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Michelin Pilot Sport Two (PS2) 225/40/18 92Y Extra Load : Review

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tony_danza:
Yes, but it is exponential. The more air in the tyre, the more there is to expand.

My average increase at 34 may be 5PSI hot. At 44PSI it could be 10PSI - I have used my average as a conservative estimate.

The point is he's allowing himself all that threshold, yet a touch below is making him spit bile.

A tyre at that pressure on a car of our weight is a greasy mess and makes driving it like trying to keep a cat in a bath tub.

RedRobin:

--- Quote from: stealthwolf on October 22, 2009, 11:18:55 pm ---
Given that tyres vary in their pressure as you drive, combined with weather conditions, you cannot guarantee what pressures you might reach when say driving on a long journey on a hot day with a full load. If you set the tyre pressures at, say 42psi, you may exceed 50psi, in which case you risk tyre failure. In this case, it would be negligent for the manufacturers if they did not put a lower limit eg 40psi, so that 50psi is never reached.

It may be the case that the PS2s bugger up after 60psi, so to keep on the safe side, Michelin may have used 50psi as a safety limit as exceeding this would mean the possibility of exceeding 60psi when driving would be prevented.

After all, unless you have a TPMS like RR, you're not gonna stop on the motorway at intervals just to check tyre pressures.  :grin:


--- End quote ---

....So far - A varied journey on Tuesday of 512 miles and 100 today, both in all sorts of conditions and speeds - I have found that the pressures have only fluctuated about 3 psi. Whereas the tyre temperatures have fluctuated as much as 15ºC and the fronts are mostly hotter than the rears (as you would expect).

^ This is according to my TyreSure TPMS.

Teutonic_Tamer:

--- Quote from: RedRobin on October 22, 2009, 10:18:01 pm ---
--- Quote from: Teutonic_Tamer on October 22, 2009, 10:01:31 pm ---
Thanks - yes, I knew that your kit had the transmitters in the new valves, which get mounted on the inside of the rim - but when something 'transmits' - then there also needs to be a 'receiver' too.

So on cars with factory fitted 'direct acting TPMS' (direct acting means it measures the actual pressure, rather than uses wheel rotational differences from the wheel speed sensors) such as Renaults, Vauxhalls and Audis - they use those same valve transmitters as you have in your TyreSure kit, but they also have four remote 'antenna' in each wheel arch.  So basically, not only are the actual tyre valves 'coded' to the TPMS 'head unit' (for want of a better phrase), but also the wheels are 'positioned' on the vehicle too.


--- End quote ---

....No antennae in the wheel arches but you do have to 'connect' the wheel positions individually to the display unit as part of the setup. You then revise it as you revise tyre positions etc.

[We ought to be discussing this in the review thread]

--- End quote ---

OK, do you wanna ask the mods to copy the relevent posts over!  :happy2:

Teutonic_Tamer:

--- Quote from: stealthwolf on October 22, 2009, 10:39:12 pm ---
--- Quote from: Teutonic_Tamer on October 22, 2009, 09:38:13 pm ---Can I kindly suggest you actually read the full text on the side of the tyre to which that comment relates to!  I'll give you a clue - it does NOT apply to the UK or EU. :wink:
--- End quote ---
Honestly, TT it was something I noticed but didn't pay much attention to. I've never needed to inflate the tyres above 40psi! Will have a closer look tomorrow!
--- End quote ---

 :happy2:


--- Quote from: stealthwolf on October 22, 2009, 10:39:12 pm ---
--- Quote from: Teutonic_Tamer on October 22, 2009, 09:38:13 pm ---There is absolutely NO confusion. 
--- End quote ---
I'm not the one confused TT. I've only ever checked my tyres when cold - as we've discussed in person - using a PCL type guage in the mornings when the atmosphere is cooler. I'm a good boy!  :innocent:
--- End quote ---

Sorry mate, I didn't mean to imply you personally were confused - more of a 'general' comment.  :wink:


--- Quote from: stealthwolf on October 22, 2009, 10:39:12 pm ---I inferred that the previous poster may have been confused/misinformed about the '50psi' warning and may have interpreted it as not to exceed 50psi at all (so s/he may have thought that the limit would have been exceeded when the tyres were hot rather than exceeding the limit when tyres were cold, if that makes any sense!).
--- End quote ---

Exactly - and he still hasn't got it! :stupid:



--- Quote from: stealthwolf on October 22, 2009, 10:39:12 pm ---
--- Quote from: Teutonic_Tamer on October 22, 2009, 09:38:13 pm ---And just to clarify, a tyre can heat up in as little as half a mile.
--- End quote ---
Which is something you reminded me at the JKM meet and hence have never bothered checking tyre pressures unless when cold.
--- End quote ---

 :happy2:


--- Quote from: stealthwolf on October 22, 2009, 10:39:12 pm ---
--- Quote from: Teutonic_Tamer on October 22, 2009, 09:38:13 pm ---Tyres are categorically and specifically designed to cope with increases in pressue as the tyre heats up - and they have absoultely MASSIVE threasholds for 'overinflation'.
--- End quote ---
This is something I'm well aware of but wasn't sure whether the previous poster was!
--- End quote ---

Again, not at you mate, but arrogance is bliss elsewhere, if you get my drift!  :wink:



--- Quote from: stealthwolf on October 22, 2009, 10:39:12 pm ---
--- Quote from: Teutonic_Tamer on October 22, 2009, 09:38:13 pm ---I've regularly inflated road-legal tyres to over 140psi - and have NEVER had a tyre fail due to over pressure!
--- End quote ---
For educational purposes, why would you do this?
--- End quote ---

Think BIG, very big.  :wink:

stealthwolf:
You mean like lorries and tractors? But surely the tyres are designed to withstand such pressure on such vehicles?

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