Tire size question

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BGPick

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The truck currently 215/85/16 tires. Can I upgrade to 235/85/16’s on the stock wheels without any fitment issues?
 

1987 GMC Jimmy

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That should be fine. If it were me, I’d stick to whatever the sticker on the driver door says it came with because of speedometer concerns. I get enough tickets to either fight, get fixed, or pay with a speedometer that reads pretty much on the money.
 

BGPick

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Yeah, true. Plus I’ve heard for winter/snow it’s better to have a thinner tire that “cuts” through the snow rather than a wider tire that “pushes” through.
 

1987 GMC Jimmy

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That sounds logical with regard to the aspect ratio, but you’d only be changing the diameter so I’d expect similar performance in snow conditions. It’s up to you; I’m sure it’ll be just fine either way.
 

Craig 85

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235/85R16 is the stock size for C20's. Check the driver door for a sticker like this.

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1987 GMC Jimmy

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If that’s the case, I’d go back to the stock size.
 

BGPick

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According to my sticker 215/85/16 is the stock tire size. It’s a 2WD if that makes a difference.
 

bucket

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Odd, I thought all of the C20's with 16's got the 235 tire.

At any rate, GM didn't seem too concerned with the speedo accuracy tolorances. You may actually have a slightly incorrect speedo reading right now. A 235/85 or even a 265/70 would work fine.
 

BGPick

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Yeah, my speedometer seems a little “floaty” as it is so I’m not too worried about that. More worried about fitment and/or premature tire wear due to it not being the right size.

It does give me a lot more tire options If I upgrade to the 235/85’s

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shiftpro

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Yeah, true. Plus I’ve heard for winter/snow it’s better to have a thinner tire that “cuts” through the snow rather than a wider tire that “pushes” through.
Yes for civilians... wider meats for 'drivers'.
I like wider (but not steamroller wide mall cruiser) rugs in every circumstance... mud, rain, snow, dry pavement, gravel. But I also like to drift and powerslide. Keep my mo up. Saves gas by keeping your mill 'on the pipe'.
But I realize this driving concept is not for the masses.
Oh and I'm not suggesting the OP is a granny by any means. Err, now that I think of it maybe he is...
Let's try convince him to drop a BB in it!
 

Crispy

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The difference in width here is just under an inch, I dont think that makes much of a difference in getting through snow. Also, I've driven in snow (and slid) with all different sized tires from 15x6 to 20x12.5. Adjusting for the conditions + driver skill makes all the difference.

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Craig 85

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That interesting. I've had a square body C20 pick up and Suburban and both were 235's. If fact, all my friends that had these truck new back in the day all had them. I've never seen a 3/4 ton with 215's.
 

roundhouse

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Easiest way to know for sure is find a local tire store and see if you can talk them into mounting it

You should be able to fit 31s on a 2wd with no issues
 

Scrapman

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A buddy gave me some 16"s off of his 08 chevy dually..stock tires they were 215/85/16 My 86 dually runs 235/85/16 but with spacers so tires dont rub with a load on the truck...with 215"s on i wouldnt have that problem of rubbing
 

78C10BigTen

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Easiest way to know for sure is find a local tire store and see if you can talk them into mounting it

You should be able to fit 31s on a 2wd with no issues
My 78 c10 has 31s on factory ralleyes and fit fine. Ive been thinking about bumpin the back to 33s and the front to 32s.


Sorry i just looked back and your talking about 16s, mine are 15s
 

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