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Tire size effecting Tow rating

Gren71

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I recently put 35's on and I lost a significant amount of power. enough to be annoying...boggles my mind how people are throwing 37's on and not being concerned by the power loss for daily driving.

My questions is that does tire size alter tow rating? I cant seem to find much on here about it.

Ive read else where that a rough average is about 250lbs of tow loss, per 1in of tire increase from stock. I can keep googling all day but i dont know enough to really decipher what I am reading. Im hoping there is a subject matter expert on here, or at least some one who knows more than me!
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RedTRex

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It would be affecting vice effecting. Anyway, I tried proving how mods to my JK enhanced my tow rating beyond the 3500lbs to my local RV dealer because I wanted to buy a trailer that weighed a little above, he wouldn't let me take it off the lot. So like you found out there is no info available in the Google machine for how modifications change the rating. Good or bd.
 

Jeepers!

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Larger tires = lower torque. So the tow rating will be affected. How much? ¯\_(ツ)_/¯

Gear ratio plays a role as well.
 

RIPLER

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Is this the reason why the Rubicon with factory 33's have a 7000lbs rating vs 7650lbs for the Sport S with max tow?
 

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bgenlvtex

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Bigger tires and no regear is absolutely going to affect power.

You are effectively changing the final drive ratio of the vehicle.

People do it all the time, with a total disregard for how it is going to affect the function of the vehicle.

Then they will bitch about it being underpowered and poor fuel economy.
 

Ronson

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I put 37" on my JKU and had to re gear down to 513 gears just to get back to stock gearing.
 

Centexan

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It is my understanding that nothing we do in the aftermarket will change the factory tow rating--that number is set. There are thing that we can do that alter a vehicle's ability to tow, such as regearing, tire size, forced air induction, etc.
 

Pion

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I've posted elsewhere in the forum about this - there was some data taken on a website I found and while Centexan is right that the factory tow rating doesn't change, the true capability does and I think it was around 10% per added inch of diameter. So going from 33 to 35 would drop a Rubicon 1400lb of towing to 5600lb.
 

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smlobx

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One other very important aspect that hasn’t been discussed is braking distance.

Going from 33 to 35 inch tires increases the circumference of the tire 6.7% and therefore also increases the stopping distance by that amount.

If you assume a stoping distance of 240 feet from 60 mph that distance will now be 256 feet assuming all other things are equal. Of course bigger tires mean heavier tires and more rotational mass which would further increase the stopping distance...
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