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tyre pressures.

Discussion in 'Tyres Wheels and Brakes' started by Phil, Nov 27, 2010.

  1. Phil

    Phil Senior Member Premium Member Contributing Member

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    What is something that we bike riders do about every 200 to 300 kilometers, you got it, we pull in and refuel our trusty steeds for without the magic juice (petrol) we aren't going anywhere. Which ever method we have at our disposal, fuel gauge, warning light or even the reserve tap the result never changes, we need some gogo juice .I hear Mr.Watson saying: elementary my dear fellow and he is correct, however we never look beyond the refueling process.

    This brings me to the subject of tyre pressures. You have just refuelled your machine, isn't it a perfect time to check the pressures in our tyres whilst the helmet and gloves are off. Of course it is, and yet the greater majority of us simply rarely give this simple task any thought at all. The simple task of maintaining correct pressures in our tyres has a two prong effect, I) Correct pressure insure better stability of our bikes  2) correct pressures will extend the life of our tyres. If you have just purchased a new set of tyres for your bike or  out getting quotes you may well still be in shock, motorcycles tyres are extremely expensive. I recently had a new set fitted to my bike and got little change out of $500.00, this is coupled to a very short life span, about 10,000 kilometers, well you do the maths.

    Premature wear on tyres comes down to 2 basic factors, under inflated tyres and riding technics. So do your hip pocket a favour, keep your tyres inflated at the correct pressures and you will save money, as for riding techniques; thats up to you. Bikes with correct tyre pressure do tend to handle better, as the manufactures designed them to do so go on give it a go and you won't be disappointed with the outcome.

    Enjoy the ride 
     
    Phil
     
  2. johnno

    johnno Active Member

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    so true, low tyre pressures can really effect the handeling of a bike, nice one Phil +1

    Johnno
     
  3. Mark

    Mark New Member

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    Hi Phil,

    Can I add that whilst tyre pressures are very important to safe riding, good tyre life and a good feel on the road, they should be checked when cold, at the start of the ride, the pressures will vary greatly during a ride depending on the type of riding we are doing, and will affect the bike accordingly.

    If for example you take a hot ride over Mt Mee, (I am talking about the weather here of course!!) and stop for fuel in Woodford before heading back down the freeway you are going to want to let a little bit of pressure out of the tyres because yo have just worked them very hard.

    They will cool a little heading down the freeway and will not return to their optimum operating pressure, which is quite a lot higher than the pressures measured cold.

    There are a lot of opinions and ideas on this, I  have read many different articles in the bike press and none of it seems to agree.

    The most recent in the UK's Superbike mag though seems the most thorough.  They took a variety of bikes, all shod on identical tyres at manufactures recommended pressures and then tested how each bike felt with less and less pressure in the tyres.

    The outcome indicates that most bikes operate best within just a few psi of the tyre manufacturers recommended cold pressures.

    Personally on the Sprint, I run 34 front and 38 rear, increasing to 36 and 42 with luggage/pillion.

    I think we have opened a can of worms here, should be interesting to see what responses we get.

    Stay safe in the wet.
     
  4. Phil

    Phil Senior Member Premium Member Contributing Member

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    Hi Mark
    Enjoyed reading your article on Tyre pressures. I also have perused many an article on this subject and opinions differ greatly. Originally I was only trying in a small way to get people thinking about checking pressures for the majority of people I spoke to, few if any did. Many admitted that this only occur ed when the bike was serviced. 6000 kilometers between checks is in my opinion disturbing to say the least.
    Recently I was in Brisbane and visited my sons motorcycle mechanic , whilst there a lady rode in on a large Honda and complained that she was struggling with the new tyre pressure gauge that she had recently purchased. The mechanic checked the pressure which were spot on. However your take on this could prove most legitimate as when pressure were checked, HOT or COLD. Certainly is an interesting pont
    Look forward to more articles in the future.  Phil
     
  5. kiffsta

    kiffsta Administrator Staff Member Dirty Wheel Club Contributing Member

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    I wanted highlight this area, again, this morning I noticed  my Across was out of fuel and I was running late for work  so I jumped on my 650, I went to take my first corner and my bike bike didnt want to turn, it was incredibly heavy and sluggish. I stopped at my local servo and my front tyre was at 18 psi, I pumped it up and my steering returned to normal.
     
