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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - speedometer for 3.9 gears

Those little right angle speedometer gearboxes, I believe made by Smiths, come in differnt ratios. If one had a 0.9:1 your MGA speedometer would not need to be recalibrated after a 4.3 to 3,9 differitial gear change. Anyone know what ratios are available, or how to find a source? Thanks for any replys, Bill.
w.g cook

Don't know about the right-angle gearboxes, but an early MGB speedo should do the trick. Early ones are marked Jaeger, too. Don't forget to factor in the change from 14" to 15" wheels, too.

Derek Nicholson

I thought they all were 1:1, maybe not. Per Clausager's book, page 51, when MGA's had different axle ratios, they changed the actual speedos. The 3.9:1 was offered as an option and would use Smiths SN.6104/15 or SN.6161/15. Finding one of those may be tough but it's one solution. I put a 3.9 in too but haven't crossed that bridge yet.
Scott

Nisonger in NY can recalibrate your speedometer.
These folks sell the variable ratio adaptors.
http://www.gaugeguys.com/ratioadapt.htm
Doug
D Sjostrom

Some reference information for ratio changing:
http://mgaguru.com/mgtech/dash/st203.htm

Barney
Barney Gaylord

This thread was discussed between 20/05/2005 and 21/05/2005

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.