70mph in 2nd gear

1. Byard Regular Poster Joined: Jan 2009 Chesterfield Posts: 263 BMW 330d, Arctic Steel Silver TU5JP4, 1.8 Focus

   #1 25th May 2010, 17:08

   Got 17"s on at the moment but wouldn't have thought it would have put the speedo out that much ... its more like 72-73 on the speedo, rev limiter is standard also
2. user_10473 Saxperience Forum Bum Joined: Jun 2006 Swansea Posts: 4946 Bianca White Peugeot 106 S2 Rallye, Saxo VTS

   #2 25th May 2010, 17:10

   http://www.alloywheels.com/tyrecalc.asp
   
   Try it yourself.
3. raunchz Saxperience Addict Joined: Jul 2005 Solihull / Bournemouth Posts: 14233 2015 Lapiz Blue Golf R

   #3 25th May 2010, 17:10

   and what gearbox are you using ?
4. saxtreme Established Member Joined: Jan 2010 Posts: 1660 yamaha tzr50/dt125 cars: 1.0i spree

   #4 25th May 2010, 17:15

   wow mine said i would be doing 77.8 wen speedo says 70
   
   standard's 155/55/13
   alloys 195/45/15
   
   wat big difference.. will have to watch speed cameras
5. Mochachino Saxperience Hardcore! Joined: Nov 2007 Guantanamo Bay Posts: 28700 oyster card

   #5 25th May 2010, 17:17

   Quote:

   Originally Posted by saxtreme wow mine said i would be doing 77.8 wen speedo says 70 standard's 155/55/13 alloys 195/45/15 wat big difference.. will have to watch speed cameras

   theres literally like 1 or 2mm different between them tyre size, wont make that much difference to the speedo.
   
   17s would though.
6. user_10473 Saxperience Forum Bum Joined: Jun 2006 Swansea Posts: 4946 Bianca White Peugeot 106 S2 Rallye, Saxo VTS

   #6 25th May 2010, 17:20

   Quote:

   Originally Posted by db_sax theres literally like 1 or 2mm different between them tyre size, wont make that much difference to the speedo. 17s would though.

   There's quite a difference between the sizes he's posted.
   
   But I find it hard to believe his first set were 155/55/13's ???
7. Toms112 Established Member Joined: Dec 2008 Wisbech/Peterborough Posts: 2218 2008 Ford Fiesta ST150

   #7 25th May 2010, 17:21

   I don't like that calc tbh. Most results I got just didn't make sense.
   
   I suppose the calc works if your speedo reads 70 when your actually doing 70 which most don't.
8. Mochachino Saxperience Hardcore! Joined: Nov 2007 Guantanamo Bay Posts: 28700 oyster card

   #8 25th May 2010, 17:23

   Quote:

   Originally Posted by Mr_P There's quite a difference between the sizes he's posted. But I find it hard to believe his first set were 155/55/13's ???

   Sorry didnt read the 13, i expected 14" vtr wheels. If it was 14" then my post is correcto...13" then incorrecto..
9. williamsvts Saxperience Post Whore Joined: Feb 2006 northumberland Posts: 7693 pulsar gtir, mk4 astra sxi

   #9 26th May 2010, 09:14

   speed sensor is taken from gearbox, so wheels size wont affect the speedo - rpm readings, just actual speed.
10. Gareth_R Established Member Joined: Mar 2010 Basildon, Essex Posts: 1042 Citroen AX VTS

    #10 26th May 2010, 11:19

    when doing any changes to wheels, speedo etc its worth going out with a sat nav that measures speed and do some runs at various speeds like 30, 50 and 70 and check how far out the speedo is.
    
    E.g. i went from 55 profile 14's to 45 profile 14's and it made quite a difference, speedo went from being pretty much right to about 10% out!
11. chinkostu Saxperience Post Whore Joined: Aug 2008 The wrong carpark Posts: 5152 Xantia 1.9TD

    #11 26th May 2010, 12:25

    Quote:

    Originally Posted by saxtreme wow mine said i would be doing 77.8 wen speedo says 70 standard's 155/55/13 alloys 195/45/15 wat big difference.. will have to watch speed cameras

    never noticed that much of a difference on my 1.1, went through thousands of speed camera's
12. Furioman Frequent Poster Joined: Jan 2004 Denny United Kingdom (Scotland) Posts: 666 Ford focus 2.0 Saxo VTS

    #12 26th May 2010, 17:41

    with 195/45/15 my car over reads by quite alot 26mph when dials say 30mph
13. jon748 Infrequent Poster Joined: May 2010 Posts: 116

    #13 26th May 2010, 19:29

    see what speed your doing wi sat nav etc