Bronco Engine RPM Calculator (for specific tire sizes & axle ratios)

[PG_Bronco]

Well Ford used a target of 2950 rpm (+/- 50). I know that because if you look at gear vs tire size, you end up with most of the vehicles running very close to that based on the tire size of a given trim and the gears installed. This also coincidentally puts the engine right on the beginning of the torque peak.

Non-sasquatch Badlands is the right answer.

Thank you! I still have the OBX, maybe I’ll powder-coat them and interchange them.

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[mpeugeot]

Thank you! I still have the OBX, maybe I’ll powder-coat them and interchange them.

They look really sharp once powder coated with proper tires. If I remember correctly, there are a handful of 285/70-75/18's that would be a good fit (34" tall). There is an all terrain in that size that's 58 lbs.

 

[PG_Bronco]

They look really sharp once powder coated with proper tires. If I remember correctly, there are a handful of 285/70-75/18's that would be a good fit (34" tall). There is an all terrain in that size that's 58 lbs.

Awesome, thanks for all the advice. I just took it out in the blizzard we have in Michigan and the KO2’s did great. I’m very torn on what to do!

 

[Texasgrillchef]

So... I starting looking at tires I could put on my Bronco when it eventually (hopefully) gets here next year. I'm still debating between the Black Diamond and Badlands, which have different axle ratios. I was doing some math to figure out what the engine RPM would be at specific tire sizes & axle ratios....

...and then I got carried away and created this:

I've included all of the standard Bronco axle ratios, the transfer case ratios, transmissions, and available tire size.

Available for download off of Google Docs:

Excel | OpenDoc

I couldn't find any detailed dyno results for the Bronco, so I didn't pre-program the RPM details. But If I did have the dyno details, the color code would be this:

• Red - Undesired RPM. Typically either above red line or so low that the engine is likely to stall.
• Blue - Geared towards fuel economy
• Yellow - Geared towards power
• Green - The "sweet spot" between power and fuel economy

The plus side of my inability to find dyno details is now you can specify the RPMs details however you see fit. Which allows you, in effect, to create your own axle ratio chart.

If anyone notices any errors (mathematical or otherwise), please let me know.

for so,e reason when I click on the link all I get is the 7 speed manual version I have the 10 speed automatic

 

[RagnarKon]

for so,e reason when I click on the link all I get is the 7 speed manual version I have the 10 speed automatic

Many of the boxes are drop-down boxes that allow you to make the necessary selections.

 

[Texasgrillchef]

Many of the boxes are drop-down boxes that allow you to make the necessary selections.

Thanks I figured it out, it was an issue with my excel app on my iPad! lol go figure!

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