I am putting 285/75 BFG All Terrains on my truck on Friday. Anyone know if it will mess with the speedometer and make it register incorrect speeds? If so, how many mph is it off? I had the same size tires on my Chevy and it changed the speedometer by 4 mph... according to the highway patrol anyway !!!! The Chevy guys wouldn't even check to see if it threw off the speedo, let alone change the computer to recognize the larger tires(they said they were too big for Chevy specs.) And just for the record, that will be my last Chevy truck.

 

Yes it will, about 5 MPH should be close

 

Thanks Dave. Another question I have is what is the largest size you can put on a 99 F250 4x4 without having to add a lift or experience excessive rubbing when making sharp turns??

 

According to a tire size-speed calculator formula, I found on another site, the change in speed with 285s would only be about 3 mph. I am planning on running the same tires as my next set. I am also looking into the Bridgestone Dueler A/T Revo. I am told they have excellent tread life and clean out better in the mud than their old design. Prices on both the BFGs and the Bridgestines are pretty close to the same.

 

99Turbo,
It kind of depends on how you drive your truck as to how big you can go. If you're going to be roughing it up on trails and stuff you can't run too big or else you'll tear your fenders apart. If you're just doing on road driving you can afford to run a little bigger. I'm not sure what size you can run without over doing it. I have an F-350 and don't even think I can run 285's like the guys with the X springs up front. Somebody here should be able to tell you what you can run by looking at the specs of your truck.

 

99Turbo, I put the 285's on my 2000SD/PSD about 3 weeks ago. Shifted up from the stock 265's. I have had no issues to speak of. When I turn the wheels all the way to the left or right, I get a very slight rub on my mud flaps. Not a big deal, not causing any damage to the tires or flaps. As far as the speedometer goes, I have noticed (and checked some available web sites to confirm) the errors will be more noticable at higher speeds (about 1 mph error at 30, 2 at 50, 3-4 at 65). I have confirmed the errors with radar (no, did not get the data when I got pulled over by a person with flashing lights and the noisy siren thingy) I have available here. Love the tires, got them at Les Schwab dealer up here in Washington for about $140 each. Hope this helps and wish you the best of luck.

-Glenn

 

Thanks alot guys. It is pretty impressive at the responses on this forum. It is definitely the best forum I have seen for the PSD owners out there.

 

I like to consider this my home away from home. Just one big happy (mostly) family! I've only been on for just a few months and have learned so much from these guys.

 

Yea man - this is the place for learnin'!!
I had 285/75's on my truck with no rubbing ever - I have 305/70's now with a 2" leveling kit and they rub a little bit. If I did any hard off roading I'd have to go with 4" up front to keep them out of the fenders.