Speedometer correction?

[Fairtax4me]

Got me some big ol' stock 97 outback size tires (205 70 15) to throw on the Legacy. Now since these are substantially larger than my 185 70 14s, it's gonna throw my speedo off by a couple few MPHs. (not that kinda speedo)

Any easy way to correct that? Swap in an Outback speedo? Or would it have to be a gear swap?

I tried searching but the answer eludes me... as usual.

[nipper]

usually there is a black box that is used to correct it, but usually it is just easier to get a GPS, check the 30, 45, 55, 65, 75 numbers and just put it in your memory. It will be even all across the board, but just nice to make sure.

[Fairtax4me]

I've been meaning to check it against a GPS anyway. It's accurate at 25. The radar boxes they put in random places around here always say 23, which I know is 25, they just want you to go that extra 2mph. It's how they get you.

I'll do that first and see how it changes with the new tires.

 

What's this black box thing though? After market?

[Yo'J]

Tire size difference is the same across the board 'percentage wise'. I.e. the percent of difference. I think its good to be able to do the math in your head as an exercise.

 

This works. www.miata.net/garage/tirecalc.html

[Fairtax4me]

Tire size difference is the same across the board 'percentage wise'. I.e. the percent of difference. I think its good to be able to do the math in your head as an exercise.

 

This works. www.miata.net/garage/tirecalc.html

 

I've had that site bookmarked for years.

 

I can and already do with my truck (riding on 31"s), but I drive the truck once a week. I drive the soob every day!

[Yo'J]

I drive my lifted soob every day, I guess I don't mind. No one else drives the soob though as the unknown could be a ticket in the waiting. "but Officer the speedo said 60!" (*14%)

[idosubaru]

i've seen aftermarket converters, just little boxes. speedo cable plugs into it and then you get another cable from the box to the car. no way to "convert it" with other parts from other subaru's unfortunately. the one's i've seen are rather expensive - well relatively speaking, not really all that expensive. like $200-$300 comes to mind.

[987687]

I don't even have a working speedometer. Just have a few tach>gear>speed ratios in my mind. Been driving it like that for months past may cops and never had an issue.

[nipper]

http://www.bluegauges.com/prod_yellow_box.htm

 

http://www.speedometermaster.com/

 

http://www.fmdkinc.com/wiz.htm

[Fairtax4me]

Thanks for the links Nipper.

The yellow box thing looks like what I'm looking for. Just a simple converter, and cheap too.

[987687]

What year is the legacy? early ones had a cable speedo so that wouldn't work.

[T'subaru]

Seeing this will be an issue when im done modding my wagon I did some checking around, and also looked for the adapter boxes. I havnt checked cost out yet but if it saves me a speeding ticket or two and having to do math in my head while I drive..its gotta be worth it

http://www.tacomaspeedometer.com/index/index.php?option=com_frontpage&Itemid=32

 

Id think there would be similar companies in most major cities.

[Fairtax4me]

What year is the legacy? early ones had a cable speedo so that wouldn't work.

 

96. Pretty sure it's electric. I don't recall unhooking any cables except the clutch and hill brake when I had the trans out, but that was in Jan.

[nipper]

96. Pretty sure it's electric. I don't recall unhooking any cables except the clutch and hill brake when I had the trans out, but that was in Jan.

 

 

1995 was the transition year, so yours is electric.

[987687]

Yep 96 is electric.

[Fairtax4me]

Yeah, I thought so. Think I'll send an email to bluegauges.com and see what they say about using the yellow box on a Subaru. I guess it should work, right?