BARRACUDA1968
Well-Known Member
- Joined
- May 4, 2011
Anyone have a link to where I can get a speedo gear for 28" tall tire?
http://www.tciauto.com/tc/speedometer-gear-calculator
Believe you can get the correct gear from GM, easy 10 minute job to change out. Can't remember what color gear I used, been a while. You would be changing the driven gear only.
Once the speedo cable is disconnected at the transmission, there is a retainer bolt that needs to be removed--then the driven gear assembly basically pulls out. Have a pan handy, trans fluid will most likely come out depending on how you lift the car up to get under it....How did you change the driven gear? Does it just pull out of trans once I remove the speedo cable ?
Once the speedo cable is disconnected at the transmission, there is a retainer bolt that needs to be removed--then the driven gear assembly basically pulls out. Have a pan handy, trans fluid will most likely come out depending on how you lift the car up to get under it....
Seems to me the black gear is correct for the 28" tire.
OK, how much will I be off from stock tire height?
My car came with a gnx dash with a VDO speedometer. When the speedometer reads around 90 mph, I'm actually going around 70. I looked at the calculator but I would need to know the number of revolutions per mile. Can anyone help me? Thanks.
This is why I suggested measuring the exact height with the tires installed in the car.Revolutions per mile will be a little different for each tire brand and series. Close, but not exactly the same. This is because the tires are constructed a little differently, and flex a little differently at speed (or even at different speeds, in different conditions).
So you get in the ballbark with gearing. But it's probably a waste of time calibrating your speedometer, if doing so is difficult, unless you plan on buying exactly the same tire every time forever.