Spare wheel issue

[MercerS]

Good morning, everyone,

 

I got a puncture on Thursday evening near home and managed to get home on the deflating tyre which was the front drivers side. The tyre is a 235/45R18. Once home I swapped on my 'full size' 205/55R16 spare, and as the tyres were already all at 3mm decided to order four new Cross Climates. The car is a 2018 2.0TDI 4x4 estate. I noticed when the spare was on that it was much less in diameter than the normal wheels and tyres.

 

Originally I was to get the new tyres on Monday, but Blackcircles have pushed this back to Wednesday now due to delivery issues.

 

This morning I had a short errand to do and took the Superb. Well, it is almost undriveable, It feels as though the brakes are gently grabbing at what I presume is the spare wheel as the car seems feels to be 'missing' and juddering like an old fashioned misfire. At the short stretch (a mile) of dual carriageway the car would not go above 40mph and traction control light came on and off. Once I got to my mum's house (the journey is approx. two miles) on leaving the car there was a terrible smell of rubber or clutch from the front wheel well where the spare is. Most odd.

 

I know there can be an issue with fitting a lower diameter spares on the rear of 4x4's but this is on the front.

 

I am technically minded and happy to work on older cars, but this really has me perplexed. The loss of tyre pressure indicator stayed on continually despite trying to set it to compensate. I am assuming that maybe I shouldn't have done that as that was causing the monitoring system confusion but why the car should drive so badly as to be effectively undriveable is worrying me.

 

What makes it doubly annoying is the car came with the bottle of skoosh and I went out and bought Skoda's 16inch full size spare just to cover me for this very eventuality.

 

Have I missed something? The handbook makes no mention of it. Any advice appreciated?

 

All the best

Sandy

[Kenny R]

Personally I would always put the space saver on the rear.

[MercerS]

1 minute ago, Kenny R said:

Personally I would always put the space saver on the rear.

 

Thanks. I thought for the 4x4 that was recommended though.

[MercerS]

4 minutes ago, MercerS said:

 

Thanks. I thought for the 4x4 that was recommended though.

Sorry, I meant wasn't recommended.

[JR RS]

The front wheels r both driving and steering wheels - don't put the spare on the front, AWD or FWD, unless u really have to.

 

As to why ur car is misbehaving - makes no sense.

Should b no reason for it to affect the way ur experiencing it.

 

When I put my 16" spare on my, only the ACC was disabled, as it knew there was a spare tyre on.

 

The TPMS will b unhappy because the spare is spinning at a different speed to the other 3 wheels.

Edited 3 September, 2022 by JR RS

[Ootohere]

SIMPLES.

 

The Full Size Spare is not Full Sized enough for the 235/ 45 R 18's.  Not an ickle bit smaller, it is far too much smaller. 

 

Re TPMS.

When you fit a spare you can reset the TPMS and maybe first time or after a 2nd the car is fine with an odd one out tyre pressure.

(You can set 4 different pressures. )   it need not be 2 front, 2 rear, it can be 2 front, 1 rear and another rear and no TPMS warning.

Try it sometime. 

 

 

Edited 3 September, 2022 by roottoot

[Ootohere]

http://briskoda.net/forums/topic/439605-spare-wheel-what=size-will-fit-in-boot-space-on-a-superb-3-hatchback

See post by @dieselV6

 

Many more threads than just these on here.

http://briskoda.net/forums/topic/492555-upgrade-to-spare-wheel

 

http://briskoda.net/forums/topic/478495-superb-spare-wheel-well

 

http://briskoda.net/forums/topic/487896-spare-wheel-for-super-2018-18-wheels

 

 

 

 

 

Edited 3 September, 2022 by roottoot

[KenONeill]

1 hour ago, MercerS said:

At the short stretch (a mile) of dual carriageway the car would not go above 40mph and traction control light came on and off.

