Resurrecting this thread as I am tempted to install DB7 18" wheels on my facelift XJS and looking for advice.

The wheels I am interesred in are Speedline split wheels (pics attached):

The spec for my car is 16x7J ET 28.5 with 225/55 ZR16 tyres (no load index at that time).
The new rims are 18x8J ET 14.5 and I intend to put Avon ZZ5 225/45 R18 95Y tyres.

The tyre perimeter would be exactly the same, so no issue from that side (in principle).

The only issue is the offset, 14 mm difference, pushing the wheels outside, with two possible consequences:
- hitting the rear inner liner fenders arches at heavy suspension travel, even if not impacting the fender lip;
- increased wear of bushes and uneven wear of tyres (on the inner side).

From the experience reported here, in principle space issues should be just OK to mount the wheels.

But is there any feedback on increased wear of suspension components and tyres?
Also any feedback on harscher ride due to the low profile tyres?

 

If the offset is different, the leverage exerted on the wheelbearings by the weight of the car and movement of the suspension will be increased from factory spec. Over time this is bound to mean they will wear somewhat faster. Similarly so with the stub axle wear. To what extent this would be dangerous, if at all I have no idea.

The ride will be noticeably affected, kiss goodbye to that magic Jaguar velvet-ride-with-good-handling compromise. Even the fitment of 16 inch facelift OEM 5 spoke rims and tyres on my XJS, in place of the original 15 inch ones, quite definitely adversely affected the ride; but it did greatly improve high speed stability. I would be just as concerned about whether the rims and tyres will actually go in without bad fouling.
Greg

 

Greg,

Merci pour la réponse.

Alternatively, do you think that running 17x8J wheels with 225/50 R17 tyres (so just one step instead of two) on 8j wheels, with an offest adjusted within ET 25-30 with spacers to preserve suspensions, would give an acceptable ride?

17" rims were proposed e.g. by Arden specifically for XJS, albeit with specs departing more substantially from Jaguar specs, to give some more "sporty" look and ride, in particular regarding offset: 17x8.5J ET13 and even a more extreme 17x10J ET 19.
I attach a pic of an XJS Eventer equipped with 235/45R17 tyres on 17x8.5J ET13 wheels front and rear and of a coupé with the larger rims on the rear.

Arden actually rebranded OZ Futura rims that can be found aftermarket, including with less agressive specs (e.g. 17x8J ET30).
I would be tempted (nice look and acceptable ride).
What's your opinion?

 

17 inch would give a better ride than 18, but why go bigger anyway? Lots of modern Jaguar owners report that, even with all the modern suspension trickery, their cars are pretty uncomfortable on poor surfaces with the optional bigger rims that are offered. I would not go wider than 8 on the rims if you use the car in all weathers.
Greg

 

Merci Greg.
Point taken.
I give up for DB7 wheels and may stay on 16".
Only if I can get a good deal on 17x8J OZ wheels with right offset will I make a try.

 

14.5mm offset on an 8" rim will not fit, without widening the guards.

8" rims need 33mm rear and 20mm front with 245 tyres to completely clear guards and suspension.

I have a set of 16x8 BBS with 245 50 16 all around with above offset and they never scrub, even on full bump or full lock. Ride height is standard.

These were for a XJ40 with 33mm offset all round. The guy I bought them from machined an insert (that was fixed into the wheels) for the front to decrease offset to 20mm, (it's illegal in Australia to use spacers or adapters).

The only pain is having 3 sets of nuts, front use long flange (like original but longer in the flange to fully seat on the stud) spare uses stock which I keep in the jack bag, and rear uses tapered seat.

 

Warren,

You are right: for 8" rims, the ideal offsets are those you indicate.

The TWR XJRS Jags (the sporty versions of the V12 XJSs) were produced with a set of staggered 16x8J wheels and a strange tyre mounting:
- for front, the rims hade a 19 mm offset to clear the suspensions and the tyres were 225/50;
- for rear, the rims (with the same width) had a 33 mm offset to clear the rear wheel arches and the tyres were 245/55, so a wider size (as often) but unusually a higher flange profile.

So already, the choice of 8" rims (instead of 7" or even 6" for the earliest XJSs) required to decrease the front offest and to increase the rear offset.

Alternatively, the TWR XJR40 wheels (same wheel design than for the XJRS) had the 33 mm offset front and rear.
So many XJS owners put XJR XJ40 wheels which are easier to find (more XJR40 were produced than XJRS) but are obliged to puts spacers in the front.

