Max Wheel / Tire size

[syndicate1]

I'm fired up that I'm finally picking up my newly acquired '74 bronco on Saturday! The truck is solid and runs strong. Original owner, 100% stock, garage kept, no rust, no lift, and never off road. The only mod to the truck are the cut fenders with fiberglass flares. I'm not planning to do any mods in the immediate near future. The truck has been sitting and needs new tires and while I'm at it I'll put on a set of 15" MT Classics or 15" AR Baja's. I haven't decided whether to go with a 15x8 or 15x10.

I'm leaning towards the BFG AT or the GY Duratracs. What is the biggest tire size I can safely install without a lift? 30? 31? 32?

Thanks for the feedback!

 

[Justafordguy]

With just a little trimming you can run a 33" tire. The Duratracs are really nice tires.

 

[syndicate1]

With just a little trimming you can run a 33" tire. The Duratracs are really nice tires.

The truck is clean so I'm planning to keep the truck as-is for now.

 

[Prizefighter]

You can run a 33" tire with no lift if the fenders have been trimmed. It will rub on the radius arms at full turn, it doesn't hurt anything but could damage the lugs on the tires if done hard enough for long enough. Another bit of advice is you will probably want to change your gearing in your axles to accommodate the larger tires.

 

[AaronWelch]

I would agree that 33's are doable. I think that talking about re-gearing the axles is a little premature. What engine / transmission do you have? Power steering? Disk brakes? Only street use or some mild off road? There are other questions that need to be answered before you just stuff the biggest tires you can on her. Just my $.02

Aaron

 

[Broncobowsher]

Yep, cut and flared can handle up to 33s completely stock. Doesn't mean you should go right out and get 33s, just not larger than 33s.

 

[syndicate1]

I would agree that 33's are doable. I think that talking about re-gearing the axles is a little premature. What engine / transmission do you have? Power steering? Disk brakes? Only street use or some mild off road? There are other questions that need to be answered before you just stuff the biggest tires you can on her. Just my $.02

Aaron

The truck is an Explorer edition with a 302, C4 auto transmission, power steering and power drum brakes. The engine has under 1k miles since the rebuild. I'll use the truck primarily on the street

I'm sensing 33's are boarder line. Am I better off with 32's? Would 32's rub?

 

[sykanr0ng]

I ran 31 inch tires on my first two Broncos, which were mostly street driven and mostly stock.
Never felt underpowered or that I needed different/better gears than stock.

Getting farther from the stock tire size will increase the need to change the gears to keep the RPMs in the best range for power and fuel economy.

 

[AaronWelch]

Yea my old 66 had 32's with the rears trimmed like yours. with a 302 you should be fine. Most 32 inch tires are really not 32 inch. You would probably be ok with 33's as well. Only one real way to tell. My current truck is getting a 351W and i really want to go to 35's I think I will be ok but may need to regear if I dont like how it runs with them.

Aaron

 

[Bonco4Broncos]

You stated that the Bronco has been sitting awhile. You may want to think about flushing the brake system as well as the cooling system. It would not be a bad idea to change the fuel pump as after sitting they are prone to failure, and change the fuel filter out when you do this. Also inspect all the brake lines. check the metal lines for leaks and badly rusted areas and the flexible ones for signs of age. Congratulations and welcome to the herd of Bronco owners. On a stocker I would go with a nice set of 31s. JMHO

Dwight

 

[rguest3]

If you are going with 15s then I would suggest 15x8" wheels.

Wheels - MT Classic, US Wheel Slots

Tires - Toyo AT2, BFG KM2 - 31x10.50

 

[Broncobowsher]

If going new wheels and tires, skip the 15s. They are getting harder to find. The bulk of modern tires are in the 17s now. 15s are going the way of the 14s (Have you looked for a 14" tire recently? They are few and far between and anything with a good name is even harder to find). There really isn't much of a price jump to go up a rim size or two anymore. Really opens up the tire options.

 

[syndicate1]

You stated that the Bronco has been sitting awhile. You may want to think about flushing the brake system as well as the cooling system. It would not be a bad idea to change the fuel pump as after sitting they are prone to failure, and change the fuel filter out when you do this. Also inspect all the brake lines. check the metal lines for leaks and badly rusted areas and the flexible ones for signs of age. Congratulations and welcome to the herd of Bronco owners. On a stocker I would go with a nice set of 31s. JMHO

Dwight

Thanks for advice about the brake lines and fluid. The fuel pump and filter are on my to do list as soon as I run through the gas out of the tanks. Regarding the cooling system, The previous would start and run the truck once a month. I visually checked the condition of the antifreeze, it's very clean and I still plan to flush the system. Would you recommend flushing the system before or after some local daily driving?

 

[syndicate1]

If going new wheels and tires, skip the 15s. They are getting harder to find. The bulk of modern tires are in the 17s now. 15s are going the way of the 14s (Have you looked for a 14" tire recently? They are few and far between and anything with a good name is even harder to find). There really isn't much of a price jump to go up a rim size or two anymore. Really opens up the tire options.

Good suggestion to consider 17's. If I went with either of the two wheels I'm considering, what offset would I need? Would 32's still fit?

 

[bronconut73]

I think 33x12.50 BFG A/T on a 15 x 8 MT wheel would be perfect.
The BFG A/T has a classic tread that still looks right at home on a stock eb.
Even though it is a "classic" looking tread it is actually very high tech. Good about not hydro planing and provide great all around traction quietly.
Before so many great mud terrain tread designs hit the market in the last decade or so the BFG A/T was the "Go to" tire for alot of us.