15" pepperpot tyre choice

[carlston]

My winter wheels are A3 pepperpot alloys (6J x 15 H2 ET38) shod with Michelin Alpin A4 185/60 R15 88T.

This is a non-standard size (declared to my motor insurer) and so tyre pressures are not listed inside my fuel filler flap.

¿What tyre pressures should I run with two passengers, and fully loaded?

The 185/60R15 tyre size has a load index of 84 when inflated to 3 Bar (44psi). Both 175/60R15 and 185/50R16 have a load index of 81 when inflated to 3 Bar (44psi). 205/40R17 has a load index of 80 when inflated to 3 Bar (44psi). So inflate 185/60R15 to about 3 psi less than the 175/60R15 and 185/50R16 sizes, and about 4psi less than the 205/40R17 size.

What are the recommended tyre pressures for the standard tyre sizes?

 

[Stevieb]

I would like a better ride on myA2 tdi 90 which currently is fitted with 195/45/16 Chinese Ditchfinders.
what would you suggest please?

 

[Proghound]

OEM size for those rims is 185/50x16, but 195/50x16 or 185/55x16 also work on the same rims and give you slightly taller sidewalls (185/55 more so) which is where the roughness in the road is absorbed. Avoid XL-rated tyres to get more pliant sidewalls. For real comfort, get 15" rims and go as large as you can on the sidewalls. I'm running a set of Cross Climates in 185/65x15 on pepperpots, and they're like driving on clouds.

 

[greywolfhound]

I think it depends on the make of tyre with regards XL tyres as we have nokian XL in both weatherproof and wra3 style and they are softer than other tyres I have used you can push your thumb in side wall and nice ride ...in both 185 60 15 and 205 50 16 respectively..this topic is very subjective as we all have our favourites ?

 

[Providence]

I'm running 195/60/R15 Bridgestone Turanzas on A1 alloys. Speedo reads 49 at actual 50. The tyres are comfortable, quiet, low rolling resistance and very good grip. I can thoroughly recommend them. I really don't regret swapping from the RS style 17".

 

[carlston]

I would like a better ride on my A2 TDI 90 which currently is fitted with 195/45/16 Chinese Ditchfinders.
What would you suggest please?

If you have 6Jx16 ET35 5x100 57.1 rims, then 195/55R16 would give you an excellent ride. These have a similar outside diameter to 185/65R15 and 205/45R17 tyres, so are about as large as you can go without rubbing.

195/55R16 tyres have a load index of 87 at 3 Bar (44psi) and 185/50R16 tyres have a load index of 81 at 3 Bar (44psi), so you could lower your tyres pressures by about 6psi. This will really help soften the ride as tyre pressure has a big effect on ride.

185/65R15 and 195/55R16 are both popular sizes, so there is plenty of tyre choice at reasonable prices.

 

[carlston]

I'm running 195/60/R15 Bridgestone Turanzas on A1 alloys. Speedo reads 49 at actual 50. The tyres are comfortable, quiet, low rolling resistance and very good grip. I can thoroughly recommend them. I really don't regret swapping from the RS style 17".

What width and offset are the A1 alloys? I've seen 6Jx15 ET29 and 6.5Jx15 ET34. The 6J rims are presumably for 185/60R15 tyres as standard, and the 6.5J rims are presumably for 205/55R15 tyres as standard.

 

[greywolfhound]

I'm running 195/60/R15 Bridgestone Turanzas on A1 alloys. Speedo reads 49 at actual 50. The tyres are comfortable, quiet, low rolling resistance and very good grip. I can thoroughly recommend them. I really don't regret swapping from the RS style 17".

Those tyres were on my short list ..?good to know they work well ..

 

[Providence]

I don't know the width and offset. I bought them from A2Steve on the assurance that they were suitable. They had 205/55R15 on them when I got them. I forgot to say that the lightness of the wheels (and maybe the tyres) has made the steering quicker and the acceleration is faster. It's a 1.4 Sport that's been running on Shell V Power for 18 months. I had it serviced in May and have not reset the DIS which shows 40.1 mpg at an average of 32 mph.

 

[bretti_kivi]

195/60R15 are too big. Remember that 175/60R15 is the definitive reference size and you're pushing well over 4% on that. 3% is tolerance, if I remember correctly. After that, too little mileage on the odo, numbers on the speedo etc. They're even 3% bigger than the largest standard tyre, the 205/40R17.

