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Having bigger rims or really, just different sized rims & tire combo from that of OEM alters the speedo reading - that's to say with larger rims (than OEM), you're actually going slower than what the speedo shows. Smaller rims (than OEM) would conversely mean that you are going faster that than what the speedo shows on the dial.Quote:
Originally Posted by Mz_Civic
Recalibration eliminates the disparity between road speed and the speed indicated on the speedo! ;)
cheers
Got that the wrong way around...
With larger rims, 100K's on the speedo will be 100+ road speed, resulting in a speeding fine much easier...
For speedo claibration places, call the RTA or ask a Taxi company where they get their speedo calibrated.
Paine & Townsend in Grafton NSW is one place that I know of, that can recalibrate your speedo.
Also, an engineer can certify and tyre/rim combination legal if it passes safety criteria and the speedo is calibrated to suit.
Quote:
Originally Posted by iamhappy46
That's actually not right. An engineer can certify anything up to a point but not beyond that...Quote:
Originally Posted by fusionprelude
This is what the RTA's VSI 9 says regarding wheels that require an engineer's certification
I would advise anyone interested in this topic to thoroughly read the RTA's Vehicle Standards Information Sheet 9 so you know exactly what the rules are otherwise you could end up getting nicked at a defect station or worse, being involved in a crash and finding out that your insurance in void because you were driving a defective vehicle.Quote:
There are limits on the size of wheels that can be certified by a signatory. These limits are as follows:
Rear wheels
The maximum permitted rear rim width for a particular vehicle is determined by its unladen weight (10 litres of fuel, no occupants or luggage) in accordance with the following:
- up to 800kg rim width increase allowed of 26mm (1inch)
- 801-1200kg rim width increase allowed of 39mm (1.5inches)
- 1201kg and over rim width increase allowed of 51mm (2inches)
Front wheels Front wheels shall be:
• No wider than the maximum permitted for rear wheels on your vehicle or 204mm (8 inches).
• No narrower than 70% of that fitted to the rear wheels.
• No narrower than a standard wheel fitted to the your vehicle as original equipment.
Front wheel drive vehicles
Except where the original manufacturer provides to the contrary, front wheel widths shall be no more than 26mm greater than the widest optional wheel offered by the vehicle manufacturer. This requirement also applies to fourwheel drive vehicles with constant front wheel drive.
If the engineer certifies the vehicle as passing certain criteria(like clearances around the wheel/not rubbing on body or suspension parts) then the car becomes legal... Make sure the engineer writes down the wheel and tyre package.
If the insurance company ever cancels your policy after an accident for mods approved by the engineer, the engineers public liability or relevant insurance is required to pay the claim. Is one reason why engineers cost so much, they have to pay their insurance premiums!
Read the VSI 9, what you are saying isn't accurate according to that document. There are definite limits to what an engineer can certify in terms of aftermarket wheels. They are not just bound by wheel clearances and rubbing issues (in NSW anyway)... This is the same thing that I've been told by the RTA technical advice line and 2 engineers.Quote:
Originally Posted by iamhappy46
ok i barely even read the first post but this question has popped up a few times so i pasted my reply from an older thread. prolly restating things already said but sue me:p
Quote:
Originally Posted by panda is the best
--- The maximum permitted rear rim width for a particular vehicle is determined by its unladen weight (10 litres of fuel, no occupants or luggage) in accordance with the following:
up to 800kg rim width increase allowed of 26mm (1inch)
801-1200kg rim width increase allowed of 39mm (1.5inches)
1201kg and over rim width increase allowed of 51mm (2inches) --
So according to the above and everything that has been said so far...this is what i understand.
1. my current 205/40/17 setup is illegal for 2 reasons
a) exceeds allowed 15mm excess in overall diameter by 5mm
b) exceeds allowed 1" excess on rim width by .5"
2. This can be made legal by getting an engineering certificate since
a) my car falls in the 801-1200kg bracket where rim width increase allowed of 39mm (1.5inches)
b) overall diameter can be made within 15mm excess by having 35 profile rubber
OR
if engineer deems that 205/40/17 setup is fine even though it exceeds overall diameter limit by 5mm, and writes it on the certificate.
However i still have a few questions to verify the max optional tire size & rim width available to ensure i actually do NEED the engineers certificate 2 certify all is legal
1. where can i find the tire placard on my car?
2. where can i find the door jamb on my car?
Check your Owners manual for the rim/tyre combinations that can be used on your car.
Ye it shows different variations, and states that they are the only "recommended" options for rim/tyre.
for rim the largets option is 15 x 6 JJ....hav no idea wat JJ stands for
for tire its 195/55/14
Regardless...i just called one of the engineers in my area. He said for the rims/tires, coilovers, plus exhaust, it'll be $500....i think ill just pay it and get it over and done with and drive with some peace of mind, since id imagine if i just get coilovers + exhaust covered in the certificate, itll be like $100 difference or so, so its not worth it if i get defected for them at the end newai.
Same 'standard' price for an engineers certificate to get whatever you want covered.
Have a read of these for some more info:
Tech Info
Tyre Crush
Cool, you're putting out good info, rep pt for you!Quote:
Originally Posted by iamhappy46
cheers
my setup is legal when i run 17's
i got 195/60 r14 and ill be puttin on 205/40 r17
6.2mm difference in size :):)