@Smiffy I recently purchased wheels and tyres (20" BK Racing) and it was all double dutch when I first starting looking at it but its all quite simple -
Load rating - Ensure the wheels are properly load rated for your van. They need to be able to take 50% of the max axle load. Your tyres also need to be load rated for the same value. Load rating will be stamped on the rim.
Centre bore - The wheel needs to sit securely on the hub so if the alloy has a larger centre bore than the hub it could theoretically wobble about and put shear strain on your bolts. Its a simple fix though with spigot rings which are little plastic inserts that convert your wheels centre bore to your vans centre bore. You just need to know the two sizes.
Offset - This value (ET40, ET52 etc) determines how far in or out the mounting surface of your wheel is - Positive offset is when the hub mounting surface is toward the outside. Negative offset is when the hub mounting surface is toward the suspension
Rim width - This is noted as 9.5J, 10J etc. Basically 10J is a 10" wide rim etc
PCD - This is your bolt spacing. You need 5x120 for your van i.e. 5 holes at a 120mm diameter spacing (if you draw a circle through them all)
So putting all that together you need to find a wheel and tyre combo that is suitable for the load. the wheel has to have a suitable offset for your van to avoid rubbing etc (although you can fix negative offset with spacers). Your tyre needs to be suitable for the rim width too so that its not stretched on or squashed on.
If you go to www.willtheyfit.com it lets you type in your standard wheel details (offset etc can be found on google) and you can then type in the wheels and tyres you are considering and it tells you the speedo error and how much closer or furhter away to the suspension your combo is which lets you decide if its suitable. For tyres I recommend www.blackcircles.com as the prices are good and you can choose a local garage to fit. It also tells you the tyre load ratings on there 103XL etc
On this site (and other sites) people say things like I have 20" alloys and 275/40 tyres and they dont rub and im lowered 50mm. Then others fit the same size alloys but a different make and they do rub. This is because most people fail to mention the offsets and they are different for different wheels but using the site I linked above will help you here.
As a point of reference my steel wheels were 16" 6.5J ET51 with 215/65 tyres and I fitted BK Racing 170 20" Alloys 8.5J ET40 with 255/40 R20 101XL Tyres. (Mines is a T30 so these are correct load rating)
Hope that helps a bit
Load rating - Ensure the wheels are properly load rated for your van. They need to be able to take 50% of the max axle load. Your tyres also need to be load rated for the same value. Load rating will be stamped on the rim.
Centre bore - The wheel needs to sit securely on the hub so if the alloy has a larger centre bore than the hub it could theoretically wobble about and put shear strain on your bolts. Its a simple fix though with spigot rings which are little plastic inserts that convert your wheels centre bore to your vans centre bore. You just need to know the two sizes.
Offset - This value (ET40, ET52 etc) determines how far in or out the mounting surface of your wheel is - Positive offset is when the hub mounting surface is toward the outside. Negative offset is when the hub mounting surface is toward the suspension
Rim width - This is noted as 9.5J, 10J etc. Basically 10J is a 10" wide rim etc
PCD - This is your bolt spacing. You need 5x120 for your van i.e. 5 holes at a 120mm diameter spacing (if you draw a circle through them all)
So putting all that together you need to find a wheel and tyre combo that is suitable for the load. the wheel has to have a suitable offset for your van to avoid rubbing etc (although you can fix negative offset with spacers). Your tyre needs to be suitable for the rim width too so that its not stretched on or squashed on.
If you go to www.willtheyfit.com it lets you type in your standard wheel details (offset etc can be found on google) and you can then type in the wheels and tyres you are considering and it tells you the speedo error and how much closer or furhter away to the suspension your combo is which lets you decide if its suitable. For tyres I recommend www.blackcircles.com as the prices are good and you can choose a local garage to fit. It also tells you the tyre load ratings on there 103XL etc
On this site (and other sites) people say things like I have 20" alloys and 275/40 tyres and they dont rub and im lowered 50mm. Then others fit the same size alloys but a different make and they do rub. This is because most people fail to mention the offsets and they are different for different wheels but using the site I linked above will help you here.
As a point of reference my steel wheels were 16" 6.5J ET51 with 215/65 tyres and I fitted BK Racing 170 20" Alloys 8.5J ET40 with 255/40 R20 101XL Tyres. (Mines is a T30 so these are correct load rating)
Hope that helps a bit
