Speedometer gear headache

[ratdude747]

I changed tires this weekend, and as a result of them being a tad small (215/65R15 vs the old 215/70R15), my speedo/odo is also off.

Despite being a 1995, I found that my VSS has a cable-style gear on it:

(that's ATF, not blood).

Despite being green, it's actually 16 teeth.

However, when I run the numbers, I need a 16.48 tooth gear. That rounds back to 16... but it's right on the line. According to tire size ratios and some empiriacal data, I'm reading 3.3% too fast.

I'm not in the budget for a speedo healer ($220, no thanks). Is 3.3% close enough to be OK? Or do I need different tires. The latter isn't so good, as I bought nice tires; they're Continental Control Contact Tour AS's (I know, car tire, but I don't offroad and they ride really well).

What to do?

 

[Spott]

If that's the nearest solution, then it must be "good enough". You'll have to determine for yourself if you can live with that.

The only other alternative I can think of is to see if there are other options for speedo drive gears, such that a different drive/driven gear combination might get you closer. For example, in my '88 I could use a 6-tooth ivory-colored or 7-tooth burgundy-colored drive gear, in combination with any of the common driven gears.

 

[ratdude747]

If that's the nearest solution, then it must be "good enough". You'll have to determine for yourself if you can live with that.

The only other alternative I can think of is to see if there are other options for speedo drive gears, such that a different drive/driven gear combination might get you closer. For example, in my '88 I could use a 6-tooth ivory-colored or 7-tooth burgundy-colored drive gear, in combination with any of the common driven gears.

Ah the spiral gears. I'm sure for the 4r44e there is but I worry such a change would make all the speedo gears gears out of range. I'll look into it.