Consciences on Truck Tire Size 37 or 39-40

Evans Motorsports

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We are in the process of restoring a Class 8 truck, SB Chevy 600 hp prox. Planning on running SNORE TT or Class 8 in Snore, More or BITD if other Class 8s enter. Im going to be widening the rear housing, replacing the rear axels, gears, brakes and adding new hubs. Truck has been on 37s all its life. I have been thinking of regearing for the new BFG 40s. Working off the reasoning of the bigger the tire the smaller the bump. Several 1450 and 8 trucks have switched. Some have said 40s are for TTs and I replyed, 4WD is for rock crawlers but TTs are now running AWD! I wanted to hear some feedback positive or negative about making the switch?
 

Steve_Sourapas

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The BFG 40's are the best tire on the market today for overall off road performance for a full size truck if it has any power at all. Suggest you try a set before you re-gear and I would be happy to give you a set of my take off for you to try.
 

BTFfabrication

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Your right in making big bumps smaller, but if your built anything like me, a wheel/tire combo probably weighs more than I do! Haha I need another cheeseburger.
 

scottm

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Borrow a 40 first and make sure it clears the firewall, swaybars, bumpers, etc, over the full range of steering and travel. Then you have to think about upgrading brakes, driveline, spindles, hubs and axles. I figure a final diff ratio of around 5.6-5.8:1 will be about right (5.30:1 is not low enough imo). Oh and make sure your spare carriers clear the rear tires!
 

Evans Motorsports

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The BFG 40's are the best tire on the market today for overall off road performance for a full size truck if it has any power at all. Suggest you try a set before you re-gear and I would be happy to give you a set of my take off for you to try.
You may remember the Truck from CWI Jeff Geiser campaigned the truck for Dave for a few years,After Dave broke his back in the first race of the truck. Its no #1 of 5 class 8s built by GB I'm told. I would like a set of take offs to try, I will get back to you when I'm closer to doing some testing. We have a 530 gear set, may go to 587 with 40s.
 

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Evans Motorsports

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Borrow a 40 first and make sure it clears the firewall, swaybars, bumpers, etc, over the full range of steering and travel. Then you have to think about upgrading brakes, driveline, spindles, hubs and axles. I figure a final diff ratio of around 5.6-5.8:1 will be about right (5.30:1 is not low enough imo). Oh and make sure your spare carriers clear the rear tires!
Has a Christman rear end its being completely gone through and widened 3 inches. All new, I borrowed a 40 on a rim for clearance and tire mounting, just in case I make the switch.
 

Zac Reish

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The BFG 40's are the best tire on the market today for overall off road performance for a full size truck if it has any power at all. Suggest you try a set before you re-gear and I would be happy to give you a set of my take off for you to try.
This is pretty cool.
 

EOR1488

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You may remember the Truck from CWI Jeff Geiser campaigned the truck for Dave for a few years,After Dave broke his back in the first race of the truck. Its no #1 of 5 class 8s built by GB I'm told. I would like a set of take offs to try, I will get back to you when I'm closer to doing some testing. We have a 530 gear set, may go to 587 with 40s.

That truck is beautiful and has been a beast since it was made. Definitely be cool to see it out again
 

green787

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40's have no consciences.... :)
 

Evans Motorsports

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New front hubs 6 on 6.5, new uprights, with big bearings. They are in the works. Plus just Received Gearworks TT T-400 trans as the old trans had a cracked housing along with some cracked gears so we went full tilt on the trans and Torq converter.
 
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