Speedo over reading.
Discussion
Hi Christian.
Not sure if the settings on my car will be the same for yours, but have a quick read of this thread I started last year.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Mine is an R400D, but has 13" wheels and CR500's.
If not, then Caerbont or Caterham will give you their recommended settings.
Cheers. Jon
Not sure if the settings on my car will be the same for yours, but have a quick read of this thread I started last year.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Mine is an R400D, but has 13" wheels and CR500's.
If not, then Caerbont or Caterham will give you their recommended settings.
Cheers. Jon
Edited by JONSCZ on Sunday 10th August 20:40
Adjusted mine this year when I moved from 15" to 13x6" all round, I was sent these instructions from Caterham:
"See attached ‘speedo input codes’. To get the unit into calibration mode, hold the central speedo button and turn the ignition to the on position which should give you a flashing cursor. Push it until the first desired number is displayed, wait a second, and it should move across to the next window. Proceed until the full code is entered."
It's easy to do, though mine still over-reads a bit using the settings above. Still, I'd rather it over-read than under-read!
"See attached ‘speedo input codes’. To get the unit into calibration mode, hold the central speedo button and turn the ignition to the on position which should give you a flashing cursor. Push it until the first desired number is displayed, wait a second, and it should move across to the next window. Proceed until the full code is entered."
It's easy to do, though mine still over-reads a bit using the settings above. Still, I'd rather it over-read than under-read!
Chrisp5782,
What year is your car?
Have you had your speedo out and looked at what you have in the way of dip switches.
Later cars have multiple switches and are very adjustable.
Unfortunately, earlier cars have just four dip switches, but these simply set a "high" or a "low" setting.
On my 2002 car, when I swapped from the original 14" with 185/60 - 14 tyres (where the speedo reading was reasonably accurate) to 13" wheels with 185/60-13 tyres, I had to swap the speedo drive gear in the gearbox to get the speedo reading close.
Additionally, earlier cars with an electronic speedo used a sender actually attached to the gearbox (as my 2002 car does), but later cars (I think most metric, so generally post 2006) use a sensor that picks up on a toothed ring on the RHS drive shaft at the wheel end.
What year is your car?
Have you had your speedo out and looked at what you have in the way of dip switches.
Later cars have multiple switches and are very adjustable.
Unfortunately, earlier cars have just four dip switches, but these simply set a "high" or a "low" setting.
On my 2002 car, when I swapped from the original 14" with 185/60 - 14 tyres (where the speedo reading was reasonably accurate) to 13" wheels with 185/60-13 tyres, I had to swap the speedo drive gear in the gearbox to get the speedo reading close.
Additionally, earlier cars with an electronic speedo used a sender actually attached to the gearbox (as my 2002 car does), but later cars (I think most metric, so generally post 2006) use a sensor that picks up on a toothed ring on the RHS drive shaft at the wheel end.
Mines a 2004 car with the button on the face of the speedo, I believe that's where I access the calibration mode.
I've got 205/55/R13 on the rear of the car and the table above gives an input value for that spec so I'll give it a bash.
I'm happy with a little over read but currently you'd think I was in an F1 car if you were to believe the speedo!
I've got 205/55/R13 on the rear of the car and the table above gives an input value for that spec so I'll give it a bash.
I'm happy with a little over read but currently you'd think I was in an F1 car if you were to believe the speedo!
Edited by Chrisp5782 on Monday 11th August 17:21
On my 2002 car I also have the button on the face of the speedo, but pressing the button simply swaps from odometer to the trip function. Press and hold resets the trip.
You'll need to remove the speedo, and see what there is under the removable rubber cap on the back of the speedo case.
I think it's unlikely that a 2004 car will have a programmable speedo, it's much more likely to be set by DIP switches.
You'll need to remove the speedo, and see what there is under the removable rubber cap on the back of the speedo case.
I think it's unlikely that a 2004 car will have a programmable speedo, it's much more likely to be set by DIP switches.
Red Seven said:
On my 2002 car I also have the button on the face of the speedo, but pressing the button simply swaps from odometer to the trip function. Press and hold resets the trip.
You'll need to remove the speedo, and see what there is under the removable rubber cap on the back of the speedo case.
I think it's unlikely that a 2004 car will have a programmable speedo, it's much more likely to be set by DIP switches.
I suspect you're correct and my cursory check of the back (speedo loosened and head in the footwell) was insufficient. I don't remember seeing a rubber cover - I'll check again. You'll need to remove the speedo, and see what there is under the removable rubber cap on the back of the speedo case.
I think it's unlikely that a 2004 car will have a programmable speedo, it's much more likely to be set by DIP switches.
Thank you.
Chrisp5782 said:
Okay!!! Speedo out - four DIP switches on the back, now the million dollar question - what do I set them to!?!?
See the post from _Tim_ here http://www.blatchat.com/T.asp?id=76795As I said earlier, there are just two settings, a high setting and a low setting.
I ended up swapping the speedo drive gear to get mine close enough (over ten years ago now)
Red Seven said:
See the post from _Tim_ here http://www.blatchat.com/T.asp?id=76795
As I said earlier, there are just two settings, a high setting and a low setting.
I ended up swapping the speedo drive gear to get mine close enough (over ten years ago now)
Mine was set to the higher range (more revolutions per mile?) but.....I noticed that one of the switches (switch one) wasn't completely switched home. Hopefully this was the cause of the over read?As I said earlier, there are just two settings, a high setting and a low setting.
I ended up swapping the speedo drive gear to get mine close enough (over ten years ago now)
I can't check against the GPS until the morning but I'll report back my findings.
Thanks very much to everyone who's offered advice and assistance.
Just to add a different experience. I recently bought a 2005 K-series R300. Analogue Caerbont speedo. 195/45-15 CR500. Speedo was massively UNDER reading – indicated 40mph was about 65 actual. I used above info to go into calibration mode (button press during ignition-on etc) and found the setting was 115114. I reset it to 039751 from table above, test drove but it had stopped indicating at all. I set it back to 115114 and it still didnt work - zilch. Scratching head I tried 000000 and test drove - nothing. I then keyed on with the button held down again but this time the digits automatically started resetting themselves to 002500. I test drove again and was back in business with a moving dial, but this time with a real 40mph indicating about 160mph! I then tried 008000 – resulting in about 25% over read and iterated up and down settling at 008800 and bingo – actual 40 reads 41mph. I have no idea why this is the right number but hope it helps someone especially the 000000 re-boot.
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