Probably a topic beaten to death...

[Ho Lee Kau]

julian64 said:

Farlig said:

julian64 said:

2.38-2.45 bar.

Can I just say I love your enthusiasm.

The above figure equate to 34.986 psi to 36.015 psi. You are specifying the pressure down to 0.15 psi.

Ehh no, not quite; you´re taking what is an already higher resolution measurement of pressure & quoting it to three decimal places.
When measuring in bar, if you quote only one decimal place the resolution is not fine enough.
ie going from 2.3 to 2.4 bar is the same as going from 33.4 psi to 34.8 psi or rounded 33 to 35 psi, certainly sufficient to make a difference.
So measuring in bar, one must quote 2 decimal places to achieve a sensible resolution, whereas measuring in psi, there´s no need to use more than one decimal place, if that.
(Oh & your conversion factor is wrong... 1 bar = 14.5038 psi => 2.38 bar = 34.519 psi & 2.45 bar = 35.534 psi)

I think you need a whoosh parrot. My post was based on fag packet 14.7 psi = 1 bar. I didn't look it up because it doesn't matter. It was intentional designed to highlight the idea that there is a different between precision and accuracy. People on this thread are being incredibly precise to the point of ridicule but have no concept of their accuracy in getting pressure into a wheel.

You on the other hand come to correct my maths down to one ten thousandth of a psi when your foot pump could probably only be 'accurate' to 2-3psi despite the 'precision' on your gauge.

And that completely bypasses the question of whether one of you could actually tell the difference in riding with a change of 5psi which I would be willing to bet none of you could in any sort of blind trial.

So ........whhhhhoooooshhhhhhh

Yes, probably 5psi one would not feel on the road...or track unless one is top level rider.
Still, tire pressure is an important topic, and 0.1 bar could mean a lot.

[Ho Lee Kau]

moanthebairns said:

tight5 said:

Ho Lee Kau said:

I felt the rear stepping out momentarily
It was a warm (15C+) day and dry

Were your tyres up to temprature ?
Cold tyres don't work too well !!

Pressures from the manual for me.

Would a few psi even cause a "stepping out" issue.

I mean I've had a near enough high side in the rain on st tyres, on greasy roads, cold tyres, fked tyres and on the track....

And all of these were rider error (too much throttle/lean asking too much etc), or/and cold tyres.

Would a few psi cause "stepping out". How bad a stepping out are we talking here, out your seat, balls off the tank, buy a lottery ticket or the bike telling your "WARNING, WARNING, I'm getting pretty fed up being a motorbike, I'm just letting you know I'm thinking about turning myself into a scud missile if you keep ham fistedly applying that throttle you clown".

Well, three things, 1) not too much throttle, FOR SURE, 2) tires were NOT cold, 3) lean angle was not too high.
The stepping out, well, I felt it and it was not a good feeling, I am very fond of my body as well as my bike (even though it is old and used and beaten up and I dropped it already 2 times).
I decreased the pressures yesterday and went for a ride, it felt better, but, of course, I am not Rossi/Marquez/Crushlow, I cannot tell with minute precision if things are better or worse, plus I am not pushing to the limit.
I still think it an important and interesting question, the tire pressure, and I am collecting information from everyone here to make an educated guess.

[Ho Lee Kau]

308mate said:

moanthebairns said:

tight5 said:

Ho Lee Kau said:

I felt the rear stepping out momentarily
It was a warm (15C+) day and dry

Were your tyres up to temprature ?
Cold tyres don't work too well !!

Pressures from the manual for me.

Would a few psi even cause a "stepping out" issue.

I mean I've had a near enough high side in the rain on st tyres, on greasy roads, cold tyres, fked tyres and on the track....

And all of these were rider error (too much throttle/lean asking too much etc), or/and cold tyres.

Would a few psi cause "stepping out". How bad a stepping out are we talking here, out your seat, balls off the tank, buy a lottery ticket or the bike telling your "WARNING, WARNING, I'm getting pretty fed up being a motorbike, I'm just letting you know I'm thinking about turning myself into a scud missile if you keep ham fistedly applying that throttle you clown".

Or a few inches across a manhole cover that felt like a lot?

manhole covers in November rain taking a corner after red light in dense traffic....tell me about it, it's freaking scary...

[Ho Lee Kau]

moanthebairns said:

Why is it bikers would go in a car, get a bit of understeer or oversteer and think, oh at the limits there back off. Right back on it ah fk it.

But when the bike gives them a signal of loss of traction due to you riding like a berk, fk my bikes broken, not enough air in the tyres, too much, they are gone, its the suspension, oil. I'm not for a second saying that sometimes this isnt the case but why do we all think that....

I do not ride like a "berk", in the sense 1) I've got good training and I am overly cautious on public roads, 2) I know my limits, I am a novice.
It was definitely not my "skills", it was either tire pressure or road surface or badly set-up suspension (I had it modified, as said above). Personally, I think the tire pressure was too high, because I've seen guys take same corner knee down at higher speed on a more powerful bike.

[Ho Lee Kau]

Farlig said:

julian64 said:

I think you need a whoosh parrot. My post was based on fag packet 14.7 psi = 1 bar. I didn't look it up because it doesn't matter. It was intentional designed to highlight the idea that there is a different between precision and accuracy. People on this thread are being incredibly precise to the point of ridicule but have no concept of their accuracy in getting pressure into a wheel.

