ok another wheel question

[gary1998]

just picked up some bigger alloys being after these ones for a while they were cheep (and the excat ones i wanted)
so had them will need bigger tires
does this combo sound ok for a 1y with standard 1.7 gearbox



tried the wiki says i'm not a member or something like that



Mercedes 16
16 x 7.5j
et 47
thinking these tires

Rear tyres 205/75/16
Front tyres 205/75/16
not worried about speedo being off as it's broke


10mm spacers at the front, 22mm spacers at the rear

running 195/90/15s now so hope to reduce revs at top end
and have the look i'm after

[g60steve]

Mercedes 16
16 x 7.5j
et 47
thinking these tires

Rear tyres 205/75/16
Front tyres 205/75/16
not worried about speedo being off as it's broke


10mm spacers at the front, 22mm spacers at the rear

running 195/90/15s now

195/90/15's.....that size doesn't even exist?

205/75/16's are waaaaayyy too big....9.51% and 62mm bigger than the standard 14" wheel/tyre set up!
Plus they're too narrow for 7.5" wheels...215's or 225's are required.
215/65/16's are 5.21%(34mm)bigger.
225/60/16's are 3.68%(24mm)bigger.

ET47 and 7.5" wide will require at least 15mm spacers for the front and 20mm will be ok on the rear.

Why do people continue to buy alloys before finding out what's required to fit them?

[AdrianC]

195/90/15's.....that size doesn't even exist?

Mebbe they're 195/60s, but somebody fitted them upside-down?

[gary1998]

So just had a look on van now are 195/70/15 this is where i went wrong i was calculating from these
instead of standard size i kinda knew about spacers I'm thinking brickwreks 25 mm all round
and 215/65 if there 34mm bigger

I'm wondering how many mm bigger is too much for my engine/gearbox combo

[g60steve]

i kinda knew about spacers I'm thinking brickwreks 25 mm all round

I give up.......

[gary1998]

kinda knew about spacers was wrong choice of words ..i did know without a doubt (sorry)
i was'nt second guessing your reconmendation of 15mm and 20mm (sorry again)
was only thinking brickwerks 25mm spacers all round because they are tried and tested and seem to be less fussing about ..
i've read all i can find about the subject not all sunk in as i've no head for remembering numbers
thing is i cant find anywhere what the best wheel/tire combo
is most suitable to my engine/gearbox combo


i'm sorry for asking what is a stupid question to someone who knows these things
but if i dont ask how will i learn these things

[chapperss]

25mm spacers on the front will mean your wheels will stick out quite a bit at the front. if your bus is lowered you may have tyre/wheelarch interference issues! You want as thin a spacer as you can get away with so you clear the upper wishbone ball joint. so as G60steve said 15mm would be a better bet.

[chapperss]

as far as tyre size goes just use one of those on line tyre size calculators. put in the stock t25 tyre size and your new wheel size and get a tyre as close to the original size as possible.

[AdrianC]

i've read all i can find about the subject not all sunk in as i've no head for remembering numbers

That is kinda key here, though.

A pair of 15mm spacers will make the front track 30mm wider. A pair of 25mm spacers will make it 50mm wider.

There are two basic aims to getting the offset right :
- Keeping the centreline of the wheel in the same place as with the standard wheels, so that you don't overload the wheel bearings.
- Stopping a borderline over-large wheel and tyre from rubbing or sticking out.

The second is always really easy to address - don't use borderline over-large wheels and tyres... A lot of people put the cosmetics of big wheels and tyres above the functionality, then can't understand why they get all sorts of problems. Simple, because they've made the problems for themselves.

The first is also relatively easy. Look at the offset of the standard wheel - 30-39mm, according to https://club8090.co.uk/wiki/Wh ... eel_offset_(ET" onclick="window.open(this.href);return false;)
Put a wheel with a lower offset on, and the centreline is being moved outwards. Spacers will make that worse.
Put a wheel with a higher offset on, and the centreline is being moved inwards. A spacer equivalent to the difference between that new offset and the standard offset will bring it back into range. So a wheel with 45 offset and a 10mm spacer will be 35mm effective offset (45-10=35), which is between 30 and 39, so OK.

For a 25mm spacer to keep the offset right, you'd be looking at a wheel between 55 and 64mm offset.

[chapperss]

Nicely explained Adrian. my 17x7" t5 steel wheels have an offset of 56mm and I have 15mm adaptors(which work like spacers for this discussion) so I have an effective offset of 41mm. which is pretty much spot on, and they look right on the arches too.

[g60steve]

my 17x7" t5 steel wheels have an offset of 56mm and I have 15mm adaptors so I have an effective offset of 41mm. which is pretty much spot on, and they look right on the arches too.

ET41 and 7" wide wheels isn't really 'spot on' ?
I say that because 5.5" T25 steel wheels are ET39 and 6" wide T25 alloys are ET30....hence the advise to keep within those range of offsets.
With wheels wider than 6" the offset can be slightly below ET30 to clear the upper wishbones....but that ET depends on the width.

Projektzwo and Oettinger fitted 7"X16" alloys with an offset of ET23.

So....with your 7" wide wheels and an effective offset of ET41 the wheels naturally sit 18mm further in so surely they're very close to the upper wishbones?

[chapperss]

I forgot about my front discs!(plonker) push the wheels out a further 7mm a side. so effective offset is 34. but I have a good 12/14 mm wishbone/inside of rim clearance.

[kevtherev]

eh?

[chapperss]

I have passat 312mm vented front discs, fitted too machined down stock discs to make hubs. this widens the track by 7mm a side.