HI, I did check the threads and could not see a clear answer to this.

I have the 2013 3.0 litre SS V6 and 19 inch stock wheels.

Can I put 285 (or even 295) width tire on the rears or not? I think 285 would work but not 295? Just need to know if my rim is wide enough.

Thank you!

 

I've personally seen an XJ with 295 in the rear... with 22" rims. So I know its possible. They tucked inside the fender and all. I think it all depends on the right offset.

 

I've got 295/30R21 rear on 10,5" wheel. No issues, fit perfectly, not even a tight fit. It's all about offset to have it in right place.

 

what's your offset? Both front and rear.

 

Front 9x21 et30 with 245/35, rear 10,5x21 et40 with 295/30. Front et35 would be better as I had to roll fenders and still the load figure of 245 does not quite match the original tire (as it should). 255/35 would, but then you would need to stretch fenders even more. At rear, et35 would sit a bit closer the fender line. I think there would be space even without rolling/cutting inner liner.

You can see how they sit from my profile.

 

They will fit if you have the right rims and offsets.
I have a 2014 XJR and stock it comes with this;
Lightweight, forged 20-inch alloy wheels use 265/35-20 front tires and 295/30-20 rear tires.
They are mounted on these rims Front: 20 x 9-in. Rear: 20 x 10-in.
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Thanks, I have the stock 19 inch rims... so to narrow my question down, it is really will a 285 40 19 fit on those?

Or do I have to stick with 275's... on a stck 19 inch rim

I will also go look at my car and see if it says on the rims what width the wheel is...

Thank you!

 

Thank you! I've asked so many people with aftermarket wheels..and they either didn't know or didn't want to tell..or never responded lol. I appreciate the info..since I'm in the market for wheels.

I did see yours...and they look great! Perfect stance. Did you lower your car?

 

QP7, Lets make the answer easy on this. If your car has different size tires on the front compared to the rear, then yes, you can fit 285's on the rear. Just keep in mind that you will need to also adjust the size of the front tires to make them roll the same number of revolutions per mile. Otherwise, your ABS system is going to see your tires rotating at different speeds and this may cause the ABS to kick in early since the tires will be spinning closer to the point that the ABS will want to kick in.

So, will they fit. Yes. But, the solution is not quite a simple one though either.

 

Yes, around 50mm all over.

I have never heard that different tire sizes (rolling length) cause problems in rear wheel drive car. I have larger tire in rear and no problems with ABS or fault codes what so ever. I know different size wheels cause issues in four wheel drive cars for transfer boxes or quattro differentials.

 

Pacer, how does the ABS system work? Yes, the ABS works by pulsing the pressure to the brakes to prevent the tire from locking up, but how does it know that the tire is locked up? It has to look at the speed of the other tires and do a comparison. ABS is not going to wait for the tire to completely lock up. IT is going to look for a tire to be spinning at some point different than the others (the average of the tires). So, if you have a tire that is say 5% different and the ABS kicks in at 10% different, now you only have 5% of the speed difference. This will cause the ABS system to engage sooner (with less wheel speed difference). As in the XJ, yes, the front and rear tires are different widths, but the overall tire diameter is the same. Therefore, the tires spin the same number of turns for each mile they roll.

 

While that all seems valid, we are not talking about 5 or 10% differences here. No drag racing with XJs. When I say, I have different sizes, I mean 0,5 cm in diameter. That is less than the thread in new tire and equals less than 1 percent difference. I don't expect anyone to install 245 and 295 with the same aspect ratio. So, if one is on the map with tire sizes, no issues with ABS.

 

Pacer, I know that when I bought my 2016 XJ, the BMW dealership I bought it from had just put new tires on the car. In their infinite wisdom, they put 275/40's on the rear and 245/40's on the front. The car drove fine going straight, even though it was AWD. But, I could feel the ABS wanting to kick in under some circumstances (wet turns at a decent speed). So, I do not know the exact % slippage that is needed to make the ABS kick in, but I know from experience that 5% difference in the aspect ratio on an XJ with staggard wheels (factory sizing) puts you pretty close. The tires that BMW put on only made like a 2% difference between the front and rear. Then you throw in another 1 or 2 % for making a turn and it isn't all that much.

