Running a smaller size tyre as a spare

Post by **Davidh** » Mon May 17, 2004 2:30 pm

I'm sure a lot of you guys have had the problems of not having a full size spare tyre.
What I'd like to know is whether or not it's a big issue for your diff's and transfer case.
Most people say only LSD diffs will have a problem with a smaller tyre on the same axle, and that an open diff will be ok.
Similarly, a diff with a locker in it, will be ok if you don't engage it.
Is this the case?

Now, transfer cases. How will they behave to having one tyre on an axle being smaller? Viscous t/cases, part-time, full time etc. How will they go?
Obviously if you had a part time, you could put the smaller tyre on the front end and leave it in part time, but on a full-time, can you do this?

Post by **Daisy** » Mon May 17, 2004 3:47 pm

varying sizes can be on an open diff centre - not recommended thou.

Rear diffs - of course being an lsd or any sort of locker - its still not recommended having a different tyre size at all on the rear.

I must ask.. why would you want to run a differnet sized tyre? perhaps you dont have a 5th.. then its still worth lookin into gettin a 2nd hand one.. even with mimimal tread - just worth the hassle to prevent further problems.

TOM

Post by **Guy** » Mon May 17, 2004 3:54 pm

GQ wrote:varying sizes can be on an open diff centre - not recommended thou.

Rear diffs - of course being an lsd or any sort of locker - its still not recommended having a different tyre size at all on the rear.

I must ask.. why would you want to run a differnet sized tyre? perhaps you dont have a 5th.. then its still worth lookin into gettin a 2nd hand one.. even with mimimal tread - just worth the hassle to prevent further problems.

TOM

I may be an issuse if you run 35's or bigger, making carrying a full size spare quite difficult ..

Post by **-Scott-** » Mon May 17, 2004 6:11 pm

There is also that narky old legality issue - "same size and type on an axle" or something. For an emergency, to get to a repairer, you could probably talk your way out of trouble.

Scott

Post by **Wooders** » Mon May 17, 2004 6:12 pm

Small variance is ok with an open diff, or an unlocked selectable locker.....but really best to have the same size if you have LSD, Auto locker or spool......

But even with an open diff - if you have a big difference between the tyre szies it will effect you handling at speed....sepiously best to try and keep 'em roughly matched IMHO.....

Post by **Area54** » Mon May 17, 2004 7:13 pm

Better to have a full size spare - when you hole one on the trail, the driving doesn't have to stop for the rest of the day/weekend. Heaps of second hand good'uns around.

Post by **Spartacus** » Mon May 17, 2004 7:20 pm

a mate told me that different tyres f-cuk diffs.

best to move the broken rear onto the front and have
two same tyres on the drivewheels.

i thought it this was half right advice.

lucas :evilbat:

Post by **MYTTUF** » Mon May 17, 2004 7:27 pm

Wot Area 54 said.
You need a same size spare to keep you moving while you're out there but sometimes carrying it can be a prob but it is still worth that hassle. Get a same size spare even if its old its still better than a smaller size one.
You can get a narrower tyre the same height which is better than a smaller one.

Post by **N*A*M** » Mon May 17, 2004 7:37 pm

if you are camping (hence don't have the space for a full size spare) carry a space saver spare on the rig and leave a full size spare or comprehensive tyre repair kit at the base camp or trail head

Post by **Wendle** » Tue May 18, 2004 7:03 am

i drove around on 37"s for a year or so with no spare at all, just carry a repair kit, mobile telephone, and case of beer and it isn't a problem..

Post by **80diesel4play** » Tue May 18, 2004 8:56 am

Wendle wrote:i drove around on 37"s for a year or so with no spare at all, just carry a repair kit, mobile telephone, and case of beer and it isn't a problem..

Like your style big fella!!!

I know others that follow this philosophy!!

Prolly half our club...

Post by **Shorty40** » Tue May 18, 2004 9:44 am

N*A*M wrote:if you are camping (hence don't have the space for a full size spare) carry a space saver spare on the rig and leave a full size spare or comprehensive tyre repair kit at the base camp or trail head

Where can I get me a space saver 38" tyre :?:

Post by **turps** » Tue May 18, 2004 10:31 am

Theres no legal problem with having a spacer spare. Most new cars now come out with a spacer. Mechanically it would be better if you had a part time 4wd. Then which ever flat you got rotate the tyres so the space saver is on the front. Then just take the car out off 4wd, also take the front hubs out. Then the only difference is the car will handle wierd as the it is now driving on the edge of the tyres (cos they are leaning over - due to one being smaller).
Had this happen on a 60series. We didnt know the full size spare was a nissan split rim (which dont fit on the front of 60's due to offset - rubs on tierod) and the actual spare was a 29" tyre (the rest where 32"). We just did what I wrote above and it was fine there was a couple of times when it had to go into 4wd, but since it was a very broken up surface there was no chance of windup.

In vic the car is un-roadworthy if the spare is wornout, but if you take the spare off then the car is roadworthy again (as long as the rest of the car would pass).

Post by **Guy** » Tue May 18, 2004 10:45 am

turps wrote:In vic the car is un-roadworthy if the spare is wornout, but if you take the spare off then the car is roadworthy again (as long as the rest of the car would pass).

Initally when I heard about this I thought .. thats farken stoopid .. but after a bit more thought it does make sense, as it's not illegal to have a flat tyre, but it it illegal to drive on a bald tyre ..

Outer Limits 4x4 Board

Running a smaller size tyre as a spare

Running a smaller size tyre as a spare

Who is online