As @JR RS says above, you've confused the wheel speed sensors with an odd diameter wheel. This could affect any or all of ABS, TPMS, traction control and limp mode. In this context, you do realise that you are not supposed to drive more than 50 miles or drive at over 50mph on a space saver wheel?

[Ootohere]

Actually you are supposed to drive to a place of safety or get a repair done ASAP if using an Emergency Spare Wheel.

 

This is not a Space Saver, or a Saver of Space

this is a poorly sized 'Full Sized Spare Wheel.    Not Full Size by any stretch of the imagination.

 

50 MPH as a maximum would be unsafe. 

Thank goodness stuff disables it's self to save people from their own actions. 

[MarkyG82]

As above re wheel speed sensor. Also the diff will be going nuts, especially if you have a trick diff (not sure if they do on the 4x4?).

I think the reason you are talking about with spares on the back of 4x4 is due to the diff. As the system on these cars is essentially on-demand-4x4, you won't have the same issue. Crack on with putting it on the rear.

[Bap33]

I won’t tell more about the smaller size of the spare wheel.

However here are the consequences of having it on the front axle.

Since ot doesn’t spin at the same speed as the other front wheel, it will trigger:

- ASR which will try to reduce fuel injection top stop what the control unit considers as lack of grip

- EDS which will brake the smaller wheel on straight lanes, since the difference of rotation speed will be considered as differential slipping.

- Haldex since different speeds on both front wheel will considered ad lack of grip and therefore a good reason to activate rear axle to recover grip and traction control.

 

There may be other side effects from other control units as soon as you brake. ESP for instance…

 

Well, not very surprised you feel it’s a mess! 😉

 

IMHO, just swap your spare wheel with one of the rear wheel until you can get your tyre repaired/replaced.

 

Same size wheels on front axle will bring back both ASR and EDS in normal operation conditions. Grip will be more even on front axle and should avoid triggering Haldex.

[Carlston]

The 6.5Jx16 ET46 rim fitted with a 205/55R16 tyre is actually from an Octavia MK3 and this tyre size has an outside diameter about 5% smaller than the standard Superb MK3 tyre sizes.

 

The smell is the brake pads overheating as the car's electronics think that the wheel is spinning, so the electronics keep applying the brake on that wheel. You can check this by feeling if the metal rim on that wheel is becoming hot. The heat from that brake will be transferred to the metal rim (alloy rim or steel rim).

 

Is there a button on the dash somewhere that you can press to temporarily disable these electronics while the temporary spare wheel is on the car, so that the brake on that wheel won't be repeatedly applied?

 

It would have been better if Skoda had used a 6Jx16 ET43 rim fitted with a 215/60R16 tyre from the Karoq as a spare wheel as that should fit in the spare wheel well with the carpet flush, and not cause the electronics any problems because 215/60R16 is a standard Superb MK3 tyre size. So for the 215/60R16 tyre size, the Superb MK3 uses a 6.5Jx16 ET41 rim whereas the Karoq uses a 6Jx16 ET43 rim.

 

As you can see in the below chart, the actual width of a 205/55R16 tyre fitted to a 6.5J rim is about 214mm which is about the same as a 215/60R16 tyre fitted to a 6J rim. The widest tyre that will fit in the Superb MK3 spare wheel well with the carpet flush is about 215mm (actual width not "nominal" width), so the 215/60R16 tyre fitted to a 6.5J rim is too wide at about 221mm. Notice that the tyre width as indicated on the tyre's sidewall is the "nominal" width and not the actual width of the tyre which varies depending on the rim width that the tyre is fitted to.

 

Actual tyre width measured from sidewall to sidewall

205/55R16 fitted to 6.5J rim about 214mm

215/60R16 fitted to 6J rim about 215mm

215/60R16 fitted to 6.5J rim about 221mm

 

Overall Tyre Width (mm)

	Tyre Size	Tread Depth (mm)	Overall Diameter (mm)	Overall Width (mm)	Approved Rim Width Range (inch)
	205/55R16	8.5	632	214	5.5-6.5-7.5

https://www.toyo.co.uk/tirefinder/index/width/205/aspect/55/rim/16

 

Edited 3 September, 2022 by Carlston

[KenONeill]

39 minutes ago, Carlston said:

the tyre width as indicated on the tyre's sidewall is the "nominal" width and not the actual width of the tyre

I was always told that was the (still nominal) tread width, not the width of the tyre sidewall.

