wheels on an XJ-S.  In fact, the Aston Martin DB7 -- 
which was based on the XJ-S floorplan -- comes with 18” wheels, and these wheels will fit the XJ-S.  Justin Pashley 
reports that buyers of DB7’s quite often opt to install custom wheels on their brand-new cars, so the OEM wheels are 
commonly available in the UK as “take-offs” for reasonable prices.  “I use a 225/40-18 tyre which look great.  I have 
had no problems with clearance.”  Note that the DB7 wheels have a smaller offset (14.5mm) than XJ-S wheels, which 
means that the 225mm tires are about the widest that will fit without flaring the fenders. 

Paul Hackbart adds, “There is the Aston Martin wing emblem on the center cap.  It is the same diameter as the plastic 
Jaguar face on OEM center caps.” 

James Dichter says, “Very important!!!  If you are considering Aston-Martin DB7 wheels make sure they are stamped 
"1G" on the inside back of the rim.  If the rims are not stamped then they are defective!  The wheels will bend out of 
shape when driven over rough surfaces.  This was just brought to my attention by an Aston-Martin/Jaguar dealership.”  
Pashey looked into this and reports that “defective” may not be the right word; the earlier wheels are fine, but it was 
found they can be damaged by hitting a curb or pothole at speed so AM beefed them up a bit.  The 1G apparently 
indicates the heavier version. 

The bolt pattern on Jaguar wheels is the same as on some full-size Chevys.  However, the offset (the distance from the 
mounting surface to the centerline of the wheel) is 28.5mm, or about 1” greater than most Chevy wheels.  If a set of 

 
 

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typical Chevy wheels is mounted on an XJ-S, they will stick out the sides of the car, since they will be located 1” 
farther outward. 

The world of Chevy wheels is not that simple, though.  Some Chevys have different offsets than others; some cars even 
have different offsets in front than in back.  And aftermarket Chevy wheels can be anything, since sometimes additional 
width is added entirely on the inside, increasing the offset by 1/2 the additional width.  With a little care, it is possible to 
find aftermarket Chevy wheels that will work on a Jaguar.  If the wheel has enough meat to it, it may also be possible to 
machine off some of the mounting surface, thereby increasing the offset. 

When fitting non-Jaguar wheels, it is highly recommended that the center hole fit snugly around the pilot diameter on 
the hub.  While some wheel manufacturers claim the wheel will be held satisfactorily by the lugs themselves, this is a 
much looser tolerance arrangement and has been known to cause problems.  If you buy wheels with too large a center 
hole and have problems, it is possible to have a machine shop make a set of plugs that will provide a proper size center 
hole in the wheel, and then you will need to get the tires rebalanced with these plugs in place. 

The lower ball joint from the XJ40 (the 1988-on boxy XJ6) will replace the ball joint on the XJ-S.  The part number is 
CAC9937.  According to XK’s Unlimited, this will provide more clearance for wider wheels.  See page 367. 

 

ALLOY WHEELS -- AVOIDING DAMAGE AT TIRE SHOPS:  The specified torque on lug nuts on earlier Jaguar 
alloy wheels is 45-50 ft-lb., and 75 ft-lb. on later ones.  This impresses some people as not being very tight.  However, 
higher torque is unnecessary and causes damage to the aluminum wheels; this is true of all alloy wheels, and in this day 
and age your tire store should know better.  If the shop installs your wheels with an air wrench, tell them where to get 
off and take your business elsewhere. 

There are now machines in better tire stores that mount tires on wheels by gripping the wheel from the inside with soft 
grippers and never touching the wheel’s pretty outside surface.  Check out the price lists for new Jaguar alloy wheels 
and decide for yourself if it’s worth finding a store with this equipment. 

You might also want to watch how the wheels are mounted on the balance machine.  Some shops will happily spin a 
retaining ring onto the machine that presses down on the face of your wheel, sometimes leaving little dings whereever it 
touches.  The gorillas in the shops normally don’t consider this significant and act perplexed when you object. 

 

WHEEL STUDS:  The studs on the front end of an XJ are different than the studs at the rear.  The studs at the front 
work like Chevy or Ford studs, with a head and a knurled interference fit.  To replace them, you have to separate the 
brake rotor from the hub -- which means you might as well have the assembly on the bench and be repacking wheel 
bearings while you’re at it.  Thread a scrap nut onto the stud and whack it with a hammer to remove.  To install a new 
one, lube the threads well and use a nut and a couple of washers to pull it in. 

If you need new studs for the front end, it is possible to find Chevy or Ford studs that will work.  The 1/2”-20 threads 
are common on American cars.  What you’ll have more trouble with is the head; Chevy and Ford studs typically have a 
square corner under the head, but the Jaguar front wheel studs have a countersunk style taper under the head.  Chuck 
Sparks points out that this really doesn’t hurt anything; find a stud the right length, right thread, and the correct shoulder 
diameter and pull it in, it’ll work fine.  However, it’s really not too difficult to chuck the studs up in something and 
grind a small taper on the underside of the head so they actually fit perfectly.  Tip:  I found that the shaft holding my 
grindstone was 1/2”-20, so I merely removed the grindstone and used a lug nut to hold a stud onto the end of the shaft.  
Fire up the motor and hold a file or stone against it, voilà!  Tapered head.  It doesn’t need to be a full taper; just a little 
bevel on the bottom corner so it sits flush against the countersunk hole will do it. 

The studs at the rear are 1/2”-20 thread on both ends with a little shoulder about 1/2” from one end.    These are 
threaded into the hub and staked on the back side to keep them from coming out.  In theory you need to have the hub 
off to replace them, not to thread them in but to do the staking; there’s a shield in the way when assembled.  You can 
just screw them in on the car with Loctite studlock and they’ll work fine, but each time you have the wheel off make 
sure the stud is fully seated and secure before putting the wheel back on.