 

Yeah, 245+275 with the same aspect ratio 40 is just wrong especially for AWD. And I can believe that it may cause issue for ABS as well. That's just too much, even for eyes.

 

All great posts, thank you Thermo and all...

I looked at my stock 19 inch wheel and it does not say (or I can't see) on the rear wheel what width the rear wheels are. So what I would like to do is put 295 40 19 Pirelli PZ4's on - time to see what this baby can do with proper sport tires. When I got the car it had run flat P Zero's all round and the car felt like a Ferrari when I went for it - but a very hard ride. Still, it did feel unbelievable for a sedan. So I am almost tempted to put the run flats back on as that felt so amazing, but it was (almost literally) shaking the car to bits on bad roads, and I now have Michelin Pilot Sport 4 on the front (non run flat..) so run flats n the rear will not get that sensation back. Still, I'm giving up grand touring tires to go Max Sport Summer tires...

So..., will 295 x 40 fit on my stock 19 inch rears? And Thermo at 295 40 vs 275 40 I am only 16mm larger diameter than the fronts (245 x 45), or 2.28% larger. And that will fit part of my plan to go to 255 45 on the front when I change those - hence less than 1% difference then. I could go 285 40 with P Zero or 275 45... but I like the look of 295...

...And those 295's PZ4's are a high 108 load index sidewall, so presumably stronger and better protection from pothole blow outs...?
Thanks, all.

 

QP7, if this is the AWD car, then I would be questioning the decision to put the wider tires on the back with the current rear tires. I made mention of my 245/45 vs 245/40 situation I had. That had a difference of 3.7% with the front tires spinning faster than the rears. At 2.3%, you are going to have some more margin than I did, but still not necessarily good on the transfer case. it really likes to spin everything at the same speed. there is a reason why Jaguar picked 275 rear and 245 for the front. This makes for an almost perfect match for everything front and rear.

WIth this being said, it is your car and it may be just fine to do what you are after. I know I would not do it on my car. I do not feel like risking the transfer case. Granted, I drove for like a month before I realized what was going on.

 

Many, many thanks indeed Thermo - that is very much appreciated. If it assists at all, my car is not AWD, just RWD - does that solve the problem at all?

Or not, I wont be offended if it does not... :-) :-)

 

With this tool you can find exact size alternative with same rolling distance:
https://www.wheel-size.com/calc/

Insert your OEM tyre size and check table bellow what sizes having same rolling distance.

 

QP7, you will not have any issues with potential tire wear or driveline issues as you have nothing tying the front and rear tires together. So, you are good there. Where you still have an issue is with the stability control/ABS. Driving in a straight line, can't see it being an issue. YOu take a corner slow (say 20 MPH and less) should be good there too. Now, you take a corner (like where 2 roads meet) at a decent speed and maybe even apply a little bit of brake because you entered it a bit hot, you may feel the car really apply the brakes because it is seeing things too far out of whack and it is trying to get the car back under control. It is just a little unnerving when the car starts doing things on its own. On the other hand, you may find that the car will be allowed to get a little more "squirley" (back end moving around) when it is raining for example. What I mean by this is that if you are driving at say 60 mph and get on the gas to get around someone, the rear tires are going to have to spin faster than they would have normally to get the stability control to kick in. Now, we are only talking 1-2 mph more, but once the rear tires are slipping, they are not helping to keep the car straight. So, you may find the rear end moving around a bit more before the car tries to correct itself. Some people may like that. I just hate having the car step in for me.

 

Many thanks, Thermo - very informative as always. Appreciated.
Do you think the last issue you brought up would be less of a problem, if I just went at 285 40 19, rather than 295 40...?
(I could also go back to my last idea of 275 x 45 - i.e. more sidewall.)