Jump to content
The mkiv Supra Owners Club

GPS and Speedo accuracy


Bobbeh
 Share

Recommended Posts

Went out with the GPS this evening to see how far out my speedo is on my 18s...

 

26 mph on gps = 30 on speedo

30 = 34

59 = 70

 

I used the cruise control to keep the speed the same throughout the test. Anyone else done this? Might have to put back on the 17s and see how it is then.

Link to comment
Share on other sites

Went out with the GPS this evening to see how far out my speedo is on my 18s...

 

26 mph on gps = 30 on speedo

30 = 34

59 = 70

 

I used the cruise control to keep the speed the same throughout the test. Anyone else done this? Might have to put back on the 17s and see how it is then.

 

thats pretty much how mine is on 17"

Link to comment
Share on other sites

Yeah this is why I took it out and did a test, I usually get people sitting up my ass in built up areas and the like but no wonder as im doing like 26 in a 30, on the bright side theres no way of getting a ticket.

 

I'm gonna take out my Civic tommorow and compare :)

Link to comment
Share on other sites

With new 285-35 tyres on 18's -

 

80 on the speedo = 81 on the GPS.:)

 

Mine are worn 285/30s on the back, what are the lower speeds like on yours? I was thinking that at certain speeds you'd get more accuracy... maybe the higher the better it will read, obviously not too keen in testing that out on the roads ;)

 

Gaz, have fun - I'll guess around 160-5 on the clock :)

Link to comment
Share on other sites

Yeah sorry I meant stock 16" rims and stock tyre size on them, too. :thumbs:
It wasn't you I meant specifically Steve, one of the other replies mentioned 17" wheels

but like I said, it's not the wheels that matter.

 

 

 

PS & OT

I've just seen your email, will reply shortly.

Link to comment
Share on other sites

It wasn't you I meant specifically Steve, one of the other replies mentioned 17" wheels

but like I said, it's not the wheels that matter.

 

 

 

PS & OT

I've just seen your email, will reply shortly.

No worries, you're right though so I was just adding in that extra, important detail.

 

OT - Cool :)

Link to comment
Share on other sites

Interestingly, the vehicle speed sensor reading on mine is within 0 to 2mph of the road angel (depending on how old the tyres are) all the way up to north of 170mph, yet the speedo still has that error built in :think: Are they deliberately nerfed perhaps?

 

Speedo needle is in a different time zone at 170+mph btw ;)

 

-Ian

Link to comment
Share on other sites

On 275/35R18's my speedo reads out by near as dammit 10% as far up as I've been (an indicated 175). Interesting when I had the Apexi AVC-R wired up it was almost identical to the GPS reading so I agree with Ian that I think the speedo dial is designed to over-read, probably for some kind of safety?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.