spare wheel question

[markeyszoo]

I have 225 x 18 tyres on the front and 255 x18 on the rear. i have in mind to replace the yellow spare with a full size rim, say 255 x 18.

If I do can i run it as both front and rear spare or does this make for a different wheels/same axle problem.

[Linas.P]

I would go with either 225/18 or even better with spare from IS/RC200t which is about the same size as 18" wheel. Well I guess that defeats the purpose of full size spare. 

You can't fit 255 in the front, so that is out of question. By the way why do you want to replace spare? 

[markeyszoo]

2 hours ago, Linas.P said:

I would go with either 225/18 or even better with spare from IS/RC200t which is about the same size as 18" wheel. Well I guess that defeats the purpose of full size spare. 

You can't fit 255 in the front, so that is out of question. By the way why do you want to replace spare? 

I do not want to be miles from home and have to limp home on motorway at 50mph.

why can not fit 255/18 on front?

[Linas.P]

Because it won't fit - 255 will catch on at least arches. I think 235 is most you can get, maybe 245 with different offset, especially on 18s"

50MPH is not exactly "limp mode" and considering british motorways one is lucky to even reach such speed 😄 

The way I see it - 50MPH is enough to get you to the tyre shop where you can get the tyre fixed or replaced, I never had an issue using spare, but obviously that is your decision not mine. Generally, I understand when people without spare (like IS300h) wants to get spare, because glue kit is frankly useless and I been in that situation myself where I had to get trailer, just because car did not have spare and glue kit did not work and left me stranded, but spare is generally enough to get you where you are going. This would be first time where somebody is looking to get full size spare on car with staggered set-up. Normally people are getting full size spares on AWD, because different size spare could mess-up the differential and thus it makes sense, but AWD cars usually have square set-up.

[LenT]

5 hours ago, Linas.P said: 

The way I see it - 50MPH is enough to get you to the tyre shop where you can get the tyre fixed or replaced, 

Exactly so!

I take it, Mike, that by ‘yellow spare’  you refer to the SpaceSaver wheel.  

Well, normally it would be illegal to fit different sized tyres on the same axle. But an exception is made for a SpaceSaver precisely because it IS speed limited and provided you can demonstrate that your journey with it is for the purpose of travelling to a tyre repair/replacement facility and not merely to go about your business.

I too require different sizes front and rear.  I’ve only had to use the SS once, when a well-meaning lad snapped the tyre valve clean off!  In such circumstances the gloop kit would have been useless, so I was grateful to have the SpaceSaver to get me to a tyre retailer.

I don’t think the speed restriction is really too onerous considering the rather more significant problem that it solves. 

[scudney]

Lol a bit over the top,but I have 2 spares,1 in the wheel well and the other in the boot 🙂

[Linas.P]

maybe a little bit... 😄

I just check tyres before I set-off for longer trip.

[SeanR]

A bit of a divvy question whilst on the subject, actually been on my mind recently.

 

If changing the 17" wheels for Lexus 18" wheels, would i need to buy a new space saver or would the one in the boot be ok to get me to a garage ?

[NemesisUK]

It'll be fine as the rolling circumference will still be the same.

[J Henderson]

On cars with 18" wheels the space saver is still the same. I believe there's just one wheel that's fitted to all cars - a 17x4 steelie.

However, there is a variance in tyre size depending on OEM wheel fitment.

125/70R17 is specced on cars with 16 or 17" wheels. Meanwhile a car that had 18" wheels from the factory has a wider tyre on the spare - 145/70R17.

Unless you don't have a spare at all, I wouldn't bother pursuing the "correct" one.