Kawa. 250r + long distance + heat = tyre pressure?
February 1, 2010 at 6:56 am #3684paulurmstonParticipant
Hi there everyone… I have a question about tyre pressure.
This Tuesday (as in 32 hours from now) I will be taking my first long trip in Chile. Now, the distance is 480 Kmh’s (that’s as good as 300 miles).
Now, the weather report for this week is 25-30 degrees (77-87 fahrenheit).
I am trying to remember as I write now (it’s 4am here) that the MAX tyre pressure is 32 front and 36 rear.
I assume that is the same with all factory fitted tyres on the 2009 model 250cc.
My BIG question is WHAT should be my ideal tyre pressure… taking into account the distance and heat.
I will be traveling alone, with a rucksack. I weigh around 85 kilos, with lets say another 10 in the bag (around 220 pounds).
Anyone have any ideas… I guess I should have them at around 30 front / 34 rear… but I would like another opinion.
ThanksFebruary 1, 2010 at 8:16 am #24325
Finding an ideal tire pressure is a VERY complicated business, and differs from brand to brand, and from tire to tire. Trust me on this one: don’t mess with tire pressure unless somebody that knows what they’re talking about has told you otherwise. By “somebody that knows what they’re talking about,” I really mean “tire company representative,” or maybe the occasional dealer.
The recommended tire pressure is the COLD tire pressure. If you’ve ridden at all, especially in warm-ish weather, the tire pressure you read will not be helpful at all. You need to let your bike cool down for a while before taking a reading. The weather you describe is not particularly hot, and I honestly don’t think it warrants any change in tire pressure.
The only situation in which I’ve ever actively modified my tire pressure is at the track, where it’s absolutely necessary for safety and ideal performance. In that case, manufacturers provide well-researched tire pressures for track use…it’s not simply a matter of letting arbitrary amounts of pressure out of your tires.
Ok, blah blah blah, I’ve rambled enough. In summary: just use the recommended tire pressure.February 1, 2010 at 12:04 pm #24330paulurmstonParticipant
Thanks. Will do. I was just a little worried as of course… once I hit 120Kmh’s… it’s a little late to start worrying.
I’m sure I will be fine. Just worrying I guess.
In Chile, there isn’t really very much in between towns to help if you get stuck.
Thanks again.February 1, 2010 at 12:45 pm #24332TrialsRiderParticipant
30 front / 34 rear sounds about right, manufacturers generally recommend higher values at higher speeds, …would be interesting to see if it changes much with high altitude, you could test that better than most of us For comparison, I ride a much heavier BMW K100RS and the one up numbers are 33/36, two up 36/42 and two up riding above 180 kph calls for 39/42. In my experience too high pressure results in your suspension over reacting to even the smallest road ripple, and on gravel roads it feels unstable owing to the reduced foot print, very low pressure is most noticeable in the rear first when it starts to squirm, even traveling in a straight line. I encountered a rear flat at high speed once, riding two up! …couldn’t figure out why it was under-steering and felt like the bike had a hinge in the middle, until I stopped and looked down to see the rear tire totally flat. Thankfully it was the rear tire, we were both very light weight riders, both very experienced, so nothing bad happened.
Now for something completely different; on my competition trials bike I ride 5.5 psi in the front and 4 psi in the 2 ply tubeless rear, but then in trials you seldom ride faster than 30 kph and you want only enough air pressure to keep the tire on and not dent the rim when you hit the big sharp rocksFebruary 1, 2010 at 2:36 pm #24333
You don’t want to use maximum tire pressure. You want to consult the recommended single/double passenger ride pressures listed in the manual (and under the removable pillion seat in ’08+ models). The Ninja is a light bike. 32/36 front/rear is way too high.February 1, 2010 at 2:43 pm #24334AParticipant
Don’t know what the surface condition is like in Chile.. but I change my tire pressure according to road surface, or trail surface..
I’ve ridden a KTM 640 Adv. from coast to coast, 5-600 miles a day on pavement is no problem with tube/tire combination with myself at 160 lb. and 80+ lb. of gear.February 1, 2010 at 2:46 pm #24335
Eternal is correct……. Except…… The manu tire specs are for the OE tires that came with the bike. Assuming you listen to the MoM and don’t tear the tags off pillow cases and such you will never have a different tire on the bike and will be in the good for what t hey call for, BUT, if your like some of us “outlaws” and like trying things out for your self then once you replace your tire or even better to do it before hand…check with the TIRE manufacturer to see what their recommendations are for the application. THis also holds true for automobiles …..though they are less then giving on the information.
