Probably a topic beaten to death...
Discussion
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 fYou 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
k 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
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.
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....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.
I worry about today´s doctors too, especially ones that don´t believe in hearing protection...
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.
Now I don't know what you are using to fill the tyres on your bike, but the compressor I use would be pretty chuffed if it could specify a pressure within 5psi, and that's before the heat of riding mucks about with it another 5-10 psi
So I tend to run my bike at 30psi cos its the big figure on the very small dial I use, and check the rims aren't touching the ground when I sit on the bike. Then I'm good to go.
Thank you! 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.
Now I don't know what you are using to fill the tyres on your bike, but the compressor I use would be pretty chuffed if it could specify a pressure within 5psi, and that's before the heat of riding mucks about with it another 5-10 psi
So I tend to run my bike at 30psi cos its the big figure on the very small dial I use, and check the rims aren't touching the ground when I sit on the bike. Then I'm good to go.
Yes, that is why I have a digital pressure gauge (Oxford Air Gauge, I bought it because it got top marks in a test of 10 gauges) and a Michelin pump with a digital gauge. I always use both and they are within 0.2 bar off each other....and both could be wrong, so maybe I need a third gauge, which is known to be precise!
Oh, I do not measure by psi, I measure by bar.
scorcher said:
33F and 34R on my KTM 950 using Michelin Pilot Power 2CT's. Drop them to 32/32 when its really warm. I always thought 36/42 seemed too hard. Usually best just to drop a couple of PSI out at a time and see how it feels. You can always put them back up again if it doesn't suit!
Exactly!I think I will drop to 2.2 front and 2.4 rear, cold, see how that feels.
cmaguire said:
cbmotorsport said:
Well, you evidently know more than all those boffins that design motorcycles and tyres and spend hundreds of millions of pounds in R&D. :-)
The manufacturer settings are a catch-all though, based around the tyres they supply the bike with and that you might ride with a pillion or be fat etc36F 42R is mostly manufacturer default.
I just go with 33/34F and 38R as a start on the road.
Checking the rear after riding on some decent roads in Spain that 38 had become 44. I have M7RR on the GSXR and they occasional step a little on the back (No heroics going on in my book) but I get the same with the PR4 on the Street Triple. A friend I ride with of similar speed never seems to have a problem, even though he leans a little more than me. My suspicion is that my style of riding with my balls on the tank, as opposed to his where he sits further back in the seat, might have something to do with it as he has more weight on the rear.
.
Exactly! And in the summer the tires get really hot, so 44 is pretty normal then. That's why Triumph recommends 2.35 and 2.48 on SC for the street, I bet!
I also tend to slide forward a lot. Really, I have to work on my posture on the bike...
Birky_41 said:
MattOz said:
Tyre pressures.
I use 33psi front and 35psi rear, so what's that, 2.3 and 2.4 bar respectively. That's on my K7 GSXR1000, using Supercorsa SP's.
This ^^ I run maybe 1psi more on front not that I could really tell (probably in my head) with M7RR's and 34/35 rearI use 33psi front and 35psi rear, so what's that, 2.3 and 2.4 bar respectively. That's on my K7 GSXR1000, using Supercorsa SP's.
Dont overthink it. Just bung that in them cold, go out and ride. You'll be fine.
Unless you are on the 954 in which case you can run anything as that handles like a Aprilia RS250
Besides, like mentioned above, the gauges all show different values, who knows what the true pressure is, one has to test oneself forward.
954
But I liked the new GSXR1000 and the RSV4RF left a great impression as well.
Fireblade SP was great as well, I guess I just have too many Hondas to spare some love for another one. The underdog Gixxer is more my bike.
Loyly said:
moanthebairns said:
36 F 36 R cold, I'm doing it all wrong. Anyone who measures tyre pressure in bar is just weird.
HO LEE KAU is in Switzerland IIRC so maybe they do it differently there. My pump and gauge are pretty accurate (I use a foot pump and an electronic gauge, which tally very closely when measured). But, it sounds as though I'm overthinking my pressures a bit much. I always thought that they were critical since you rely on such a small contact patch on a bike. I'm glad to see some more relaxed attitudes to this.
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.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.
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)
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 ?It was a warm (15C+) day and dry
Cold tyres don't work too well !!
Pressures from the manual for me.
I use 1861 Hgmm front and 2712 Hgmm rear.
I've done about 8000 Furlongs (US) with those pressures and having experimented with it just slightly below the manufacturer's recommendations work best for me.
If I do a 5 hour ride I just can't keep the heat in them for the duration to warrant lowering the pressures much.
I've done about 8000 Furlongs (US) with those pressures and having experimented with it just slightly below the manufacturer's recommendations work best for me.
If I do a 5 hour ride I just can't keep the heat in them for the duration to warrant lowering the pressures much.
Prof Prolapse said:
I use 1861 Hgmm front and 2712 Hgmm rear.
I've done about 8000 Furlongs (US) with those pressures and having experimented with it just slightly below the manufacturer's recommendations work best for me.
If I do a 5 hour ride I just can't keep the heat in them for the duration to warrant lowering the pressures much.
That's all very well and good but you're going to notice a difference whether the ambient temperate is 288K or 298K.I've done about 8000 Furlongs (US) with those pressures and having experimented with it just slightly below the manufacturer's recommendations work best for me.
If I do a 5 hour ride I just can't keep the heat in them for the duration to warrant lowering the pressures much.
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
Tango13 said:
O/P, Just how knackered is your suspension?
Last Sunday I was out in similar conditions running 36f/42r with 80 lbs/ft or 110nm of torque from 4,000rpm to 9,700rpm and I had zero problems with grip. Even in much cooler conditions the rear has only ever let go once and that was more of a gentle drift than a 'slip'
This is a 2002 bike, but 2 years ago I ordered a new WP shock with hight adjustment and replaced the components in the shock with Race Tech components (springs, valves + oil), I lifted the bike about 20mm front and rear. The suspension parts + work cost me more than the bike (that's how much I like this old bird)! Last Sunday I was out in similar conditions running 36f/42r with 80 lbs/ft or 110nm of torque from 4,000rpm to 9,700rpm and I had zero problems with grip. Even in much cooler conditions the rear has only ever let go once and that was more of a gentle drift than a 'slip'
In other words, the suspension is fresh.
King Herald said:
julian64 said:
2.38-2.45 bar.
So I tend to run my bike at 30psi cos its the big figure on the very small dial I use, and check the rims aren't touching the ground when I sit on the bike. Then I'm good to go.
I love the way some people bandy around tiny fractions of a bar, like it is some surgical procedure and they are filling their tyres with nitrogen, in a climate controlled sterile zone, to be used on an indoor air con racing track. So I tend to run my bike at 30psi cos its the big figure on the very small dial I use, and check the rims aren't touching the ground when I sit on the bike. Then I'm good to go.
Tell this to TRIUMPH!
(That's in their manual, you know.)
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