Wheel swapping, astra ah and vectra b

[thirteen]

18's of an astra ah should fit right onto my vectra b, is that correct?

just need someone to confirm. thanks :D

[auzvectra]

not sure, the stud pattern is the same, just the offset.
i am pretty sure the offset on the veccy is bout 40mm.
i gotta set of 18's fo rsale! :lol:
off my old veccy b that is.

[InsaneAsylum]

should be fine. i'd check the rolling diameter of the tyre though, so that the speedo isn't out.

[auzvectra]

and the load and speed rating's, they are cruicial.
most tyre places dont care, but they arent the 1's gettn the fine, or voided insurance!!
225/40/18's is a good size, just a slight bit bigger.
as 35 series are too low load rating.

[thirteen]

which tyre size wont have the speedo reading wrong? 40 or 35 series?

[auzvectra]

what are the standard veccy wheels again, i forget.
is it 205/65/15's?
or 205/70/15's?
if it's 65 series then the 225/40/18's are 6% out, doesnt sound right.
if it's 70 series then they are 4% out

65 series on the 225/35/18's are 4% out
70 series are 2% out.

just work the calculations out.
1 inch = 25.4mm
15"= 381mm
18"= 457.2mm
ect...
the profile height e.g.
205/70/15 =
205 X 0.7 = 143.5
143.5 (profile) + 381 (mag height) = 524.5mm (total whel height)

225/35/18 =
225 X 0.35 = 78.75
78.75 + 457.2 = 535.95mm

535.95 divided by 524.5 = 1.0218303145853193517635843660629
being 102%ish = 2.18303145853193517635843660629 % larger.
too many numbers :bang: .
hope that helps.

[thirteen]

standard vectra tyres are something like 195/65/15 in which case the 225/40/18 would be around .2% out. which should be fine yeh?

[auzvectra]

so to answer ur question, if the wheels are 205/70/15's standard, then u need 225/30/18's to keep it correct on the speedo.
which are about 0.0004 % larger, n i dont think u can get that size neway.
i tryed for mine, but then found out about the load n speed ratings.
so it's either suffer 4% or have no insurance.
u can geta pulse converter from jaycar to alter the speedo neway to corect it.
it's a build urself kit.

[auzvectra]

check ur tyre plaque to get the exact tyre size.
many people change the size of tyre to suit the cheaper tyres at the time.
if that is the size, it would make the 225/40/18's 7.76 % larger.

[180HOA]

I know with the TS's Holden can calibrate the speedo for different wheel/tyre combinations using Tech2... it's a quick job, and I assume it would be the same for the Vectra's?

[dug74]

Just use the tyre calculator....so much easier

Cheers

http://www.miata.net/garage/tirecalc.html

[oneightoo]

should be fine. i'd check the rolling diameter of the tyre though, so that the speedo isn't out.

so if i get say some 4wd wheels and someone willing to cut big holes in my guards, i could really travel further than the speedo thinks??

hyperthetically speaking of course..

[180HOA]

so if i get say some 4wd wheels and someone willing to cut big holes in my guards, i could really travel further than the speedo thinks??


Haha. Yes. Also, if you drive everywhere backwards, your odometer reading reduces...

[oneightoo]

hmmm i could be onto omething here.. imagine the resale value on my car after 10 years thats only done 271kms..

i smell gold

[180HOA]

i smell gold


that's why the ford taurus has a small, but loyal, following... it looks the same going forwards as backwards

[auzvectra]

Just use the tyre calculator....so much easier


but thats too easy, cheat :D

[InsaneAsylum]

should be fine. i'd check the rolling diameter of the tyre though, so that the speedo isn't out.

so if i get say some 4wd wheels and someone willing to cut big holes in my guards, i could really travel further than the speedo thinks??

hyperthetically speaking of course..

back in the day there was a sik dude with a sik gemini cruising around a beach with 17" chrome MOMO extreme rims (yes they were cool back in '98 )

anyway, the speedo was out that much that it would show 60 when he was doing 100. didn't get off the line too well either but i spose sik drivers lie too