Hi,
I also have been looking and researching into spacers for the past few weeks and likely to place an order this week. I have winter wheels that are 255/50/19 all round. Therefore the rears will definately look lost in the M-sport arches! Some say who cares? you're using the winter wheels for safety not looks, but I am a bit vain I am afraid and having spent £££ on a decent car, you want it to look good all year round...
I am not an expert in wheel sizes and fitment but can share what I have learnt thus far.
Choosing spacer size:
This is completely dependent on what you currently have versus what you are about to replace with and the sort of look you are after (eg. completely flush with the wheel arch or if you don;t mind the wheels sitting slightly inwards etc). I am aiming for the look to be completely flush like my current 20" alloys and flared m-sport arches.
It is essentially to do with the wheel offset. I had no idea what offset was but quite simply it is the distance in mm from the midline of the allow wheel. Offset is mainly positive i.e (more outward from midline) but you can have negative offset also eg. ET -35
For example, my current wheels at the back are 315/35/R20 and have an offset of 37 (i.e. 37mm outward from the midline). The wheel to be replaced is 255/50/R19 with an offset of 48, so not only are they narrower (255mm), but the centre bit that attaches to the hub is further away (48mm), therefore the already narrower wheel is going to sit further in.
I found two different ways to ensure you have the correct size spacer:
1) Put the wheels on an physically measure the distance from the tyre sidewall to the edge of the wheel arch. With this method you will know exactly the size you are after and can have a play around to see what suits. Can be a bit of a flap jacking the car up and getting a hernia lifting those heavy wheels off though!... I therefore opted for method 2 below....
2) The following link shows most of the standard BMW alloy sizes:
http://www.alloywheelsdirect.net/inform ... _chart/bmw
Make a note of your tyre sizes (eg 255/50/R19) and wheel width (eg 9, 10, 11 inches) as well as the offset of both sets of wheels (eg 48).
I then went to the following website to workout what the difference would be to size the spacers (bearing in mind I wanted them to look flush with the arches like my current 20" wheels)
http://www.rimsntires.com/specs.jsp
You plug in your existing larger wheel in column 1 and the new wheel with tyre combo in column 2
It may look complicated but you only need to look at the 'Rim Lip' row and it tells you how much wider the larger wheel is in mm. This would translate to your spacer size.
In my case it was 25mm for the front and the closest was 35mm for the rear.
This will give you a guide on how far the wheel would differ.
Choosing spacer type:
As others have mentioned, H&R seem to have a very good reputation as well as Eibach. I wouldn't skimp on spacers as they are the only lump of metal that is connecting your wheel to the hub and bear in mind the amount of torque in these diesels that transmit to the wheels!! Obviously hubcentric is important as the forces not only transmit evenly through the spacer, but you won't get any wobble as the spacer is dead centre on the hub. Most websites allow you to specify the vehicle so you don;t need to know about bore sizes.... but for the X5 E70 it is 74mm
I'm looking at the H&R spacers as they are manufactured in Germany to a high standard and have a TUV approval rating (I think TUV is synonymous with VOSA here in the UK).
I also understand that the spacers you bolt on to the hub are more robust than the ones that use longer wheel bolts - although you may not have much choice if you are choosing a narrow spacer.
Prices:
I have searched various sites for the best deal.
In the UK I have found performance direct to be one of the cheapest. You can type in your vehicle and they will list all the spacers. In my case it was the H&R TRAK+ DRA 50 spacers (i.e. 2x 25mm spacers) and the DRA 70 (i.e. 2 x 35mm spacers) for the rear. Comes in around £210 inc VAT and delivery.
You could also order directly from ebay in Germany (ebay.de). It is cheaper and the delivery is not too steep since we are in the EU. Works out £20-£30 cheaper approximately from what I have seen here in the UK.
I'm going with performance direct as they are UK based supplier and delivery is 1-2 days - I;m sure they are sourcing everything from the EU anyway and making their markup.
I hope the information helps from what I have learnt and anyone please correct me if any information is inaccurate