There's a list of rim widths and suitable tyre sizes in the definitive sizes thread. The offset for the A1 rims will be around the same as the A2, most seem to be +37 and a 6.5 or 7J.

As far as pressure goes, I've run all sorts and settled if I remember correctly at around 2.3 to 2.5 bar all round. Nokian once recommended 2.4/2.7 front / rear for the 215s and that was way too much. 2.2 was squidgy, a little higher gave a good feel, especially to the back end on gravel.

- Bret

 

[bretti_kivi]

If you have 6Jx16 ET35 5x100 57.1 rims, then 195/55R16 would give you an excellent ride. These have a similar outside diameter to 185/65R15 and 205/45R17 tyres, so are about as large as you can go without rubbing.

Again, too big.

195/55R16 tyres have a load index of 87 at 3 Bar (44psi) and 185/50R16 tyres have a load index of 81 at 3 Bar (44psi), so you could lower your tyres pressures by about 6psi.

This is such bunkum it's not funny.
Load index is a function of the build and carcass and nothing else, being marked on the outside of the tyre. Higher load indices generally indicate better wear properties for a lighter car, all other changes excluded, but the wear may not be even and sawtoothing can happen. 3 bar isn't recommeded on any A2 tyre, anywhere. A larger load index may or may not also mean a stiffer carcass to get it, so you negate the effect of the higher sidewall to an extent.

This will really help soften the ride as tyre pressure has a big effect on ride.

agreed on this one

185/65R15 and 195/55R16 are both popular sizes, so there is plenty of tyre choice at reasonable prices.

... and both too big. 185/60R15 is about the limit.

 

[Providence]

Hi Bret,

On the 'definitive tyre' thread (written by you I believe), it says that one of the allowable 17" tyre sizes is 205/45R17. This is 1mm more in diameter to 195/60R15.

So can you explain why the larger 205/45R17 is allowable but the 195/60R15 is 'too big'?

 

[carlston]

For real comfort, get 15" rims and go as large as you can on the sidewalls. I'm running a set of Cross Climates in 185/65x15 on pepperpots, and they're like driving on clouds.

185/65R15 are an excellent choice for comfort and the pepperpots 6Jx15 ET38 look great. However, I would be inclined to go with slightly narrower 5J or 5.5J rims to improve the ride even further. If you're happy with the ride on 6J rims, then stick with them as wider rims do tend to give sharper and more precise steering/handling, etc., as the rims will tend to move about less inside the tyres when cornering.

BMW for example, often fit their tyres to quite wide rims relative to the nominal width of the tyres for this very reason, but the penalty you pay is a harder ride. In the past, 185/55R15 and 205/55R16 tyres were regularly fitted to 6J and 6.5J rims respectively, but now VW group cars often fit these to 0.5" narrower rims, ie. 5.5J and 6J, to get a better ride.

 

[bretti_kivi]

Hi Bret,

On the 'definitive tyre' thread (written by you I believe), it says that one of the allowable 17" tyre sizes is 205/45R17. This is 1mm more in diameter to 195/60R15.

So can you explain why the larger 205/45R17 is allowable but the 195/60R15 is 'too big'?

205/45R17 fits. That doesn't mean it's legal.

- Bret

 

[bretti_kivi]

185/65R15 are an excellent choice for comfort and the pepperpots 6Jx15 ET38 look great. However, I would be inclined to go with slightly narrower 5J or 5.5J rims to improve the ride even further. If you're happy with the ride on 6J rims, then stick with them as wider rims do tend to give sharper and more precise steering/handling, etc., as the rims will tend to move about less inside the tyres when cornering.

BMW for example, often fit their tyres to quite wide rims relative to the nominal width of the tyres for this very reason, but the penalty you pay is a harder ride. In the past, 185/55R15 and 205/55R16 tyres were regularly fitted to 6J and 6.5J rims respectively, but now VW group cars often fit these to 0.5" narrower rims, ie. 5.5J and 6J, to get a better ride.

you will not get 5.5J and 185 past TÜV, they are considered too narrow. Same with 195 on 7J, that's considered too wide.

- Bret

 

[carlston]

ETRTO (European Tyre and Rim Technical Organisation) are the tyre industry body that sets the allowable range of rim widths for any given tyre size. Their publications are expensive. However, you can find some of the information on Toyo's website when it comes to rim width recommendations.

