inaccurate trip meter

[dlb]

My current Tercel is a Frankenstein of transmission-to-the-cluster parts. The diff is from an '87, the trans is from an '83 (which shouldn't make a difference but is still worth noting since the speedo gear is in there), the speedo cable is from an '83, and the cluster is from an '83. I have seen others report that you can swap the 83/84 clusters with the later ones and the speedometer is accurate, and that seems to be true but I have found my trip meter is off quite a bit.

When running 185/65r14 tires which are 3% larger than stock, the trip meter reads 5% too high.

When running 185/70r14 tires which are 6% larger than stock, the trip meter reads 2% too high.

So if I were running the stock tire size, the trip meter would be reading 8% too high, which is about the difference between the 3.7 and 4.1 gear ratios. Between the speedo gear in the transmission, the speedo cable, and the cluster, I'm not sure which are causing the inaccurate reading. I don't actually care about it too much, I just correct it when I log my mileage, but if I come across a later cluster I will swap it in and see if that fixes it.

[Mattel]

David, your car sounds like the one in a Jonny Cash song