Author Topic: Bigger tire size  (Read 6544 times)

Offline oldblue76

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Bigger tire size
« on: October 30, 2015, 08:59:37 pm »
I have a 76 Chevy K10. Currently has stock tires on it. I am needing to replace all tires and am wondering how big I can go on with stock wheel and stock ride hight thanks.

Offline FlatBlack77

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Re: Bigger tire size
« Reply #1 on: October 31, 2015, 08:10:37 am »
33x12.50r15s is about as big as you can go on stock 15x8 rally wheels without major trimming. they fit on my stock 79
"When you are a hammer, everything looks like a nail"
'77 C/10 - 350/350 mild street motor

Offline roundhouse

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Re: Bigger tire size
« Reply #2 on: October 31, 2015, 09:24:57 am »
Yep 33x12.50 will fit fine on stock rally's on most trucks with no lift and no rubbing
Looks good too


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Offline timthescarrd

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Re: Bigger tire size
« Reply #3 on: October 31, 2015, 05:28:31 pm »
There's a couple things to consider with this, If you off-road where your suspension is going to articulate very much anything above 31x10.5 is probably going to rub.  for mostly pavement driving then 33x12.5 should be fine.  If you springs have sagged considerably then 31x10.5 may even rub.  Also consider the drivetrain, what transmission and rear gear ratio do you have.  If you have 2.73 or 3.08 then larger tires tend to lug on steep hills or towing.


Offline oldblue76

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Re: Bigger tire size
« Reply #4 on: October 31, 2015, 07:44:28 pm »
I have the SM465 and I believe the owner before me (Wife's grandfather) put a different rear end on the truck to better on the highway. I havent had a chance to see what gear ratio is in the rear end. My front leaf springs have sagged.

Offline enaberif

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Re: Bigger tire size
« Reply #5 on: November 02, 2015, 09:24:41 am »
You need to swap both front and rear gears in a 4wd.You can't just do the rear and be ok.

Might be time to check your diffs and gear ratios.

Offline Irish_Alley

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Re: Bigger tire size
« Reply #6 on: November 05, 2015, 11:30:27 pm »
front "sag" is called negative arch and thats how they come
also check this out.
http://forum.73-87chevytrucks.com/smforum/index.php?topic=31301.0
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline ehjorten

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Re: Bigger tire size
« Reply #7 on: December 04, 2015, 09:25:22 am »
My '77 K20 is all stock suspension with the negative arch front springs as Irish just explained.  I have 31's on it that are the Toyo Open Country MTs.  I thought I had the actual P-Metric tire size on my phone, but I don't.  Anyways...the tires don't rub in the wheelwell, but I am certain 33's would if you actually used your suspension.  The side lugs on the tires will rub the drag-link a little at full lock.  31's are perfect for stock ride height on your truck.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6