You on the other hand come to correct my maths down to one ten thousandth of a psi when your foot pump could probably only be 'accurate' to 2-3psi despite the 'precision' on your gauge.

And that completely bypasses the question of whether one of you could actually tell the difference in riding with a change of 5psi which I would be willing to bet none of you could in any sort of blind trial.

So ........whhhhhoooooshhhhhhh

I´m an engineer, I work with pressures & conversions every day - can´t help it. On the other hand you absolutely cannot quote figures to three decimal places when your conversion factor is one decimal place irrespective of what you are trying to convey - you´re wrong - my point is there are a fk load of people outside of the UK & USA who work in bar and to get a decent pressure resolution you HAVE to use 2 decimal places, so whoosh your imperial self dude...
And +/- 0.344738 bar (5 psi) can very easily be felt on a bike - but perhaps not by someone who doesn´t get counter-steering: whhhhhoooooshhhhhhh

owned again

[Ho Lee Kau]

mckeann said:

Ho Lee Kau said:

I have to try this on my K6.
I have Racetec K3 RR on it now, switched from SC SP as those wear too damn fast (especially front sides, as I ride K6 only on uphill-downhill hairpins).
I have 2.3 front and 2.6 rear, cold.

You know the K3 and the SP are basically the same tyre yeh??

They are similar purpose tire, yes, I know. SC V2 is a bit older than K3 RR, I believe.
I've read comparison reviews and it seems K3 last a bit longer than SC, which last nothing at all for my type of riding (nothing super-agressive but up and down hills a lot). Now I am testing my first set of K3 tires on GSXR.

[Ho Lee Kau]

Farlig said:

julian64 said:

I worry about todays engineers.

Two decimal places is 0.15 psi One decimal place is 1.5 psi. Please post again to confirm you need the resolution greater than 1.5psi in your back tyre, and need to go down to two decimal places for bar.

because

1) Its funny
2) I'm about to ask you to show me a foot pump I can buy that will deliver either accuracy for my bike.

Don´t take the piss out of an engineer when you obviously have no idea how to measure pressure yourself. Anyone with a modicum of a clue / wnating to track changes & differences uses a proper pressure gauge to get accurate & repeatable results. The gauge on the foot pump is for indication only: You pump up to higher pressure then use an accurate gauge to bleed off to your desired pressure. Whhhhhhoooooosh....

I worry about today´s doctors too, especially ones that don´t believe in hearing protection...

I do exactly as you mention. I pump up with foot pump then bleed of with Oxford Air Gauge. The question is - how accurate is Oxford Air Gauge? I've read comparison tests before buying one, and Oxford was second best overall and very accurate. I wouldn't mind buying another digital gauge, for "statistical purposes", let's say. What would you recommend?

[Ho Lee Kau]

Birky_41 said:

How you find the pressure changes? I've just knocked up nearly a thousand miles on my m7rr's and have found them pretty good apart the back moving around a bit which I still think is the tread pattern

I really like that tire! I switched from a series of Pirelli Angel GTs (old and updated) and even though Angel feels ok on 696 Monster, I like M7RR much more, perfect all-season tire, imho. I've "knocked up" 10000 miles on it in all types of weathers.
OK, so far I use it only on my daily ride - CBR600F4i.

Daytona is on Supercorsa SP V2 and GSXR1000 is currently on Metzeler K3 RR (switched from SC V2).
The 954 is on Michelin Pilot Power, these are old tires (in terms of technology, the tires themselves are 1 year old) but they work fine on 954, I've never had any issues.

I like M7RR but that stepping out saps my confidence, therefore I will play with pressures for now but will probably try something different to see how it feels, Michelin Power RS caught my interest lately.

[R1 Dave]

I had M7RR on my RSV4; excellent tyre.

[Ho Lee Kau]

Birky_41 said:

How you find the pressure changes? I've just knocked up nearly a thousand miles on my m7rr's and have found them pretty good apart the back moving around a bit which I still think is the tread pattern

Could be a thread pattern, true.

The Angel GT have too many holes on the sides, nice for water egress, but not much rubber on the road at full lean. I had these on my CBR600 before and I decided to switch to M7RR in the end, which I always liked...until I got the rear twitching.

Have you tried Michelin Power RS?

[Ho Lee Kau]

R1 Dave said:

Am I right in thinking the manufacturers recommended pressures are actually for two-up? I've always used the standard pressures (36/42) but very rarely take a pillion.

Personally, I think these are recommendations for full load on highway.

Even cars have at least two recommendations for tire pressure!

2.9 bar cold rear tire....I think NOT.

[Ho Lee Kau]

Jazoli said:

R1 Dave said:

Am I right in thinking the manufacturers recommended pressures are actually for two-up? I've always used the standard pressures (36/42) but very rarely take a pillion.

No, most bikes will have 2 recommended settings, i.e 36/36 for solo riding and 36/42 for 2 up if you read the manual.

I have found that it makes feck all difference in the real world, 99% of people would not be able to tell the difference of 5psi, the handling only suffers once you get below 20psi, my SV had 13psi in the front tyre when I bought it and the air line at the nearest garage was broken, it rode home fine at 90 plus, it was just a bit slow to steer

imho, rear is more important, bigger contact patch and that's where most of the weight is anyway most of the time