Rob_Mitchell Posted July 23, 2009 Share Posted July 23, 2009 hello i was just wondering if anyone has come across this problem in the past.. my speedo is reading approx 10mph fast and have to keep checking my speed using sat nav which is not ideal.. please help:( Quote Link to comment Share on other sites More sharing options...
benkei Posted July 23, 2009 Share Posted July 23, 2009 Have you changed the dials on the clocks or have the needles been off at any point? The clcoks are precisely set at the factory, and taking them off completely throws the readng out the window. I had this with my MR2, took about an hour of trial and error to get it right again! Quote Link to comment Share on other sites More sharing options...
Guest rustybolt Posted July 23, 2009 Share Posted July 23, 2009 i have the same problem i have not tampered with mine Quote Link to comment Share on other sites More sharing options...
SteveC Posted July 23, 2009 Share Posted July 23, 2009 If you're doing around 30mph and it's indicating 40mph, then there's something wrong. However, I know when my speedo is showing 100mph, really the cars doing 93-94mph (on satnav). All speedos are slightly out and always - well, should always - read fast. Quote Link to comment Share on other sites More sharing options...
Guigsy Posted July 23, 2009 Share Posted July 23, 2009 it will also depend on the combination of wheels and tyre sizes. For instance my tyres are a smaller profile compared to what i should have to make the roling size correct. So at about 70 or so it off by about 7-8 mph, and about 100 its about 10mph out. Quote Link to comment Share on other sites More sharing options...
benkei Posted July 23, 2009 Share Posted July 23, 2009 it will also depend on the combination of wheels and tyre sizes. For instance my tyres are a smaller profile compared to what i should have to make the roling size correct. So at about 70 or so it off by about 7-8 mph, and about 100 its about 10mph out. I thought the speedo came from the gearbox? I'd imagine there'd have to be some odd combination of wheel and tyre sized to make a 10mph difference at 30! How long has this problem been going on mitchell? Quote Link to comment Share on other sites More sharing options...
merckx Posted July 23, 2009 Share Posted July 23, 2009 Use the sat nav to calibrate the speedo by pulling off the needle and repositioning it. Quote Link to comment Share on other sites More sharing options...
Guigsy Posted July 23, 2009 Share Posted July 23, 2009 I thought the speedo came from the gearbox? I'd imagine there'd have to be some odd combination of wheel and tyre sized to make a 10mph difference at 30! How long has this problem been going on mitchell? Yeah but if your wheels are smaller. your going to need more turning to go at the same speed as someone with bigger wheels... hence the speedo being off... I think. Quote Link to comment Share on other sites More sharing options...
Scott Posted July 23, 2009 Share Posted July 23, 2009 Use the sat nav to calibrate the speedo by pulling off the needle and repositioning it. Yourself, @ at least 100mph, along to benny hill music. Remember to record it all Quote Link to comment Share on other sites More sharing options...
Scott Posted July 23, 2009 Share Posted July 23, 2009 Yeah but if your wheels are smaller. your going to need more turning to go at the same speed as someone with bigger wheels... hence the speedo being off... I think. Correctamundo. Change the rolling radius, change the distance travelled per rotation of the wheel, drive-shaft, prop-shaft, flywheel etc, etc, etc I bought wheels for my MR2, they came off a supra. Tyres were good so left them on. Made my speedo read accurate.... not a good thing. Quote Link to comment Share on other sites More sharing options...
benkei Posted July 23, 2009 Share Posted July 23, 2009 Yourself, @ at least 100mph, along to benny hill music. Remember to record it all You have to take the needle off, put it to around -10mph and go for a drive, see where it is then. Then just keep making adjustments until it is accurate again. Very repeatative and annoying! Quote Link to comment Share on other sites More sharing options...
