JJHACK

I have been in South Africa working for a while now. I have not been able to visit the site for almost a year! I'm back home and want to put on some bigger tires if possible.

My 2004 cummins 4X4 short box quad cab has a tuff country 4.5" lift right now with 35X12.50 tires. My axles are 410's

I would like to run a larger tire and have read many of the posts here where guys are running 37X12.50's with a 4 or 4.5" lift. I did not think they would fit with a 37" tire unless you have a 6" lift? Tuff country says that 36" is the recommended diameter with the 4.5" lift

What do you guys say who have done this already? Also what wheel backspace do I need if I put on a 12:50 or 13:50 tire? I may go with the 36X13.50 Swamper Iroc tire. That meets the Tough country size recomendation. I know I would nee a 17X9" wheel though so I have to know what backspace to look for.

If you have played with this already on a 2004 let me know what you have figured out.

boarbuster

I know for a fact the 37's will fit with 4" lift and they only rub when i turn the wheel all the way. As far as rims i didn't think that it was necessary that i buy new ones because after all i don't expect them to last more than 15k miles anyway.

Hal

I think you are stuck with 35s unless you lift the front. Not enough clearance when you turn...

JJHACK

The funny thing about 36" and 37" tires is that one manufacturer lists the size as 36 yet the tire can be from 35.5 to 36.5 yet another lists a 37" tire as a 36.3 to 37.5 its a freaking joke the way this is done!

I do know that by looking at the BFgoodrich site they list their 37X12.50 All terrainTA'a as 36.3" tall actual size even though they list it as a 37X12.50
This tire will be 1.5" taller then the ones I have now and I have a ton of wheel-well space to work with.

Since Tuff country says that a 36" tire is the recommended size this seems to be a logical choice. I could also choose the Swamper Iroc which is an actual 36" diameter tire( but 13.5" wide). The BFG's are a better on road and plenty good off road especially on rocky logging roads tire for me.

Funny thing is that BFG lists the mud terrain at 36.8" which is much closer to actual listed size.

Now I just need to find a 9" wide wheel with proper back spacing. What should the back space be?

bigblock2stroke

That's because the size of the tire increases (the tire expands) as you go up in speed. Picture top fuel dragster doing a burn out. Tire gets narrower and larger diameter

JJHACK

I'm sure the will increase in size a bit but not an inch in height or width. I'm not spinning them on the pavement!

Superswamper Iroc lists their 36" tire's actual diameter at 36.8

BFG lits their All terrain TA 37" tire at 36.3

So the bigger tire is rated at a smaller size then the smaller tire is? Just kinda silly to me. The 35" tires are no different,......... the actual size ranges an inch either way.

Ramtough

The actual offroad tire makers are usually on par with their sizes while normal makers that do car tires as well arent as accurate... Usually. Many also miss out on tread height as well i have ssen some as low as 13/32 to a swamper as high as 26/32.