[Carlston]

31 minutes ago, KenONeill said:

I was always told that was the (still nominal) tread width, not the width of the tyre sidewall.

 

The "tread" width of a 205/55R16 tyre is much less than either the "nominal" width as shown on the tyre's sidewall, ie. 205, or the actual width which depends on the width of the rim that the tyre is fitted to.

 

The 205/55R16 is just one example, but if you measure the "tread" width it is always much less than either the "nominal" width or the actual width of a tyre.

 

You might find that the tread width of a 205/55R16 tyre is about 170mm, but it will certainly be nowhere near 205mm.

 

To work out what will fit in the spare wheel well, you need the actual width of the tyre as measured from sidewall to sidewall (and measured at the widest point). Measuring the tread width won't help you find out if a tyre will fit in the spare wheel well.

 

The tread width also depends on the aspect ratio. For example, the tread width of a 205/55 tyre is much wider than a 205/70 tyre. The tread width of both these tyre sizes is nowhere near 205mm.

 

As you go down the below tyre sizes, the tread width becomes narrower because the tread width not only depends on the nominal sidewall to sidewall width (as shown on the tyre's sidewall), but also on the aspect ratio. Hence if you drove behind a car fitted with 205/40 tyres you would notice that this tyre size had a wider tread width than 205/70 tyres. All of these 205 tyre sizes, have a tread width much less than 205mm.

205/40

205/45

205/50

205/55

205/60

205/65

205/70

 

Edited 3 September, 2022 by Carlston

[Carlston]

6Jx16 ET43 5/112 57.1 steel rim (from Karoq)

mytyres

https://www.mytyres.co.uk/rims/details?vehicleId=1128135213981897840&rimCode=ALCAR6665

"skoda eshop cz"

https://eshop.skoda-auto.cz/cs_CZ/plechovy-disk-16-/p/5Q0601027CJ03C

oponeo

https://www.oponeo.pl/felga-stalowa/vw-w6665#22470029

 

The 6Jx16 ET40 steel rim from the Superb MK1 could also be used as a spare for the Superb MK3 with a 215/60R16 tyre, and fit flush in the spare wheel well.

 

6Jx16 ET40 5/112 57.1 steel rim (from Superb MK1)

mytyres

https://www.mytyres.co.uk/rims/details?vehicleId=180495828815717488&rimCode=ALCAR9490

 

Edited 3 September, 2022 by Carlston

[Ootohere]

On the same 17" Gigaro rims. 205/40 R 17 XL. 

 

Off the car the Pirelli Zero Nero with the stonger sidewalls that disguised the pulling to the left that dealers never managed to fix so Skoda Approved the tyres changed under warranty.

On the car the OEM Dunlop Sport Maxx that gave good grip in the warm and ok in the wet unlike the Pirelli Ditch finders.

Lovely secure feeling on the road with the Dunlops. the Pirelli needed steering assistance reduced to not feel skittery or light even if you reduced the tyre

pressures..

 

On the front a 215/40 17 Goodride tyre & next to it the Pirelli in 205/40 R 17.  Same rims.

Edited 3 September, 2022 by roottoot

[MercerS]

Many thanks for the replies. I will swap the spare to the rear. The tyre place is 2 miles away from my house.

 

I spent Thursday evening searching through all the threads regarding spare wheels and the different wheels as options. I had thought that it was because I had specifically asked the Skoda dealer to provide the 16inch full size spare as opposed to the 18inch space saver, but a quick check of tyre calculators shows they are exactly the same in diameter and circumference so it couldn't have been that. 

