[Chrisbo]

Hi,

I currently have the 16" ED wheels on my 320D and looking to swap them out for the 400m alloys set which are staggered:
ED 16x7 ET31
400M Front 18x8 ET34
400M Rear 18x8.5 ET47

I've checked a few places and found that they should fit fine. However, I haven't been able to find out if running the same 4 tyre sizes would be fine on a staggered alloy setup.
I would want to run 225/45/18 on these instead of 225/45/18 Front and 255/40/18 Rears. Is this ok for these alloys? I've read on different websites that 225 is too small for 8.5" alloys, but some say that it is fine.

Thanks

[metallicpea]

Originally Posted by Chrisbo

Hi,

I currently have the 16" ED wheels on my 320D and looking to swap them out for the 400m alloys set which are staggered:
ED 16x7 ET31
400M Front 18x8 ET34
400M Rear 18x8.5 ET47

I've checked a few places and found that they should fit fine. However, I haven't been able to find out if running the same 4 tyre sizes would be fine on a staggered alloy setup.
I would want to run 225/45/18 on these instead of 225/45/18 Front and 255/40/18 Rears. Is this ok for these alloys? I've read on different websites that 225 is too small for 8.5" alloys, but some say that it is fine.

Thanks

The specs listed for the tire will tell you min and max recommended rim width.

Why are you wanting to do this?

[5ilver-5amurai]

Originally Posted by Chrisbo

Hi,

I currently have the 16" ED wheels on my 320D and looking to swap them out for the 400m alloys set which are staggered:
ED 16x7 ET31
400M Front 18x8 ET34
400M Rear 18x8.5 ET47

I've checked a few places and found that they should fit fine. However, I haven't been able to find out if running the same 4 tyre sizes would be fine on a staggered alloy setup.
I would want to run 225/45/18 on these instead of 225/45/18 Front and 255/40/18 Rears. Is this ok for these alloys? I've read on different websites that 225 is too small for 8.5" alloys, but some say that it is fine.

Thanks

I'm no tire expert but I don't think you can fit a square set of tires on staggered rims. The tire is a fixed size as is the rim. If they don't match, then it won't fit properly. Someone correct me if I'm wrong please.

[Logicoeur]

The main reason for staggered setups is to put the power down. Since you are in a 320d I don't think this is at all necessary.

In any case you'd want to use staggered tires as well to keep xdrive happy. The staggered tires in this case is to keep the running diameter of the tires very close, front to back. Too much delta in this will make the front and rear tires spin at different speeds out of spec for the front and rear differentials.

If you are rwd then you won't care about the running diameters as all the power/drive is sent to just the back wheels.

Running square tires on staggered wheels will give you a slightly shorter running diameter in the rear compared to the front.

[Chrisbo]

Originally Posted by metallicpea

The specs listed for the tire will tell you min and max recommended rim width.

Why are you wanting to do this?

I've googled it and 8J and 8.5J width alloys should fit 225 wide tyres according to multiple sites.
The reason is mainly cost of not having to buy different (more expensive) rears to the fronts and being able to swap them out in case of anything happening to one of the tyres.

Originally Posted by 5ilver-5amurai

I'm no tire expert but I don't think you can fit a square set of tires on staggered rims. The tire is a fixed size as is the rim. If they don't match, then it won't fit properly. Someone correct me if I'm wrong please.

https://mechanics.stackexchange.com/...im-width-chart

Loads of these charts are on google, different alloy widths can fit multiple different tyre widths.

Originally Posted by Logicoeur

The main reason for staggered setups is to put the power down. Since you are in a 320d I don't think this is at all necessary.

In any case you'd want to use staggered tires as well to keep xdrive happy. The staggered tires in this case is to keep the running diameter of the tires very close, front to back. Too much delta in this will make the front and rear tires spin at different speeds out of spec for the front and rear differentials.

If you are rwd then you won't care about the running diameters as all the power/drive is sent to just the back wheels.

Running square tires on staggered wheels will give you a slightly shorter running diameter in the rear compared to the front.

I don't have XDrive.
And is the only reason for that being that they might be stretched slightly on the back in comparison to the front so they are only ever so slightly different running diameters? How much difference would it actually make?

[HighlandPete]

Originally Posted by Chrisbo

I've checked a few places and found that they should fit fine. However, I haven't been able to find out if running the same 4 tyre sizes would be fine on a staggered alloy setup.
I would want to run 225/45/18 on these instead of 225/45/18 Front and 255/40/18 Rears. Is this ok for these alloys? I've read on different websites that 225 is too small for 8.5" alloys, but some say that it is fine.

Thanks

You can run the 225 section on the 8.5" rim. It is at the limits of ETRTO standards. as a reference, the measuring rim is 7.5", for the 225x45 R18 tyre.

Also ask why you want the narrow section on the rear, what are you trying to achieve?

[HighlandPete]

Originally Posted by Chrisbo

The reason is mainly cost of not having to buy different (more expensive) rears to the fronts and being able to swap them out in case of anything happening to one of the tyres.

