Bigger tyres and Speedometer Correction?

Bigger tyres - or just use a GPS or scanguage or both!
 
I noticed that my speedo is vertually spot on now, since I put on a the new tyres 65's as opposed to 60's (which I'll need to replace again very soon)

This is when compared to both my GPS & Scanguage :)

Regards
Mr Turbo
 
I'm in the same boat as you, MrT. My speedo is very close to spot on against a GPS...

But the same cannot be said for the odometer. It now reads less than it should... I've checked with GPS, Scangauge as well as those streches of road with the posted kilometers... Seems to be out by about 6-8%...

Pedro
 
Thats strange pezimm.

I always check my odometer against those signs (check odometer signs, normally on a 5km stretch) & mine is spot on for that 5km check.

Regards
Mr Turbo
 
^ Yeah, I also test it on those 5km streches and get to the end around 5.3-5.4km...

Scangauge spot-on...

Put it down to car personalities...
 
Gidday Pedro

pezimm said:
...

Put it down to car personalities...
Click to expand...

I'd go along with that ... :lol: :ebiggrin: :cool:.

Roo2 is exactly 5% under, from 60 to 100 kmh anyway. I figured that fitting 215/65 16 would fix the problem, but that size is illegal on Roo2 ... :shrug: :shake:
 
Watch this....

[ame="https://www.youtube.com/watch?v=bMs7w72QTVM"]Speedo Corrector - YouTube[/ame]

2 Aussie guys who do DIY mods on cars in Aus. They are pretty big now Moog even has a Foz XT 2010 :cool: They have some good vids and are pretty entertaining!

With my speedo when I'm doing 100km/hr on the speedo my foz is actually doing about 105km/hr. This I have notice has helped my fuel economy when cruising at higher speeds as my SF Forester has a low 5th gear.... I now do 2900 at 100km/hr(actual speed), verse 3200rpm with stock size tyres.
 
Last edited:
Kevin said:
Bigger tyres - or just use a GPS or scanguage or both!
Click to expand...

stilson said:
I've got about the biggest tyres that will fit without serious modification and my speedo is bang on.
Click to expand...

pezimm said:
I'm in the same boat as you, MrT. My speedo is very close to spot on against a GPS...

But the same cannot be said for the odometer. It now reads less than it should... I've checked with GPS, Scangauge as well as those streches of road with the posted kilometers... Seems to be out by about 6-8%...

Pedro
Click to expand...

I should have said this in the first post: What is your bigger tyre size?

Cheers,
 
mr turbo said:
I noticed that my speedo is vertually spot on now, since I put on a the new tyres 65's as opposed to 60's
Click to expand...
Sorry mate I should have been a little more specific.
The size I'm referring to is 215/65/16

Regards
Mr Turbo
 
taza said:
Watch this....

Speedo Corrector - YouTube

2 Aussie guys who do DIY mods on cars in Aus. They are pretty big now Moog even has a Foz XT 2010 :cool: They have some good vids and are pretty entertaining!

With my speedo when I'm doing 100km/hr on the speedo my foz is actually doing about 105km/hr. This I have notice has helped my fuel economy when cruising at higher speeds as my SF Forester has a low 5th gear.... I now do 2900 at 100km/hr(actual speed), verse 3200rpm with stock size tyres.
Click to expand...


Awesome show. :discomonkey:
 
Thank you all for the replies. I have worked out that 215/65r16 give me more accurate speed reading than the stock 215/60r16. Now time to contact the engineer.

Cheers,
 
After plenty of research on this subject due to a navara at work, I have come to the conclusion that (at least in the D40 Navaras case) the factory has fudged the speedo to make their fuel economy figures look better.

ADR rules state that over 40km/h (or is it 60?) that all vehicles can read +10% +4km/h (ie: it can read over but not under the vehicles true speed)
In the case of the above mentioned Navara it reads 114km/h on the speedo when the GPS reads 100km/h. A few people on the navara forum even hired a dyno to get an accurate measurement of speed and odometer to fight their warranty claims getting knocked back. They found that the speedo was right on the border line of the ADR Allowance but the ODO was spot on.

I'm not entirely sure how much this applies to the forester and I may have gone into a bit of a rant, but basically I wouldn't be concerned about having your speedo corrected as the bigger tyres would probably make it more accurate anyway and as for the ODO I think the difference would be negligible.
 
During my research on the Navara I found only one person who had their speedo fixed under warranty and afterwards it was spot on but his fuel economy suffered horrendously.

PS: my SH9 is only about 4-6% out by my GPS
 
Last edited:
You must log in or register to reply here.
Back
Top