Warp11XX Posted February 18, 2005 Share Posted February 18, 2005 I see about a bajillion threads and references to tire pressure and the infamous and ongoing cupping joke :shock: but I don't see any real advice on what tire pressures are best for performance and/or tire life. Mutually exclusive... I'm sure, but... I am assuming that everyone has the same multi location info tags and recommendations that my '03 has...42 psi...no negotiation, no alternate info, no nothing but the 42psi reference. So my stupid flamebait question of the day (week, month, year...take your pick) is: What are the choices related to tire pressure running the stock Sportmax II Touring tires? Is anything below 42 going to cause heat related problems? I ain't the dainty little waif I used to be, so think about this from the standpoint of a 305 pound rider with the occasional passenger. The stealership had them pressured to 35psi according to what I discovered on day 2. Seemed fine and felt great but I pressured them on up to 42 just because the Honda owners manual says so and the frame tag says so and we all know that whatever is put into print at least twice is absolute gospel and cannot be refuted and is always correct. :bs: Right? Whats the real deal folks? Inquiring minds and all that.... :mrgreen: Quote Link to comment Share on other sites More sharing options...
bartonmd Posted February 18, 2005 Share Posted February 18, 2005 the best pressure to run, hands down, in the stock tires on the XX is "0." They should not be able to hold any pressure in the trash dumpster, not on wheels. Mike Quote Link to comment Share on other sites More sharing options...
bartonmd Posted February 18, 2005 Share Posted February 18, 2005 although, seriously... for your weight, I'd probably not go below 38R/36F if it was me, but I can run my Pilot Roads at 33R/32F without cooking them, BUT I weigh 185... Best bet would be to ride hard on them and check how hot they are, then drop them a couple PSI and do the same until they are NICE AND HOT... what will probably be as low as you want to go with them. On the other side of the coin, I'd run 42 when highway or 2-up... but that's just me too... Mike Quote Link to comment Share on other sites More sharing options...
Warp11XX Posted February 18, 2005 Author Share Posted February 18, 2005 the best pressure to run, hands down, in the stock tires on the XX is "0." They should not be able to hold any pressure in the trash dumpster, not on wheels.Mike This is just my newbie perception of these tires, I'm sure, but you have to keep in mind that I've been riding the BB's great grandfather for the last decade and a half ('82 CB900F2) and these lowly "touring" tires have more contact area on the back tire alone than what my F2 has in total tire size. I am still just overwhelmed with the fact that tires like this even exist... :rockon: Quote Link to comment Share on other sites More sharing options...
bartonmd Posted February 18, 2005 Share Posted February 18, 2005 don't worry, I came from a 700cc Nighthawk S... 110/90-16 front, 130/90-16 on rear... oh... I know.... Mike Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted February 18, 2005 Share Posted February 18, 2005 I'm up there at 280 also. I've been running 42 F and R since owning this bike. Any less and I lose that light feeling in the corners. Still not sure if that press. is too high for tire mileage or not. I'm the tire eater on this forum, I get at the most 5K miles out of a rear ST tire, Uaually less then 4K Miles. Quote Link to comment Share on other sites More sharing options...
cbrxxquad Posted February 18, 2005 Share Posted February 18, 2005 i know i will regret this,,,,, but i posted a calculation to get required tire pressures at what weight therory i have but it was not accepted well might want to ignore this i am so easy you just keep sucking me back in http://cbr.geckobox.net/forum/viewtopic.ph...7717&highlight= Quote Link to comment Share on other sites More sharing options...
Bixxer Bob Posted February 18, 2005 Share Posted February 18, 2005 Ok guys, here's an angle on this tyre pressure thing. For your weight to make any difference, you'd have to be squeezing the tyre all over. What is actually happening can be demonstrated, if somewhat exagerated, with a baloon. Inflate a baloon. The pressure inside is higher than atmospheric pressure because of the baloon skin trying to squeeze it. Now press down on one side of the baloon. Assuming you haven't burst it with your girly fingernails, some of it will pop out at one side. The skin will be stretched further, but the pressure inside will still be the same. Now consider your tyre. The weight of the bike and you is pushing down, squashing the bottom of the tyre, but the top is stretching to absorb the pressure, so the pressure inside is the same. That's why the carshop will inflate your tyres before putting them on your car, and then not need to re-check the pressure afterwards. Hi from a newbie by the way........ Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted February 19, 2005 Share Posted February 19, 2005 i know i will regret this,,,,, but i posted a calculation to get required tire pressures at what weight therory i have but it was not accepted wellmight want to ignore this i am so easy you just keep sucking me back in http://cbr.geckobox.net/forum/viewtopic.ph...7717&highlight= I'm interested, but I asked a question, you didn't answer it and the thread died. So again, in your figures, did you come up with 19 PSI??? We know that's wrong. For Bixer Bob, I hope you're kidding, That's just like the flat on the side of the road. "It's only flat on the bottom". Quote Link to comment Share on other sites More sharing options...
