Unusual size tyres?

[PSbridge]

I've had a 1.9TDI Roomster since new in 2009. It hasn't got tyre pressure monitoring system, so bought the correct bandwidth valve caps from one of those countless publications selling what appear to be "good ideas"!. These caps have shown "green" ever since fitted, so no problems with tyre pressures. My MoT was around 4 months ago, and from the finger marks on the wheel rims, and caps, it was obvious that the tyres were checked and pressures taken as you would expect on a service / MoT.

With a forecast of ice / possible snow, I decided to check my tread depths for winter running, down to 3mm on the driver's side front, a fraction less on the passenger side front. The caps all showed green, but noticed that the passenger side front tyre looked a bit flat at the bottom. I took the cap off, checked the pressure, down to 10psi as opposed to 27 in the other wheels. Inflated the tyre again, put the cap back on, green showing again until the next morning inspection, this time the telltale had disappeared, meaning a pressure loss. This time it was 2psi down, ie 25psi and was indicating correctly of a loss of pressure, a pity it didn't do that for a loss of 17psi!

The conclusion from this is that they may work, on the other hand might tell you all is well when it clearly isn't!

Moral: Don't trust them without actually checking the pressure! Rather defeats the object of buying them.

Then came the interesting bit, a couple of National chains advised that the 205/45/16 87W tyres were an unusual size so had no stock at all. A family run tyre business, local to my area, also advised the same, but they went the extra mile and resourced a couple for me. There were 2 types of tread pattern, old and new, I selected the latest of course, but they came back later to tell me that there was no source holding these, so had ordered the older pattern for me, which turned out to be identical to my originals anyway.

If you have this size of tyre, there doesn't appear to be a ready stock to draw from?

The puncture was quite unusual as well, there was a tiny leak in the inside sidewall of the tyre. The fitter showed me just a puncture hole, no abrasions, so not pothole inflicted. Suggestions were a sharp bit of stone, metal, glass etc was propelled into the sidewall due to airflow under the car. Repairs to sidewalls are not allowed, so although the tyres were "legally" OK, but at 3mm ought to be changed sooner, rather than later, the decision in this instance was already taken!

 

Peter

 

 

[Huskoda]

Are these the LED valve caps that work by holding the valve open all the time? I personally wouldn't touch them, but hey ho.

 

205/45/16 are not a cheap (ie common) tyre size, but there are quite a few about if you buy from the internet and are the standard 16" for Fabia IIs and their derivatives (Roomster).

 

http://www.camskill.co.uk/m62b0s344p0/Car_Tyres_-_MPV_Tyres_-_People_Carrier_Tyres_-_16_inch_R16_inch_-_205_45_16_205_45R16

[Robjon]

Hi Peter,

 

205/45/R16 87W is standard issue on Roomster Scout and an option on all other models.  My local ATS was able to obtain one within 12 hours when I potholed one with just 2,000 miles on the clock.  On another occasion, my local dealer was able to obtain one immediately when his Tech noticed inner sidewall damage during annual service.  Perhaps I was lucky?

[PSbridge]

They must be a mechanical type mechanism, screwing them on raises a green marker inside the plastic dome, removing them causes the marker to drop down out of vision. You are right in that they must depress the centre pin of the actual valve and hold it open to detect any loss of pressure. In my case it failed to detect a loss of 15psi, over an unknown period, but reinflating back to 27psi caused another loss of 2psi overnight. It worked correctly this time! I'm just estimating that the damage to the sidewall was probably a week ago using the 2psi / day rate of drop, conclusion - they are rubbish as you say. I certainly will not replace them, I'm using the standard caps as supplied by the tyre fitter.

I was surprised at the queue at the company who obtained the Bridgestone tyres for me, it was like the queue at the local chippy on a Saturday tea time, and they had 8 bays fully working! I'm guessing that the adverse winter weather forecast caused a sudden surge in work, and the other outlets consulted didn't want the extra work of ordering them in. If I had tried on a quieter day, maybe they would have been more interested, who knows?

I didn't check with my local Skoda dealer, who took up the franchise just after I purchased the car from another town! I will call in there when passing next time to see what their set up is with regard to tyres.

It proved to be an interesting exercise though because I even got the spare wheel out to check its pressure and discovered that it is a "Dunlop Sport" restricted to 50mph. Obviously this is much better than a tube of sealant as supplied today. I knew that it was a steel rim as opposed to an alloy, but had never twigged that it was a restricted speed tyre because the labels faced downwards to the floor of the boot! As the centre fixing spindle scewing it to the boot floor had either paint, or sealant, jamming the threads, it took quite a while to free it. Obviously there is no requirement to check it on a sevice or MoT, it had never been out since new until I freed it yesterday! It was the correct pressure, but in hindsight, maybe I should have added a few more psi to make sure it would be correct at anytime in the future.

 

Thanks for all the comments

 

Peter

 

 

 

[PSbridge]

Went out to check the pressures after standing for 24 hours and a bit surprised at what I found!

The rears, should have been checked at the last service a few months ago were balanced @ 28psi, the new fronts were @ 40psi!

I thought that I had converted the information inside the fuel flap correctly that on the 1.9 TDI, they should be 2.1 bars lightly loaded or 2.2 bars with a full load, and that a bar equated to 15psi approx.

I approximated this to 32psi in all 4 wheels, meaning that the fronts were a fair bit over inflated, and the rears a little under.

Obviously with tyres now costing £120 each, I'd like to get it correct before I bomb down a motorway, and wondered if the Tyre fitter knew something I didn't about the Roomster, or whether they just blew it up until it looked about right? There is nothing I can see in the handbook which helps, just the information that the values are inside the fuel cap flap.

 

Peter

 

 

[softscoop]

205/45/16 certainly aren't the most common, but I wouldn't say they're unusual.

 

I've never had any problems getting tyres in that size at all.

 

Decent tyres can be had from http://www.blackcircles.com and the like for far less than £120 a corner.

[Huskoda]

Went out to check the pressures after standing for 24 hours and a bit surprised at what I found!

The rears, should have been checked at the last service a few months ago were balanced @ 28psi, the new fronts were @ 40psi!

 

I believe when tyres are fitted, they test the seal at 40 PSI. Looks like they didn't let them down a bit afterwards.

 

http://www.yokohamatire.com/tires_101/tire_care_and_safety/match_mounting/

[PSbridge]

Thanks for the link, I can see why 40psi came into the equation now. Oddly enough, the steering felt very light on the way home, probably the over inflation which I discovered when I tested the pressures the next day. All now set at 32psi, the spare temporary wheel checked and inflated to around 36psi, so that if I did have a cause to use it out on the road, at least I can let it down a little to balance with the rest.

 

Thanks to everyone who helped.

 

Hopefully we are all OK now until the rears approach their end of life tread depth.

 

Peter

[AnotherGareth]

a couple of National chains advised that the 205/45/16 87W tyres were an unusual size so had no stock at all. A family run tyre business, local to my area, also advised the same, but they went the extra mile and resourced a couple for me.

I just looked on mytyres - they have 54 XL tyres listed in this size.

[grafitti]

I prefer having my fronts at high pressure, to me they handle better and carry the weight of the 1.9 tdi more smoothly. Generally I inflate the fronts to 38 and the rears to 34