Wheel concerns regarding a Mark IX

Good day, fellow Jag-Lovers. Long-time contributor over on the E-Type forum, but a relative newbie on the Saloon forum. I’m bringing my 1961 Mark IX out of its 30+ year hibernation, and I’ll be having a lot of questions to pose in the coming months. While I’m quite conversant on the E-Types, I recall very little about the big saloons… I used to correspond with Larry Martz (RIP) back in the day.

On to my first concerns. I’ve just purchased a set of P225/75 R16 tires for the Mark IX, which of course are much wider than the 6.70 inch originals. Clearance under the wheel wells should not be a problem, but now I’m curious as to the width of the stock rims. I’m sure that information is in my factory manual, but those are in storage (somewhere). Secondly, I was counting on the fact that since the wheels are steel disc type, that I could run tubeless with the “modern” tires. That may not be the case, however, so I thought I would pose that question here as well.

I’d appreciate any insight you could contribute regarding issues in installing these tires to the original steel wheels. Thanks! Jay

your tires are too wide for the wheels

I use 205s on my Mk9. I think that’s the widest you can go.

No tubeless tires , as the ridge holding the tire in it’s place is missing on the rims.

Update from the OP…
Just got back from the tire shop this afternoon, and I’ve got some good news for fellow Mark IX owners!
The P225/75 R16 tires not only fit the OEM rims beautifully, but they sealed airtight without using inner tubes. The pull-through valve stem fit the hole in the wheel, the tire beads seated on the rims, and the 12 rivets that hold the spider to the rim didn’t leak air. Good news all the way around.

These were Goodyear Wrangler ST tires, and the advantage of the size I chose is that there were a LOT of options to choose from compared with any of the narrower tires. The wheel rims turned out to be over 5 inches wide, from sealing surface to sealing surface, so they were plenty wide to fit these tires. The new tires are 29.4 inches tall, which is 1.4 inches proud of the OEM tire height, meaning the speedometer will no longer be accurate.

I’ll report back once I get these on the car; I suspect I’ll have some clearance problems on lock-to-lock turns, but we’ll see…

The nominal width will be 5.5 inches but you could have the less common 5 inch rim on a wheel. That would be from a 120 or Mk5. Possibly early 7s also had a 5 inch rim on the wheel but not sure.

Ok it will fit and hold air, but the rim is still missing the ridge holding the tire on the inside.
That means, as soon as you hit something from the sides you will have a flat tire.
So be aware of this, and take a little compressor along.

Regards,
Peter Jan

I think the fronts will be ok, but the rears may foul the front edge of the wheel cover, you might just be ok, but worth checking.
I have 205s on mine and there is only about 20 mm clearance.
I have used tubeless for the last 10 years without any problems. There is a difference between these rims and modern tubeless rims, but my tyre fitter said there was unlikely to be a problem during normal use.
The tyres I use are Bridgestone Dueler 205/80 R16 . H/T689 . 2 steel ply, 2 poly, 1 nylon.
They look good and don’t have that flat sort of profile, more of a cross-ply profile. Also no ugly lettering.

The 5" wide rim was used on Mark V, XK120 and Mark VII up to about '53 or '54, then it was 5.5" after that. Tubeless tires were offered by Jaguar in the '50s on the 5.5" rims.
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The idea of the extra ridge to help hold the bead in place came along later. It really only comes into play when you are down to like 10 psi and rounding the corners too hard, then the bead rolls off into the center well and you are flat. It happened to me last winter with my modern Volvo which has the ridges. Pressure gets really low at -10 deg F. Miserable changing a tire in that weather too.