Spare tire storage/location

[MeatyCrab]

Hey dudes,

I'm thinking of getting larger tires soon (33" vs stock 255/70) and was thinking about where to put the thing. I'm assuming it won't fit underneath without any serious modification.

My choices are on top, in the cargo area or have a bumper carrier made.

The other alternative that I was thinking about, was to leave the spare at home, and only take it out when I go on trails and stuff. Is this a dumb idea? I'll get a can of tire foam pluggy stuff.

I've heard that with tire technology these days, it's rare to get a flat on the street, especially with LT tires.

Is this logic OK?

The reasons to not bring a spare (on the street) are to reduce weight, therefore mileage (wishful thinking?) and handling.

Also, because it won't fit in the stock mount.

Any suggestions?

Thanks,
BK

------------------
Don't forget to put your pants on.

 

[Ray Lobato]

Yo BK,
Don't leave home without one. Put it in the cargo area and strap it down, nothing like having a 50 pound projectile shooting at the back of your head when you have to stomp on the brakes. The extra 50 pounds from the tire will only save you about .002 gallons, so it wouldn't help as far as gas mileage goes. Yes it might be rare to get a flat, but when you do get one and don't have one, tha's when you kick yourself for not having one. Think of it as insurance. Dead Link Removed

------------------
Happy Wheelin'
Ray L.
97 XLT 4X4 4.0L SOHC

 

[Rick]

I have two 33" spares for my Explorer now. One is mounted to the rear bumper/tire carrier and the other is mounted inside the truck.

I removed the small section of the split rear seat and bolted angle iron to the studs where the seat had bolted to. I stand the tire up verticle and strap it to the angle iron anchors with two ratchet tie-downs. It's rock solid and easily removed when needed.

------------------
Rick Horwitz
Editor
explorer@4x4central.com
Editor
www.4x4central.com

 

[tiessen]

Rick,

can you please post pics of both the tire carrier bumper and the cargo area tie down for us all.

Cheers

Dale

 

[Trckmagik]

Yeah! Rick we need to see the inside of your explorer. If my rear cargo area was not full of speakers then I would install one of those tire carriers that you see in the back of Baja trucks and mount a tire right there. This would be better than getting stuck w/out a spare and it would look nice to! Let me know where I can get a safari type roof rack for my Explorer. I am being picky. I dont want it to far off the roofline. What brand do some of you guys have on your roofs?

------------------
Brian Green
92 2wd Explorer w/
6 inch Suspension lift
92 2wd Ranger w/
5.5 inch suspension lift

 

[briantf]

I consider spares a temporary solution, so why would you neccessarily need a similar sized spare?? Why not keep the original and make do until you get back to civilization?

Depending on the extremes, I can see that not working, but it seems to me that leaving the stocker underneath for everyday driving harms nothing (even with a ltd. slip), and you can drag along the matching sized spare if you head out to the boonies.

By the bye, my good buddy is in Oz right now, he emails with this:
"They have
real 4X4's down here- all of them have snorkels and non of them are clean-
lots of red mud all over the windows and you could see the water lines very
high on the side of the trucks."

I'm VERY jealous!!

Best Regards,
Brian in CA

 

[Kyle K.]

Brian wheel speed abs crap aside you are still in bad shape if the flat is on the rear of the truck. unless you want to change the same size tires to the rear and put the small spare on the front and disengage the 4wd you need a fullsize spare. you know an open diff transfers power to the wheel that turns easiest then consider that when you have a 33 and a small spare 28" that were traction to be transferred to the opposite tire while in motion the gears would get a wake up call, with a lim. slip or locker you absolutely could not do it, you would probably not even get moving .. much. a desperate solution to this is to air the big tire way down til it is closer to the same size just long enough to get help or service.

please don't grenade your diff tryiong this.

dodger

 

[briantf]

Heh! Kyle, do you even know what a limited slip does, as opposed to a locker??

Too bad all those Mustang/Camaro/Corvette owners have destroyed their limited slip rearends running those space saver spares!

Seriously, relax.

Brian

 

[Tom Wilk]

Greetings,

Well, I did some thinking about using a smaller spare, and this is what I came up with.

BTW, when I had my Mustang, it did have that miniature spare tire. The manual also had a warning that extended use of that spare with a limited slip differential would result in the "loss of effectiveness" of the limited slip.

This makes sense, since the axle shafts will be spinning at different speeds. The differential spider gears will rotate to account for the different speeds, a motion which the clutch packs tend to resist in a limited slip. So, there will be wear and tear on them. I imagine that the amount of wear would be dependent on how far you drive it.

I did some calculations based on having a 28" tire on one side of the rear axle and a 33" on the other. At 50 MPH, the 28" tire will be spinning at 600 RPM, while the 33" would be spinning at 509 RPM. The difference will have to be made up in the differential. As far as the ring gear, it will spin at a speed somewhere between 509 and 600 RPM, probably somewhere near the middle or about 535 RPM if bearing friction and such are about equal between the two axles.

The difference between the wheels is what will put wear on a limited slip, though I don't think it would cause too much wear if you just drove a mile or two to the gas station for repairs.

With the control trac system, there might be a tendency to incrementally engage the clutch in the transfer case, depending on what speed the ring and pinion tend to rotate. I would think that as the control trac system increased the clutch's engagement interval, there would be a tendency for the pinion speed to match the speed of the 33" tire, assuming that the fronts had 33's as well. This again leaves the burden on the differential gears to rotate enough to let the 28" tire spin at it's higher speed. In effect, the 28" would be free-wheeling. With a locker, this wouldn't be a problem, as it is designed to allow a tire to spin faster than the drive train through the ratcheting mechanism (or whatever it is called). So, as far as I can tell, that wouldn't be a serious problem.

The real problems I see with using a smaller spare come in the area of handling and off road capability. If you are out on a trail, you would want a spare that gives you equal or near equal traction to the other 3 tires. You also want to retain ground clearance. In both cases, a smaller spare would not be as useful as a full sized spare. A smaller tire won't traverse smaller ruts as well as a larger tire either.

On the road, there will likely be a significant difference in handling with a smaller tire. It's load rating will probably be smaller, and as a result, its sidewall will flex more when cornering. The truck will feel like it's rear end is not connected to the vehicle. You're going to sway about when cornering. Braking, ABS notwithstanding, will be awkward as well. The brake on the smaller tire will tend to lock up quicker, as the rotor has a better mechanical advantage when comparing the distance from wheel center to tread against that of the larger tire.

But the most important reason for not using a smaller spare is that it will look geeky. People will point at you and laugh if you have three large and one small tire on your car. Trust me on that one. Dead Link Removed

------------------
Tom