Where are rolling road dyno's??

[Scoobydoo]

Now that the cops want to enforce a lower tolerance level on speeding, I want to know what my speedo is telling me in comparison to what my car is actually doing. I know the best way of getting this checked is on a rolling road.

I'd like to know where in the North Island, are there rolling road Dynos? The only one I know of is at Gary Capper in Pukekohe, Auckland.

Any others??

I don't care for any comments about "not needing to get it done", or "they read higher anyway". I'm already aware of all this, I just want the info I'm asking for. Other people may be interested in the same thing.

[Guest Fastfour]

Best place to go is someone that calibrates your speedo, as opposed to a dyno.

[funkytown]

 Fastfour said:

Best place to go is someone that calibrates your speedo, as opposed to a dyno.

out of interest where do they do this even.. wud also be interested when the STI is running as GPS reads about 8-10kms to fast that gps says

[Guest boostcut]

theres only a couple of people in nz that calibrate speedos. one who is an old motherfucker who has a shack inbetween 1st and 2nd ave in tauranga. john hardy. hes about 90 and worked at smiths gauges in england for years. he repairs all guages and if he cant fix it properly then he wont charge you. i think he only makes about 10 bux a year and does it just so his wife doesnt nag him all the time

[Scoobydoo]

I rang VTNZ, VINZ, Wellington Vehicle Compliance (certification guys), AA vehicle inspection and they all told me to ring each other haha. Tried an Auto sparky and they gave me a name of an outfit in Auckland, who I'd have to send the speedo unit to them.

No point putting in on a Hub Dyno cos then you don't get the exact measurements depending on what wheels you have.

AA vehicle inspection said they used to have a rolling road, but don't any more

I saw on campbell live tonight an outfit in dunedin was doing checks on their cars on their rolling road, thats what I want to do on mine.

[Guest SPANKU]

 CUDDAS said:

jase do you have to give up a chase at 180kph, as i'm sure that down here they would want to catch them aye.

& you would know it doesnt take much to get to 180kph & it still keeps going.

i will remove post if un-appropriate.

180km/h on 18s are actually 170ish km/h hahaha

usually if you have larger wheels you are actually going slower then you think

[Guest]

 SPANKU said:

180km/h on 18s are actually 170ish km/h hahaha

usually if you have larger wheels you are actually going slower then you think

how do you figure that? if the wheels are bigger, and therefore have a bigger circumference, for any given axle speed the car goes faster with the larger wheels. is there something i'm not getting?

[B4 2000]

A larger diameter wheel take longer to complete a full circle, therefore, your speed is actually less than what the speedo tells you. Visa versa with a smaller diameter wheel.

That's how I understand it, but I could be wrong too.

[Koom]

 B4 2000 said:

A larger diameter wheel take longer to complete a full circut, therefore, your speed is actually less than what the speedo tells you. Visa versa with a smaller diameter wheel.

That's how I understand it, but I could be wrong too.

Wrong way round.

But its all a moot point as it only depends on the tyre's diameter.

[Guest lan_killa]

bigger circumfrence = you will be going faster than your speedo says you are. This is because your speedo works on axle revolutions. If you have a tyre with a curcumfrence of say 30cm if it does 1 revolution you will of traveled a distance of 30cm, If If you have a tyre with a curcumfrence of say 70cm if it does 1 revolution you will of traveled a distance of 70cm but either way your speedo has only seen 1 revolution.

Easy way for you to see what im on about... get 2 rolls of tape, 1x big roll (ie packing tape) and 1x small roll (ie sellotape found on your desk etc) stand them on the desk next to each other and make each roll do 1 revolution, the larger roll will travel a longer distance.

Robinson instruments in Auckland do speedo calibration, surely there must be someone in wellington that does it. Other option is provided your tacho is accurate use my ratio calculator found here:

http://www.clubsub.org.nz/forum/index.php/topic,11040.0.html

this will give you a firm idea of what revs+what gear = what speed, but tyre wear can throw this as can an inaccurate tacho

[Guest SPANKU]

 jake_the_muss']

[quote name='SPANKU said:

180km/h on 18s are actually 170ish km/h hahaha

usually if you have larger wheels you are actually going slower then you think

/quote]

how do you figure that? if the wheels are bigger, and therefore have a bigger circumference, for any given axle speed the car goes faster with the larger wheels. is there something i'm not getting?

on my navman. im running 215x35x18 and my speedo is way off but when i put the 16" gold wheel on with the factory spec tires when going 100km/h it is 100km/h. when i hit 180km/h navman, tomtom and uniden unit says im on 170km/h. when i hit speed cut its when my speedo is at 6 oclock but thats at just over 190km/h

this the reason why spark38 got his calibrated.

this also happened my ver5 RA also when putting in a bigger wheel

the theory of a bigger wheel should say im running slower i know but something wrong with my ( apart from not having any motor lol )?

[Koom]

The tyres on your 18's are ~4% smaller in diameter than the tyres on the 16's (based on a 205/55 16" tyre). So that will make your speedo read ~4% faster than what you are actually going with the 18's on. And thats only if the speedo maintains constant accuracy across the full range of 30kph - 180kph which I also highly doubt.

[Guest SPANKU]

aaaah.... its smaller. thanks

[Scoobydoo]

 lan_killa said:

Robinson instruments in Auckland do speedo calibration, surely there must be someone in wellington that does it. Other option is provided your tacho is accurate use my ratio calculator found here:

http://www.clubsub.org.nz/forum/index.php/topic,11040.0.html

this will give you a firm idea of what revs+what gear = what speed, but tyre wear can throw this as can an inaccurate tacho

yeah that's the name of the place I was given. I'll ring them later today and see what they say, if it's something that can be done locally

[sultan]

in AK we have these speed pole things that show you how fast you're going, do other areas of the country not have them?

[Koom]

 sultan said:

in AK we have these speed pole things that show you how fast you're going, do other areas of the country not have them?

The ones I see just say "slow down" on them with flashing orange lights ???

[99GTB]

I've seen some they show your speed then a or a

[Divine]

Arn't these things a certain distance apart?

[Johnnynz]

 Koom']

[quote name='sultan said:

in AK we have these speed pole things that show you how fast you're going, do other areas of the country not have them?

/quote]

The ones I see just say "slow down" on them with flashing orange lights ???

ROFL!!!

[Guest lan_killa]

i dont trust those signs that tell you your speed... I reckon they intnetionally read high so that you drive slower

[sultan]

they've read accurate on two of my cars, but my wrx with 215/35/18 is off by 10% and i'd believe it to gauging by the speed at which i have to do to keep up with traffic

[MercuryFree]

 sultan']

in AK we have these speed pole things that show you how fast you're going, do other areas of the country not have them?

We do have them in wellington, they're decently accurate but not as accurate as he's wanting I assume.

[quote name='Divine said:

Arn't these things a certain distance apart?

img]http://img412.imageshack.us/img412/1853/81439818.jpg[/img]

I'm pretty sure they are in americaland etc, but not here.

[Guest SPANKU]

hey! i know that spot

[pl0x]

 lan_killa said:

i dont trust those signs that tell you your speed... I reckon they intnetionally read high so that you drive slower

Ones round here are very accurate (shows your speed until you go over 85 (80km zone) after 85 just says slow down), with a calibrated trip meter it reads spot on up to 85

[Guest SPANKU]

 lan_killa said:

i dont trust those signs that tell you your speed... I reckon they intnetionally read high so that you drive slower

same here. i think that the faster you go the more inaccurate it gets?