Hi,

We have a Scala SE 1.0 TSI 115 PS 6G Manual, bought new October 2019.

On the inside of the fuel filler flap is a table giving recommended tyre pressures.  The table proposes the very high pressure of 4.2 bar for a spare tyre 125/70 R18.  But that size would be a skinny space-saver tyre, while the spare supplied is a Continental Ecocontact 5 195/65 R15 91H, a proper road tyre that is slightly narrower, with a slightly deeper profile and a fractionally larger circumference than our road tyres, which are Michelin Energy Saver 205/55 R16 91V (2.3 bar front and 2.4 bar rear under partial load).  (Those road tyres are obsolete, as I found the hard way when trying to buy an additional one to use as a spare.)

I think I’ve seen some reference to 195/65 R15 91H tyres being supplied for winter use in eastern Europe; anyway, I think a set of four would be pretty adequate for normal driving, and I’m sure that, if we need to resort to using the spare, a pressure similar to the other tyres would be better than one about 75% higher.  I enquired from our dealer, but was told that their mechanics use 4.2 bar, which does at least prove that excessive pressure isn’t likely to burst relatively fat tyres!  They refuse to ask Skoda the recommended pressure for the tyres actually supplied, and when I’ve asked Skoda UK about our car, they just refer me to the dealer.  I also asked Continental, and was told “the Continental EcoContact 5 195/65 R15 91H is not classified as a Space Saver tyre, therefore required standard pressure recommend by Skoda in this instance.” but, understandably, they’re not prepared to recommend pressures for specific vehicles.

Please can anyone tell me the recommended pressure for a 195/65 R15 91H spare tyre on our Scala?

With thanks in advance,

Chris

The maximum pressure the tyre can take is 3.0 Bar. This will be marked on the sidewall.

You want this pressure in the tyre when it is in the boot.

Or at least above the loaded / Eco / High speed pressure that your normal tyres require.

If / when you have to use the tyre adjust the pressure down to the same pressure as the rest of your tyres have in them.

 

Thanks, AG Falco

 

 

& remember if you put the spare wheel on that the tyre is brand new and not worn in and an odd one out in width and circumference by a little so still treat like an 'Emergency Spare' and reduce your speed even if there are no warning stickers on the wheel.

Reset your TPMS when you fit the spare, and reset it again when the original goes back on and you have checked or reset the pressures.

Check the TPMS at regular car checks and when you change / adjust tyre pressures.

Thanks for both replies.

Our spare Continental Ecocontact 5 195/65 R15 91H is actually marked “MAX INFLATION PRESSURE 350 KPA (51 PSI)” (3.5 bar).  So it certainly shouldn’t be inflated to 4.2 bar!

AG Falco’s advice seems to be that, if we need to drive on our spare, it should be at the same pressure as the slightly broader, lower profile road tyre on the same axle.  I’ve never been sufficiently conscientious to change tyre pressures according to planned loads, and I anticipate that we will only very rarely drive our Scala with a full load.  Also, in my experience, modern tubeless tyres maintain their air pressure for very long periods (if I set pressures in winter, the rise in pressure resulting in the temperature increase through to the summer seems plenty to compensate for any loss of air over that period).  If we need to fit the spare at the roadside, the conditions might be difficult, we may not have a pressure gauge available, and won’t have a pump in case we release too much air.  So I think our best approach will be to aim to keep the spare inflated to the same pressure as the rear tyres (only 0.1 bar higher than the front).  Any slight mismatch if the spare is fitted on the front shouldn’t cause problems.  The wheel is marked Maximum 50 mph (although the H rating signifies that a set of four of the tyres on a suitable car should be good for 130 mph!)

 

With thanks,

Chris

1 hour ago, ChrisNewman said:

Thanks for both replies.

Our spare Continental Ecocontact 5 195/65 R15 91H is actually marked “MAX INFLATION PRESSURE 350 KPA (51 PSI)” (3.5 bar).  So it certainly shouldn’t be inflated to 4.2 bar!

