Am I Being Thick . . . .

[Shredder]

I'd assumed a Kombi LWB with -40mm springs, 20" rims and 275/40 tyres would have a lower overall height than the equivalent VW Sportline

Looking at the wheel and rim calculator thingy, I'm not so sure now, unless I've done something wrong.

Which would have a lower total vehicle height ??

Just on the off chance, has anyone had to measure the exact height of a Kombi -40mm springs, 20" rims, 275/40 tyres??

One last one ..... I can't find what height the roof rails add to a van. I can guess from sight, but anyone know??

 

[RattyMcClelland]

275/40/20 is huge compared to 255/45/18 found on the sportline, it's 41mm bigger in diameter.
So 40mm drop will bring you're van back to stock height.
The sportline is 30mm lower with its springs.
So you would need to drop 70mm or go 275/35/20.

 

[Shredder]

Thanks for that !

So, as my rolling diameter is 41 mm bigger than a Sportline and my coil drop is -40mm, my overall vehicle height will be 30mm taller than a Sportline due to the Sportline -30mm springs you mean??

That makes sense. Therefore good news for increased ground clearance compared to Sportline??... but not so good for garage door clearance ! LoL

So, when you input the correct data into 'willtheyfit.com' for a Sportline vs mine, one of the readouts given is 'ride height gain' which is 20.65mm. What's going on there??

 

[Mooncat]

Don't forget you need to use the tyre/wheel radius, not the diameter when working out the ride height.

So you will end up with a 19.5mm drop with 275/40/20 tyres and 40mm shorter springs. This is 10.5mm higher than a standard Sportline.

 

[Shredder]

AAhhhhh ...... of course, it's the damn radius, as ride height adjustment must be from the axle !! NOW I see where the 'ride height gain' reading on will they fit.com comes from and when I work it out myself manually, I get exactly their 'ride height gain' for my bus. Therefore, the ride height gain on mine over the standard Sportline is 20.65mm, not accounting for the Coil lowering of - 40mm on mine and - 30mm on the Sportline.

Appreciate that pointer a lot thanks ........... now, unfortunately, I feel like I've lived up to my Thread title on this one

 

[Wills]

Your speedo will also under-read by a significant amount too!!! That extra rolling circumference is a ticket generator :-(

 

[Loz]

...and the reduced braking efficiency

 

[Shredder]

Yes ... that was another benefit of using the calculator on will they fit.com ... it gave me the exact speedo error of - 5.67% for my set up. So, I'll always be aware and GPS speed will also be up on the Nav as well.
I understand the braking power on the T32 is monstrous, plus the traction of 275 width tyres .... there's only me and 2 mountain bikes in it to bring to a stop
I guess the bottom line is, we all seem like tarts and want our trucks looking sexy ....... and I'll admit, as a first time Transporter owner, I've fallen straight into that trap for sure

 

[Mooncat]

now, unfortunately, I feel like I've lived up to my Thread title on this one

Not at all - you knew it was wrong! It's those that don't know they don't know that fall into that category.

The other thing is, when most people lower their vehicles, it's a cosmetic enhancement to reduce the wheel arch gap. In this case you are getting the visual upgrade without having to rip the bottom of your van off on every speed bump.

 

[MicP]

Also your final drive ratio will change affecting your acceleration etc

 

[Shredder]

Not at all - you knew it was wrong! It's those that don't know they don't know that fall into that category.

Thanks for giving me a way out of this one Mooncat

Also your final drive ratio will change affecting your acceleration etc

Hadn't thought of that. I'm guessing acceleration could be slowed ? In reality, would it actually be imperceptible on a 204ps carrying no weight ?? I've not seen performance reduction come up as an issue with these types of commonplace cosmetic conversions before....

 

[Dogs Dung]

acceleration will be reduced

I had 20s on and changed them for 18 inch sportlines, I have found the van is much more punchier on acceleration

 

[Shredder]

I had 20s on and changed them for 18 inch sportlines, I have found the van is much more punchier on acceleration

Interesting thanks. Is yours a Kombi as well?? Which engine do you have (hp) ??

 

[Chopman]

Wheels will affect performance and economy, but it's not quite as easy as saying "bigger wheels are worse", it never is.

The issues are weight and overall rolling radius.
Wheel weight is important because of where it is. Adding 150kg into the back of your van may have negligible impact, but adding 5kg onto each of your front wheels will be significant.
Rolling radius has an effect on gearing which is often small - but in your case, adding 6% additional circumference on top of the heavier wheel will probably be noticeable as well.

 

[RattyMcClelland]

Heavier wheels give better ride quality.

 

[Chopman]

Heavier wheels give better ride quality.

Quite possibly as the suspension will react slower due to the additional unsprung weight.

 

[Shredder]

Heavier wheels give better ride quality.

Hooray ......some good news about my set up

Quite possibly as the suspension will react slower due to the additional unsprung weight.

One would hope that the manufacturers testing of these springs for the T6 considered rebound characteristics when deciding on the spring rate / materials etc in the design of the springs

 

[Mooncat]

It's more to do with the damping in your shocks. The unspung mass reacts slower so your wheels aren't kept in contact with the ground as well as a lighter wheel. If you look at a lot of motorcycles since the early 90s, they have upside down forks fitted for exactly this reason.

 

[Shredder]

I guess at the end of the day the proof of the pudding will be in the eating. I'm sure everyone's preferences or perceptions on ride are going to be different.

When I test drove a new Sportline, I found it exceptional and preferred everything about it's ride/handling to my last generation Vito Sport (17" rims) that I'm coming out of. The Sportline was literally in a whole different league of better. Whereas, I guess others, may think the Sportline harsh or too firm. I thought it was very comfortable and more importantly to me, it felt very sure footed.

I'm sure mine will be an order of magnitude firmer again but for my taste that will be perfectly fine. I do relatively little bimbling on rough country roads. This purchase was for more of a longer distance, kit-carrying motorway weapon, particularly on trips to The Alps

 

[Mooncat]

There are plenty of T5s and T6s running huge wheels out there and you tend to see them on the road rather than parked in a hedge so I'm sure you'll be fine. Your comments about the Sportline are interesting as when I went from standard 17" Devonports with 215/60s to 18" Sportlines with 255/45s, it made a huge difference to the feel of the van. With Devonports, it always felt like the front end was tucking under (best description I can think of) but with the wider tyre and reduced tyre wall it felt totally planted.