RRSPORT.CO.UK

    Forum   Gallery   Shop   Sponsors
Home > General (L494) > Speedo correct?
Post Reply  Down to end
Page 1 of 1
 
Cornishman



Member Since: 12 Jul 2018
Location: Cornwall
Posts: 27

United Kingdom 
Speedo correct?

When driving on the dual carrageway at an indicated 70 mph along with everyone else, we all do down here , of course, !! I always seem to be traveling 1 or 2 mph more, is my speedo correct, as I’m running 22inch tyres. Good question for Tyrefitter perhaps?

Post #570413 Tue Dec 04 2018 11:49am
View user's profile Send private message View poster's gallery Reply with quote
rangiejools



Member Since: 11 May 2008
Location: Mornington Peninsula Vic
Posts: 184

Australia 

All tyres fitted to an RRS are the same diameter whether on 22 inch wheels, 21s or 20s. The speedo on an RRS is about 4-5% optimistic. For instance when I see 105kph on my speedo I am actually doing 100kph. SDV8 arrived and fantastic even the infotainment!
1983 2 door Range Rover ARB Bar X9000 winch ARB Rear Bar now semi retired.
Many big trips done in this one.
1982 Rangerover nearly restored.
22 Defender D250 with lots of stuff for outback touring
Nice 2013 Freelander TD4 manual (for daughter to learn on) with much better stereo compared with previous SD4 SE with Meridian which sounded bad!
2013 Land Rover Defender ute.


Last edited by rangiejools on Tue Dec 04 2018 11:57am. Edited 1 time in total

Post #570414 Tue Dec 04 2018 11:55am
View user's profile Send private message View poster's gallery Reply with quote
Tim in Scotland



Member Since: 30 May 2005
Location: Driving along in my automobile
Posts: 17476

2013 Range Rover Sport SDV6 HSE Stornoway Grey

There is a 10% high margin of error permitted on uncalibrated speedos so at 70 speed limit you can be up to + 7 mph out. You can get an indication of errors using a phone app route guidance program online for your phone - one that shows your speed and you can compare the readings. Don’t use the in car nav system as it is an average not an instant reading

Post corrected to remove the -% 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW


Last edited by Tim in Scotland on Wed Dec 05 2018 9:09am. Edited 1 time in total

Post #570415 Tue Dec 04 2018 11:55am
View user's profile Send private message View poster's gallery Send e-mail Reply with quote
kmpowell



Member Since: 23 Oct 2016
Location: UK
Posts: 259

As Tim says, ff you download a GPS speedo app you will get a better picture of your actual speed. On mine 74mph is 70mph. 95mph is 89mph (tested on a private road of course). SOLD - MY16 SDV6 Autobiography Dynamic - Fire Engine Red, Fixed contrast pan roof, TV, Dual Screen, 5+2, Privacy, Noble paddles.

Post #570416 Tue Dec 04 2018 12:19pm
View user's profile Send private message View poster's gallery Reply with quote
Lindab



Member Since: 20 Nov 2017
Location: Dundee
Posts: 864

United Kingdom 

I have a Road Angel in my car which is GPS based. At 70mph on Road Angel the RRS speedo is showing 74. I never look at the car speedo now, always Road Angel. Only downfall of Road Angel is it is not bright enough especially on a sunny day. I emailled them about it, but no reply although they are quick enough to phone you when the subscription is coming up for renewal.

Post #570419 Tue Dec 04 2018 12:38pm
View user's profile Send private message View poster's gallery Reply with quote
00by



Member Since: 25 May 2018
Location: Northants
Posts: 81

Tim in Scotland wrote:
There is a 10% margin of error permitted on uncalibrated speedos so at 70 speed limit you can be +/- 7 mph out. You can get an indication of errors using a phone app route guidance program online for your phone - one that shows your speed and you can compare the readings. Don’t use the in car nav system as it is an average not an instant reading


You're right on the 10% margin of error, however it is only in one direction - your speedo can read up to 10% too high but cannot read lower than your actual speed. (Well, it obviously can technically, but not legally.) MY16 RRS 3.0 SDV6 HSE Dynamic

Post #570425 Tue Dec 04 2018 2:17pm
View user's profile Send private message View poster's gallery Reply with quote
Cornishman



Member Since: 12 Jul 2018
Location: Cornwall
Posts: 27

United Kingdom 
Speedo correct?

Thanks for all the info, will get the app, will be interesting.

Post #570431 Tue Dec 04 2018 4:49pm
View user's profile Send private message View poster's gallery Reply with quote
Tyrefitter



Member Since: 19 Jul 2015
Location: Bridlington East Yorkshire
Posts: 3675

United Kingdom 2013 Range Rover Sport SDV6 Autobiography Fuji White

Is yours a RRS1 or 2 & what size 22’s are you running.? But as everyone says speedos are always set under the actual speed you are doing,I’m running 295/40r22’s the same as they fit on the svr’s with 22’s & mine is more accurate to the Satnav than it was with the 275’s. Andy.
21 Ford Ranger
Gone but not forgotten
Focus RS Red Edition
2015 RRS AB Fuji.
2014 RRS SC Santorini
2016 VW Amarok
2014 RRS AB Fuji
2012 RRS Red Edition Fuji
2015 Nissan Navara
2012 RRS SE Santorini
2008 RRS White
2007 RRS Santorino

Post #570432 Tue Dec 04 2018 5:20pm
View user's profile Send private message View poster's gallery Reply with quote
Cornishman



Member Since: 12 Jul 2018
Location: Cornwall
Posts: 27

United Kingdom 
Speedo correct?

Sorry Tyrefitter, it’s a my16 hse 306, still running original continentals cross contact lx 275R40 x22

Post #570456 Tue Dec 04 2018 8:22pm
View user's profile Send private message View poster's gallery Reply with quote
Oldandconfused



Member Since: 18 Jun 2017
Location: Norfolk
Posts: 746

United Kingdom 2010 Range Rover Sport 3.0 TDV6 HSE Zermatt Silver

As far as I'm aware, the accuracy of speedometers is governed by EU directive and must not under-read, and can over-read by up to 10%. I use a sat nav, I have a Garmin, the wife used a TomTom. Give it a try and compare it to your speedo so you know where you stand..

Post #570484 Wed Dec 05 2018 9:04am
View user's profile Send private message View poster's gallery Reply with quote
PIG88



Member Since: 23 May 2018
Location: North of Watford
Posts: 194

United Kingdom 

Speedometer 55 Pro is a good app for checking your speed. It also has a feature which reverses the figures and gives you a speed head up display on the windscreen if you put your phone on the dashboard.


 Current: 2020 P400e HSE Dynamic

Gone: 2016 SDV6 HSE
2012 SDV6 SE

Post #570502 Wed Dec 05 2018 5:09pm
View user's profile Send private message View poster's gallery Post Reply
Post Reply  Back to top
Page 1 of 1
All times are GMT

Jump to  
Previous Topic | Next Topic >
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Site Copyright © 2005-2024 Futuranet Ltd & Martin Lewis
RRSPORT.CO.UK RSS Feed - All Forums

Switch to Mobile site