My 9 came with Dunflop OE 404 something others…. lasted maybe 4 thousand miles on the rear. Jumped to the Metzelers that were highly recommended. Now Dunflop are the OE and the bike recommends 32 psi in the rear….really soft ride. Go to Metzelers web site and for their tires they recommend a higher pressure. Somewhere around about up to 40 psi.
Tires are always a point of contention with people. ..Do I go higher, lower, or what the MoM says. I always tell people the answer is “Yes”. Watch your tire wear and your pressure (Cold is sitting 3 hours without moving) and compare. If you don’t have that luxury generally add about 4 to 6 psi for warm…. rode on tires…..meaning the air expand once heated adding pressure….so if it is readin 45 psi …..cold will be around 42–ish cold.February 1, 2010 at 7:49 pm #24337
I completely ignored the possibility that he’s not runnin’ the stock rubber. Nice catch Munch!February 1, 2010 at 8:40 pm #24338AParticipant
Is there a possibility that he’s not even running on pavement?February 1, 2010 at 10:02 pm #24339
You guys are making this more complicated than necessary. The OP’s going for a ride in fair weather, not racing. Lighter bikes have narrower tires; heavier bikes have wider tires, some people weight more, some weigh less, etc. Some run several psi lower for better traction, some run several psi higher for better mileage. General recommendation I’ve seen – 33 front / 36 rear. Works well enough for the 3 bikes I have, and seems to work with most people most of the time.February 1, 2010 at 10:27 pm #24340
Well let me be the exception to that rule then… I have to run 36 ft / 40 rear. Due to extended highway runs over 75+mph.
Not all lighter bikes have narrower tires etc. A Vulcan 900 is best example. The custom has a front tire half the width of the Classic Lt though the bike is the same size and weight. Not all tires are created equal either, goes well past just the brand but also the intended use. It depends on the structure of the carcass and the compounds used in the tire.
Like I said before some Manu’s will specify product particular information like Metzelers. Where they give you a starting range and inform you to bump it up to X amount of PSI if a certain speed is expected to be traveled.
I like the thought of 87 degrees being fair weather though… have to keep that in my head as I stare at the snow.
THE absolute best you can do is start with the bikes recommendations…. check with the manufacturer of the tire to see if they have any ideal options listed on their site. IF there are none use your own powers of deduction… just would not got BELOW the bikes original specs.February 1, 2010 at 11:08 pm #24341
The manuals for my GS500, SV650, YZF600R all say something like 33/36 for normal rider and normal riding, and something like up to 34/42 for over 195lb and/or higher speed. I figured a Ninja 250R the OP has is pretty close to my “type” of bikes. I’ve read people say they run lower pressure than 33/36 on tracks (higher speed) for better traction. So 33/36 is pretty safe, all purpose middle-ground, give or take a few psi up to the individuals’ preference. Anytime I’m on the freeway it’s always 75 mph + (indicated) to stay a little ahead of average traffic.
I don’t know jack about cruisers, so they may well be very different from the standard bikes and sport bikes I’m more familiar with. Lots of times their tire seletions are more for the “looks”, right?February 2, 2010 at 12:36 am #24342
“Lots of times their tire selections are more for the “looks”, right?”
Tread patterns have varying degrees of purpose….more forward bite, more side traction, noise reduction, stability within the tire structure etc. There is a whole world of things that define tires and tread design. Not to mention the compounds that are used on the “rubber” part, all the way down to wether or not they use a biased ply or radial….. and if radial wether its traditional steel belted or using a different cording. Ever wonder why 99% of motorcycle tires are directional? Not just cause it looks “cool” but it gives the engineers a better degree of traction control and stability. Easier to predict how something is going to react to abrasion and heat when going one direction the having to figure in both. Look at Bridgestone and Michellin…. both are offering a 3 compound 3 section tread on their tires. A harder compound in the middle for life of straight highway riding softer on the edges for maximum (for that tire) traction in turns. These are not just sales points (though good ones) these are actual facts of the product and need.February 2, 2010 at 1:16 am #24343
Munch, did you misunderstand my question? I wasn’t talking about tire tread pattern. I was responding to your note that two cruisers could have the same weight but very different tire selections (width, diameter), presumably to get the classic look, chopper look, low-rider look, or whatever type of look they try to achieve for that cruiser.February 2, 2010 at 2:06 am #24344TrialsRiderParticipant
Not wanting to complicate things, but after reading articles like the following along with several more published by the major tire manufacturers, they have me seriously considering nitrogen fills for my street ride from now on!
…you can make your own decision if it’s worth the effort.
On the subject of tire trouble in very remote areas; my K100 came equipped with a really handy little tubeless tire emergency repair kit / CO2 cartridge tire inflater. Similar kits are available aftermarket and a highly recommended toolkit accessory.
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