 

It wont do it any harm at all, the tyre is rated to be safe at 3.5 bar driven at 130mph supporting a 650kg load, which if you were able to do would soon raise the pressure beyond 4.2 bar, it will be fine sat in the boot at 4.2 bar.

 

Consider the pressure that is used by the tyre fitters to mount the tyre on the rim and to seal the bead before letting it down to the supposed required pressure whch will be 30psi that they send every car out with

 

When fitted to the vehicle the pressure should be reduced to the correct one not for fear of the tyre bursting but for the maximum grip and to avoid uneven tyre wear.

Edited 12 March, 20215 yr by J.R.

Thanks for explaining that the “MAX INFLATION PRESSURE” is very different from the maximum pressure the tyre is designed to withstand.

If driving under maximum speed and load can increase the tyre pressure from 3.5 bar to 4.2 bar, this implies the temperature will have increased in the region of 50°C.  Will the increase be that great, and do you know at what temperature tyres might begin to suffer damage?

Chris

Is that really an issue?

 as the heat issue is unlikely to be that great driving with a spare tyre to get it fixed at 50 mph in the hottest of UK weather.

 

Spare tyre / wheel in the car and left at 40psi and checked regularly when the cars tyres are or even at 35psi.

Tyre pressure gauge foer nearly no money in the car to adjust pressure.

 

3.5 bar / 50 PSI is the pressure that new cars in transit have the tyres at for being strapped down on a transporter.

Edited 13 March, 20215 yr by e-Roottoot

Present version of the 'Highway Code' on page 129:-

Tyre Pressures. Check weekly. Do this before your journey, when tyres are cold.

Warm or hot tyres may give a misleading reading.

 

Note:- 3 points and or £2500 fine for an incorrectly inflated tyre. ( Per Tyre ) See page 126.

            This is incorrectly inflated for the load being carried at the time.

 

 

Tyre Pressure goes up when hotter and down when cold.

Tyres will get hotter, when driven, the faster you go, the heavier the vehicle is, the lower the pressure that is in them.

When a tyre hits a pothole / speed bump the pressure momentarily increases beyond the maximum inflated pressure limit of the tyre.

 

Thanks, AG Falco

 

Edited 13 March, 20215 yr by AGFalco
added is

8 hours ago, ChrisNewman said:

Thanks for explaining that the “MAX INFLATION PRESSURE” is very different from the maximum pressure the tyre is designed to withstand.

If driving under maximum speed and load can increase the tyre pressure from 3.5 bar to 4.2 bar, this implies the temperature will have increased in the region of 50°C.  Will the increase be that great, and do you know at what temperature tyres might begin to suffer damage?

Chris

I can rustle up 1076kg of ballast but I'm afraid that I cannot go out and drive at 130mph to try it for you as I have been under curfew for the last hour and three quarters.

 

As e-Root-toot says, does it really matter?

19 hours ago, e-Roottoot said:

Spare tyre / wheel in the car and left at 40psi and checked regularly when the cars tyres are or even at 35psi.

Tyre pressure gauge foer nearly no money in the car to adjust pressure.

The cost of a pressure gauge isn’t a problem.  But, as I mentioned before, the potential conditions when changing the wheel, the absence of a pump if too much air is released accidentally, and whoever might be using the car if the spare wheel is needed, all are.

In my opinion, the crucial issue is whether the Continental Ecocontact 5 195/65 R15 91H should be used at approximately the same pressure as the Michelin Energy Saver 205/55 R16 91V opposite, or whether a slightly narrower and deeper profile tyre should be at a slightly higher pressure to compensate for those factors.  As I can’t get any advice from Skoda, I’ll take AGFalco’s advice that it should be the same, and thank him once again for it.

I still think the most practical way for us to achieve a satisfactory pressure at an emergency wheel change, now that I have a sensible pressure to aim for, is for me to inflate our spare to a similar pressure to the rear tyres, and check it regularly enough to be reasonably sure it will always be close to that intended pressure.

15 hours ago, J.R. said:

I can rustle up 1076kg of ballast but I'm afraid that I cannot go out and drive at 130mph to try it for you as I have been under curfew for the last hour and three quarters.

