10.5j et37 20inch rims on e83

[wilsbrough]

Need a quick bit of help as the title says, I bought these alloys which were supposed to all be 9.5j et40 20inch wheels for my e83. However they have just arrived and two of them are the bigger size. Before I throw a hissy fit and have a mare trying to return them, to save the bother does anyone know if these will fit the rear of my car?
Many thanks
Andrew

[Horizon]

[quote="wilsbrough"]
Need a quick bit of help as the title says, I bought these alloys which were supposed to all be 9.5j et40 20inch wheels for my e83. However they have just arrived and two of them are the bigger size. Before I throw a hissy fit and have a mare trying to return them, to save the bother does anyone know if these will fit the rear of my car?
Many thanks
Andrew
[/quote]

Be VERY VERY careful with the E83 X3 regarding wheels and tyres. Mine has 255/40/19's all round now.
I have the Msport so it came with a staggered setup, 235/45/19 on the front and 255/40/19 on the rear, as they were not star marked BMW approved tyres you could feel the wheels slipping due to the incorrect rolling circumference, also it was lurching when coming to a stop. I could feel the transmission was winding up.
This was on the way home from the garage I bought it from. As I've heard the horror stories of smashed transfer boxes due to non star marked tyres I worked out that as there was only 1/2" difference in the rim widths and the tyre wheel calculator said 255' s were compatable with 8.5j and 9j rims I fitted a brand new set of matching 255's on both front and rear . Problems have gone away.
Yours being 1" difference in rim width could be a problem. If you go staggered and risk winding up the transmission if suitably sized un star marked tyres are used.
Also Depending on offsets could catch the suspension.
My 19,s look big enough on the X3, and considering it's an Msport it rides very well, 300% less crashy than our E93 Msport on 18's

[wilsbrough]

Thanks for that.

I did do a little bit of research before buying them and found out BMW did put a 20x9.5 et43 on the x3 and you could get a Hartge spec with 20x9 et40 and a 21x9.5 et40 so thats why i got these supposedly 20X9.5 et40's as they should be ok. but the spanner being the 10.5 et37. Being a little ignorant about wheel size, would you know how much more this larger wheel would stick out? is the difference in 1j an inch? Also does the lower number et mean it may rub on the inside of the wheel arch? As in theory it will sit further in. And a final question (sorry for picking your brains) you talked about staggered wheels. Mine currently are 235x18 on the front and 255x18 on the back, far as i know this is how it has always been since the first owner drove it out the showroom. I was going to fit 255 on the front and 285 on the back (as this is what the BMW and Hartge spec 20's came with) Are you saying to ditch this approach and have the same width front and rears? Again sorry for the ramble but any help is much appreciated.
Thanks
Andrew

Ps, nice looking X3 there.....

[Horizon]

http://www.4wheelparts.com/tire-wheel-p ... acing.aspx

http://www.tyresizecalculator.com/chart ... size-chart
The biggest problem is the rolling circumference difference in non star marked tyres.
When I removed my offending tyres the difference in rolling circumference was 35 mm between the front and rear tyres !!!!
That means that the rear was traveling 35 mm per revelution that distance over a mile is massive, just think how much strain that puts on the transmission. BMW recommend 1% max difference.
Star marked tyres are made to standardise the rolling circumference between different profiles/ widths.
By all means fit 20" rims but go with the same width rims and matching identical new tyres.
If you don't fit star marked tyres, which are not only hard to get in certain sizes, you risk smashing the transfer box or diffs, or both.

[wilsbrough]

Thanks.

Thats one of the parts i don't quite get. Atm my fronts are r50 18, but the backs are r45 18? And i've seen this on quite a few x3/x5/x6 setups, and to be honest also on lots of others in the bmw range, where the rear tire is smaller than the front, ie the front will be 50, the backs 45, or fronts 45 and backs then 40 etc, all on the same diameter wheel. but surely this means the rolling circumference is different?

[Horizon]

You misunderstand

[X5Sport]

The proper 20" Harge set is...(if it was still available that is)....

Wheelset (p/n HAR 36201120)

Front Wheels: 9Jx20 ET40 (p/n HAR 36650940)
Rear Wheels: 10Jx20 ET40 (p/n HAR 36651040)

Tyres to fit this set would be...

front: 255/35R20 97Y XL
rear: 285/30R20 99Y XL

This is a staggered setup.

As Horizon says, the difference in wheel rim width is covered by the change in tyre sidewall height/width ratio and is expressed in %.  That is either 30% or 35%.  The sidewall height doesn't change but compared to the tread width it is a difference percentage of that width.

[wilsbrough]

Thanks again for the input and who says you cant teach an old dog new tricks, I genuinely did not know that. Always having had cars with the same width tire front and rear, I just assumed the r rating was some sort of measurement of the side wall.... :-[ Its a shame these did not come with tires so I could have tried them for clearance. Don't really want to spend £500+ on a set and find they rub..... I think my standard wheels are an 8j but with an et of 46. The 10.5 have the et of 37, so will sit further out, but in theory the inside wheel edge could be 55mm further in. That's before tire goes on. Pretty damn close.... Tho interesting to know the rear hartge wheels were a 10j mine would only be 1/4 inch wider on the inside/outside than those.

[wilsbrough]

Sorry for dragging up an old post, but after a bit of trouble I finally got a full refund (only after ebay stepped in) So I have seen a set of non-staggered alloys I like. However they are 9.5j with an et53.... Would the consensus be they are going to stick out too far. I think the widest I have found documented was bmw put a 18" wheel with a 8j et51 on. These new ones are also 20"....

[Horizon]

[quote="wilsbrough"]
Sorry for dragging up an old post, but after a bit of trouble I finally got a full refund (only after ebay stepped in) So I have seen a set of non-staggered alloys I like. However they are 9.5j with an et53.... Would the consensus be they are going to stick out too far. I think the widest I have found documented was bmw put a 18" wheel with a 8j et51 on. These new ones are also 20"....
[/quote]
Use this sites wheel finder, enter your model and year and 20" rims and it will show you what will fit

[wilsbrough]

[quote="Horizon"]
Use this sites wheel finder, enter your model and year and 20" rims and it will show you what will fit

[X5Sport]

If you haven't already found it, the OEM range can also be found here:  http://www.alloywheelsdirect.net/bmw_al ... e83_alloys

If nothing else it tells you what was used and act as reference material for your own searches