Well when they arrive I'll mount one wheel and tire and put on the back and then we'll know.

 

Have you read this Bernard fitted 17x8 +20 on the rear and they rubbed

1/2 way down the page
Rim and Tire upgrade Decision

 

Congratulations Roamer. Welcome! Looks like a nice example - for a 6 cylinder that is

 

Keep in mind his car is a 1978 and mine a 1995. Have no idea if any difference. Plus he was mounting a larger tire than I am. I'll let you know in a week or so. I am pretty confident there will be no issues. But hey I've been wrong before!!!

 

Hey now!!! Half the cylinders half the headaches

 

The wheels showed up today less than 24 hours after ordering. I cannot believe how good they they look for the price!!! Metallic gun metal spokes and machined lip. Lets hope they fit!!!

 

I am also curious to know if your wheels/tyres will fit.
You are right that what matters in principle is the tyre rubbing (so mainly the increased outfit of a smaller offset 20 instead of 29), not the increased rim width from 7" to 8".
But a 225/55 R17 tyre is somehow taller than the 235/50 R17 mentioned by Warren (radius is 0.25" bigger).
Also consider that an 8" rim tends to widen the overal width of the tyre compared to the same tyre mounted on a 7" rim because of the stretching (the standard is 0.4" per additional inch of the rim).
So that with reduced offset, increased rim width and taller tyre, you may have increased risks of rubbing of the tyre on the rear inner fender well on bumps.
Let us know on your fitting and your driving.

 

That's a great looking wheel! I'd love to one day get something like that on my XJS, but with chrome spokes. Definitely gives the car a muscle car style vibe. The XJS certainly feels like its styling can be tweaked to have an old-school flavour or a much more modern look.

 

According to the size calculators the overall width of a 225 tire is the same whether on a 7 or 8 inch wheel. On an 8 inch wheel there is very little tire extending past the lip. After putting a bare wheel on the car and measuring, it's going to be close for sure. My setup should have 5 mm more clearance than Warren's.

I called the folks at Vision Wheel and the guy said it will clear and he has seen the wheel on an XJS. The tires will be in this week and we shall see. I have some doubts!

 

Thanks. It was either these or an American Racing wheel that was way more modern looking. I like the old school look. And they do make these in chrome.

 

This is because the calculators neglect this effect.
You can find some good information off Tire Rack that says Tire Tech Information - Tire Specs Explained: Section Width

Quote:
"Section Width

A tire's section width (also called "cross section width") is the measurement of the tire's width from its inner sidewall to its outer sidewall (excluding any protective ribs, decorations or raised letters) at the widest point. This measurement is made without any load placed upon the tire and after the tire has been properly mounted on its industry assigned measuring rim and has been inflated and reset to its test pressure after 24 hours.

Because a tire's section width is influenced by the width of the rim upon which the tire is mounted, the correct industry assigned measuring rim width for the tire size being measured must be used.

The width of a tire mounted on a narrow rim would be "narrower" than if the same tire was mounted on a wide rim. ...

The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10".



Hopefully it will work on your wheels.

 

The tires came in today and I had one mounted. Put it on the left rear and it looks like there's plenty of clearance to me. Way more than I expected. I rocked the car up and down as hard as I could and can't get it to touch.

Anyone know what the maximum suspension travel is??

 

Seems that the tyre clears the outside lip (that's already good) but difficult to judge from your pics if it will clear the inner side of the fender on full compression.
Could you take a pic from the ground upwards, if possible edging and parallel to the outside of the tyre?
Or you have to drive and test it on bumps

 

According to the offset calculator your wheel will be 13mm closer to the wheel arch than mine.

It's not the lip where it will rub it's above the lip on bump.

 

All other things equal, in principle the only thing that should put his tyre closer to the wheel arch is the smaller offset, by 28 - 19, so 9 mm.
Indeed, if there were no effect from the wider rim (in principle 0.4" from what I quoted before), the increased width from 7" to 8" does not move the centerline of the tread, so does not put the tyre closer from the wheel arch.
But if we take into account half of that 0.4" which stretches the tyre (which is about 5 mm), then yes it is approximately 14 mm more outside in total, but at a level of mid sidewall which is lower than the tread level, so maybe still OK.
(not including the increased diameter of the tyre that may also worsen the situation)
Overall it's ...on the edge

 

This does not take into account the wider rim. The 8" rim is 25mm wider than the 7", 12.5mm + 9mm = 21.5mm closer to the fender lip.

To see where the outer part of the tyre is, use a plumb bob from the inner fender this will give you an idea where the outer could potentially rub.

I went through this in detail before I changed my rims to ensure I had no rubbing issues front and back.

 

Warren,
I assumed that this part of the wheel (the rim edge) never comes close to the inner fender even at full bump and that therefore the increased rim width was not that important (in comparison to a modified offset and an increased tyre width).
But you may be right if you went through the process in detail yourself.
So let's have the feedback from Roamer.
I myself have a set of rear 16" BBS wheels that are 8.5" wide and have a 30 mm offset (planning to mount 225/55 R16 tyres, cuz I think that 245/50 R16 would be too wide) and I am therefore interested to see the result.

 

The increased rim width is important as the outer lip holds the tyre, and with the additional height of the 225 55 17 it could rub on bump.

I have 245 50 16 on an 8" rim ET33 and my tyres only miss the inner fender on full bump by a few mm.

One thing with these aftermarket rims is the hub is usually pretty thick to accommodate multiple offset fittings in 1 forging, so they can be machined to increase the offset.

 

All I know is there looks to be plenty of clearance to me. When will I drive this car and bottom out the suspension? Answer never. If I hit a giant pot hole and the tire rubs for a split second so what?? And I'm not even sure it would hit.

From what I have seen today I will go ahead and mount the other three tires and wheels. BTW the calculators seem dead on. My new setup sticks out exactly 9 mm more just like all the calculators said it would. Note the wheel sticks out another 12 mm or so. But that is independent of the tire.

 

Roamer, you have got yourself a Bargain... great looking wheels... let the group know how the Wheel / tire combo works out.. any touch or scrape condition. Luvmyxjs, provided some great advice. Cheers