 

I now appreciate that modern spare wheels are of the get you to a tyre shop, whether the spare is full sized or a space saver. I never got anywhere near 50mph though, the car just wouldn't let me.

 

What now intrigues me is if your normal front tyre is going flat, or you get the TPMS warning that it is going flat and so its rolling circumference reduces does it trigger all the symptoms I saw running the spare?

 

Also, does the Skoda TPMS system allow you to set the individual tyre pressures for each corner? From what I saw, it basically just allows you to set the pressure on all the tyres based on what you have pumped them up to. My assumption then was it used the ABS speed sensor to monitor how fast the wheel was turning and hence alert you that the rolling diameter of the wheel/tyre had changed, in other words, going flat.

 

As I also mentioned there is nothing in the handbook alerting you to swap wheels around to make sure the spare is on the rear.

 

Thanks to all once more.

Sandy

[KenONeill]

3 minutes ago, MercerS said:

From what I saw, it basically just allows you to set the pressure on all the tyres based on what you have pumped them up to. My assumption then was it used the ABS speed sensor to monitor how fast the wheel was turning and hence alert you that the rolling diameter of the wheel/tyre had changed,

Correct presumption.

 

But, if you set the tyre pressures say clockwise from RHF, to be 10, 20, 30 and 40 PSI, and then set the TPMS, have you not just set it based on what the pressures were when you set it? Your issue was that one tyre is a different rolling diameter to the other 3, and indirect TPMS presumes that all 4 tyres have similar rolling diameters.

[Ootohere]

The warning is not only 1 going flat.

Some people get a warning and when they check the pressures they were as set.

There can be a warning if a wheel bearing is going or a brake binding and then the rim gets hot and the tyre has expended.

Not common but it happens and drivers should be aware of that. 

 

PS.

All tyres do not need to be set at the same pressure obviously, and some might not have 4 identical tyres fitted, 

some like me have larger (circumference) tyres on the front sometimes. 

Or people have different pressures front and rear.

You can even fit a spare and reset the TPMS and get no warning with an odd one out, actually 2 odd if the other side is different from the pair at the other end of the car.

Edited 3 September, 2022 by roottoot

[Carlston]

2 hours ago, MercerS said:

I had specifically asked the Skoda dealer to provide the 16inch full size spare as opposed to the 18inch space saver

 

A 205/55R16 tyre isn't really a full size spare on the Superb MK3 because the outside diameter is much less than the standard tyre sizes (215/60R16, 215/55R17, 235/45R18) on the Superb MK3.

 

It's a bit like if the dealer had supplied you with a full size spare from the Citigo. It may be a full size spare on the Citigo, but it certainly isn't a full size spare on the Superb MK3. However, the Citigo spare wheel wouldn't actually fit the Superb MK3 due to the difference in wheel bolt PCD, 4/100 vs 5/112.

 

Edited 3 September, 2022 by Carlston

[MartiniB]

11 hours ago, MercerS said:

searching through all the threads regarding spare wheels and the different wheels as options

just in case not all, there are huge amount of similar threads

 

Copy-Paste from another thread ->

Pros and Cons have been described already:

 

a)  same size as all other wheels
 + can be installed on any axle
 + can be used for unlimited distances
 + no size diff = no speed limits
 + Cruise control will be available
 - boot floor will be pushed few cm up
 - most expensive

b) custom 205/65r16, full diameter (my choice)
-> https://www.briskoda.net/forums/topic/442912-full-size-spare-wheel/page/2/?tab=comments#comment-5040470

 + minor width diff will provide safe driving on + 30% of speed printed on spare disc. Important note, when installed on rear axle.
 + can be used for longer distances
 + minor circumference diff will provide ability of Cruise control usage. In theory, i haven't had to test it after OEM 205/55r16 were replaced.
 + fits in it's place, doesn't change size of boot.

c) OEM 205/55r16
 + lot wider than 'd' = safer than 'd', but don't think printed speed limit can be exceed more than + 10%, even when installed on rear axle.
 + fits in it's place, doesn't change size of boot
 - huge circumference difference disables usage of Cruise Control

