Tire Decision and Speedo Calibration

[Zilverado]

Okay, so I think I've made a decision about new tires for the truck...

I will likely be buying a new set of BFG All-Terrain T/A tires for our Pathfinder. The current set is only 4 years old and they still have a fair amount of tread left (I have not measured it yet). The plan is to recycle the "used" tires onto the 8" wide rally wheels on the truck - since it is not a daily driver, I anticipate the BFG's will still last me a number of years.

The BFG's are 31x10.5 R15

So the questions are...

* I assume the truck wheel wells should accomodate the slightly larger diameter tire? The truck actually has the heavy-half (camper special) suspension system, so it has slightly higher ground clearance than the standard C-10.

* Since the overall diameter of the BFG's is slightly larger than the P265/75 R15 currently on the truck, my speedo/odo will be slightly out. Should I look at changing the gear head on the tranny end? If so, what size would I be looking for?

Any help/comments would be appreciated.

Thanks Guys (and Gals).

[Zilverado]

OK, so I did a little looking around, and it seems a 265/75 R15 is only about 1/2" smaller in diameter - 30.6" vs. 31". This results in about 2" (or 2%) difference in overall circumference of the tire.

So, I'm guessing I really have nothing to be concerned about here?

[dswancutt]

They will fit. My 78 k-10 was came from the factory with 10.5 x 31. I actually did the opposite of what everyone does and went to 235/75, I found that it handled better, it both the rain and snow.

[Zilverado]

So I took a little closer look at the BFG's I want to transplant onto the truck. According to the BFG information, the All-Terrain T/A starts off with 16/32" (1/2") of tread depth. I measured the remaining tread yesterday and it looks like right around 12/32" (3/8") left. So I feel pretty confident in putting these babies on the truck and getting a number of years out of them yet.

And of course White Letters Out!!!

[Zilverado]

OK - now I feel like an idiot.

I took another look at my truck tires and it seems I've been running 235/75, NOT 265/75.

So the 31x10.5 will definitely be bigger, but they should still fit right?

[Palf70Step]

They should fit, and the 31s are about 1.5" taller. Your speedo will be around 5 MPH off at 60 (you'll be doing 65 when speedo say 60). I had a set on my 82 2wd for a while and hand no clearance issues. They work great on 8" ralleys.

[Zilverado]

Yeah they actually fit great - no clearance issues.

A little dirty, but...