Simple question, but since I have never given it too much thought...

What's the largest wheel / tire that will fit in the spare tire well on the 2004-2008 F150?

Or more simply put, will a 35x12.50/17 on a 17x9 rim be too big?

I am torn right now. I know 33x12.50/17 on that rim will fit. A neighbor has that setup on his XLT crew cab. I am about to buy new tires, and I am more concerned about the 12.5 wide than the 35" tall. Experience teaches me that the 1" extra ground clearance gained doesn't gain me diddly squat when driving down the beach to my favorite fishing spots...

 

Yes, a 35" tire will absolute fit but here a few tips to think about:
1. Full sized spare is only a concern if you have a limited slip rear end. If not, then you can run any sized tire back there.
2. Be sure your exhaust clears it. I ran a full sized spare for about a year but my exhaust was so close to the tire that it actually melted some of the tread after a long tow of my boat. I have since removed it and will put the stock spare back and swap front to back if I blow a rear tire.
3. A 35" spare is HEAVY. I used spare tow chain to secure it to the frame if/when that spare tire cable broke.
4. I got my 35" spare from the dumpster of the local tire shop...for free. Dont pay for one if you can help it.




Good luck man!

 

Exhaust is factory, so no problem there... The plan is to reuse one of my existing 35s as a spare... Yes a 35 IS heavy... I have already had a Ford pickup spare tire winch cable break on me. Happened on my old 2000 Ranger that was on 31x10.50/16s... I attributed that to the stress the cable went under when the truck was wrecked. Long story...

As far as tire size / differential issues, while I don't have a limited slip back there yet, that's on the agenda.... The truck is more or less a hauler and weekend toy only now, so for its age, it has relatively low miles, and assuming no major changes in employment for either msyelf of my wife, we are planning on finishing what we started to do before her layoff in 2009.

FWIW, the stance on your truck is right where I want to be... Not too tall, but tall enough to clear rubber and give me decent approach / departure angles...