Fun, Friendly and Free
Welcome,
Guest
. Please
login
or
register
.
1 Hour
1 Day
1 Week
1 Month
Forever
Login with username, password and session length
News:
Forum back online. Please post!
Home
Forum
Battle
Search
Login
Register
Mud-club
»
Vehicle & Technical
»
Discovery
»
speedo's wrong now!!
Print
Pages: [
1
]
Go Down
Author
Topic: speedo's wrong now!! (Read 8475 times)
0 Members and 1 Guest are viewing this topic.
Jake
Regional Rep
Posts: 5474
Attack: 100
Defense: 100
Attack Member
Karma: +0/-0
<insert witty comment here>
South Molton, Devon. UK
Referrals: 0
speedo's wrong now!!
«
on:
December 01, 2004, 16:53:40 »
Hi all.
I've fitted 235/85R16 tyres to my discovery and now the speedo is reading wrong. Does anyone know how i can remidy this. Or is it impossible.
Ta :oops:
Logged
Jake
Owner - Land Rover Discovery 2
Driver - Land Rover Defender 100" Trayback
Thrasher
Administrator
Posts: 3102
Attack: 100
Defense: 100
Attack Member
Karma: +7/-0
Northampton
Referrals: 0
speedo's wrong now!!
«
Reply #1 on:
December 01, 2004, 16:57:10 »
....you can - but most of us just work it out ;-)
There is something twirly in the big lump of spinning cogs that works the speedo. You need a different sized one :-)
I'm sure someone will pop along with a part number and the number of hours/days it will take!
Logged
--
Neil
strapping young lad
Posts: 3326
Attack: 100
Defense: 100
Attack Member
Karma: +0/-0
Referrals: 0
speedo's wrong now!!
«
Reply #2 on:
December 01, 2004, 16:57:31 »
your speedo will be slow so you need to get it adjusted.. ive seen an article on doing this in an old lr mag
short of going to a garage and having it reconifgured there isnt much you can do if this article isnt available (and i aint got it)
d
Logged
Jake
Regional Rep
Posts: 5474
Attack: 100
Defense: 100
Attack Member
Karma: +0/-0
<insert witty comment here>
South Molton, Devon. UK
Referrals: 0
speedo's wrong now!!
«
Reply #3 on:
December 01, 2004, 17:00:44 »
I've susted it to being approx 4mph out at 30 (26 on the clock) but its
the other speeds i have'nt worked out yet. Oh well. I'll just have to carry
on then.
Cheers guys.
Merry Xmas!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Logged
Jake
Owner - Land Rover Discovery 2
Driver - Land Rover Defender 100" Trayback
Paul
Administrator
Posts: 4935
Attack: 100
Defense: 100
Attack Member
Karma: +3/-0
Hinckley, Leicestershire
Referrals: 0
speedo's wrong now!!
«
Reply #4 on:
December 01, 2004, 17:02:05 »
Use a GPS to find out what it should be reading and stick some tape
on it so you can easily work out your speed.
I fitted 235/85's on my Range Rover and it made the speedo read spot
on with my GPS, Must of been reading wrong to start with.
Logged
Paul Wright
Sooty
Moderator
Posts: 734
Attack: 100
Defense: 100
Attack Member
Karma: +0/-0
Referrals: 0
speedo's wrong now!!
«
Reply #5 on:
December 01, 2004, 17:14:13 »
Most speedometers read about 10% under to allow the manufacturers to fit any speedo to any car without having to calabrate every one off the line to avoid one reading 30MPH at 33MPH and maybe being prosecuted for somebody being done for speeding.
I have 235/75 fitted to my 110 and the speedo is now spot on, all my company cars (unmodified) read 10% under.
As Paul says, check it against a GPS, you may be suprised.
Logged
Too Much Tarmac
Cheers Bev
http://members.mud-club.com/profiles/sooty/
Discovery V8
Discovery 300tdi
Range Rover V8Efi
hobbit
Posts: 4750
Attack: 100
Defense: 100
Attack Member
Karma: +0/-0
Referrals: 0
speedo's wrong now!!