Yesterday I measured precisely the space left under the rear wheel arches and there is only a 10 mm margin at best, so obviously a 14 mm offset (intead of 28) would not allow mounting the wheels even with thin 225 wide tyres without requiring substantial fender work.

 

That would work.

Also some BMW wheels can be made to fit easily, they are 5x120, but you can use wobbly nuts to correctly secure them, and spacers for the front.

 

Not to hijack the thread or anything, but I was talking to an ex the other night (Thanks Adele) who suggested hub rings to expand wheel options. Anyone given this a shot on our cars?

 

LUCK!

 

Spotted a nice set of OZ Racing wheels (similar to the Arden's) in 17" with right british specs (Center Bore, PCD) and acceptable ET.

The wheels are all 17x8.5J ET20, which is better that ET13 usually found for these wheels and intermediate between ET19 for front and ET33 for rear that are the Jaguar TWR specs for 8" rims.

In principle ET20 should be just OK (large enough to clear the suspensions and steering on the front and small enough to clear the rear wheel arches), but on the edge...
I don't know precisely how the rims may fit with tyres.
And here comes my dilemna before ordering.

I am tempted by Avon tyres that are renowned to well correspond to the grand tourer behaviour and smooth ride of classic Jags.
I have basically three options:
1. 225/50 R17 XL 98Y
2. 245/45 R17 95Y
3. 235/45 R17 94Y or XL 97W

All the tyres have speed and load indexes that correspond to the XJS weight requirements (except maybe the 94Y variant of the 235/45 R17, on the low side).

According to Avon specs, the two first options have basically the same rolling perimeter than the factory spec 225/55 ZR16.

The first option (225/50) may be a bit stretched on the 8.5" rim (requiring some higher tyre pressure for safety) and a bit rigid because of the high XL index but should be the thinnest (233 mm of section width) to pass correctly under the rear wheel arches.

The second option (245/45) would be the thickest and the softest, providing a ride that should be smoother and well fitting the XJS behaviour.
But it may be a bit too wide to pass under the rear wheel arches (243 mm of section width) and the steering may be heavier.

The third option has a smaller rolling perimeter than the two others (a bit out of tolerance, though) and would be intermediate in terms of width (236 mm) and ride.

If the tyre clears the rear wheel arch, I would favor the 245/45 option.
If not, and because of the surprisingly very small difference between section widths of the three tyres (I was expecting a difference of 10 mm between each of them), I would go for the 225/50 option.

What are your opinions?

 

8.5" ET20 will stick out 19mm further than 8" ET33, they will not fit under the rear guards, they will hit.

 

Warren,

Thank you for the feedback and advice.
You are right in principle.
That would exclude the 245s.

There is still a chance though that 225s just clear the rear fender with a tiny marge, at least for a good part of the suspension travel.
It seems to have worked for bigpigpants with DB7 wheels that have an even smaller ET14 offset (see his comment on the previous page):

AFAIK these wheels started life on a DB7 - they are 18 inch Speedline Mistrals & I think they are 8 inches wide. I've never been able to confirm the exact offset of the wheels & I first tried 245/40/18s on them & there was a lot of fouling on the rear wheelarch inner edges, so I tried 235/40/18s & they still fouled the rear arch inner edges - they are now fine with 225/40/18s.

If not, I will be bound to roll the fender lip...

 

What he said. I have a facelift XJS and bought it with 18's on it (from a later model Jag). Cosmetically, its really a matter of opinion but I think a 17 would be perfect in that respect....the right one of course. I'd love to find a 17 spoke actually.

As far as the ride with an 18....its rough. And the tramlining is something you have to be prepared for for your own safety. She is my favorite car ever but you have to respect her with 18's or she will kill you.

 

The Mistrals looked the business on the car IMHO but the ride was very firm & a bit "crashy" on poor surfaces. The 225 40 18 tyres were also fine in terms of fouling especially with wheels of such incorrect offset. I removed the Mistrals & sold them. Currently I have a set of early XJR wheels fitted & as the offset of these is nearer being correct, the 255 45 17 (I think! Could be wrong as the car is not here right now) do not foul the arches.

I have a set of 18" Pentas but I don't think I'll ever fit them & as I got a good deal on 4 X 16" 5 spokes with excellent Pirelli 225 55 ZR 16 tyres, I might go back to standard wheels & tyres.

Rgds.

A.

 

Its not the LIP that is the problem. The XJS inner rear guard is very shallow so its above the lip where the rubbing will happen.

I will be surprised if they don't rub, check out the 4th section down.


Rim and Tire upgrade Decision