Correct pressure for "get you home" spare tyre?

[Sad555]

After picking up a large stud in the rear tyre yesterday driving on the M5 ,getting the AA to recover the car on a low loader to a service area a couple of miles away,dropping the car off and then calling another AA mechanic to change the wheel.?any way after fitting the spare and checking the pressure on their system found it should be 38psi which sounds about right for a standard tyre,even if not the same size as the others,and by the size of the damage glad I was carrying a spare and not gunk.

[StevesTruck]

As per p.209 eng. pdf manual:

"The inflation pressure for this spare wheel is identical to the maximum inflation pressure of the standard tyres"

I'm assuming they're saying set it to the highest pressure given for a tyre on a fully loaded car, in case you have to fit it to a fully loaded car.

I normally keep mine at about 45psi (tyre pressure for my car is 32psi). Far easier to take some out than put some in if it's gone down between checks. The spare sits face down in my car, so it only gets a poke each week to check it's not gone flat, rather than the pressure gauge on it like the road wheels do.

[Michaelski]

Am still waiting for some knowledgeable ubermenschen to give the answer to the definitive recommended tyre pressure for a space-saver spare for a 75PS Greentech - even more so, as I've now just bought a SE for a member of the family, and it too has no recommended pressure for the space-saver - and we're talking safety, if not life or death, here.    And whilst on the subject, there have been comments to the effect that a "normal" spare wheel would not fit in the tyre well.

 

However (& it is a BEEG however) IF a space-saver has the same overall dimesions as a normal "road" wheel (albeit, perhaps less wheel & more tyre) to give the same rolling measurements, then if a space-saver will go in the boot, then so will a normal wheel + tyre - or is my logic flawed?

I guess that it mostly comes down to the manufacturer saving some £100+ on every car that they manufacture, plus of course the £50 - £150+ that they then make on flogging space-savers to a goodly number of buyers.

But it's hardly rocket science for Skoda (or the Dealers) to say with any degree of credible assurance, that "this is a space-saver wheel & tyre, & THIS is the correct tyre pressure for it".

 

Life used to once be so easy!!!!    sigh.

[Urrell]

From my manual page 192
""The tyre pressure for the spare wheel should correspond to the highest pressure specified for your vehicle.""

[Michaelski]

Thanks Urrel, That is what I've set mine to, but it was more a case of inspired "logic" than based on informed knowledge.    In my last car (accepted that it cost more than 4 times what I paid for the Citigo) the space-saver was clearly (very clearly) specified as a space-saver, & the manufacturer's recommended tyre pressures also included the SS - it was set at 60psi.   However, it was never used in the 10 years that I owned the car, so hopefully, neither will the new one. However, for peace of mind, it is nice to know, so thanks once again.

[Frenchtone]

std wheel probably will fit, but will no doubt raise the boot floor level because of its lateral dimension, and as such could you live with that situation?

[DGW]

However (& it is a BEEG however) IF a space-saver has the same overall dimesions as a normal "road" wheel (albeit, perhaps less wheel & more tyre) to give the same rolling measurements, then if a space-saver will go in the boot, then so will a normal wheel + tyre - or is my logic flawed?

The standard tyre size for my 2015 Yeti 1.2TSI DSG Outdoor is 225/50 R17 94W mounted on a 7J x17 ET45 alloy rim whereas the full size (but not same size) spare is a 195/60 R16 89H tyre mounted on a 6J x16 ET40 steel rim. Two problems arise when trying to fit that standard tyre into a wheel well designed for a full size spare. First, the diameter of the standard tyre is 0.67" greater than the spare so the wheel will not sit in the small shaped recess for the spare; and second, the tyre width is 1.18" greater. The end result is that the standard wheel raises the centre of the boot floor by more than the latter figure resulting in a noticeable gap, and any load would be carried by the alloy rather than the boot floor. Also that wheel cannot be secured since the securing screw is not long enough.

I investigated buying a standard alloy as a spare to avoid having a speed limited spare but binned the idea because of the poor fit and inability to secure it in place.

P.S. Why on earth a car with a top speed of 108mph needs tyres with a 168mph (W) speed rating is a separate issue which is beyond me.

[Sad555]

The only problem I have with the spare wheel is the shape of it,as it has to be located outer wheel face up which means if the hollow of the wheel was face up it would provide some more valuable space for storage,apart from that I find the spare fine.