«
Reply #6 on:
December 01, 2004, 18:17:23 »
My 235/75s are the same, my speedo is reading down 2/3 mph, according to the gps, my fathers zafira is worse, 5/6 mph down at 70
The disco at that 2/3 I can live with, least you can sit on the needle and know you are within the limit
Logged
Kev
'91 stretch Discovery 200 Tdi
Hybrid for running round (got to go now)
Srs 3 Lightweight petrol (got to go)
Srs 3 Lightweight petrol, runabout
Not every problem can be solved with duct tape, and it's exactly for those situations we have WD 40
thermidorthelobster
Posts: 3557
Attack: 100
Defense: 100
Attack Member
Karma: +1/-0
Referrals: 0
speedo's wrong now!!
«
Reply #7 on:
December 01, 2004, 18:21:37 »
When I went from 235/70s to 235/85s (the same diameter as 265/75s), the speedo went from reading about 7% under to 3% over. I can live with the 3%. At 40mph it's pretty accurate, it's around 70 you have to be aware of the couple of mph difference.
Logged
David French
Tree-hugging communist
1999 Discovery II TD5 Manual
Patriot roof rack
,
QT Services diff guards
front & rear, DiscoParts steering guard[/url],
Autologic
ECU upgrade, 2"
Old Man Emu
lift, 235/85R16
BF Goodrich All Terrains
,
Safari snorkel
,
DiscoParts jackable sills
, Warn Tabor 9000
Ex Disco 200TDI, P38a 4.6HSE and 101FC 6x6 Camper.
Africa Trip Blog
scorpio
Posts: 177
Attack: 100
Defense: 100
Attack Member
Karma: +0/-0
Referrals: 0
speedo's wrong now!!
«
Reply #8 on:
December 01, 2004, 20:18:40 »
I put 235/85's on mine and it made the speedo read spot on.
Logged
Peter
Drive British drive Land Rover
Discovery 300 TDI
Discovery 3 TDV6s
turtle
Posts: 2489
Attack: 100
Defense: 100
Attack Member
Karma: +0/-0
Referrals: 0
speedo's wrong now!!
«
Reply #9 on:
December 01, 2004, 20:31:37 »
Put 265/75R16 on my defener and its put the speedo right out, gald I have the GPS to keep me in line :D
Logged
Phil
My profile
Mark_Sims
Guest
speedo's wrong now!!
«
Reply #10 on:
December 01, 2004, 21:53:38 »
235 70's on mine put it at approx 27 on GPS when speedo reads 30, up to 75 on speedo and GPS reading 70.
Mark
Logged
Mace
Posts: 968
Attack: 100
Defense: 100
Attack Member
Karma: +0/-0
Referrals: 0
speedo's wrong now!!
«
Reply #11 on:
December 02, 2004, 10:08:00 »
try this website for % changes to speedo readings
http://members.shaw.ca/jbarge/tires.html
or this web site for more info on % changes
http://www.tyresave.co.uk/tyresize.html
The conversion on a Defender LT77 gearbox involved changing the drive cog at the bottom of the speedo cable where it enters the gearbox. Land Rover sell different toothed cogs for this purpose. It's a pain in the butt to do so most people don't bother for £10 worth of parts. I've not explored the options on an R380 gearbox, but I'm sure it's just the same but probably more difficult to get at.
Logged
Mace
"What a waste! What a waste! But the world don't mind"
Discovery 300Tdi 3dr
Matt_H
Posts: 948
Attack: 100
Defense: 100
Attack Member
Karma: +0/-0
Referrals: 0
speedo's wrong now!!
«
Reply #12 on:
December 02, 2004, 23:13:38 »
or even better, use my website
http://www.m-v.demon.co.uk/tsc.htm
you can enter up to 4 tyre sizes and the 5 speeds andit will give stock and proposed tyre sizes.
My disco came with 205/16s on and I put on a set of grizzly 235/75/16 and it's about right a couple of mph under at the key speeds so no speed camera flashes. I'm planning on goign to 235/85/16s, which will put it 4.3 mph over stock at 70.
A trick we used to do when chaning tyres on things like minis and imported bikes and cars was to put a sticker at the new 70/50/30 mph zones. The other thing we used to do was to use a bicycle computer with a magnet on a drive shaft to count the axle revs and work out the speed from that.
As most others have said though you need to know how accurate yuor speedo is to start with. See if you can borrow a GPS and measure your speed over as straight and flat a road as possible and keep your speeds constant (gps takes a second or two to regester speed changes normally).
Matthew
Logged
Print
Pages: [
1
]
Go Up
Mud-club
»
Vehicle & Technical
»
Discovery
»
speedo's wrong now!!
SimplePortal 2.3.5 © 2008-2012, SimplePortal