The Stovebolt Site Forums The Parking Lot Big Bolts Bias to radials

As I get my 1951 6400 back on the road I've been thinking about tires. It currently has 9.00-20s all around which fit pretty well and give me a bit more speed. Has anyone made the switch from bias to radials on these old trucks? Does it make a noticeable difference in steering accuracy, ride quality etc? Or should I just get a new set of bias tires? Thanks for any input

I bought my 54 all original in 1983 and the first thing I did was put radials on it.

For me it is radials all the way. I also like em tall 👍

I got my truck last January and it had 25.5" tires on it. It now has these 255/70/15" on it. They are just under 29" and made it feel and look so much better on the road. This 62 C10 has a 3.90 gear out back, so the tire height really helped. I can also slide under this truck now. Before It was a little low for me.

My story is not very good for comparing bias ply to radials. The tires were in real rough shape when I bought the truck, 5 bias ply and one radial, they rode hard and weren't round. As I continue to make improvements on it, I had all 7 wheels sandblasted, I painted some myself and had some powder coated. All 7 wheels now have radials, metric 22.5" Michelin for the steer tires and 10R-22.5 Firestone for the drives they are smooth as silk on the road.

Thanks for the input gents, however ... comparing 4-wheel half-tons to 6-wheel 2-tons may not be an accurate comparison.

I've gone both routes with Big Bolts -- Bias ply to radials ('65 GMC 4400) and old bias ply to new bias ply ('49 Chevy 4400).

On the bias ply to bias ply ... on that truck, I also replaced the king pins, rebuilt the tie rod ends and drag link, and rebuilt the steering box. Those tires were 8.00 20's, as I recall... Anyway, at 55 ish, no difference between the two trucks, steering wise. The GMC was a firetruck with less than 10,000 actual miles on it so the front end was all still "new."

Both trucks, even at crawling/granny gear speeds, steered like they had power steering -- I could pretty much steer them with one finger (as long as they were moving ... )

Point being -- There is no argument that radials are superior to bias ply. But not radically so. If your truck wanders at speed or is hard to steer at slow speeds ... it's not the tires. Radials will help, but not fix, steering issues.

Direct fit single piece wheels to fit the AD Big Bolts are scarce. If you need to replace the tires anyway, tubed radials are a good option. I run tubed radials on my '73 Cornbolt 1-ton dump and they do great.

And for what it's worth -- I'm on my 3rd set of bias plys for the '49 1-ton that gets a lot of highway miles. Would it ride and steer better with radials? Probably. But ole charlie rides and steers good enough for me. Besides, Billy Marlow got the last set of single piece 1-ton wheels ... Thus winning for himself the Order of the Blue Falcon.

Thanks for the input. The truck only goes about 45 mph currently since it still has the 235. Eventually though I would like to swap a V8 as a sort of truck tribute to my grandpa's 1948 GMC which he and my uncle swapped a 283 into. If the bias ply tires would be happy at 55 mph I think I would be content too

Unless your changing the trans nor rear, adding a V8 won't give you any more speed...3500 rpm with a 6-cylinder is the same as 3500 rpm with a V8.

I'm also in the radial camp! My '56 8400 had Bias tires on it when I got it back in 1997 and the first thing I did was to put radials on it and it made a BIG difference.

My .02 cents!

Mike B

Technically you are correct that 3500 rpm is 3500 rpm but the 235 doesn't have enough power to pull it on even a gentle hill and on a splash oiled engine I'm pretty sure that it won't last very long when run close to redline. The V8 will run all day at 3500 and have some power as well. Thanks for the tire experience, I'm still looking for a set of 22.5 wheels but have had zero luck so far. I will just keep shopping and see if I can find a set of radials for my current rims. Btw Mike B the PTO you sold me a while back is installed and works fantastic!