 - huge circumference difference isn't healthy for 4x4

d) OEM 125/70r18
 + fits in it's place, doesn't change size of boot
 - huge width difference = absolutely unsafe, even when installed or rear axle.
 - huge circumference difference disables usage of Cruise Control

 - huge circumference difference isn't healthy for 4x4

 

-> https://www.briskoda.net/forums/topic/494383-can-anyone-with-a-20-tsi-220-factory-spare-wheel-tell-me-the-size/?do=findComment&comment=5550057
-> https://www.briskoda.net/forums/topic/493502-full-sized-tyre-as-spare/?do=findComment&comment=5556680

 

[JR RS]

12 hours ago, MercerS said:

Also, does the Skoda TPMS system allow you to set the individual tyre pressures for each corner? From what I saw, it basically just allows you to set the pressure on all the tyres based on what you have pumped them up to. My assumption then was it used the ABS speed sensor to monitor how fast the wheel was turning and hence alert you that the rolling diameter of the wheel/tyre had changed, in other words, going flat.

 

Ur assumption is correct with regards to how it works.

 

The factory TPMS in the various Skoda models is Indirect TPMS (Tyre Pressure Loss Indicator) - it uses the ABS wheel sensors to compare the rotational speed of the 4 wheels.  

If one of the them is loosing air, it will spin at a different rotational speed and trigger the indirect TPMS.  Difference must b 4 psi or more.

If u fit a different sized rim/tyre, like a spare, it will have a different rotational speed and also trigger the indirect TPMS.

 

The second version is the Direct TPMS (Tyre Pressure Monitoring System). There r 4 sensors, one inside each wheel, and a control module.  The 4 sensors detect the pressure in each tyre and sends it to the control module.

This shows individual tyre pressure readings on the infotainment screen.

If it detects a 4 psi or more drop, it will trigger the TPMS.

 

I retrofitted direct TPMS in mine - it's much better and I can see real time tyre pressures any time.

Easy to monitor, rather than waiting for it to trigger.

 

 

Edited 4 September, 2022 by JR RS

[Ootohere]

^^^ The point is with the OEM system you can put your tyres to 4 different pressures and set the TPMS and then get no warning as long as none of the circumferences change much from what was set.

 

You can fit the Spare, reset the TPMS and get no warning, you might get the puncture fixed put the wheel back on and not reset the TPMS and then you will get a warning.

 

Easy enough to know. If on your way to do tyre pressures, let a few pressures down and drive. Get a warning.  Stop & reset the TPMS and drive with the odd tyre pressures / circumferences and see if you get a TPMS warning.

Then obviously when you put air in you will be resetting the TPMS.   

[MartiniB]

1 hour ago, roottoot said:

You can fit the Spare, reset the TPMS and get no warning,

not true! after few minutes warning comes back what disables usage of Cruise Control 😞

~80 kms long trip were enough for decision of replace OEM 205/55r16 spare wheel tire to 205/65r16

[Ootohere]

@MartiniB So not true in your experience.

I am not talking about what or what not gets disabled / imobilized.  

Just TPMS,s alerts, with the simple system as fitted to Skoda, VW Group and others. 

 

So true according to me who when i pick up Used Cars , Cars from Auctions etc checks fluids and tyre pressures and then to see if the TPMS's work before they get prepped for resale will stop and let air out a tyre to check the TPMS works, then reset, then drive and let air out another, etc. In my pack there is always a couple of cans of tyre weld just incase.

That is how you can check Used Cars TPMS's. 

 

I used to change many wheels & tyres and balance and fit different sizes for Track, Sprints, Hill Climbs and set or not set TPMS's. 

 

With Snow Chains or Snow Socks fitted i then switch off the TC / ASR and then reset the TPMS as usually they are just on the front drive wheels and not going on all 4. Or rear wheels on some AWD / 4x4's RWD,s.

Edited 4 September, 2022 by roottoot