 

As e-Root-toot says, does it really matter?

As far as using our car is concerned, it doesn’t matter at all.  Even if I did fit the spare and ballast our Scala up to the maximum tyre load, it won’t do 130 mph.  I’m merely curious about the effect of fast driving on tyres, and asked because you seem knowledgeable.

19 hours ago, AGFalco said:

Present version of the 'Highway Code' on page 129:-

Tyre Pressures. Check weekly. Do this before your journey, when tyres are cold.

Idealize cautious advice, but what proportion of drivers do you think actually do that?  I can’t remember the last time I saw anyone else, except perhaps our next-door neighbour, checking tyre pressures.

I aim to give our tyres a visual check that they’re not too soft, on our flat concrete drive, before setting off whenever I use the car, in case I’ve picked up yet another screw.  Also, I connect the pump, look at its gauge, and inflate the tyre if necessary, often enough that I don’t get nasty surprises when I see their pressures.  I avoid hot days, and when it’s sunny I’m careful to wait until all tyres have been in the shade for an hour or two.

19 hours ago, AGFalco said:

When a tyre hits a pothole / speed bump the pressure momentarily increases beyond the maximum inflated pressure limit of the tyre.

 

Thanks again for your advice about the pressure I should be using, but I’m pretty sure the change in pressure from hitting a pothole or speed bump would be modest compared to the 20% + rise J.R. says that driving at the maximum rated load and speed would cause.  If the bump was reasonably gentle, the suspension would take most of the impact.  With a sharp-edged pothole you’d hit the rim and damage it or the tyre long before you reduced the volume within the tyre that much.

Maybe it is mainly female drivers that check tyre pressures at Filling Stations, as that is who i notice commonly doing it.

 

Hopefully there are many enthusiasts and drivers in general that check tyre pressures regularly, reset the TPMS, top up the windscreen wash, check oil and coolant levels and generally make sure their car is serviced and maintained.

 

 

Very handy,  easy to use and easy to let the pressure down a bit and see by how much.

I use them all the time when inflating all kinds of tyres onto rims then deflating to the correct pressure, or checking pressures.

That is with any car i am going to be driving as i want to know the pressures are safe. 

Edited 14 March, 20215 yr by e-Roottoot

33 minutes ago, e-Roottoot said:

Maybe it is mainly female drivers that check tyre pressures at Filling Stations, as that is who i notice commonly doing it.

Sorry, I should have been more clear and said “I can’t remember the last time I saw anyone else, except perhaps our next-door neighbour, checking tyre pressures on their drive.”  I do see a small proportion of drivers checking their tyres at filling stations, rather than before their journey while the tyres are still cold, although I doubt whether many of them fill up weekly.  I pump my tyres at home rather than using filling stations, not only so that the tyres are cold, but also because I’m wary of their equipment; if I always use the same gauge, I’ll get consistent results.  I consider it’s more important to have the tyre pressures well balanced than at exact pressures.

Thanks for showing the Draper pressure gauge.  Being a lot newer than the one I’ve been using, it should be more accurate, and it would be convenient to be able to release excess pressure in a controlled, measured way, if necessary.  But rather than putting one in each car, and hoping either of my sons would think to use it correctly if changing a tyre on a wet night by a busy road, I still believe I’ll do better to aim to ensure that the spares are already at suitable pressures.

So that is the 'Best plan' to check your spare tyre pressure when you do the other 4.

So that was dead simple.  

If everyone does that then that is 'simply clever'.    However many do not, as witnessed if you work someplace where the Spares Pressure or tread gets checked.

 

We are back to the OP and Technicians or others at Dealerships doing whatever or not knowing what is done.

 

Having Inaccurate tyre pressure gauges are a pretty poor show.............

 

Filling station services provided like Air Compressors that you pay 20 pence, 50 pence or whatever to use are maintained and checked by Service Station Maintenance operatives, as any Multi National charging for a service of equipment badly maintained or inaccurate are on a hiding to nothing. 

Edited 14 March, 20215 yr by e-Roottoot

Air only ever comes out of a tyre when left.