Not sure what year they debuted, but if that truck has the two ton Chevy 10 bolt 8.75" bolt circle motor wheel pattern, then you can just buy brand new 22.5" steel wheels for it. Pretty sure you can get the smaller 10 hole pattern in 19.5" wheels, too. Accuride used to make a set of the two ton Chevy wheels and they were lighter than the Sanska ones I just bought, but the Accurides are hen's teeth these days, where as the Sanskas can be bought in any quantity desired for $299 apiece online, with free shipping. They're made in Turkey, oddly enough, also DOT stamped; it's my understanding that there was a run of these wheels made in China that were not DOT.

And yes, radial tires make a really big difference, especially if you'd like to exceed 55mph or go around a corner or not have the rig shake itself half to death from the cold flat spots on old bias tires, or follow the grooves in the road. Also, less rolling resistance equals better fuel mileage. Unless you need the exact look for a vintage restoration to roll in a parade, I can't think of a single reason to run bias versus radials on a rig that you actually intend to drive.

This truck unfortunately has the 10x7.25 wheels.

the added expense of new 22.5 wheels so you can run radials on your truck may make the decision for you! (assuming your current wheels are usable). They don't make 20" radials, you have to bump up to 22.5 wheels so, that adds another huge chunk of change!

There are actually a few different radial 9r20 tires available but they are twice as expensive as the bias ply alternatives. Hard to know if the extra $1200-1500 cost would be worthwhile.

Glad it worked out!

19.5 10-lug wheels will bolt right on, but may not fill the wheel well like the 20/22.5's did and won't have the same diameter.

Mike B

Again, FWIW ... I *do* run bias plys on a truck I routinely run 65-70 mph with. Flat spots are usually gone within a minute or two and I do not get shakes, a death wobble or excessive wander. My truck will do in excess of 70 mph but I don't like going there for several reasons.

Besides ... running out the flat spots to me is part of the charm of owning and driving an *antique* truck. When I desire the modern driving experience, I take the '14 E-350.

Just sayin' ... for the record and for those who, like *me* find the upgrade to wheels capable of handling the radials (plus the radials themselves) to be prohibitively expensive ... Staying with Bias Plys is *not* the end of life as we know it, will *not* result in your death and will not present hazards to life and limb.

Life with bias plys is perfectly enjoyable, manageable and even survivable.

Would *I* like to upgrade to radials on my '49? Heck yes. Are bias plys equal to radials? No. Can you drive them? Heck Yes.

The upgrade to radials, as desirable as it may be, is getting harder to do all the time without resorting to costly and time consuming modifications like endless searches for unicorn wheels like those single piece wheels for the pre-'60 trucks with the 5/10-bolt patterns, changing axles, spindles, etc, etc.

So before those of you who have done this upgrade decades ago, when wheels and other parts were more plentiful than they are today, start sending guys off on fools' errands to search for unicorns, let's all pause, take a deep breath and let a little reality sink in here.

Who wouldn't want to load up the ole dollar gun, set the selector to "Full Auto," aim it at the truck and hold the trigger down? Not all of us can do that.

Replacing old bias plys with new bias plys is *not* the end of life as we know it -- it can be a viable option that provides a perfectly viable driving experience ... as long as one remembers to drive appropriately (as one *should* anyway).

You wanna drive like its a Corvette? Well go get a stinkin' corvette, then.

And Oh By The Way ... my truck has Huck Brakes, too. Gasp!!

In my case, I had a bus full of RH5 wheels so if I wanted to keep driving it, I had to buy new wheels. Serviceable 20" wheels kinda don't exist anymore around here, plus the tires are more difficult to find. Yeah, if your current wheels are still serviceable and you can find bias tires for it that you can afford, then it's certainly worth saving some money if you aren't driving it much. Keep in mind however, that fewer and fewer shops are going to know how to work on the old multipiece rims, because everything's been drop center for three decades now. If you're motivated, the Ken-Tool serpent mounting tool is $60 on eBay and I promise it's easier to do a 22.5" wheel with that than it is to bust a split rim. I've done both.

