Thanks guys. I see that most wheel and tyre packages come with 275/40/20?
They do indeed, and that's the advice I got and plunged ahead.
Personally, they are too big, (certainly on the front) for the van. The 40 profile allows additional comfort, but at the expense of a 5 or 6% error in speedo and MPG reading.
I can also feel the power steering pump having to work harder!

I'm going to reduce my fronts to 260/40/20.
 
It's all down to personal choice really. i don't like the tyre shape miss match when you run the same size tyres on staggered rims. Fronts always look too 'bulbous' to me.
My choice is 10" rears with 275/40, and 8.5" fronts with 245/45. Very close rolling diameters, but a little bigger than stock, but relatively the same width change to the wheels within a few mm, so very similar shape when you look at the van from an angle.
 
So much depends on the width of the wheel, so generalisations about tyre size vs wheel size i.e. "xxx/xx tyre is perfect for 20" wheels" only caters for the speedometer accuracy, not the fit or available load rating.

I'm focussing on 8.5J x 20" wheels, and this is what I've put together to help me decide, but you'd need to consider the same for the rear if your rears are a different width wheel e.g. 10J x 20". These are all images from members' T6s on 8.5J x 20" wheels.

1602083651957.png
 
So much depends on the width of the wheel, so generalisations about tyre size vs wheel size i.e. "xxx/xx tyre is perfect for 20" wheels" only caters for the speedometer accuracy, not the fit or available load rating.

I'm focussing on 8.5J x 20" wheels, and this is what I've put together to help me decide, but you'd need to consider the same for the rear if your rears are a different width wheel e.g. 10J x 20". These are all images from members' T6s on 8.5J x 20" wheels.

View attachment 87476
I was reading one of your other threads ref LR and RR wheels earlier and it's great to see a new member doing such thorough research for themselves. Nice work. :thumbsup:
 
What can I say, I used to have an RX-7 :rolleyes: so now I modify once and try and get it right first time
 
Lol... just found a good discussion on tyres for 8.5J x 20 in a thread about splitters (Page 9)
 
Hi currently on standard 215/65/16 alloys that are 6.5 wide with 51 offset. Looking at new 20" wheels which are 9JxET40.

Everyone seems to go for either 275/40/20 or 265/40/20 tyres but according to WillTheyFit.com these give significant errors to the speedo etc (both around 5%).

Whereas 255/35/20 is bang on and 255 is supposedly the correct width for a 9" wheel. Do people avoid these as 35 is too low profile and uncomfortable?

Of note this is for a camper so we will be driving into fields etc!

Cheers for any advice! I'm guessing there is more to it than binary online calculators...
 
Hi currently on standard 215/65/16 alloys that are 6.5 wide with 51 offset. Looking at new 20" wheels which are 9JxET40.

Everyone seems to go for either 275/40/20 or 265/40/20 tyres but according to WillTheyFit.com these give significant errors to the speedo etc (both around 5%).

Whereas 255/35/20 is bang on and 255 is supposedly the correct width for a 9" wheel. Do people avoid these as 35 is too low profile and uncomfortable?

Of note this is for a camper so we will be driving into fields etc!

Cheers for any advice! I'm guessing there is more to it than binary online calculators...
One of the primary reasons for tyre size choice is load rating. 275/40 and 265/40 are easily available in load rating suitable for all vans including T32. 265/40 is a better choice than 275/40 and whilst you would expect a Speedo error the 265/40 often reads close to spot on because the speedo is set to over read from the factory. I would be very surprised if you can find a 255/35 20” tyre that is load rated for any transporter.

For T32 you need load rating 103
For T30 you need load rating 102
For T28 you need load rating 100
 
I'm getting 275/35/20 tryes on a conversion... But I'm also getting upgraded shocks.. Are you upgrading shocks or lowering?
 
Mine is a T30 - just had a look and yeah "no results found" for 255/35/20 102

5% Speedo error seems a lot as it'll also affect the odometer and trip computer presumably?

Any other options or just suck up the error?

Yes looking to lower it a little - KW ST X coilovers I believe are the way to go.
 
Thanks Chris - just re read and notice your point about them ove reading in the first place.

I knew all cars over read - does that mean everyone's odometer is out too? Never thought about that before.

Will check out the 265/40 option and also pay Bognor Motors a visit when the conversion is finished as they're just down the road.
 
Thanks Chris - just re read and notice your point about them ove reading in the first place.

I knew all cars over read - does that mean everyone's odometer is out too? Never thought about that before.

Will check out the 265/40 option and also pay Bognor Motors a visit when the conversion is finished as they're just down the road.
A good size for T30 is 275/35, whilst slightly wider than ideal, these are a closer size circumference to OEM and are what VW fit to 20” wheels for transporters.

The ST X coilovers are a fantastic option for a T30, they ride beautifully and go up to 65mm down from standard, maybe even slightly more than that with a camper conversion.

Despite speedometers being set to over read, odometers are usually quite accurate, so over size tyres will make your van think it is travelling a shorter distance than it actually is.
 
Yes Chris - great shout. They only have a 2% error and I can get some with the correct 102 rating at a decent price (looking at Goodyear Eagle F1 Assymetrics 2s).

Will 35 profile be okay comfort-wise on the KW ST Xs assuming I don't go nuts with the lowering? Not sure how much to lower it by - I just want the wheels to look right in the arches so will judge when fitted.

The wife is keen to make sure I don't rattle the family to bits...especially when bouncing across campsites!

You've been a great help - thanks loads.
 
Yes Chris - great shout. They only have a 2% error and I can get some with the correct 102 rating at a decent price (looking at Goodyear Eagle F1 Assymetrics 2s).

Will 35 profile be okay comfort-wise on the KW ST Xs assuming I don't go nuts with the lowering? Not sure how much to lower it by - I just want the wheels to look right in the arches so will judge when fitted.

The wife is keen to make sure I don't rattle the family to bits...especially when bouncing across campsites!

You've been a great help - thanks loads.
You’ll be fine on the 275/35 with the ST X. They are a very comfortable option even at full lowering. Excellent tyre choice.

It’s a shame you’re not closer to me, we supply and fit the ST X suspension and can get very good prices on wheels and tyres too.
 
Yeah was just looking your location up... Lovely part of the world too.

What goes around comes around so I've no doubt plenty of people in your area will read your excellent advice on this forum and come to you.

As a new member to this game its great to have so many helpful people who are happy to help the rest of us out. Thanks again.
 
Can I ask if 275/35/20 will ride okay on the standard OEM suspension?

All i know is that's it's VW choice for 20" wheels, they won't offer any other sizes... I can image it will be a harsher ride but unfortunately I've never experienced it myself.
 
All i know is that's it's VW choice for 20" wheels, they won't offer any other sizes... I can image it will be a harsher ride but unfortunately I've never experienced it myself.
I think I’ll hire one of Leighton Vans for a day with the 20s before committing the money.
 
I have just fitted 275/35 20s with 102 load rate tyres. The ride is better that the 17in continental van contact tyres which were 107/109 load rated that came off.
 
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