So if the spare wont get checked regularly then put too much in when is is checked.

It is better to have a little too much air rather than too little.

I set my spare to the max load pressure for the car.

If when you go to use the spare and find it is flat it is no use at all.

 

As a rough rule of thumb, the wider the tyre, the lower the profile, the faster the car goes, the heavier the car is, then the higher the pressure wanted. 

Slow tractors with big profile tyre = low pressure.

Faster lorries with heavy loads = high pressure.

 

Thanks, AG Falco

Seeing the hose on the Draper 69924 pressure gauge has stimulated further thoughts, and I’ve spoken to our younger son who lives at home and, in normal times, commutes to work in the Jazz.

I realize I wouldn’t use the Draper pressure gauge regularly, because normally I need to add air rather than release it, so it’ll be more straightforward to stick to my foot pump with its gauge, but it would be beneficial to calibrate that gauge against newer one.

But making regular checks on the pressure of our spare wheels in our Jazz and Scala is a nuisance, because the valves point downwards.  The ideal would be some sort of gauge on a hose that I could connect permanently and air tightly to a spare tyre, and read without disturbing the tyre, but I doubt whether that’s feasible, particularly as the valves must be very close to the bottom of the spare wheel wells.  So perhaps it might be a good idea to pump the spares to their maximum inflation pressures, attach a card stating that the pressure should be reduced to what’s appropriate for the axle, as read from the fuel filler flap (doorjamb for the Jazz), and keep a gauge with a release valve in the spare wheel well.  Then I should only need to check pressures in the spares occasionally.

I’ve always preferred to have five road wheels, and I’ve been luck that both the Jazz and Scala have wheel wells large enough to hold a standard wheel (although our Honda dealership claimed there wasn’t room).

• If we need the spare, we can “fit and forget”.
• Having an extra wheel makes it easier to rotate the tyres and equalize wear, which I aim to do annually, and of course I adjust pressures in the process.
• If one tyre gets damaged and written off, we still have a set of four matching tyres with similar wear.

I’ve bought a fifth wheel and tyre for the Jazz.  I bought the wheel for the Scala, but then found that the road tyres supplied were obsolete, so I’ll need to wait until they’re worn out to get a matching set of five.  (Then I’ll no longer have any uncertainty over what pressure to use in the spare!  But unfortunately the Scala seems to lack points for raising one end of the car at a time with a trolley jack, to lift it easily onto four axle stands and simplify switching wheels.)

I had a look online for potential gauges, and noticed the TireTek TT-GH01-QBR2-E Flexi-Pro 60Psi Tyre Pressure Gauge is similar to the Draper 69924, costs a couple of pounds more, but its gauge is marked up to 60Psi/4.1bar rather than the 100Psi/7bar of the Draper 69924, which should make for easier, more accurate reading.  I might even buy one of each model, to check their readings against each other!

I’d welcome any further comments or suggestions.

With thanks,

Chris

I have one of these gauges as well & had it for years. 

They are accurate.   I use them when checking Motor Bike & Push Bike tyres when they have a Schrader Valve.

I often use a Pushbike high pressure track pump with a gauge to check car / 4x4 tyre pressures and put some air in rather than a foot pump.

(Because i only have one foot and foot pumps are like pedal bins, something i do not use.)

23 hours ago, ChrisNewman said:

pump the spares to their maximum inflation pressures

 

post no 2 then. 

 

 

Thanks, AG Falco

8 hours ago, e-Roottoot said:

I have one of these gauges as well & had it for years. 

They are accurate.

Thanks for your reassurance regarding the TireTek 60psi/4bar Tyre Pressure Gauge.  I found the same eBay offer, and then found it for “£13.85 Dispatched from and sold by Amazon EU, eligible for FREE click and collect without a minimum order”.  I need to be careful of various eBay sellers offering versions at a better price with chucks at different angles that I suspect are less convenient for conventional car tyres, or gauges marked only in psi, as the Scala tyre pressure information is only in bar (although with my foot pump I work to psi targets printed on a sheet in my garage, because those are the outer markings on the dial, so can be read more precisely, and also avoid needing a decimal point).  The Draper and TireTek gauges look so similar, except for the brass or silver look to the metalwork, and the gimmicky tyre-shaped housing for the TireTek dial, that I wonder whether they both come out of the same factory in China!

