1970 C-10 Tire Sizes

[Eric1970]

I have read all of the relevant threads concerning tire sizes.

My research indicates that the original tires that came with this vehicle are either G78x15 or H78x15. It is unclear whether there were originally different size tires on the front or rear, or whether it was a matter of load rating all around.

The original sizes translate to:
P215/75r15 or P225/70r15 (G-rated), or
P225/75r15 or P235/70r15 (H-rated).

I would like to keep the appearance as original as possible, and am mounting the front tires on 15" diameter x 8" wide Wheel Vintiques 6-bolt rally wheels.

I plan on using 15" dia. x 10" wide Wheel Vintiques 6-bolt rally wheels on the rear in the future.

I have noticed that almost everyone likes to use larger tires, and was curious as to why.

I am planning on installing BF Goodrich Radial T/A P235/70r15's on the front this week, and am interested in all of your opinions before I order the tires.

I am also interested if any of you has an opinion on BF Goodrich Radial T/A's vs. Long Trail T/A's.

Any information and all of your opinions are welcome and appreciated.

Thanks,

Eric

[ncbugman]

Originally Posted by Eric1970

I have read all of the relevant threads concerning tire sizes.

My research indicates that the original tires that came with this vehicle are either G78x15 or H78x15. It is unclear whether there were originally different size tires on the front or rear, or whether it was a matter of load rating all around.

The original sizes translate to:
P215/75r15 or P225/70r15 (G-rated), or
P225/75r15 or P235/70r15 (H-rated).

I would like to keep the appearance as original as possible, and am mounting the front tires on 15" diameter x 8" wide Wheel Vintiques 6-bolt rally wheels.

I plan on using 15" dia. x 10" wide Wheel Vintiques 6-bolt rally wheels on the rear in the future.

I have noticed that almost everyone likes to use larger tires, and was curious as to why.

I am planning on installing BF Goodrich Radial T/A P235/70r15's on the front this week, and am interested in all of your opinions before I order the tires.

I am also interested if any of you has an opinion on BF Goodrich Radial T/A's vs. Long Trail T/A's.

Any information and all of your opinions are welcome and appreciated.

Thanks,

Eric

Eric,
I`m interested in seeing if those sizes you posted will fit w/ o rubbing the fender wells........
I`ve been given 4 .....8 x 15 white wagon wheels but they look too big ie too wide

NCBUGMAN

[Eric1970]

Hi, Bugman.

Hopefully, I'll get the sizes right before I order the tires.
If you read the many threads concerning wheel/tire size for the '67-'72 series pick-ups, you'll notice that just about everyone seems to be going even bigger (wider), which is why I was asking.

The sizes listed in the original post are closest to the direct factory equivalents.

I'm still interested in hearing from some of the others who have the same size or bigger tires.

I'll definitely let you know how it turns out.

[SS Tim]

Originally Posted by Eric1970

I have read all of the relevant threads concerning tire sizes.

My research indicates that the original tires that came with this vehicle are either G78x15 or H78x15. It is unclear whether there were originally different size tires on the front or rear, or whether it was a matter of load rating all around.

The original sizes translate to:
P215/75r15 or P225/70r15 (G-rated), or
P225/75r15 or P235/70r15 (H-rated).

I would like to keep the appearance as original as possible, and am mounting the front tires on 15" diameter x 8" wide Wheel Vintiques 6-bolt rally wheels.

I plan on using 15" dia. x 10" wide Wheel Vintiques 6-bolt rally wheels on the rear in the future.

I have noticed that almost everyone likes to use larger tires, and was curious as to why.

I am planning on installing BF Goodrich Radial T/A P235/70r15's on the front this week, and am interested in all of your opinions before I order the tires.

I am also interested if any of you has an opinion on BF Goodrich Radial T/A's vs. Long Trail T/A's.

Any information and all of your opinions are welcome and appreciated.

Thanks,

Eric

The base C/10 tires in '70 were tubeless G78-15-B tires on 5.5" wheels. Optional tires included "G" or "H" with white walls (5) or off road tires (2 or 3) that could be installed only on the rear. The spare could match either front or rear depending on the RPO selected. Tube type tires were also offered.

As a 235 tire runs about 9" wide you might not like the look on an 8" wheel and you are definitely going to want a wider tire for 10" wheels.

