Under Pressure

[The Doctor 46]

Barbel Mick. Yes, that's the one and thank you Gert for posting it. 

[nigel s]

Just been on Michelins website and it says to stick to the pressure recommended in the BIKES owners manual....?
Not saying 36/42 is NOT an industry std though.

We had a similar situation at work ( boat building ) when all the manufacturers of resins/ bonding pastes / gelcoats supplied data sheets reccommends a 2% catalyst ( hardener ) rate for everything. Some at this rate were unusable... WTF?
Rep came round...yes 2% is right....
Not happy with that we contacted the manufacturer, and they sent round the Chemist who actually designed the stuff. I was at a big firm at the time and we used to buy their entire batch so warranted a visit.
"Oh no ...the 2% is a std for COMPARISON. That way it takes out a variable in different manufactures products so it is easier to compare..use it at what works for you, within limits "....ahhhhh

So what I am thinking is an industry std is not set in stone , nuclear weapons excepted..maybe.. most days.. . I would be interested to hear from the actual tyre testers who helped develop the tyre, that may give a different recommendation depending on the tester  asked

Any hoo.. I ride my 650 with 30/ 36 ..not as in the manual.... ( 33/36 )
I used to be 33/36 on Road 6s and it was fine. I then upgraded the Suspension ( Nitron TVT forks and shock ) and 33 at the front on the very same tyre was horrible, MCT recommended a drop in front pressure and after dropping 1 psi at a time settled on 30 ...and it also lasted 17, 000 miles. ish, so nothing wrong there 

So test, record,  test, record is what I do now till happy, cost's nowt but time

Ho Hum

[Gert]

This might be stating the obvious... Tyre pressures should normally be set on a cold tyre.  A too low tyre pressure will heat up the tyre a lot quicker and often give a better grip. The downside is that the tyre will wear a lot quicker.  The trick is to find a happy balance of tyre pressure that offers the rider a good mileage (tyre life and fuel consumption) while still retaining a good road grip.
The owner's manual gives a suggested starting pressure, however, the tyre pressures will vary depending on tyre brand / tyre construction (eg radial / cross-ply / bias-ply), total bike loaded weight (rider, luggage & passanger), various road surfaces and finally riding style (as in hard braking / cornering / accelerating).
I think that for convenience or a possibly a softer ride, many riders may choose an average between their on-road typre pressure and off-road riding tyre pressures. Maybe this is to save the hassel of first stopping, to let the tyre cool down enough, before re-inflating to the their on-road pressure.

[nigel s]

 Another problem when recommending a pressure to others ,when a psi or two can make a difference , is gauges.
I have 5 ,if you count the one on my bicycle floor pump ( which is way out ), and they all read a bit differently to each other
For my motorbikes I use my Venhill , it seems to have the most repeatable performance and has an air bleed , making it easy to use and  I stick to the readings I get from just that one.
https://www.ebay.co.uk/itm/311412786072?var=0&shprz=EBAY_GB_131090&_ul=GB&mkevt=1&mkcid=1&toolid=20006&mkrid=710-53481-19255-0&campid=5338986375&customid=Cj0KCQjwqv2_BhC0ARIsAFb5Ac_sATMdhCuhFWCfGOSwmauXI_9GiwnUSk7xxnSA7gCsbaazVRTuLQcaAoQeEALw_wcB&gbraid=0AAAAADcddnYDsu3cTC2RIYDGIqip4h5aG&gad_source=1&gclid=Cj0KCQjwqv2_BhC0ARIsAFb5Ac_sATMdhCuhFWCfGOSwmauXI_9GiwnUSk7xxnSA7gCsbaazVRTuLQcaAoQeEALw_wcB

So if I say , for example , 30 psi in the front , it is 30 psi with MY Venhill (  though you are welcome to come round and use it  )........what that is on yours ?...........

Ho Hum

[nigel s]

Quick edit I didn't get to in time to relate.
 Years ago ( probably nearer decades now ) Bike , I think, mag gave away a pencil type gauge free with the mag.
That's handy for keeping on the bike....I thought..... It now lives in my bolt bowl , where it was thrown in disgust.
I tried it and it would give a different reading within 15 psi  either side every time I used it
They could have replaced the scale with a sticker that just said " SOME "   

Ho Hum

[MisterDavey]

You raise a good point regarding gauges.
I have three that match. A Halfords analogue gauge, foot pump, (has the same gauge fitted) and an Airman, which I keep in my tank bag.

[nigel s]

Yes , I never trust the garage forecourt ones that have been thrown around and abused, I would be better off just using right boot to get an accurate reading 

Ho Hum

[crump]

Something that has always been on my mind regarding tyre pressure monitors. Pressures should always be taken with cold tyres, I'm assuming TPMs are constantly taking measurements, so how does it allow for temperature changes as the tyre gets hot? Is there some kind of clever chip that allows for that?

[Rixington43]

My bike track pump was not cheap but the guage lies like a US politician.
I reckon it's out by 6psi.
Dad bought me a serious PCL inflator for Christmas, now I just need to yoink his hydrovane trolley compressor and I'm good to go 😉.
I always have a pencil type PCL guage in my tank bag too as I don't trust forecourt ones all that much either.

[2112]

 Years ago ( probably nearer decades now ) Bike , I think, mag gave away a pencil type gauge free with the mag.

I still have the same gauge embossed with 'Bike' in pale blue on the side. Virtually useless, but I've kept it for some reason ?

[Barbel Mick]

Regarding forecourt air pumps ...... I'm sure I read somewhere that now they charge for the air, the pumps have to be calibrated?
I very rarely use them though & prefer to use one of those dial types, which produces the same reading as a cheap(ish) air pump I keep on the bike. Either could be a few psi out but I'm pretty sure either or both are accurate enough? 

[nigel s]

A note of warning on some of the posh pumps Mick mentioned.
I had a flat on my Gen 2 fazer  ( no repair kit ....I know..I know  ) and managed to get to a M&S petrol station that had a posh all singing and dancing digital pump , it even had a card reader FFS..£1 a go ..
But I had NO air left in the tyre . It was one of those you connect the hose , set the psi , then it does it for you.
Would not work
Went into shop to ask and they said no, it will not work if 0 psi 'cos it thinks it is not connected.........

Another tip....don't tell the RAC you are at a Wild Bean Cafe ( safely off the road, with good ammenities in other words ) they MAY take 4 hours to turn up, while you watch a dozen others use that same damn pump just fine....
Next time I will push the bike onto the dual and tell them it is there , getting in the way...THEN go and have a coffee...

Ho Hum

[nigel s]

Crump,

Good point...not a clue ..sorry

[UK_Vstrom650]

The car's tyre pressure monitors show the psi going up as they warm. Cold pressure is 35psi, once they've warmed up they'll read 38psi. The alarm for low pressure sounds below 30psi regardless of warm/cold tyre. I assume bike ones are the same.

Nigel, not working at 0psi sounds like the worst design for a pump ever   

[nigel s]

Uk_Vstrom650,

I know... stupid pump  ... I didn't even get my quid back.

Ho Hum