However, at the point where you've presumably spent the hours and money to get your rig on the road, isn't another $900 maybe worth it on a truck you want to hand down to your kids, and would hope they like to drive it? Yes, I can drive bias tires. They work fine and aren't unsafe.. but radials are a big step forward, and pretty much the easiest mod you can do to make your 1960 truck drive like a 1990 truck.

Thanks, I will definitely have to check those tire tools out. My wheels are serviceable and even the tires aren't too bad but within a year or so I hope to have them replaced. If only the 22.5 10 lug wheels that fit these truck were common the decision would be so much simpler!

These are 19.5" but 10 x 7.25" https://buytruckwheels.com/products/19-5x6-hub-pilot-dual-10-hole-p-300-chevrolet-or-gmc-typical the only issue would be finding tires for them that are much over 36" in height.

I found 9.00-20 bias tires for $344; 9.00R20s for $377. So, not a big jump in price. If your wheels are still good, probably better to just put the radials on them. https://simpletire.com/brands/tiron...ost-popular&delivery=Del2&rad=DB

Almost forgot, yes I'd love to put the ole' dollar gun on full auto and aim it at my bus and pull the trigger

I had a machine gun aimed at my 54 but it was a situation where I could do that. I have no regrets because I have driven it for years and in my mind I have amortized the money over the last 40 years. I know it is a rationalizing but it worked for me. I leased a new car for 30 months many times over the same period and that money is GONE with nothing to show for it .

Hey, people spend gobs of cash on a lot less rational things than our old Chevys! I mean, I here there's a website kinda along these lines for guys who dump the money into old Dorfs..

I got real lucky with mine, the 7 wheels were all usable. Sand blast, primer, paint, powder coat and 8 tires total I have about $1100.00 in them. No way I could afford new rubber, 4 Michelin metric tires were on Craigslist at $300, the Firestone 10R-22.5 drives are virgin steers off a school bus fleet, $65 each plus mount. You can find decent tires if you have the time to wait and shop.

I drilled 8.75” wheels to the 7.25” bolt pattern, made a hub adapter, so I am all set on my 55.2 GMC.

Ed

Do you have any pictures of the hub adaptors? The 10x8.75 wheels seem slightly more common although the one local set I tried to buy got sold before I could get them. Thanks!

@EdPruss how did you make sure to get the hols drilled hub centric? Or did you have a machine shop do it?

Given the easy availability of modern 22.5" wheels in 8.75" pilot, (I have a set, there is plenty of metal there for strength) this seems like a good option if you don't care about the looks of the other set of holes. While getting all this done would be kinda expensive, it would be a one-time expense that would ensure permanent, easy availability of modern tires-even used ones that you can find for $100 each-for as long as 22.5" wheels and tires remain a common thing.

A couple more thoughts. I run all used bias tube type tires on 2 heavy trucks - a 59 GMC 10 wheeler and a 58 Chevy 6 wheeler. They are on split rims, but not the Firestone 'widow-makers'. These are not regularly driven. I look for used Goodyear and Firestones Made in USA. They are tough tires and will last for many decades if trucks are parked inside. They are cheap partly because people are afraid of them, but old bias tires are less likely to blow out than radials unless the radials are relatively new (my experience/opinion). Radials age worse and they don't like 'sitting around'. My bias tires smooth out within a mile, but yes it is pretty rough starting out. To each his own, and I'm just telling my experience, not giving advice.

@78Buckshot that's a rare deal indeed! 10R22.5s won't fit in my wheel wells, the biggest I can do is 9R22.5 or 255-80R22.5; each is approximately 38.5" give or take .2" which is 2" taller than the 8.25-20s the bus rolled in on. The new tires might rub a little bit when going all the way to lock while parking, but that's a small price to pay for lower cruise RPM, and modern day driveability.

Really excited to get my rig rolling with new tires and taller rear gears.