I'm soon going to order some 315/75 R16 tires from Tire rack and need some feedback regarding upgrading the spare tire as well...

Just for info and after reading many threads it looks like the Goodyear Dura Tracs are the best choice for me.

Now I'm not sure if I order a 5th tire for spare as well?
Currently my spare is nice packed and soon will move in the trunk.
The bigger tire takes more space and if I keep it outside it will also not be so good to the tire without cover.

Till today I never had to use a spare wheel and because it is only as an emergency solution I would rather stay with the smaler spare.

Is there a technical issue if I put on a smaller spare tire?
The differentials should have no issue to compensate this!? ...just to come home safe in case...and sure in normal mode.

Please some feedback or advice!

 

All tires need to be the same size

 

this was discussed to death and back
a guy drove 10000 miles with 2 sizes on his car!!
some new veh,pickups, come with a standard tire,smaller size.
some caddy awd come with small spare.
the war starts again i spose.
yes the diff gets a little more xercize,not much.
oh,u can drive in circles all day, same effect,etc,etc,,,

hang on,the x perts will say no

 

Thats probably the best response ever drtom. If you are leaving the spare on for a short time id say no worries 3in aint going to do much man. Im only familiar with what weve done to military vehicles, and let me tell youve ive done stupid stuff with everything from humvees to strykers and noticed that all those things that people say may cause issues doesnt really matter. I however like to think i have good luck. At any rate id say Its your call it may cause issues and you might never even have to use the spare. Do i leave my jumper cables in or do i take em out for room for more beer? Your call brother.

 

Thanks for the advice...
Actually I'm thinking the same but just in case I do forget to consider something I ask before I order.
If I would need the spare, it would just be to bring the H3 home...then fix the problem....never did I plan on driving with the spare for longer...or at higher speeds.

 

I have a h3t alpha. Given that you do not have all wheel drive you can have a smaller size spare tire. But for those of us who have all wheel drive, all the time, its best to have all the same size tire, which included the spare. I would rather have a smaller tire hanging on the tail gate.

 

The reason you cannot/should not use an odd size spare is the differential needs to turn both wheels the same speed. With a smaller spare, this is not possible because the smaller will want to turn faster. This will damage your axles and differential since it's an all-time 4wd vehicle. Not to mention if the smaller is turning faster, it may play hell with the Stabli-Trac.

On a typical car, this is not a problem because you only have 2 wheel drive and you have a different type of differential.

My advice is to get a full size matching spare and avoid any unseen headaches, especially in a emergency situation which caused you to use the spare.

 

here it comes! i warned u!,,,fine tune your bs filter and watch people come in and make stuff up with no facts to support it!

whatever u do,dont drive a hummer in circles,always drive in a straight line. if u go to walmart and drive around the lot ten times your h3 will be destroyed,all axels will fall out and the gears will disinigrate,and,,and,,the lites will burn out!

open diffs are open diffs

 

Where are your facts to support that you can have one tire with a difference of 2-3", compared to the other 3 tires, and everything will be great??

The standard differential, or what is referred to as an open carrier, is what comes with most OEM vehicles. The open carrier holds the ring gear in place and within the open carrier is generally a set of gears called spider gears. These spider gears are responsible for allowing a vehicle to negotiate a turn and allow the outside wheel to travel farther and turn faster than the inside wheel. So...if you have the smaller tire size constantly spinning faster, the spiders will always be engaged creating more heat which will eventually FAIL!

So tell you what, with all this money that you have saved by not buying useless mods (intakes, shocks, locking fuel doors, etc) that myself and others have purchased, go buy yourself a tire 2-3" smaller in diameter than what you have and see what happens.

 

I've heard arguments both ways, but ultimately I don't think any will disagree that having one tire smaller than the other 3 in an AWD car is going to cause more stress. Whether it's the same as driving around in a circle 10 times or you have a 50/50 chance of making it 10 miles... The truth is somewhere in between. How much the speedo, traction control, stability control, an ABS are affect I haven't a clue. Probably not much, but maybe?

Personally, I'd just get a same sized spare and not worry about it. If not, treat it like a donut - 50 mph and 50 miles max.