Easiest Way to Determine Rear End Gear Ratio on a Limited Slip Differential

On this episode of Budget Build Garage we show you how to easily find the gear ratio on any rear end that has a posi unit without taking anything apart! It important to understand the rear end gear ratio formula before making any decisions on rear end swaps. A quick easy way to determine axle ratio is by using the "masking tape method". The method we show in this video is specific to rear ends with limited slip. For those looking to calculate your rear gear ratio on an open differential stay tuned for our next video where Budget Build Garage walks you through that process.

Thanks as always for watching and subscribing, and we'll see you in the next one.

[hmayerv]

Nice simple and effective video. I did that to my customer's 68 Impala 396ci. Both wheels were turning same direction. So I'm guessing it's a LSD with 12 Bolts. I can't say for sure the exact no. but the no.of driveshaft turns appeared to be 4. So my guess is it could be a 4.11.
Exact calculation will be when I remove the diff cover to replace the old oil and gasket. Thanks mate.

[djhightopfade]

Saw your plate number. First thing I thought of was Street Fighter.
Another informative vid. Very cool.

[bimmerman]

Wow I don't even have to run the car and breath the nasty exhaust, excellent!!!

[jgmopar]

I had to do that with my 1971 Dodge Charger. I had no idea what gear was in it but it was horrible on the highway. Stock was 3.55 after doing this i realized the person I bought the car from changed to 4.11. fun on the street terrible on the highway.

[BudgetBuildGarage]

Thanks everyone for watching, we really appreciate it. What's your favorite method to find rear end gear ratios? Also, give our video editor Taylor a shout out for the awesome intro on this video!!!

[greggbarry]

This car Is bad ass. You should do move videos on it.

[BarryGaghan]

Is the lsd method the same for a fixed live axle ?

[carlosr]

Does the same apply if the pumpkin is off the vehicle?

[arrages]

I was just talking to someone the other day about finding out how to tell what gears I have and what would be the best for my application. DUDE, please post one for the open diff. I know I have a one wheel peeler at the moment but I want to upgrade my rear end.

I am hung up on going for a 12 bolt rear or just go ford 9. If you go ford 9 I hope to see an indepth video on how to install and challenges involved

[bjnopoli]

Supposedly my alfa romeo has a lsd, but when I spin one side the other side goes opposite direction, is it possible it still is a lsd. 1979 alfa romeo spider. Bet you don't answer.

[dontbescaredofit]

hey mate did you jack up both wheels so that both were free to spin?

[elainestamper]

Good info! Stay away from potty mouth if you want to sound professional!

[thomaswinders]

Why does only one of my wheels spin when they are both free and jacked up