3 hours ago, Nmh said:

There's clearly quite a lot of variables in play. I'm nervous about straying beyond any Skoda recommendations so my options are:

 

A) Keep my 18" Trinity alloys in the 225/40 R18 configuration but change out the Kumho WinterCraft tyres for a quieter, more fuel efficient option - (recommendations welcome). The front 2 tyres have dropped from 32 psi to 23 psi over the last 6 weeks so there's an issue there. 

or

Spend about £360 on a second hand set of Superb 17" alloys (see below) and go for a 225/45 R17 configuration. 

 

https://www.ebay.co.uk/itm/SKODA-SUPERB-2012-2015-ALLOY-WHEEL-225-45-17-2/114678740855?hash=item1ab362b777:g:Wv0AAOSwltBgJDMw

 

But my question would be, is there really that much difference in comfort between the two options? I won't be doing a huge amount of miles. Am I going down quite an admin exhaustive route of buying second hand alloys which turn out to be pups (I'm no expert)? Then possibly getting them reconditioned? 

 

I know a lot of this is personal preference. The 16" alloy option does seem too small on a car of this size. So it's either stick or twist with the 17" option....

 

You would notice a massive difference in comfort going from 225/40R18 to 205/55R16. 225/45R17 is somewhere in the middle, but closer to the harshness of the 225/40R18.

 

As you can see in the chart below, both 205/55R16 and 225/45R17 are standard tyre options on the Superb MK2 1.8TSI

Skoda Superb 2014 1.8TSi

– Generation: 3T [2008 .. 2014] [EUDM]  

– Power: 158 hp | 118 kW | 160 PS 

– Engine: I4, Petrol

– Center Bore: 57.1 mm 

– PCD: 5x112 

– Wheel Fasteners: Lug bolts 

– Thread Size: M14 x 1.5 

– Trim Production: [2008 .. 2014]

Tire	Rim
205/55R16 94V	7Jx16 ET45	2.3 / 2.1
225/45ZR17 94W	7.5Jx17 ET49	2.4 / 2.2

 

https://www.wheel-size.com/size/skoda/superb/2014/#trim-18tsi-eudm-158

Light alloy wheel ILIAS 16"

Rim size: 6.5J x 16 “ET 46

3 850,99 CZK (about £129.12)

 

 

https://eshop.skoda-auto.cz/cs_CZ/kolo-z-lehke-slitiny-ilias-16-pro-octavia-iii/p/5E0071496D+8Z8

 

Secondhand alloys often have corrosion where the tyre bead sits, which means they will leak air and you have to pump up the tyres every week. Secondhand alloys that use low profile tyres will often be buckled. It's a risk you take when buying secondhand.

 

6.5Jx16 ET46 Steel Rim (could be used as a spare)

 

ALCAR Rim type 5-hole steel wheel Size 6½ x 16 Bolt pattern 5 x 112.00 x 57.00 Offset 46.00

£ 40.00

 

https://www.mytyres.co.uk/cgi-bin/skw.pl?dsco=110&s_p=Steel-Rims&sowigan=felgen&Hersteller=Skoda&PKWtyp=OCTAVIA+1.0+TSI&PKWtypgenau=%3A549469%3A%3A999%3A85%3A201302%3A++++++%3A57.00%3A112.00%3A5%3A5E++++++++++++++++++%3A%3AP%3AE11*2007%2F46*0243*..+

 

17" Alloys for the Superb MK2

https://eshop.skoda-auto.cz/cs_CZ/hlinikove-disky/c/alloyWheels?q=%3AscoreDesc%3AcarType%3ASuperb%2BII%2B%282013-2015%29&text=#

 

Edited 13 April, 20215 yr by Carlston

51 minutes ago, Carlston said:

 

You would notice a massive difference in comfort going from 225/40R18 to 205/55R16. 225/45R17 is somewhere in the middle, but closer to the harshness of the 225/40R18.