tomek Posted February 19, 2005 Share Posted February 19, 2005 I see about a bajillion threads and references to tire pressure and the infamous and ongoing cupping joke :shock: but I don't see any real advice on what tire pressures are best for performance and/or tire life. Mutually exclusive... I'm sure, but... I am assuming that everyone has the same multi location info tags and recommendations that my '03 has...42 psi...no negotiation, no alternate info, no nothing but the 42psi reference. So my stupid flamebait question of the day (week, month, year...take your pick) is: What are the choices related to tire pressure running the stock Sportmax II Touring tires?Is anything below 42 going to cause heat related problems? I ain't the dainty little waif I used to be, so think about this from the standpoint of a 305 pound rider with the occasional passenger. The stealership had them pressured to 35psi according to what I discovered on day 2. Seemed fine and felt great but I pressured them on up to 42 just because the Honda owners manual says so and the frame tag says so and we all know that whatever is put into print at least twice is absolute gospel and cannot be refuted and is always correct. :bs: Right? Whats the real deal folks? Inquiring minds and all that.... :mrgreen: What is that? I tought they stopped making them like 20 B.C. It seems that tire pressure is like oil or your religion,very personal. Me? I`m like bartonmd,low 30`s during cold weather ,up to 42 in the summer on vacation trip on fully loaded bird with kitchen sink. Quote Link to comment Share on other sites More sharing options...
Warp11XX Posted February 19, 2005 Author Share Posted February 19, 2005 So... :roll: Bottom line from a safety standpoint would probably suggest that with my weight, I should at least keep them in the high 30's to maximum pressure range most of the time, wouldn't you think? Two thirds of my riding time will be a thirty minute slab commute to work with almost no stops. I've had pretty good performance and handling out of the much smaller tires on the F at around 38psi. It is sounding to me like they are pretty similar, just much bigger. :shock: Maybe it is just me but, does this bike just seem to inspire way more confidence, even in the damn rain, than could possibly be good for you? :mrgreen: Quote Link to comment Share on other sites More sharing options...
bartonmd Posted February 19, 2005 Share Posted February 19, 2005 about the rain... YES, my NH was scarry as hell in the rain! Didn't stop me, but I couldn't plant ANY power, although I could stop OK. The NH was made to be a standard though, and not be a wheelie machine, so it was fairly front-weight buised, making it hard to put down any power in the rain. Mike Quote Link to comment Share on other sites More sharing options...
cbrxxquad Posted February 19, 2005 Share Posted February 19, 2005 i know i will regret this,,,,, but i posted a calculation to get required tire pressures at what weight therory i have but it was not accepted wellmight want to ignore this i am so easy you just keep sucking me back in http://cbr.geckobox.net/forum/viewtopic.ph...7717&highlight= I'm interested, but I asked a question, you didn't answer it and the thread died. So again, in your figures, did you come up with 19 PSI??? We know that's wrong. For Bixer Bob, I hope you're kidding, That's just like the flat on the side of the road. "It's only flat on the bottom". sorry about missing your question i was watching and learning my self what were the thoughts on this thread and others as to what it is about pressure on a bike tire that makes so much difference in this calculation. it is correct in that it is the proper way to calculate the right pressure that a tire should be run at. that being said we all know that 19 is not the right pressure for the back of the xx or any other bike back tire. what is wrong is that the tire i used to calc the pressure is not the back tire for the xx . and the pressure rate to weight on the tire loading ascrues the numbers. i was hopping that somebody would go and look at the tires on their bike and get the numbers and plug them in to the calc and see what psi their tires have. the intresting thing i have found in doing this is that all tires are not the same rating and psi in the same size. is dependent in construction. they put this info on the tire to give the max weight and max psi and it says so,but we rairly run fully loaded, or even know the weight that is on the tire at any given moment. the point is footprint. if the pressure is adjusted to the weight the footprint stays the same,,, sound reasonable? please give me some numbers of the front and rear tires and size and make and lets see if there is some reasonable number for tire presure relative to weight. i have a scale to weight my tires loading and have used this number to set pressures and have been amazed at the results. intrested? Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted February 20, 2005 Share Posted February 20, 2005 I'm in. Let's ignore for now that Continental says to run 42 PSI only in their Road Attacks. Front tire says max load 520 lbs. at 42 PSI cold. Rear tire says max load 805 lbs. at 42 PSI cold. Bike is 550 LBS fully fueled, I'm 290 lbs. in full riding gear. I'm not sure of the front rear bias of weight though with me onboard. What do you think? Quote Link to comment Share on other sites More sharing options...
