Lifted Lib. New Tyres - Speedo is out!

AlpineRaven · Post by **AlpineRaven** » Thu Dec 20, 2007 3:55 pm

G'day,
Little problem here, got new tyres for my wagon - 205/70 15" 95H now at 60kmh on the dial GPS is showing 62.7kmh, 80kmh is showing 85kmh on GPS, 100kmh showing 107kmh on GPS.

What are the differences between Subaru Outback & Liberty have? Different speed drive? or dash or what? What can I do about it to get the correct speed instead of reminding people who drive my car.
Cheers
AP

Bumpty · Post by **Bumpty** » Thu Dec 20, 2007 6:49 pm

I'll tell you... if you post pics of the wheels on your lifted lib

Post by **Alex** » Thu Dec 20, 2007 7:00 pm

remember that manufacturer's are allowed a 10% discrepancy between the dial's speed and the actual speed.

alex

Post by **Captain Obvious** » Thu Dec 20, 2007 8:47 pm

sit just that little bit lower on the speedo while driving, we all have this problem with bigger tyres just adapt to it

Matatak · Post by **Matatak** » Thu Dec 20, 2007 8:58 pm

89rsturbo wrote:sit just that little bit lower on the speedo while driving, we all have this problem with bigger tyres just adapt to it

ermmm i dont..my actual speed is lower than my speedo reading.

daza · Post by **daza** » Thu Dec 20, 2007 9:00 pm

If you have an electronic speedo it's not too hard, but i don't know when they hit the Lib?
Daza.

Post by **Alex** » Thu Dec 20, 2007 9:39 pm

Matatak wrote:ermmm i dont..my actual speed is lower than my speedo reading.

thats cos you have an unlifted girls car, with little tyres!

alex

Matatak · Post by **Matatak** » Thu Dec 20, 2007 9:48 pm

yer right like hell id lift my lancer...and the tyres and rims ive put on needed some chopping to stop rubbing

..so i aint going any bigger there lol.

my point was neway..ive got bigger tyres and my speedo is reading over wt im doing.

AlpineRaven · Post by **AlpineRaven** » Thu Dec 20, 2007 10:00 pm

Bumpty wrote:I'll tell you... if you post pics of the wheels on your lifted lib

It has risen approx 2 inches from standard Liberty height.
Still planing to install raised King coils.
Cheers
AP

AlpineRaven · Post by **AlpineRaven** » Thu Dec 20, 2007 10:00 pm

Will provide better photo in daylight.
Rear tailing arms weren't replaced.
Cheers
AP

chriSTIan · Post by **chriSTIan** » Fri Dec 21, 2007 7:20 am

Don't forget that your odometer will be out accordingly,same on mine,it only shows 420 odd km per tank but really is more like 500km

vidler · Post by **vidler** » Fri Dec 21, 2007 7:23 am

you'll get used to it pretty quick.... my orange thing says 85kmph when the gps says 100....

vincentvega · Post by **vincentvega** » Fri Dec 21, 2007 9:11 am

thats cos your tyres are HUGE

90brumby · Post by **90brumby** » Fri Dec 21, 2007 11:07 am

my brumby is about 20% out so 60 is 72 and so on 100 is 120 etc u get use to it or u can get it fixed but i dont think it is cheap

AlpineRaven · Post by **AlpineRaven** » Fri Dec 21, 2007 1:17 pm

Okay,
Is there any mechanical differences that can be fixed? or its in the dash that can be calibrated to normal speeds? How can I fix it?
Cheers
AP

90brumby · Post by **90brumby** » Fri Dec 21, 2007 1:27 pm

if it is cable u can get a little gbox thingo put in it i belive lapsed has 1 in his wagon not 100% sure tho

AndrewT · Post by **AndrewT** » Fri Dec 21, 2007 1:37 pm

Matatak wrote:yer right like hell id lift my lancer...and the tyres and rims ive put on needed some chopping to stop rubbing ..so i aint going any bigger there lol.

my point was neway..ive got bigger tyres and my speedo is reading over wt im doing.

Something is wrong with your car then. If you have bigger than standard diameter tyres then your true speed MUST be faster than what your speedo reads - digital or not.
You must be running a different ratio gearbox than the car originally had or something like that. Or your just mistaken...you need to check it out with a GPS.

Edit - btw Matt does your speedo operate by plugging into the gearbox? Or do those funky digital ones get a speed reading by some other method?

AndrewT · Post by **AndrewT** » Fri Dec 21, 2007 1:40 pm

90brumby wrote:if it is cable u can get a little gbox thingo put in it i belive lapsed has 1 in his wagon not 100% sure tho

Yes that's correct. You can get a little gearbox which sits in-line in your mechanical speedo cable. Mate of mine got it done by some place in perth which is no longer there and I can't remember the name now. No doubt a 4x4 shop would have contact details for one....every 4x4 owner would get this problem when upgrading to larger tyres.
The box has a little set of gears which makes the speedo cable on the other side of it spin at different rate - a pre-set (adjustable I guess) ratio.

SUBYDAZZ · Post by **SUBYDAZZ** » Fri Dec 21, 2007 2:13 pm

AlpineRaven wrote:G'day,
Little problem here, got new tyres for my wagon - 205/70 15" 95H now at 60kmh on the dial GPS is showing 62.7kmh, 80kmh is showing 85kmh on GPS, 100kmh showing 107kmh on GPS.

You have increased stock size of wheel tyre combo by roughly 8.6%. Hence your speedo will read about this much less than it did at same vehicle speed before. According to your GPS it seems to be between 4.5 and 7% out. Trust the GPS more than the speedo.

AlpineRaven wrote:What are the differences between Subaru Outback & Liberty have? Different speed drive? or dash or what?

What do you mean by this exactly? There were many differences. Tyre / rim combo diameter was just one of many. It was 664mm vs 615mm for Liberty. gear ratios were also likely different. Besides that, there are many years of models variants, what are you actually after here?

AlpineRaven wrote:What can I do about it to get the correct speed instead of reminding people who drive my car.

Not a lot, unless you have a programmable speedometer like no other Subaru ever had or you spend $$$ to get a speedo cable gearbox made to suit the exact tire size you will be running or change the internal gearbox speedo cog to suit. I don't know anyone that has done this myself. GPS is good option, or just remember how much out it is or put a sticker on the windscreen to remind people?

SUBYDAZZ · Post by **SUBYDAZZ** » Fri Dec 21, 2007 2:18 pm

daza wrote:If you have an electronic speedo it's not too hard, but i don't know when they hit the Lib?
Daza.

Please elaborate on this, is there a facility to adjust what an electronic speedo reads to compensatte, and if so, how?

Alex wrote:remember that manufacturer's are allowed a 10% discrepancy between the dial's speed and the actual speed.

alex

Not quite. If a car is ADR compliant it is 4% for speedo (at a given speed) and 4% for tyres, so in theory the most it should be out is 8%. Speed cameras are usually set to 10% above the speed limit to allow for this.