 

As you can see in the chart below, both 205/55R16 and 225/45R17 are standard tyre options on the Superb MK2 1.8TSI

Skoda Superb 2014 1.8TSi

– Generation: 3T [2008 .. 2014] [EUDM]  

– Power: 158 hp | 118 kW | 160 PS 

– Engine: I4, Petrol

– Center Bore: 57.1 mm 

– PCD: 5x112 

– Wheel Fasteners: Lug bolts 

– Thread Size: M14 x 1.5 

– Trim Production: [2008 .. 2014]

Tire	Rim
205/55R16 94V	7Jx16 ET45	2.3 / 2.1
225/45ZR17 94W	7.5Jx17 ET49	2.4 / 2.2

 

https://www.wheel-size.com/size/skoda/superb/2014/#trim-18tsi-eudm-158

Light alloy wheel ILIAS 16"

Rim size: 6.5J x 16 “ET 46

3 850,99 CZK (about £129.12)

 

 

https://eshop.skoda-auto.cz/cs_CZ/kolo-z-lehke-slitiny-ilias-16-pro-octavia-iii/p/5E0071496D+8Z8

 

Secondhand alloys often have corrosion where the tyre bead sits, which means they will leak air and you have to pump up the tyres every week. Secondhand alloys that use low profile tyres will often be buckled. It's a risk you take when buying secondhand.

 

6.5Jx16 ET46 Steel Rim (could be used as a spare)

 

ALCAR Rim type 5-hole steel wheel Size 6½ x 16 Bolt pattern 5 x 112.00 x 57.00 Offset 46.00

£ 40.00

 

https://www.mytyres.co.uk/cgi-bin/skw.pl?dsco=110&s_p=Steel-Rims&sowigan=felgen&Hersteller=Skoda&PKWtyp=OCTAVIA+1.0+TSI&PKWtypgenau=%3A549469%3A%3A999%3A85%3A201302%3A++++++%3A57.00%3A112.00%3A5%3A5E++++++++++++++++++%3A%3AP%3AE11*2007%2F46*0243*..+

 

17" Alloys for the Superb MK2

https://eshop.skoda-auto.cz/cs_CZ/hlinikove-disky/c/alloyWheels?q=%3AscoreDesc%3AcarType%3ASuperb%2BII%2B%282013-2015%29&text=#

 

 

Thanks Carlston. So you'd go for the 16" and buy them new? 

 

Sounds like my current front wheels could be leaking air. I could ask Kwik Fit to check and possibly repair. My local independent garage said they steer well clear of tyre repairs because they never end up fixing them. The tyres are almost new when I bought about 3k miles ago. They don't look damaged so it could well be an alloy issue. Hmm. 

59 minutes ago, Carlston said:

 

You would notice a massive difference in comfort going from 225/40R18 to 205/55R16. 225/45R17 is somewhere in the middle, but closer to the harshness of the 225/40R18.

 

As you can see in the chart below, both 205/55R16 and 225/45R17 are standard tyre options on the Superb MK2 1.8TSI

Skoda Superb 2014 1.8TSi

– Generation: 3T [2008 .. 2014] [EUDM]  

– Power: 158 hp | 118 kW | 160 PS 

– Engine: I4, Petrol

– Center Bore: 57.1 mm 

– PCD: 5x112 

– Wheel Fasteners: Lug bolts 

– Thread Size: M14 x 1.5 

– Trim Production: [2008 .. 2014]

Tire	Rim
205/55R16 94V	7Jx16 ET45	2.3 / 2.1
225/45ZR17 94W	7.5Jx17 ET49	2.4 / 2.2

 

 

 

You do know all of this and more is in the first post of my wheel and tyre thread, right?

Yes. I found that very very helpful. 

 

I was just being specific about where my thoughts currently were. N 

2 hours ago, Nmh said:

Thanks Carlston. So you'd go for the 16"?

 

Your rims could be corroded around the rim where the tyre bead sits, or the rims could have been damaged by a tyre fitter. If the rims have been damaged by a tyre fitter, they might be beyond economical repair.

 

These ones from the Octavia MK2 are available for about £92.85 each. There are two versions, chrome metallic and silver. The chrome metallic version is being listed at a much lower price on "eshop skoda cz" than the silver version. You can also get a matching 6.5Jx16 ET50 steel rim for a spare.

 

I haven't listed any 7Jx16 rims because 7J is relatively wide for a 205/55R16 tyre, which results in a harder and less comfortable rim.

 

205/55R16 is an inexpensive tyre size, with many top brands available for about £50 each.

