Bigger tires and gear ratios - decreased towing capacity / possible future issues?

[Big Kahuna]

Just wondering what are peoples thoughts on transmission wear, drivertrain issues on adding bigger tires to the Maverick?

I was looking at 245's and 255's but then started thinking that I have a 4K and my gear ratio is 3.81.

Going to a 245 or 255 from a 225 I'm expecting a drop in MPG but I'm a little concerend about what type of issues it might create for the transmission long term. It's only a 1" tire change from a 225 to a 255 but as you can see the ratios change quite a bit. The 4K has the extra transmission cooler but trying to imagine what kind of strain it might put on this system.

I know it's likely a small worry for this scenario but I've had friends that put larger tires on their trucks without changing gearing and then their transmissions died after another 50K miles. Granted they were going from 30" to 35" but still the same idea.

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[vezpa]

There is nothing to worry about. I would suggest though if you are going to go to bigger tires, start off with the 4k package which has the 3.81. Putting 245 65 17s brings it down to 3:68 which is still better than the factory normal 3:63.

Some Maverick FX4s came from the factory with 235 65 17s so going up to 245s is a 1/2 inch difference.

The 245 65 17s which I'm running on mine are what should have come on the truck from the factory in my opinion and are perfect.

You need to go a lot bigger than 1 inch to have problems.



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[felsf50]

That is very interesting and did not consider. My XLT with 4K towing has 225/65 R17. This package includes the upgraded drive ratio of 3.81. The optional tire size upgrade is 235/65 R17.

If I had upgraded to the 235's, with your chart in mind, my GR would have dropped to 3.74??

 

[Big Kahuna]

That is very interesting and did not consider. My XLT with 4K towing has 225/65 R17. This package includes the upgraded drive ratio of 3.81. The optional tire size upgrade is 235/65 R17.

If I had upgraded to the 235's, with your chart in mind, my GR would have dropped to 3.74??

My truck on order has 4K so going to 255's would basically take it to the standard ratio as Vezpa mentioned. There could still be issues with wear and tear on CV joints, bearings, etc, but it would also erase some of the towing benefit of the 4K package as the larger tires would result in a loss of power/torque. I found this online - " The towing capacity is reduced by the same percentage of the increased tire diameter. " Going from a 29" to 30" tire is a 3.44828% increase so that would be a decrease in the amount of towing capacity from 4000lbs to 3863 lbs.

Not sure my math is all correct but that's the general idea.

 

[WellKnownHermit]

Going to a 245 or 255 from a 225....

Are you just trying to go wider? You could go to a lower profile tire but stay closer to the original diameter.

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