[ejstubbs]

My understanding is that the spare wheel stowage was changed ~2011 to have the wheel dish facing up, using the space to store the tools associated with the spare ie the jack etc. AFAIK you can't retrofit this arrangement to earlier versions because the floor pan of the boot is shaped differently to accommodate the wheel being the other way up.

I use the space under the wheel to store things like jump leads and towing strops, which can be snuggled around the retaining post. If I could be bothered, I would find a circular container which could be modified to fit over the retaining post, which would keep the stuff in rather better order. Perhaps one of those plastic tubs that you get polyfilla in would fit the bill.

[ejstubbs]

...the vehicle would be running on 3 x Alloys & 1 x steel wheel - something NOT to be recommended.

 

Purely out of interest (since it's not something I plan on doing any time soon) is there a particular reason why running on a mix of alloy and steel wheels is a bad idea?

[eribaMotters]

The spare in the Yeti is as said earlier a "normal tyre". The speed and load rating are suitable and legal for the car. I also thought the rolling diameter is sufficiently similar to that of the road wheels fitted. With these points in mind I believed the 80kph yellow sticker is an advisory only.

 

Colin

[Rooted]

'Normal tyre',

 but surely if you fit it you only proceed at 'Normal speed',  if the other 3 tyres still on the car match pretty much identically.

*Other wise reduce speed until you have front and rear pairs of tyres matching.*

(& there are cars fitted with Directional tyres, and cars with Front or Rear Pairs of different sizes, 

the spare might be OK for temp use on either side, or either end, but it is still not matching.)

 

The Spare is Maybe brand new unused, still green and fresh,

not the same Profile / width/ tread/ compound and actual size, nearly the same size, but not the same.

Ii is not a Space Saver, but a Steel Wheel, Narrower to take up less height in the Spare Tyre Well, 

so weighs less or more than the cars standard alloys and full width tyre.

 

So you still use as a temp spare tyre/wheel until you get the tyre fixed or replaced, and even then the new odd one out needs 

some running in and the pressure set to suit your safe driving.

 

Advisory because it is sensible to slow down with an odd sized or style of tyre on a car, 

maybe never an issue on a dry straight, but take a corner in the wet and it can be very noticeable, 

especially with ABS, ESP etc etc

[Carlodiesel]

For those of you who find checking the spare wheel pressure a bind, & having to unload the boot area try this.

I used to fit these on Vehicles with difficult to get to spare wheels.

You can then check your spare wheel pressure at the same time as doing the others.

 

ACCU GAGE PRO CHECK A SPARE CARAVAN CAMPERVAN WHEEL VALVE EXTENSION HOSE Z327

• £4.99
•  
• + £2.98 postage
• eBay item number:

  381056291816

   

   

   

[Expatman]

P.S. Why on earth a car with a top speed of 108mph needs tyres with a 168mph (W) speed rating is a separate issue which is beyond me.

Beyond me too! My Yeti was delivered with H tyres as original equipment - 215/60/R16 H, Conti Contact 2's - yes I am one of the few who successfully ordered a Yeti with 16" wheels. Just changed all 4 tyres and tyre dealer would not believe a Yeti had original  'H' tyres until I tool the car in and showed them. Ended up putting on V tyres because I wanted Goodyear Efficientgrip Performance and they only come in V rated or above. Only done about 100 miles with new tyres but they are grippy and very, very quiet.

[Michaelski]

In addition to receiving the answer from Urrell (thanks once again for that) I had also previously played a wild card, & asked Skoda’s technicians.

Their answer (the definitive answer) was that the spare wheel should always be inflated to the highest of the pressures for the normal road wheels.                It would appear that the “50 mph maximum” quoted on the spare for the Greentech models, is an ultra-safety precaution, as if the spare was used, they would be running on 3 x Alloys, & 1 x steel wheels.  This is born out by the spare on the SE that we have recently purchased for a family member, as the spare supplied with that, is not only identical to the 4 steel road wheels, but there is no warning attached to the spare wheel either.

And Inn Sea Dent Ali, and in view of some of the less-than-complimentary remarks about Skoda’s after-sales interest to customers, I’ve had cause to approach Skoda’s hombres with questions about both vehicles.  In all cases, their responses were fast (almost immediate, in fact) extremely helpful, courteous & indicating a desire that their customer’s were happy.     

So there you go, then!!!!!!!!!!!!!!!!      

[ejstubbs]

So good, he posted it four times...

[Sad555]

As per p.209 eng. pdf manual:

"The inflation pressure for this spare wheel is identical to the maximum inflation pressure of the standard tyres"