Swapping 20's for 18's with 3.55

[chongo]

Like the title says I am looking at going down to 18's from my 20" wheels. I just like the look of 18's better than 20's. Will I sacrifice mpg by doing so? Will I need to get the speedo recalibrated?

Thanks

[Bryce18]

Originally Posted by chongo

Like the title says I am looking at going down to 18's from my 20" wheels. I just like the look of 18's better than 20's. Will I sacrifice mpg by doing so? Will I need to get the speedo recalibrated?

Thanks

Doesn't matter wheel size for speedometer recalibration. What matters is whole wheel and tire diameter.

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[chongo]

So if I go with a 285/75/18 (34.8") tire I should be fine?

Any issues or concerns with that much sidewall?


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[coryz71]

My truck came with 18''s. I just put on 305/70r18's and now my speedo is almost right. When my speedo says 55 and I pass a laser speed sign it will say 56.

The 305/70r18 is 34.8" tall.

[Bryce18]

Originally Posted by chongo

So if I go with a 285/75/18 (34.8") tire I should be fine?

Any issues or concerns with that much sidewall?


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What size diameter is on your truck? If these new wheels and tires are bigger then your original ones. Your actual speed will be faster then your what your speedometer says.

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[chongo]

I currently have 275/60/20

34.1 or 34.8 -whatever comes factory.

[Adventure Rider]

Originally Posted by coryz71

My truck came with 18''s. I just put on 305/70r18's and now my speedo is almost right. When my speedo says 55 and I pass a laser speed sign it will say 56.

The 305/70r18 is 34.8" tall.

For the 305's did you change the rim width size to be more than the stock 8?

[Boudah]

the oem 20's are 20 x 8 " the tire is a 275/65/20 275 MM wide by 65 % for sidewall hight

so do 275mm divided by .65 = actual sidewall height. convert to inches 25.4 mm = 1 inch

or convert the 20" wheel to MM

Take the wheel dia plus add the sidewall height x 2 and thats the over all rolling diameter

take the overall rolling dia and subtract that from the overall diameter on the 18" wheel/ tire combo. You then have your answer

[coryz71]

Originally Posted by Adventure Rider

For the 305's did you change the rim width size to be more than the stock 8?

No, stock wheels.

[24ssm]

Where r u located I want 20s and I have 18s

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