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MG MGB GT V8 Factory Originals Technical - Speedo calibration

Had the speedo recalibrated some time ago, had new tires fitted but the tire guys re-shod the wheels with a larger profile tire (their mistake) but they made me an offer I could not refuse. The result is that the mileage reads exactly 10% lower than it should be, ie. instead of I mile it reads .9. This does not concern me that much.The gearing has changed a fraction but on long interstate drives it appears to be good as it helps regards fuel consumption and I still have the power in the lower gears. This is where I hope someone can help me, does this mean that the speedo reading is also 10% lower than it should be.
Mike Cook

Yes, subject to whatever error was present in original form. Usually the speedo over reads as standard so overgearing the car reduces this error and you may even find that the speedo is accurate. The same situation usually also applies to the mileage readings.

Roger Parker

Rog... i'm thinking ahead to when i will put together my going to use mgb od transmission & want to also use an early jaguar 4" 140mph you know of anyone who can convert the jag speedo to work w/mg od trans?...wheel/tire won't be a factor as i am going 15" plus one & keeping the original 14" rostyle tire/wheel diameter
Anthony Barnhill

Rog...since my last post, i dropped by my local foreign car salvage yard a few moments ago...scarffed up a jaguar 160mph speedo w/7,000rpm tach & 80psi oil pressure guage out of a '74 XJ12...can you point me to someone who can calibrate them to my 3.9 rover w/mgb od trans....tony
Anthony Barnhill

There are a couple of suggestions re companies within the UK, I.R.S. in Nottingham and Speedy Cables in London. There are many other avenues with respect to speedo and tacho changes. For example I am having a tach recal to 8cyl and speedo changed from 120 to 140mph along with face colour chanes to magnolia amongst other things via my good friend Jon Miller who is a smaller specialist mg spares supplier. Just illustrates that here there are quite a number of options. Can't speak for your side of the water though. If you want some more detail on individual companies then e-mail me dirtect as I don't always have time to come up and read all the BBS's as you now know.

Roger Parker

This thread was discussed between 12/06/2000 and 20/06/2000

MG MGB GT V8 Factory Originals Technical index

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