Have you thought of getting two pairs of front rims? Then you haven't got a compromise. You'll then have the best ride/handling balance, plus your common tyre size.

[metallicpea]

Originally Posted by Chrisbo

I've googled it and 8J and 8.5J width alloys should fit 225 wide tyres according to multiple sites.
The reason is mainly cost of not having to buy different (more expensive) rears to the fronts and being able to swap them out in case of anything happening to one of the tyres.



https://mechanics.stackexchange.com/...im-width-chart

Loads of these charts are on google, different alloy widths can fit multiple different tyre widths.


I don't have XDrive.
And is the only reason for that being that they might be stretched slightly on the back in comparison to the front so they are only ever so slightly different running diameters? How much difference would it actually make?

The price difference seems to be $20 or $30 for each rear tire. I don't think that is enough to warrant it.

Yes, each tire has a range of wheel width fitment options. Check the exact model tire you plan to buy, as they do vary.

The 225 already looks a bit stretched on the front, so it will likely looked pretty odd on the wider rear rim.

Also if you have a problem with a tire and want to swap one out, without a spare there really isn't anything to swap it with, you'll need a new tire anyway.

I don't see any substantial benefit to doing this. It will save you $50, look odd and not give you any additional practical flexibility.

HighlandPete has it right, get 4 front wheels.

[Poon Stick]

Originally Posted by HighlandPete

Have you thought of getting two pairs of front rims? Then you haven't got a compromise. You'll then have the best ride/handling balance, plus your common tyre size.

Not to mention the ability to rotate them front/back

The staggered rear rims are also a lot heavier than the front. Why carry and spin the extra weight if you're not going to use the advantage that it provides(more rubber)?

[floydarogers]

Originally Posted by Chrisbo

I've googled it and 8J and 8.5J width alloys should fit 225 wide tyres according to multiple sites.
The reason is mainly cost of not having to buy different (more expensive) rears to the fronts and being able to swap them out in case of anything happening to one of the tyres.
...
And is the only reason for that being that they might be stretched slightly on the back in comparison to the front so they are only ever so slightly different running diameters? How much difference would it actually make?

Originally Posted by HighlandPete

You can run the 225 section on the 8.5" rim. It is at the limits of ETRTO standards. as a reference, the measuring rim is 7.5", for the 225x45 R18 tyre.

My winter set currently (coming off SOON!) on my 335d is 225/45R17 on a staggered wheel set, 8x17 & 8.5x17.

It makes virtually no difference. Yeah, it's a bit more stretched on the rear. So what.

Buying a complete staggered set of wheels from a single seller is usually cheaper than buying two sets of fronts from 2 sellers. Less work/trouble, too.

[torkles]

Originally Posted by Logicoeur

The main reason for staggered setups is to put the power down. Since you are in a 320d I don't think this is at all necessary.

In any case you'd want to use staggered tires as well to keep xdrive happy. The staggered tires in this case is to keep the running diameter of the tires very close, front to back. Too much delta in this will make the front and rear tires spin at different speeds out of spec for the front and rear differentials.

If you are rwd then you won't care about the running diameters as all the power/drive is sent to just the back wheels.

Running square tires on staggered wheels will give you a slightly shorter running diameter in the rear compared to the front.

what are you talking about? running square tires on staggered wheels will give you tires that are exactly the same diameter all the way around lol. wheel width has 0 impact on tire diameter (unless we want to talk about the minute fractions of inches that come in to play because a tire might be 'stretched' on one wheel vs the other). if the tire sizes are the same, and the wheel diameter is the same, the tire diameter will be the same.

you just need to pick a tire width that will fit on both wheel widths, and make sure the tire width doesn't cause you problems with fitment on the front.

one of the benefits of a square set up is that you can rotate the tires. the question is, could you run the wider wheel on the front axle? and, would you want to?

[Logicoeur]

Lol you literally repeated everything you quoted.
We are saying the same thing.


The square tires on staggered wheels will work, yes, but that's entirely dependent on the tire specs and staggered width. There is a difference in running diameter, which may be miniscule, but alas still not zero. So in the case the square tire set is already too far stretched in the front, you will see significant delta in the running diameters, making xdrive unhappy.

[Chrisbo]

No one is selling just front alloys from the 400m range only rears on ebay in the UK. But there are loads of sets going for around £4-500 including tyres with a decent amount of tread. I'd go staggered to start with as they come with those tyres, but would rather stay square if possible. The widths of the rims are 8 and 8.5j, so according to all charts it should fit, just the rears will stretch a little so have a slightly lower ride height. This calculator shows it, but doesn't calculate the reduced ride right from the stretch.
https://www.willtheyfit.com/index.ph...8-5&offset2=47

Also for tyre prices in the UK its an additional 100-150£ for the the rears at 255 width for a premium brand, that's why I want to stick to square sets. A lot less brands make 255 width tyres so there aren't a lot either in comparison to 225 width.

I'll wait and see if 4 fronts come up or a set with square alloys.