Scott Posted July 23, 2009 Share Posted July 23, 2009 You have to take the needle off, put it to around -10mph and go for a drive, see where it is then. Then just keep making adjustments until it is accurate again. Very repeatative and annoying! You ruined it How do you do that though? Surely when you are at a stop the needle is at a stop? Quote Link to comment Share on other sites More sharing options...
benkei Posted July 23, 2009 Share Posted July 23, 2009 How do you do that though? Surely when you are at a stop the needle is at a stop? You have to turn the ignition off to de-energise the clocks. You can't do it with the engine on! Quote Link to comment Share on other sites More sharing options...
Scott Posted July 23, 2009 Share Posted July 23, 2009 You have to turn the ignition off to de-energise the clocks. You can't do it with the engine on! Yip.... so...... The speedo is reading 40mph when you are only doing 28mph. You want to lower the needle by approx 10mph. You turn the engine off and the clocks re-set to zero... how do you set the needle back 10mph with the stop in the way? Quote Link to comment Share on other sites More sharing options...
benkei Posted July 23, 2009 Share Posted July 23, 2009 Yip.... so...... The speedo is reading 40mph when you are only doing 28mph. You want to lower the needle by approx 10mph. You turn the engine off and the clocks re-set to zero... how do you set the needle back 10mph with the stop in the way? You lift it over the stop... Quote Link to comment Share on other sites More sharing options...
Scott Posted July 23, 2009 Share Posted July 23, 2009 You lift it over the stop... Does it not spring back then? Quote Link to comment Share on other sites More sharing options...
benkei Posted July 23, 2009 Share Posted July 23, 2009 Sorry, let me explain a little better... You take the needle off the clock, put it back on at around the 6 o'clock possition, then wind it clockwise up to and over the resting pin. This should put some tension back in the spring which controls the needle, so 30mph will put enough force on the needle to push it round to the 30mph mark. Note: Taking the needle off will result in ALL the pressure being taken off the spring, so you will have to wind it back further than I previously stated. I just got really quick at moving the needle after an hour of tuning it so I could make small adjustments a little better. Quote Link to comment Share on other sites More sharing options...
benkei Posted July 23, 2009 Share Posted July 23, 2009 Yeah but if your wheels are smaller. your going to need more turning to go at the same speed as someone with bigger wheels... hence the speedo being off... I think. I've always been confused by this. On bigger wheels the tyres are a lower profile, so wont they be around the same size as a smaller wheel with a higher profile tyre on? Quote Link to comment Share on other sites More sharing options...
Scott Posted July 23, 2009 Share Posted July 23, 2009 I've always been confused by this. On bigger wheels the tyres are a lower profile, so wont they be around the same size as a smaller wheel with a higher profile tyre on? Thanks for the speedo info, sounds like a pain If the sizes are correct then the rolling rad shouldn't be changed. Happens a lot though, buying a set of wheels with the wrong tyres on. As i said, happened with me Quote Link to comment Share on other sites More sharing options...
benkei Posted July 23, 2009 Share Posted July 23, 2009 Thanks for the speedo info, sounds like a pain You have no idea lol Quote Link to comment Share on other sites More sharing options...
Rob_Mitchell Posted July 23, 2009 Author Share Posted July 23, 2009 its strange aint it, i was not sure if it can be easily re-set by a company out there?? i guess no speeding tickets for me Quote Link to comment Share on other sites More sharing options...
benkei Posted July 23, 2009 Share Posted July 23, 2009 You'll struggle to find anyone who will do it, mainly because it's a pain and no one want's to do it. Just do it yourself, it's not hard, just annoying. Quote Link to comment Share on other sites More sharing options...
Guest bennyessex Posted August 3, 2009 Share Posted August 3, 2009 When I owned that car I used to think 30mph felt very slow! I guess thats why.... Hvae you found a solution yet? Could be to do with the converter as its an import? Quote Link to comment Share on other sites More sharing options...
supspower Posted August 3, 2009 Share Posted August 3, 2009 After so many months driving with incorrect readings since changing my dials i finally know how to fix it! Thanks to this thread!! Quote Link to comment Share on other sites More sharing options...
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