Last I knew, track was the distance between the centres of the rims, not the outside edges!
Ahh, you are forgetting that the factory rim is 8" & the Dynamic Steel rim is 7".
Offset is calculated from the centre of the rim. And offset is the distance to where the rim is mounted to the hub. The two dimensions influence changes in wheel track.
The calc is as follows:
Factory +53mm offset on 8" rim width.
Alternate rim (say Dynamic Steelie) is +30mm on 7" rim.
The position of the outside edge of the alternate rim in relation to the factory position is calculated as:
(+53mm - +30mm)-((8" * 25.4mm - 7" * 25.4mm)/2) = +10.3mm
This +10.3mm change occurs on each side of the vehicle, therefore the wheel track change is 10.3mm x 2 = 20.6mm.
And that is less that the maximum 25mm change in wheel track permited in NSW.
 Swaggie
					
					
						Swaggie
					
					
						Last I knew, track was the distance between the centres of the rims, not the outside edges!
MY21.5 L405 D350 Vogue SE with 19s. Produce LLAMS for LR/RR, Jeep GC/Dodge Ram
VK2HFG and APRS W1 digi, RTK base station using LoRa
 Moderator
					
					
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						Track in automotive engineering is the distance between the centrelines of the wheels, not the outside edges. Therefore, rim width makes no difference to the track, only the distance from outside edge to outside edge which is as you describe.
Therefore, a 30p offset is not in fact legal.
Graeme & rpm,
You are both bang on! I ****ed up.
Dynamic 7" steelies illegal alright.
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						 Master
					
					
						Subscriber
					
					
						Master
					
					
						SubscriberQuestion? this is one I never seem to get right, but if LR is 53mm + and Dynamic is 30mm + (which is standard Holden I think) does this mean the track is 46mm less than standard LR?. If so this would make the vehicle more unstable.
26mm increase in QLD, no decrease allowed, see page 20 of http://www.transport.qld.gov.au/reso..._vehicles2.pdf
The wheel track must not be reduced to less than the
standard track specified by the vehicle manufacturer
for the particular model of vehicle.
The track of a car or car derivative may be increased
by up to 26mm beyond the maximum specified by
the vehicle manufacturer for the particular model of
vehicle.
Ryall
I have just returned from 5,500 km trip from Adelaide to Darwin via Oodnadatta track, Finke, Red Centre, Mereenie Loop & then Stuart Highway on new Dynamic 17x7 steel rims with Cooper STT's 245/70/17's fitted. I bought 6 rims but did not need either spare. The tyres performed very well however I had constant vibration at 80-110km/hr (front & rear) despite having all wheels balanced now a total of 4 times! It was not doing this on stock 19'' alloys immediately prior (at just 4000kms) in May. I am about to put factory 19'' alloys back on whilst my Cooper agent investigates the 17" tyres/rims. However I am wondering if it's a rim issue. I have heard from a local 4x4 agent that the Dynamic 17x8's have been withdrawn due to vibration issues. Does anyone else have any clues or knowledge of 17 x7 Dynamic steel rim vibration problems on D3's?
Last edited by Blue C; 27th July 2010 at 12:11 PM. Reason: more info provided
I ran them as my daily rims fitted with Mickey Thompson ATZ's and had no issue. However, a client of mine had some vibration problems on BFG's. Both were 265/70/17 size.
Cheers,
Gordon
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