Toyo Tires Proxes CF2

Proxes CF2 has been created to take advantage of the latest materials, structures and tread pattern design in order to guarantee a high level of safety, durability, savings, and comfort.

www.toyo.co.uk

You will see that 185/50 to 185/65 has an allowable rim width range from 5" to 6.5". 195/50 to 195/65 has an allowable rim width range from 5.5" to 7". 195/45 has an allowable rim width range from 6" to 7.5". Notice, that as the aspect ratio goes down for a given tyre width, the range of allowable rim widths tends to increase. ETRTO always recommends the same allowable rim width range for 50 series to 65 series tyres with any given tyre width. 70 to 80 series tyres also have the same allowable rim width range for any given tyre width.

Notice that you need both the tyre width and the aspect ratio when looking up the range of allowable rims widths. For example, 205/80 to 205/70 have a minimum rim width of 5", 205/65 to 205/50 have a minimum rim width of 5.5", 205/45 has a minimum rim width of 6.5", 205/40 has a minimum rim width of 7".

The UK doesn't have to get past TUV. They just have to notify their insurance company of any modifications.

 

[bretti_kivi]

I think you missed the point. A TÜV approval is important for some readers of this site. Ignoring the CoC document - which also specifies rim widths in combination with tyres - is also not an option for a bunch of readers.

Source for the rim width change over aspect ratios, please? Otherwise this is just hearsay. One tyre from a specific manufacturer doesn't prove or disprove anything... though having had 215s on 7.5J at one point, I don't honestly see how they would fit on an 8.5 rim. 205 on 7.5 is pushing it. I distinctly remember hearing the metallic noise of a rim hitting the ground back in NSU in 2010 or so, when someone did a very sharp turn - that was 205s on 7.5J, I believe. I've probably still got the pictures somewhere.

I can and will supply this: https://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=754635 - which specifies minimum and "allowable" rim sizes for a wide range of tyre sizes. I see nowhere a change according to aspect ratio.
ATEOTD, the insurer is the one who has the last word in the UK, whereas for most of the rest of us, it's technical inspections that say yes or no. I would stay away from the extremes, simply because there's no point. Any given wheel width has a significant influence on the sidewall behaviour and therefore comfort. It's one of the reasons I have 195s on my 7J rims (and they are *tight*) - because that car also runs Eibach and B8. I don't expect comfort and don't get it.

- Bret

 

[carlston]

Source for the rim width change over aspect ratios, please?

Wheel/Rim Size Calculator - Shows acceptable rim width range for the tyre size

Wheel/Rim Size Calculator shows acceptable wheel/rim width range for the tyre size in accordance with the standards, it answers the question "What rims fit my car?"

www.tyresizecalculator.com

195/50R16 minimum rim width 5.5"

195/45R16 minimum rim width 6"

As you can see, the allowable rim width depends not just on the width of the tyre but the aspect ratio too.

 

[bretti_kivi]

I don't agree.

Why that would be the case makes close-to-zero sense from a logic perspective. The lower aspect ratio brings the sidewall height down. Wider rims at that point make no sense except to stretch the tyre, which changes the role of the sidewall anyway. I also know of no-one that actually works that way around: it's pretty much always rims first and then tyres to suit, because rims have to have the correct spec.

Also: if a manufacturer states one way or the other, I'm far more inclined to believe it than some advertising-funded site.

Specific case in point: Autec with their new Club Racing; flow-formed, nice and light, 7.5x17. Specified allowable tyre sizes for VAG group cars go from 205 width to 245 for the same rim. 245/35 is massive on a 7.5J. 205 is pushing it.

I still don't see what the point is here apart from posts and wierd disinformation. I'm sure you don't drive an A2.

- Bret

 

[carlston]

...245/35 is massive on a 7.5J...

The minimum rim width for a 245/35 tyre or even a 245/40 tyre is 8". If you want to fit a 245 tyre to a 7.5" rim, you would need at least a 45 aspect ratio.

Wheel/Rim Size Calculator - Shows acceptable rim width range for the tyre size

Wheel/Rim Size Calculator shows acceptable wheel/rim width range for the tyre size in accordance with the standards, it answers the question "What rims fit my car?"

www.tyresizecalculator.com