Thread: High ratio transfer Box?

Gearbox and transfer case gear ratios do not change the speedometer readings.

Aaron.

Originally Posted by Wallydog

Hi all. Anyone got a high ratio transfer box on their S3 SWB? i think one is fitted to mine but not sure. Does it affect the speedo reading ie, if your doing 80kms per hr, will the speedo read less? W.

Check the number in small font on the face of the speedo. You may have larger diameter tyres fitted than the speedo ratio thinks you have.

tyres are 235/85/R16 on std rims , kinda big! Are those tyres over the top in size? W.

Originally Posted by Wallydog

tyres are 235/85/R16 on std rims , kinda big! Are those tyres over the top in size? W.

235/85-16 are the same diameter as 7.50x16 (32") - ONE of the optional tyre diameters for SWBs.

If yours was originally specced with smaller tyres (e.g. 6.50x16s), then that is your problem.

What is the number on the speedo? - that will tell you what tyres the vehicle was specced with (the number may be on the back on later models).

1408 is the number for 32" tyres.

The speedo drive is on the final output just in front of the handbrake drum so changing the ratio of the transfer box (or even changing to low range) makes no difference, as has been mentioned.

While 7.50 tyres were optional equipment for the short wheelbase, they were fitted with 5.5" wide rims instead of the OEM 5" wide 231601 short wheelbase rims.

Fitting larger diameter tyres (7.50 16) will change the speedo ratio so you need to fit a speedo from a 109" in place of the original one.

235/85/R16 tyres while the equivalent diameter of the 7.50 16, have a wider profile and should be fitted on 6" wide (or wider) rims, not the 5" OEM rims.

Diana