Tyres again - 7J or 7.5J?

[JS58]

It's the usual story - I'm running 19" rims & the ride is not good so I've been hunting for some 17" rims, mainly on Facebook Marketplace. The approved/OEM size is 215/55 R17 on 7Jx17 ET45 rims but I have seen a set of Audi 7.5Jx17 ET45 rims for a good price (5x112 PCD so should be ok).

 

I've checked on willtheyfit.com & fairly obviously the inside edge is 1/4" (6.5mm) further inboard but given the 19" rims are 8J I don't think that's an issue.

 

Are there any other problems with using 7.5J rims instead of 7J? Will a 215/55 tyre fit & run ok?

[SurreyJohn]

Here is the Skoda wheel catalogue.   For Karoq, there are 19 inch (3 types),  6 each of 18 inch and 17 inch and 3 of 16 inch

 

https://www.skoda.co.uk/_doc/639a0118-4da5-446b-a786-86e1f789b57b

 

Even the 16 inch with 6J are ET43, and the 7J & 8J both ET45, which rather suggests that 7.5J (being between them) on ET45 should be ok

 

The recommended tyre sizes are different for 4x4 models to 2 wheel drive, 

 

215/55 R17 (668mm diameter) and 225/40 R19 (663mm) are within 5mm (under 1%) diameter difference

215/55 R17 (668mm) and 235/40 R19 (671mm) are within 3mm (under 0.5%) diameter diff

 

The 17 inch 4x4 uses 225/55 R17 (678mm diameter)

 

Bear in mind new vs a worn tyre tread depth could be 5mm (or 10mm diameter) and tyres are all similar size overall diameter.  The diameter will vary by about 1.7% depending on tread depth anyway.

 

 

[Carlston]

14 hours ago, JS58 said:

It's the usual story - I'm running 19" rims & the ride is not good so I've been hunting for some 17" rims, mainly on Facebook Marketplace. The approved/OEM size is 215/55 R17 on 7Jx17 ET45 rims but I have seen a set of Audi 7.5Jx17 ET45 rims for a good price (5x112 PCD so should be ok).

 

I've checked on willtheyfit.com & fairly obviously the inside edge is 1/4" (6.5mm) further inboard but given the 19" rims are 8J I don't think that's an issue.

 

Are there any other problems with using 7.5J rims instead of 7J? Will a 215/55 tyre fit & run ok?

 

If you're looking for comfort, 215/55R17 fitted to a relatively wide 7.5jx17 is far from the best choice. Fitting a tyre to a relatively wide rim stretches the sidewalls and makes the sidewalls more difficult to flex resulting in a harder ride.

 

Looking at the below chart, a 215/55R17 tyre fitted to a 7.5Jx17 rim would give a similar hard ride to a 215/50R18 tyre fitted to a 7Jx18 rim. Normally a 215/55R17 tyre would give a slightly softer ride than a 215/50R18 tyre, but because you would be fitting it to a relatively wide 7.5J rim it becomes about as hard riding (inability to absorb road bumps) as a 215/50R18 tyre fitted to a 7J rim.

 

If you're not happy with the soft riding 215/60R16 tyre fitted to a 6J rim, maybe consider a 215/60R16 (or even 225/60R16 which the Karoq 4x4 uses) fitted to a 6.5Jx16 rim or in the case of the 225/60R16 tyre maybe even a 7J rim. The Superb MK2 and Yeti had a 7Jx16 ET45 option.

 

The Superb MK3 has a 215/55R17 tyre size option, and a choice of 6.5J or 7J rims.

 

Maybe also consider a 215/55R17 fitted to a 6.5Jx17 ET38 rim from the Kodiaq. The Kodiaq uses a 215/65R17 tyre size with this rim, not the much smaller outside diameter 215/55R17.

 

Perhaps make the final decision with consideration to tyre prices. Some tyre sizes can be a lot more than others. For example, Octavia MK3 tyre prices such as 195/65R15, 205/55R16, tend to be a lot cheaper than Superb MK3 and Karoq tyre prices such as 215/60R16 and 215/55R17.

 

Soft ride

215/60R16 tyre fitted to a 6Jx16 rim

Medium ride

215/55R17 tyre fitted to a 6.5jx17 rim

Hard ride

215/50R18 tyre fitted to a 7Jx18 rim

 

Edited 17 January, 2023 by Carlston

[JS58]

Thank you very much for your response; I'll have to pass on the 7.5J rims then & keep searching for 6.5J ones. It's a pity as they were decent condition & a fair price.

[Carlston]

7 hours ago, JS58 said:

Thank you very much for your response; I'll have to pass on the 7.5J rims then & keep searching for 6.5J ones. It's a pity as they were decent condition & a fair price.

 

If you don't mind 225/55R17 that the Karoq 4x4 uses, then 7J rims would be fine and put the ride in the medium category as shown in the chart below.

 

I've added 215/55R17 fitted to a 7J rim to a medium to hard riding category, so a bit harder than a 215/55R17 fitted to a 6.5J rim but not as hard as a 205/50R18 fitted to a 7J rim.

 

However, if you're looking to improve your ride it's probably best to look at the soft and medium riding tyre/rim combination and not the medium to hard, and hard riding categories. 

 

Soft ride

215/60R16 tyre fitted to a 6Jx16 rim

Medium ride

215/55R17 tyre fitted to a 6.5jx17 rim

225/55R17 tyre fitted to a 7Jx17 rim

Medium to hard ride

215/55R17 tyre fitted to a 7Jx17 rim

Hard ride

215/50R18 tyre fitted to a 7Jx18 rim

 

Edited 17 January, 2023 by Carlston

[FabFabFabia]

I thought my 19" wheels were a little firm when I picked up my Karoq Edition in 2018 but once I let some air out of the tyres to reach the correct pressure (as indicated under the fuel flap) then the ride has been fine.

[kenfowler3966]

My edition is fine like yours with 45 ratio tyres. However the Sportline used even wider tyres at 40 ratio. Apparently they have a very firm ride

[croquemonsieur]

The 215/60R16 Hankook AW tyres fitted to a 6Jx16 steel rims arrived today, all properly balanced, from Germany - MyTyres.  I went for the slightly more expensive silver steel wheels that are meant to look like alloys, but.... not sure they look any better than the ordinary black ones, but got some ideas for improving their appearance - more later incl photo of the new wheels.

 

Early days yet & I'll give them time to bed in before giving a final running verdict.  They were fitted this afternoon and pumped up to 2.2bar.  At the moment, the improvement in ride over the 17" Turanza fitted alloys is not as much as I might have expected.  I still feel road ridges through the steering, though not as pronounced & there is less accompanying thump.  Mind you I thought the 17" Turanzas rode pretty well, in spite of what many say here.  The Hankooks are definitely quieter, on average & course surfaces  (including importantly at low frequencies) & should be noticeably more relaxing on motorways, when I venture out there in a week or two.  Surprisingly, the steering if anything is a bit sharper than before (feels nice) and the car feels just as stable, but I'm not the type to go pushing cars to the limit on corners.