cbrxxquad Posted February 20, 2005 Share Posted February 20, 2005 ok now we have something to compare: 42 / 520 = .08077 front 42 / 805 = .05217 rear 550 + 290 = 840 50/50 weight distribution = 420 front rear .08077 * 420 = 33.9230 psi front minimum .05217 * 420 = 21.91 psi rear minimum .08077 * 840 = 67.84 psi front maximum load .05217 * 840 = 43.83 psi rear maximum now this is what i was talking about when i was saying if your stoping hard or acelerating hard and loading max out as well as making g's in the corners the psi has got to be up there. ill go ahead and post this and see what you think about the numbers and the loading just for riding conditions. there was a really good article in cycleworld about the way the foot print reacts to stoping and then loading on accel on both the front and then the rear how the highest pressure and scrub moves front to back. was really discriptive i think that the min and max numbers and the loads should be a indicator as to how you ride. if you adjust your pressures in side the range and ride as you normally do and your bike reacts loose the min and max and where you are in the pressure range between the two seams to me i would know which way to go. to little and the bike tire rolls over and the patch moves to the inside instead of the front and the rear even though it is bigger,,,,, to much and the patch is to small and the same thing happens,,,,seams to me it would feel the same sorry if i made errors i did not proof read, ill corect Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted February 20, 2005 Share Posted February 20, 2005 Just looking at your figures I 'll keep running 42 front and rear. I was wondering if I'd get better tire mileage if I dropped press. a bit but no longer. Quote Link to comment Share on other sites More sharing options...
cbrxxquad Posted February 20, 2005 Share Posted February 20, 2005 seams to me the front tire should be a higher load rating but stopping is generally not done with added load of centrifugal force and most dont transfer all the load to the front or could be bad. i have always wondered what a tire manuf would say about the logic of my therory.bet they would say 42 reguardless of weight and i know that is wrong when it is overloaded and under loaded as with one here who was 150 on a bird. the point is know your load and rating and any difference in the way your riding is madeup in pressure. thanks for the debate stan Quote Link to comment Share on other sites More sharing options...
OzCrow Posted February 21, 2005 Share Posted February 21, 2005 I run 32f/36r in the Pilot Powers when doing some weekend scatching. When doing longer trips with a lot of high speed riding on straighter roads I up the front to 34 psi and the rear to 40psi to reduce squaring off of the rear tyre. This also applies for riding two-up. I weigh 100kgs (220lbs) but a heavier guy may actually be better off with 42psi in the rear however I would run the front at say 36psi. Quote Link to comment Share on other sites More sharing options...
cbrxxquad Posted February 21, 2005 Share Posted February 21, 2005 looking at the load ratings and the calculations it would seam to me that i would run highter pressures in the front than the rear but i guess experience tells that the front has less load than the rear than i would have thought. i am going to try something and make a excel calulaction sheet and see if i can put it on here someway. something to plug your numbers into and get an indication in to how hard you ride compaired to tire wear and where the wear is. looks to me like if we did the above calc and pluged in the pressures you run and did a wear depth mesurement across the tire at every say 1000 miles with like side note in average what kind of riding you did we might actually learn why we cup and wear out and which tires perform for the type rider we are. might take away the guessing what kind of rider you are. moderator ,,,, is there some way to do this???? i'll write it if it can de done so the post are for info to all Quote Link to comment Share on other sites More sharing options...
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