Hope this helps some.

[PAWS 72]

Eric, I'm running 255-70x15 on 8" rally's.Stock height,no problem on clearance issues.

[PAWS 72]

didnt post for some reason

[jocko]

If you want a 235-70-15, then you should probably get a 15x6 or 15x7 wheel
on the other hand, if you want to go with a 15x8 wheel - then a 255-70-15 is a better size tire for that size wheel.

recommend stack the 15x10s in the corner of the basement with some cushions on top and make a nice dog bed out of them.

kidding aside - I'm a little stumped regarding your line of questioning (and that's ok, just looking for some more detail so we can help!) - you started off asking about stock size tires, then switch to a 15x8 and 15x10 wheel discussion - the two do not go together. While a 235-70-15 will fit a 15x8 wheel, it is essentially putting the narrow limit of a tire for that size wheel onto it.

So, what look are you going for? Slightly larger than stock? or Pro-street?
For 67-72, 255-70-15 OR 235-75-15 fill out the wheelwells nicely - roughly the same diameter tires, with the 255 looking a little bigger than stock. If 255's - then recommend them at all 4 corners. If you want some "big n little" look, etc - then maybe 235-70 (or 75)-15s in front, with either a 255-70-15 (or 275-60-15) in the back.

As for choice of BFG tires - my personal opinion is that the Radial T/A's look better than the Trail T/A's on these trucks. Trail T/A is a slightly more "off-road" tire, or at least looks a little more off-road-ish.

Look forward to your new wheels & tires! Post pics when you can. And welcome to the board - tire and wheel combos are a recurring theme around here!!

[Eric1970]

Thank you all for your replies- this is a great forum!

Jocko-
The idea is to maintain the stock appearance. I have read that the rally rims were a factory option in 1970, although if that is not the case, I still like there look the best. I have only purchased the front rims (8" wide) so far. I may have been wrong about the stock rim size; 8" just seemed right for the front.

I was more curious as to why everyone goes with bigger tires than what was originally stock, other than less apparent mileage on the speedometer. Is there a technical reason for this? (mileage, handling, etc.) or is it purely aesthetic? I'm fine with them being wider, I prefer the height (which would be the biggest apparent factor) to be close.

I know that bigger tires in the back transfer more power to the road, while narrower tires get better mileage and handle better in the snow.

I would be going for stock/slightly larger than stock in the front, and either slightly larger than stock or pro-street on the back.

Ideally, I'm attempting to go for a balance between performance and (dare I say) practical. I'd like to drive this truck on a few long road trips when it is done.

Paws- sounds like 255's are the way to go. Thank you! Beautiful truck, by the way!

SS Tim- Thank you for the clarification. What were the stock size rims? were they the same all around, or different in the front and rear?

I suppose I ought to figure out how to post a build thread. At the moment, my C-10 is in a rat-rod stage. I purchased it just over a year ago, and so far, have a freshly rebuilt 350/350 and magnaflow exhaust. I am converting to front wheel disc brakes this week, using an ssbc kit that fits in the 15x8 rally rims. Otherwise, I plan on changing the tranny to a 6-speed manual (was originally a 4-speed) primarily for mileage (and I like to shift). I will be building a mechanical linkage, as 1970 was the last year of mechanical linkage, as well as relocating the fuel tank (for safety- nieces and nephews ride in my truck), and am considering using pneumatic springs so I can raise or lower the truck (primarily for better mileage, without sacrificing payload capacity). Otherwise, I'd like to keep the look itself fairly original.

[FrankieD]

See if this helps, you can play with tire and rim sizes.

http://www.rimsntires.com/specs.jsp

[SS Tim]

The stock '70 C/10 wheels were 15 x 5.5" all positions. The "Rally" wheels were not offered on the '67-72 trucks. The only factory wheels were standard steel with a choice of hub caps and wheel covers over the years.

If you want to run your 8" wheels, I agree with jocko that 255s are a good size. The most practical is the same size all around and rotate them often.

[Eric1970]

Thanks, Tim. You know your Chevy trucks.
5.5" is pretty narrow- that would explain why they used the equivalent of 215-235 tires.

Looks like I'll go with 8" and 255's all the way around for this build. Figured I'd be going over it twice in the long run, anyway. I would like the ability to return it to full stock eventually, if I should so have the whim, so no chopping or tubbing.