Light alloy wheel CRATERIS 16"

6.5Jx16 ET50 1Z0601025T 7ZS Chrome metallic

 

https://eshop.skoda-auto.cz/cs_CZ/kolo-z-lehke-slitiny-crateris-16-pro-octavia-ii/p/1Z0601025T+7ZS

 

Edited 13 April, 20215 yr by Carlston

I’m not likely to change, but if I did it would be to 215/50r17. No way I’m going to 18’s again. I’d only lose 5mm of sidewall, and more than enough to stop scrubbing in the extreme situation. 225/45r17 would lose 11mm

Lovely. Thanks for the pointer Carlston and thoughts Rkdee. Looks like I need to get the current rims checked over and see if it's currently a tyre or rim issue that's causing air loss. N

There are many reasons why a tyre might be going soft, ranging from cheap and easy to fix right up to buying new wheels.

 

Find a good independent tyre fitter in your area - ask friends/family if they have someone they can recommend. Fast-fit places will probably want to sell you new tyres without doing any real fault finding.

 

Possible causes of pressure loss:

• Loose valve stem insert - it can work loose, or might not have been properly tightened last time around
  • A valve spanner is only a few quid in Halfords and it's something you can check yourself. It's usually my go-to first fix for a tyre that's going soft
• Related to the above is perished rubber on the valve stem
  • Solution is to replace the stem - job for a tyre fitter
• Poor seal between the tyre and the rim: the tyre may not have seated quite right when fitted, or there was dirt left on the rim, etc
  • Fix is to reseat the tyre after checking the bead and rim carefully - job for a tyre fitter
• Both of the last two could/should be done together before going further: it won't cost a huge amount of money and fixes most problems with tyres losing air
• Slow puncture in the tyre: it can happen from a piece of glass, or a nail, etc. If the object stays stuck in the tyre it'll plug the hole enough that it'll only leak slowly
  • A tyre fitter should be able to find if this is the problem, and unless the damage is bad, the tyre can usually be safely patched inside
  • This has saved me from buying new tyres more than a few times
• Damaged wheel:
  • As Carlston pointed out, a clumsy tyre fitter could damage the tyre seating surface on the rim making it difficult to achieve a seal
  • Badly kerbing the wheel could do this too, or warp the wheel to the point where the tyre can't seat properly
  • Alloy wheels can crack; if this happens on the pan or rim it will leak
  • The fix here is refurbish the wheel - it should be about 1/4 to 1/3 the price of a new wheel from a competent repairer (I had mine refurbed last year at €70 per wheel including fitting of new tyres)

Unless the wheels are in really bad shape, or you just want rid of them anyway, buying new wheels is a waste of money right now.

 

If you do want to buy new rims, the following are the type approved sizes for the 1.8 TSI Facelift for year round use:

• 205/55/R16 91V on 7J x 16 ET45 rim
• 205/55/R16 94V on 7J x 16 ET45 rim
• 225/45/R17 91V on 7J x 17 or 7.5J x 17 ET49 rim
• 225/40/R18 92V on 7.5J x 18 ET46 rim

For winter use only these additional sizes are approved:

• 205/55/R16 91V on 6J x 16 ET50 rim
• 205/50/R17 93V on 6J x 17 ET45 rim (this isn't formally restricted to winter use in the tables, but given the unusually narrow wheel/tyre it seems likely that this is the intended use)

The winter sizes allow more room for use of snow chains in regions where that is required.

 

Any sizes not on these lists are not type approved by Skoda. If you want to go outside these, it will require additional due diligence on your part to ensure any wheel/tyre combination won't affect ride/handling/safety/speedometer. Changes to profile height and/or rim width and/or offset (ET) will affect scrub radius, which affects steering and handling. Your insurer will probably need to be told too if you go with a non-type approved size.

 

One exception is you can choose a size listed for a more powerful version of the car e.g. 2.0TFSI. Mostly the only difference is the speed rating, and possibly load rating.

Edited 14 April, 20215 yr by chimaera

Outstanding intel! Thank you so much for taking the time to share this knowledge. It’s a massive help and gives me a very clear road map for next steps. 

 

Off to the tyre fitter I go...

1 hour ago, Nmh said:

Off to the tyre fitter I go...

 

The easiest way to find an air leak, is to submerge the tyre/rim in water. Look for an air bubble forming to see where the air leak is.

 

When you have spotted the leak, you can use a yellow crayon to mark the spot.

 

Don't forget to check all the way around, in case there is more than one leak.