  6. BzR5150

    BzR5150 Member Premium Member

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    Have any of you guys heard of the "4psi" rule?
    I have only found out about this fairly recently myself. I found it in the 4x4 world it is universal to tires.

    "I use that 4psi rule everywhere, and for everything!! It works very well in ALL circumstances and across all variations that you can think of and a whole heap of others you never dreamed of! Use the tyre placard as a start point, drive for an hour, stop and check the pressure. If it's gone up by MORE than 4psi, your start pressure was too LOW, add pressure now! If it has gone up by LESS than 4psi, then your start pressure was too HIGH and youn need to drop 2psi NOW! Those new pressures should be used as your start points for the next cold start!"





    "Peter @ Aawen4x4 wrote:
    It came (some years back) from a tyre guru who had spent his working life in the back rooms of the tyre companies that spent mega bucks supporting some of the race teams. He had a wealth of knowledge, and had a career that included time with a couple of the large tyre companies, and some of the big names in international racing, as well as successfully running one of the more respected tyre development and testing departments in the world! I was very impressed with his down to earth approach and knowledge, and he spent some time explaining that despite all the computing power that had been bought to bear on the subject of determining the 'optimum' tyre pressure for a given tyre for ALL situations, they still hadn't been able to get anything better than the '4psi increase after an hours worth of driving' and it worked wherever they applied it!

    Since then, I've seen it appear in lots of places, the latest being the Cooper and Mickey Thompson 4WD Driver's Guides, where they have a section on tyre pressure, and they lay out the '4psi Rule'! They do suggest to use it only for bitumen road use, and despite being told by 'the man' that it worked anywhere, I too was a little slow to be convinced that it STILL works fantastically for Off-road use, surfaces, and conditions; it's just that the pressures hafta be significantly lower to start with! I suspect that is the reason for the rider in the Cooper and Mickey T documents; either that or they are protecting their butt from some percieved potential lawsuit. But it's worked for me driving trucks & buses, cars, 4WD's, and even tractors of various sorts, in all sorts of conditions, heat, snow, rocks, sand, et al, so don't be worried about applying it to whatever you are doing with tyres, it'll help get the pressures right for whatever you are doing!

    So try it yourself! If you seriously give it a proper try, and adjust your pressures in the manner it suggests, you'll get longer life from your tyres, they'll be less prone to puncturing than otherwise, and they'll give you traction, road manners, and ride characteristics that not only enhance the life of the tyre, but make it easier on the vehicle and the occupants! Like they say, use the tyre placard to get a good starting point, then fine tune it using the 4psi rule from there. Use the guides suggested pressures for off-road pressures as a start point too, and then do the fine tuning with the 4psi rule. Again, it'll enhance your driving in more ways than you expect.

    One of the first things that I noticed when I started using this rule off road was that when I went driving with others who weren't aware of the 4psi rule 2 things happened. 1 - they bagged me for stopping and playing with tyre pressures; and 2 - they thought I was a much better driver than the norm because I could go places that they couldn't without anywhere near the wheelspin or even at all! The only thing that I could see that was different was that I was using the 4psi rule and they were generally not changing pressures much at all! Now that was a long time ago, and it was when people generally worked on HIGH pressures only for off roading, to allow the tyre to cut thru the goop and get down to the firm stuff etc, and since then the whole ballgame has changed and people are much more aware of using lower pressures to enhance traction, but still, it was a telling point at the time. My tyre guru had given me a handle on something that REALLY DID WORK!

    Try it, you'll see for yourself!"

    Google it and you will find more info I'm sure.
     

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