FrankieD, that is a Great link!

Thank you all for your help. I'm clear coating the 15x8 rally's and ordering the tires today.

[ncbugman]

Originally Posted by Eric1970

Hi, Bugman.

Hopefully, I'll get the sizes right before I order the tires.
If you read the many threads concerning wheel/tire size for the '67-'72 series pick-ups, you'll notice that just about everyone seems to be going even bigger (wider), which is why I was asking.

The sizes listed in the original post are closest to the direct factory equivalents.

I'm still interested in hearing from some of the others who have the same size or bigger tires.

I'll definitely let you know how it turns out.

Eric,
I don`t understand all this "new to me" tire sizes.......... I measured the rims on the truck now they are 5.5" x15.......... my freebies are 8 x 15 , will they work ok? won`t rub the frame / fenders on the front ?
Thanks Bugman

Every body else feel free to help an "old man" out :-)

[jocko]

Originally Posted by Eric1970

Looks like I'll go with 8" and 255's all the way around for this build. Figured I'd be going over it twice in the long run, anyway. I would like the ability to return it to full stock eventually, if I should so have the whim, so no chopping or tubbing.

An excellent choice Eric! I'm with you, although rallies are not stock - they are so common on 67-72, many assume they are. And the just look darn good.

ncbugman,
Will need a bit more info - what kind of 15x8 freebie wheels do you have (rallies)? And what year is your truck?
- 71 is first year for 5 lug wheels on half ton trucks
- pre-71 had 6 lug wheels on half ton trucks
- all 3/4+ ton trucks had 8 luggers
- pre-71 6 lug wheels (steelies) will generally NOT fit disk brakes
- 71-87 K10 (i.e. 4WD steel steelie wheels AND 4WD rallies (rallies being post-72, that is)) will fit on pre-71 trucks with 6 lug wheels AND clear (most) disk brakes (i.e. these are a very common modification to pre-71 trucks, including 60-66 era, that allow a stock looking wheel (steelie) and disk brake clearance. They are 6" wide and externally identical to the 15x5.5 stock steelie once a hub cap or wheel cover is installed. Also available in 8" wide I believe.
- post-72 5 lug rallies (up to 8" wide) will fit a 71-72 5 lug truck and will not give you any clearance problems unless you go nuts on tire size. 255-70-15, as mentioned above really fills the wheel wells and clears everything.

Hope that helps, if not, let us know your specific application and we can narrow it down.

[Already Gone]

I can't post from this IPad but will tomorrow as I have 255/70's on all 4 corners on my stock heit longbox and they look right .
Posted via Mobile Device

[FrankieD]

I have 275/60R17 on mine the rims are 8" and the tires are 11" sidewall to sidewall so you should be good.

[racer57]

This might help you out

http://67-72chevytrucks.com/vboard/s...d.php?t=506127

[Eric1970]

FrankieD,

Nice Truck!
What shade of blue is that?
I was thinking of going with midnite blue after my truck is mechanically sound.

Bugman,

The consensus seems to be that 8" will work- I am unaware of what your offset is; that may be the only factor. I'm sure if they haven't already, the community here will get you squared away.

As for myself, I've decided to go with 15"x8" rally's and BF Goodrich Radial T/A's p255/70r15's for all four wheels. I'll know Sunday night/Monday morning if there's a problem. The protectant is curing on the rims in my shed now- I'll be mounting the tires Sunday evening. The corrosion-resistant protectant/paint takes 5 days to cure enough to mount tires to the wheels, and 7 days to cure fully.

[FrankieD]

[QUOTE=Eric1970;5335114]FrankieD,

Nice Truck!
What shade of blue is that?
I was thinking of going with midnite blue after my truck is mechanically sound.

Bugman,QUOTE]

"Thanks"I will PM you and let you know the color when I get home, it was already painted when I got it but the PO kepted records on everything he did to it. Here is a little better day time shot.

[Already Gone]

My stock height truck with Cooper Cobras ( I don't like like the look of raised white letters on our trucks ) 255/70 15's on 15 x 8 Rallys

[FrankieD]

Well Eric I just realized that this is your thread so here is the paint info it is KIA #B7 Blue Pearl Metallic used from 2002 to 2004 over a Pearl White Base.