Easy one. If you have to put a space saver on a 4wd or LSD equipped car are you at risk of wearing out the differentials, with the space saver being smaller than the regular wheels?

Hellcat said:

Easy one. If you have to put a space saver on a 4wd or LSD equipped car are you at risk of wearing out the differentials, with the space saver being smaller than the regular wheels?

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Only the wheel is different the internals of the diff are the same so output to the wheels remains the same - only the grip offered by the tyre is different.

unless the wheels had hugely different size wheels then it wont effect much. 4wd cars have a middle diff for this exact reason... to take up the variables between front and rear wheels

i can only imagen it possible to damage a diff due to tyre size if you ran 2 different size wheels on a single axel with differnt rolling radius tyres.

i cant see running a space saver ever causing a problem but you would never use for more than a few miles anyway, or would you?

Ry

You never know how far out in the sticks you may get a puncture.. Had to drive back from Scotland once as I got a puncture at 10pm... No other option but to drop the space saver on the rear and bring a rear tyre up front to replace the punctured one.

can only go in the old cavalier turbo
alright they had a crap 4x4 but with them even different tyre wear was seen as an issue
all 4 tyres were meant to be changed at the same time.
if you got a damaged tyre then all 4 were meant to be changed to keep the tread the same!!!

Hellcat said:

You never know how far out in the sticks you may get a puncture.. Had to drive back from Scotland once as I got a puncture at 10pm... No other option but to drop the space saver on the rear and bring a rear tyre up front to replace the punctured one.

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but a space saver is going to retain the rolling radius and so not be an issue....

Space savers are not the same radius... Bunny's Croma has large radius 17" wheels, the space saver is tiny compared to them.

really?

i understand the rim is smaller but i though they compensated by fitting a high profile tyre to it?

bulldog5046 said:

really?

i understand the rim is smaller but i though they compensated by fitting a high profile tyre to it?

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I'll dig it out and take a photo.

While we're on the topic of spare wheels - is it illegal to fit a directional tyre the wrong way?

I've been offered a tyre which would fit my newly aquired steel wheel but it's directional - and would only fit one side of the car! I guess it gives me safety on one side of the car at least over the stop and goo kit if it's illegal to fit to the wrong side of the car.

In reference to your first question, yes it would wear the internals out IF the rolling radius is different.

I was under the impression that the centre diff/transfer case was there to split drive to the front and back, not to adjust for inadequacies in the wheels. Happy to be corrected though.

the centre diff takes up differences. and slipage. if it was not there you end up binding up the drive shafts which leads to exploding diffs or drive shafts snapping like spaghetti.

pretty much all 4X4s have either a centre diff lock (offroaders usually) or the centre diff is a LSD.
if it never had a lock or LSD when one wheel starts to spin ALL the power will go to that wheel. (which would be useless offroad as you can imagine)

Hellcat said:

I'll dig it out and take a photo.

While we're on the topic of spare wheels - is it illegal to fit a directional tyre the wrong way?

I've been offered a tyre which would fit my newly aquired steel wheel but it's directional - and would only fit one side of the car! I guess it gives me safety on one side of the car at least over the stop and goo kit if it's illegal to fit to the wrong side of the car.

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It would fail an MOT so yeah pretty much so - reason for fail would be that the tyre is not fitted as per sidewall instructions. Directional tyres disperse water much better as per the tread pattern, if it was fitted the wrong way water would collect in the tread and give an aquaplane effect.

Ideally you should have a pair of rotationals fitted on an axle as they would have different behaviour in the wet leading to unpredictable handling.

Citizen Smith said:

It would fail an MOT so yeah pretty much so - reason for fail would be that the tyre is not fitted as per sidewall instructions. Directional tyres disperse water much better as per the tread pattern, if it was fitted the wrong way water would collect in the tread and give an aquaplane effect.

Ideally you should have a pair of rotationals fitted on an axle as they would have different behaviour in the wet leading to unpredictable handling.

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A pair of rotationals? WTF are rotationals? Never heard that before.

Well it'll be good for 50% of punctures

As for space saver diameter vs normal wheel.....

When I say rotational its the same as directional

Hi everyone . . .
I'm very new to the fiat 4x4s but thinking of buying one and converting it to LPG . . . .
The reason I'm posting this here is I'm wondering if anyone knows if the wheel well where the space saver is kept is big enough to house the tank?
I'm trying desperately to find a small 4x4 that has a wheel well so the valuable boot space isnt taken up by a big tubular tank . . . .
Also . . . . does anyone know if the engines could cope with the conversion?

Thanks in advance for any advice,
Charlotte

I know that there were problems with Volvo 4x4s in as much as that they would refuse to do warranty work on diffs if even one tyre on an axle had less tread than the other.

It would appear that slight differences in rolling radius between two wheels on the same axle were a problem, at least for Volvo.