20 X 9 Or 20 X 8.5

[christopher white]

I am looking at new 20 inch wheels. I can get them either 9 inch wide on a ET42 or 8.5 inch on an ET of 45-48. Using the size calculator it appears the 9/42 make the wheel 12.4 closer to the strut and stick out 38.4 mm more. The 8.5/45 make it 9 mm nearer to the strut and stick out 29 mm more. Looking under the van I do not think there is an issue with the strut but an extra poke of 38 mm sounds a lot, especially if you put a straight edge across the arch. I'm concerned though about going to the 8.5 wheels if I want to fit 275 tyres as that sounds a squeese. Am I fooling myself as I guess a the largest width is 275 on either wheel? Can I please ask what most people fit. Thanks

 

[Tourershine]

This subject is covered loads if you search through the forum, but I'm running 8.5" ET45 on 255/45/19 with no problems.

Personally if I was going for 20" id stagger 10" rear ET45 and 8.5" front ET35 on 275/35/20 all round.
I've seen this setup on another T6 and it filled everything really well, but I think you need to go low on 20s to not make it look too daft.
Others will of course have there own opinions on looks

 

[Chopman]

Depends what you're looking for really.
There is more room in the rear arch so if you want the front and rear to be filled to a similar amount and look similar, then you'll need to get different sizes/specs front and rear. If you get identical sizes front and rear then the rear will look more "tucked under" the van than the fronts will - which might be exactly what you want.

 

[.50]

Just to give you an idea of how these widths and offsets work out in realation to the bodywork, a 9" wide rim with a 48mm offset will sit exactly 10mm inboard of the front wheel arch and 20mm inboard of the rear wheel arch.

So 9" wide with a 42mm offset will sit 4mm inboard of the front arch and 14mm inboard of the rear.

An 8.5" wide rim with a 45mm offset will sit 19mm inboard of the front arch and 29mm of the rear, and the same width with a 48mm offset will sit 22mm inboard at the front and 32mm at the rear.

Staggered rears with the same offset as the front help maintain a similar poke front and rear, or you can, as I did, fit 10mm hubcentric spacers to the rear. This has the same effect but keeps it simpler in terms of consistent wheel and tyre size.

 

[GONA66]

Just to give you an idea of how these widths and offsets work out in realation to the bodywork, a 9" wide rim with a 48mm offset will sit exactly 10mm inboard of the front wheel arch and 20mm inboard of the rear wheel arch.

So 9" wide with a 42mm offset will sit 4mm inboard of the front arch and 14mm inboard of the rear.

An 8.5" wide rim with a 45mm offset will sit 19mm inboard of the front arch and 29mm of the rear, and the same width with a 48mm offset will sit 22mm inboard at the front and 32mm at the rear.

Staggered rears with the same offset as the front help maintain a similar poke front and rear, or you can, as I did, fit 10mm hubcentric spacers to the rear. This has the same effect but keeps it simpler in terms of consistent wheel and tyre size.

I too, i'm currently looking at wheel and tyre combinations , working out loads and offset etc . I have just read your post and it was a "eureka" moment ......................Thanks !

 

[.50]

GONA66 its all just numbers unless you can apply them to the actual wheel well of the van.

Willtheyfit.com is a great resource, but it can't tell how the wheel will sit in relation to your specific vehicle.

 

[GONA66]

Believe me I've exhausted the tyre comparison sites , I like to do my homework first and was just about sorted but your post giving how much each set up sits behind the wheel arch lip was great , not seen anything else explaining this before . Just to digress, I've fitted 17" x 7" Beetle alloys to my T2 Baywindow and I love em'.
I havn't got the knowledge but it would be great if there was an app with a T6 wheel arch and hub , where you could "play" around with wheel and tyre options and also incorporate a lowering facility too !

 

[.50]

Believe me I've exhausted the tyre comparison sites , I like to do my homework first and was just about sorted but your post giving how much each set up sits behind the wheel arch lip was great , not seen anything else explaining this before . Just to digress, I've fitted 17" x 7" Beetle alloys to my T2 Baywindow and I love em'.
I havn't got the knowledge but it would be great if there was an app with a T6 wheel arch and hub , where you could "play" around with wheel and tyre options and also incorporate a lowering facility too !

I'm quite inquisitive and like to know more about stuff, so I put my T6 in my garage, ( has a perfectly level floor ), and dropped a level down from each wheelarch at the wheel centre point and measured the distance back to the rim, hence my accuracy with the figures.

The only thing that could potentially scupper my findings is different wheel manufactures interpretation of where measurements are from, but I'll guess this won't be more than a few millimetres.

 

[GONA66]

I'm quite inquisitive and like to know more about stuff, so I put my T6 in my garage, ( has a perfectly level floor ), and dropped a level down from each wheelarch at the wheel centre point and measured the distance back to the rim, hence my accuracy with the figures.

The only thing that could potentially scupper my findings is different wheel manufactures interpretation of where measurements are from, but I'll guess this won't be more than a few millimetres.

Don't suppose you have the measurement inner arch lip to hub face handy ? I could potentially work out the offsets then .

 

[.50]

I havn't got it, but it wouldn't take much to get it.
Stand by.

 

[.50]

So according to findings on my T30 kombi running standard shock and 40mm springs, the face of the front hub is 97.2mm inboard of the outer most edge of the front wheel arch through the centre line of the wheels circumference.

I found this measurement buy holding a level plumb down from the wheelarch using my digital calipers to measure from this to the hub face via a removed wheel bolt. ( the bolt hole is a larger diameter than the bolt leaving a small lip of hub to measure to ).

 

[GONA66]

So according to findings on my T30 kombi running standard shock and 40mm springs, the face of the front hub is 97.2mm inboard of the outer most edge of the front wheel arch through the centre line of the wheels circumference.

I found this measurement buy holding a level plumb down from the wheelarch using my digital calipers to measure from this to the hub face via a removed wheel bolt. ( the bolt hole is a larger diameter than the bolt leaving a small lip of hub to measure to ).

View attachment 21206

"RUN THAT BY ME AGAIN" Mr Hardy says to Mr Laurel ! .
Seriously top work ! .....but just to clarify , is that the outer lip of the arch or the inner lip of the arch ? if you get me .

 

[.50]

So to check my findings.

9" equals 228mm divided by 2 equals 114. Minus the offset of 48mm equals 66mm plus the 10mm my rim sits inside the arch equals 76mm.
So this confirms to me that the rim width is measured from the inside of the rim lip as the outstanding 21mm in my calculations will be rim lip itself.

 

[.50]

"RUN THAT BY ME AGAIN" Mr Hardy says to Mr Laurel ! .
Seriously top work ! .....but just to clarify , is that the outer lip of the arch or the inner lip of the arch ? if you get me .

I have placed a spirit level against the outer most edge of the wheel arch, held it perfectly plumb and then taken my measrement.

 

[GONA66]

I honestly never thought of measuring this, but knowing this measurement makes easy work of the offset " shenanigans".
Previous post - got it thanks !

 

[christopher white]

I understand what you are saying but I still have two questions, first a 275 tyre is actually 10.8 inches wide so actually sticks out quite a lot more than just the rim? Also when I put a straight edge across my arch it is not the top that I am worried about it is the front and rear of the arch. That suggests to me the tyre will stick out quite a lot if you look down the side. Am I correct with my thoughts? Thanks