Where is a good place to get speedometer gears???? I changed my rear to a 3.07 so now when im cruisen at 70 the vette says im going 85! If anybody knows of a good website to buy that would be great... or if somebody on the CF has some they wanna get rid of!!! Thanks!

 

Here is a calculator to help determine which gears you need.

http://webpages.charter.net/khasting...peedocalc.html

Most of the gears are still available from the dealer at low cost, but here is an online alternative if you insist, prices are higher.

http://www.transmissioncenter.net/sp...n_______va.htm

 

These guys have it all

http://www.transmissioncenter.org/GM...eter_Gears.htm

 

No one "has it all" any longer! I've done probably 150 plus calibrations and I've struggled a bit recently for some gears.

Technology makes the calibration substantially easier than it used to be. Some GPS units do MPH in tenths and it's quite easy to get a percentage adjustment that's required. Stay away from some of the Internet programs that offer a "quick answer"! Some only are calculated using tire diameter in the formula and it's actually "rolling radius" that's required for a quality calibration.

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OP,

Your profile indicates an '86 MY. If that's correct, your tire sizes are factory there's only two possibilities one requires a 40 tooth driven, the other a 42 tooth driven. The drive gear (internal) remains the same BUT the 40 and 42 require a different VSS than your present. That's a tough find these days! There's people that mention rotating it 180* will accomplish the correct indexing of the driven gear. Will it work? Don't know, I've always done it using correct parts.

The calculator in the post a couple up works I believe if you're using factory ratios, tire/wheel combinations but several years ago I recall there were "errors" if you wavered at all from factory. I haven't looked at it in several years, maybe there's been revisions. Don't know. I find it easier to start from knowns and adjust for errors.

Post up your tire/wheel combination and the ratio that you replaced. If you've got a GPS post speedometer display at let's say at these GPS indicators 40MPH - 50MPH - 60MPH. There should be a consistent percentage difference. If it's not consistent you've got other problems also.

 

After changing out the little plastic gear more times that I care to remember, I got the little black box that you throw some dip switches and it corrects it. About 1000000 times quicker to install that black box than pull the c-beam out!

 

I have one made by Abbott. Works great!!!

 

If you call PATC Raptor transmissions @ 1-888-877-1008 talk to Kerry he will tell you what you need and he will have the parts. Hope this helps.I just changed my gears to 373 in my 93 vette and got every part from kerry great people to deal with.