any dramas using a different sized spare?

[grover7488]

hi

does anyone have any ideas on what would happen if you had a spare that was say a 32" muddie (810mm OD) and your other tyres were 29" roadies (735mmOD)? :confused:
If you got a flat could the spare be used in an emergency or would this do some damage to the running gear? :o

cheers

[dullbird]

yeh I was say you couldn't use it as your diff i would imagine would not appreicate such differences unless you could match the rolling diamenter with pressure in the tyres...........that would be my guess.

[CraigE]

Best to change both tyres (front or rear) if you are in a jam and need to use a different spare. My trailer tyres on 16" Rangie wheels are 225/75R16 and on the Fender 235/80R16 and while the wheels will fit and are similar the over all rolling diameter is different. So if I had a drama on the Fender and used the spare and had that fail I would take 2 wheels off the trailer (trailer spare and one of the wheel on the trailer) say it was rear LH and replace both rear wheels and put the odd ones on the trailer as it will not hurt the trailer. Safest way with minimal impact on your diffs and trans. Should be OK running different sizes front and rear for a short time but never one side only.
Cheers
Craig

[PAT303]

I wouldn't run different tyres at any time.If you can't afford 5 muddies you can't afford any,a 29'' tyre on one side and a 32'' on the other will destroy your diff in a very short space off time. Pat

[87County]

hi

does anyone have any ideas on what would happen if you had a spare that was say a 32" muddie (810mm OD) and your other tyres were 29" roadies (735mmOD)? :confused:
If you got a flat could the spare be used in an emergency or would this do some damage to the running gear? :o

cheers

you can use it in an emergency to get a few k out to the road for example, but with the LR centre diff setup, you are better having very similar rolling radius tyres across each axle, and preferably all around...

some sizes give very similar rolling radii even though they have different descriptions

eg, with 265/75/16 you can use a 235/85/16 or even a 7.50 X 16 to get you out of trouble

[grover7488]

i can afford the five mudies :o (barely!). it was just a hypothetical question as i wondered what would happen if you left the oversized spare on whilst back in the city and happened to puncture the **** "road" tyres. (another situation would be if you destoyed two of your muddies while on the trail and were hanging with guys running bigger tyres as to whether you could use one of theirs to get you going). I know that from my Pootrol :eek: owning days you could stick the odd one on the front and the stubby lever in 2H and be on your way (a bit lop-sided of course)

[numpty]

Not a real problem doing this on road, but off road with centre diff engaged would be a no no.

[350RRC]

I've driven about 100k's on bitumen with a 29" spare on. All the rest are 31's. Had no probs.

Then again, I've also driven 1000k's with the CDL on (accidently) and had no probs with that either, apart from weird tyre wear.

Must be lucky. DL

[jimbo110]

Not a real problem doing this on road, but off road with centre diff engaged would be a no no.
Many cars have space saver spare wheels which are a different diameter and width than the normal road wheels. An open diff would hardly know the difference and would be fine, a locker/LSD would be a different story. If you have standard diffs and dont engage the center diff lock on hard ground you will be fine.

[Lionel]

Many cars have space saver spare wheels which are a different diameter and width than the normal road wheels. An open diff would hardly know the difference and would be fine, a locker/LSD would be a different story. If you have standard diffs and dont engage the center diff lock on hard ground you will be fine.

I concur. Drive it as if you are using a space-saver. (Max 80 Km/h), and you shouldn't do any diff damage, provided you don't lock the centre diff.

Cheers,

Lionel

[weeds]

where bouts are you loacted?

[Albert]

Best to change both tyres (front or rear) if you are in a jam and need to use a different spare. My trailer tyres on 16" Rangie wheels are 225/75R16 and on the Fender 235/80R16 and while the wheels will fit and are similar the over all rolling diameter is different. So if I had a drama on the Fender and used the spare and had that fail I would take 2 wheels off the trailer (trailer spare and one of the wheel on the trailer) say it was rear LH and replace both rear wheels and put the odd ones on the trailer as it will not hurt the trailer. Safest way with minimal impact on your diffs and trans. Should be OK running different sizes front and rear for a short time but never one side only.
Cheers
Craig

I would dissagree with this. To run like that you will be making your center diff work hard. If you only run one different diameter wheel both the rear diff & center diff will share the difference in rotation speeds.
Al

[101RRS]

I always thought space saver wheels and tyres were to same rolling diameter - just a lot narrower.

Garry

[PAT303]

How many times do you think mechanics see broken vehicles because of things like this?.Their your vehicles and it's your money.I suppose you can aways jump on the ''LR diffs are weak'' arguement after you chew one up. Pat

[PhilipA]

AFAIR Land Rover recommend That the diameter difference between tyres should be a Maximum of 10% for emergency use. 235.85x16 is 11-12% more than 225.75x16 so you shouldn't do it.
Space savers are NOT the same diameter as the normal tyre , they are much smaller. The one in SWMBO Mazda 121 said not over 80KMH and 200Km? AFAIR.
I agree that one tyre would be better, as the rotational difference would be shared between 2 diffs.
I had the same issue as I had/have 245.75x16 on the car and 205.80.x16 on the trailer, but the rotational difference is only 6% without taking inflation into account. Luckily have never had to do it.
Regards Philip A

[numpty]

Many cars have space saver spare wheels which are a different diameter and width than the normal road wheels. An open diff would hardly know the difference and would be fine, a locker/LSD would be a different story. If you have standard diffs and dont engage the center diff lock on hard ground you will be fine.

I thought that's what I said;).

[hook]

That's why you have the trailer tyres and rims,
the same as your Vehicle.;)

[jimbo110]

I thought that's what I said;).
So did I, I was agreeing with you:BigThumb:

I just wanted to add the lockers bit.;)

[hodgo]

:eek::eek::eek:A lot of good advice given here, and I agree on highway would not hurt over a small distance 100 ks or so but If you were involved in any sort of accident you would / could have a big problem with your insurance company. My brother years ago had two different size tyres fitted on the rear of a ute lost control in the wet in a bend ute was a write off and the insurance coy wrote him off said the car was unroad worthy.

Hodgo

[jimbo110]

How many times do you think mechanics see broken vehicles because of things like this?.Their your vehicles and it's your money.I suppose you can aways jump on the ''LR diffs are weak'' arguement after you chew one up. Pat
So 1 revolution of the side gears for every 20 rotations of the wheels is going to chew the diff up? I hope you dont make too many right or left hand turns in your truck on the way to work, you'll wreck the diff. Likewise if you get stuck in mud for gods sake dont let a wheel spin, you'll wear out the diff. Different rotating speeds across the axle is what we have a diff for. The extremly slow rotation of the diff internal gears will do no harm at all, It's no different than turning a corner, and a very wide corner at that.

[jimbo110]

:eek::eek::eek:A lot of good advice given here, and I agree on highway would not hurt over a small distance 100 ks or so but If you were involved in any sort of accident you would / could have a big problem with your insurance company. My brother years ago had two different size tyres fitted on the rear of a ute lost control in the wet in a bend ute was a write off and the insurance coy wrote him off said the car was unroad worthy.

Hodgo
If the ute had an LSD that would be quite understandable, that would be very dangerous.

[grover7488]

seems like some differing :wasntme: answers! Some say yes others no.:confused: Anyone else have any expertise or experience with a similar situation?