I’ll probably order a TireTek gauge first, for its more appropriate range, and follow with a Draper one if the TireTek is as convenient as I hope.

 

Chris.

1 hour ago, AGFalco said:

 

post no 2 then. 

 

 

Thanks, AG Falco

Yes, initially I thought that just hoping that one of my sons experiencing a puncture would think to find one of the pencil-shaped gauges I’ve been used to, and then manage to let only the right amount of air out of the spare, would be reckless.  But I don’t fancy having to lift the spares out of both cars to check their pressures at regular intervals.  When e-Roottoot showed me the gauge on a hose, I wondered whether it would be possible to monitor pressure without lifting the wheel.  Then, it sank in that the dial gauge complete with a release valve would be much easier use, and that and my thought of fixing a reminder tag onto the spare wheel persuaded me in your direction.

Thanks for the advice

Chris

I carry a decent gauge and a footpump. Makes it easy for checking/correcting the pressure in any tyre that's in use or about to be, wherever I am.

1 hour ago, Wino said:

I carry a decent gauge and a footpump. Makes it easy for checking/correcting the pressure in any tyre that's in use or about to be, wherever I am.

My first three cars were Austin Mini Countrymen (banger condition), and back then I only ran one car at a time.  They had large pockets built in beside the back bench seat, and I used to keep a Sutty brand foot pump in there.  (Once, my Mini was stolen.  It was found in a car park, but the radio and all the tools had been taken.  Driving it from Aylesbury police station straight into a gyratory system on a foggy winter evening, my foot slipped straight off the brake pedal, and I realized they’d also taken the rubber from that!  I’ve never found another foot pump as good!)  But since then I haven’t owned a car with anywhere convenient to stow anything the size of a foot pump.  Anyway, during hundreds of thousands of miles of driving, I haven’t yet needed to change a tyre at the roadside while I’ve been driving.

On 12/03/2021 at 11:57, J.R. said:

It wont do it any harm at all, the tyre is rated to be safe at 3.5 bar driven at 130mph supporting a 650kg load, which if you were able to do would soon raise the pressure beyond 4.2 bar, it will be fine sat in the boot at 4.2 bar.

 

Consider the pressure that is used by the tyre fitters to mount the tyre on the rim and to seal the bead before letting it down to the supposed required pressure whch will be 30psi that they send every car out with

After receiving my TireTek gauge, when inflating the Jazz’s Michelin spare to its marked maximum pressure of 51 psi (US and Canadian regulations) to check how the gauge works, I noticed that the tyre was marked “NEVER INFLATE BEYOND 40 PSI TO SEAL BEADS”.  (But that’s no guarantee the limit will be respected.)

Amazon offered the TireTek Tyre Pressure Gauge with Flexible Air Hose, 0-60 PSI / 4 bar for £13.85 “eligible for FREE click and collect without a minimum order.  Dispatched from and sold by Amazon EU”.  Yet when I tried to buy, I found there was an unavoidable additional charge of either £4.49 for standard delivery or £4.99 for express delivery from the EU to the UK!  So I bought the TireTek from bygreen99svt, who honoured their £14.75 offer on eBay.

Having pumped the spare in our Jazz to 51 psi according to my foot pump, probably over a decade old, I was surprised, delighted and relieved that the TireTek, and the Bridgeport gauge (read on a metal rod) my wife bought for her Honda 50 back in the 1970’s, both also showed 51 psi.  However, the Schrader gauge in my AA Book of the Car Tyre Care Kit (read on a square black plastic rod), probably a couple of years younger than the Bridgeport, showed 42 psi, 82% of what the others read.

I’ve now ordered the Draper 69924 pressure gauge for our Scala; I was lucky to catch a special offer on eBay, and am buying it for only £10.44.

Thanks again for everyone’s advice.