Successful tire experiment 2014 Breakout but need tire expert psi advice
#11
08-15-2014 | 12:06 PM
Tourer
Joined: Jun 2013
Posts: 321
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From: CA
I have found a couple of articles online which seem to agree on a methodology for determining proper tire psi.
What they basically say is that you stay inside of the maximum psi as published by the tire manufacturer, and try to get the air pressure setting that produces EQUAL TEMPERATURE at the centerline of the tire as at the outer edges of the working tread.
Apparently, if the centerline temperature is higher than at the outer edges, the psi is too high (the centerline of the tire is making most of the contact with the road, and is hotter as a result).
If the temperature at the centerline is lower than at the outer edges, the psi is too low (the edges have better contact with the road than the centerline does).
The idea is to get the tire up to normal working temperature by riding the way you would normally ride, and then quickly stopping the bike and measuring the temperature at the 3 points (left edge, centerline, right edge). By the way, if the left edge differs in temperature from the right edge, there is either a misalignment or a weight distribution issue.
The trick is getting the right equipment to do the temperature check.
One writer suggested an infrared gun type temperature reader that you aim at the points on the tire is adequate. Another one pointed out that more accurate results are obtained via a device that uses needle probes that you ***** right into the tire tread, since the temperature INSIDE the rubber even a bit loses temperature more slowly after you stop than the exterior surface of the rubber does.
I have neither type of course, and given my current unemployed status, I doubt my wife would like the idea of buying a $100 infrared gun temperature reader for another one of my (many) experiments.
Any expert opinions out there?
Jim G
What they basically say is that you stay inside of the maximum psi as published by the tire manufacturer, and try to get the air pressure setting that produces EQUAL TEMPERATURE at the centerline of the tire as at the outer edges of the working tread.
Apparently, if the centerline temperature is higher than at the outer edges, the psi is too high (the centerline of the tire is making most of the contact with the road, and is hotter as a result).
If the temperature at the centerline is lower than at the outer edges, the psi is too low (the edges have better contact with the road than the centerline does).
The idea is to get the tire up to normal working temperature by riding the way you would normally ride, and then quickly stopping the bike and measuring the temperature at the 3 points (left edge, centerline, right edge). By the way, if the left edge differs in temperature from the right edge, there is either a misalignment or a weight distribution issue.
The trick is getting the right equipment to do the temperature check.
One writer suggested an infrared gun type temperature reader that you aim at the points on the tire is adequate. Another one pointed out that more accurate results are obtained via a device that uses needle probes that you ***** right into the tire tread, since the temperature INSIDE the rubber even a bit loses temperature more slowly after you stop than the exterior surface of the rubber does.
I have neither type of course, and given my current unemployed status, I doubt my wife would like the idea of buying a $100 infrared gun temperature reader for another one of my (many) experiments.
Any expert opinions out there?
Jim G
#12
08-15-2014 | 12:41 PM
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From: Detroit
#13
08-15-2014 | 12:43 PM
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From: Lethbridge, Alberta Canada
Jim G
#14
08-15-2014 | 01:16 PM
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From: CA
I got only 3500 miles on my stock tire as well and had it always at 42. I am now running at 35 psi and I can see the centerline is a lot wider. Don't notice any handling differences.
#15
08-15-2014 | 03:03 PM
Road Master
Joined: May 2011
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From: Utah
I am interested in seeing (reading about) the mileage you get out of this tire as before it sees like the only known options were the stock Dunlop, the Metzeler 260, Vee 260 and Avon Cobra 240. Although I got 8k out if the stock Dunlop running at the high HD recommended pressures. It was definitely center wear, and on a Rocker, but I still think tire life is 90% how the bike is ridden/maintained.
To really do an expirement that compares tires, you should run this Pirelli at the same pressure you ran the stock tire. Then get another Pirelli and run it at the lower pressure. That way you are only changing one variable at a time. I realize this is not your goal, but would give good data to compare.
To really do an expirement that compares tires, you should run this Pirelli at the same pressure you ran the stock tire. Then get another Pirelli and run it at the lower pressure. That way you are only changing one variable at a time. I realize this is not your goal, but would give good data to compare.
#16
08-15-2014 | 03:35 PM
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From: Texas
#17
08-15-2014 | 04:03 PM
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From: Australia
#18
08-15-2014 | 04:22 PM
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From: Lethbridge, Alberta Canada
To really do an expirement that compares tires, you should run this Pirelli at the same pressure you ran the stock tire. Then get another Pirelli and run it at the lower pressure. That way you are only changing one variable at a time. I realize this is not your goal, but would give good data to compare.
Also, he "correct" pressure for the Pirelli is not necessarily the same as for the Dunlop anyway. Pirelli proactively states in their specs (see my first posting in this thread) that the working range of this tire is 36 to 42 psi. And of course, at least until we hear from a tire expert, we have no idea what the correct specific psi within that range would be for the Breakout.
Jim G
#19
08-15-2014 | 04:29 PM
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From: Lethbridge, Alberta Canada
In providing your data, you never stated whether your bike is a Breakout or something different, but assuming it is a Breakout with the same stock Dunlop as mine had, the key difference I see is that you disregarded Harley's psi instructions and ran 30 to 35 psi instead of 42. Now that 32 to 35 sounds a bit low to me, but it does seem to support the idea that psi lower than 42 is the key. Your getting all those miles on it suggests that the lower psi did NOT hurt it, despite many industry warnings about the dangers of low psi.
Interesting, and more evidence for me to consider.
Jim G
#20
08-15-2014 | 05:23 PM
Cruiser
Joined: Aug 2013
Posts: 203
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From: OCEANSIDE, CA
Just food for thought, you all have looked into this tire with great care and given great insight.
Now I am on my second rear tire on my Breakout and I now have 11k on the bike. At 3k I noted that I was also wearing the center out of my first tire, I also noted that the tire footprint was small so I was riding mostly on the center of the tire.
Being in the auto industry a service advisor for ford, BUT not a tire expert, I decided to lower my air pressure to 30 psi in the front and rear. I went riding on california mountain turns and freeways and did not notice any deteriation of handling. Rode pretty good. After some miles I noted the footprint of the tire was much bigger and so 2+2 came up with I was wearing better. I then was able to get 6500 miles on that tire and I still had some not much tread left in the center. Maybe another 1000.
On my second rear tire I started off with 30 lbs, still have 30 lbs and still have a larger footprint. I have 4500 on it and still looks good.
Bottom line is you have to set the tire psi what you think is safe for you to get the max wear out of it, for your weight/bike and riding style. With 11k on the bike yes I ride every day to work and on weekends I ride alot. Am I riding safe?? I think so..
I have brought up that I lowered my pressure in several threads. No one has come back and said NO!! NO!!
Now I am on my second rear tire on my Breakout and I now have 11k on the bike. At 3k I noted that I was also wearing the center out of my first tire, I also noted that the tire footprint was small so I was riding mostly on the center of the tire.
Being in the auto industry a service advisor for ford, BUT not a tire expert, I decided to lower my air pressure to 30 psi in the front and rear. I went riding on california mountain turns and freeways and did not notice any deteriation of handling. Rode pretty good. After some miles I noted the footprint of the tire was much bigger and so 2+2 came up with I was wearing better. I then was able to get 6500 miles on that tire and I still had some not much tread left in the center. Maybe another 1000.
On my second rear tire I started off with 30 lbs, still have 30 lbs and still have a larger footprint. I have 4500 on it and still looks good.
Bottom line is you have to set the tire psi what you think is safe for you to get the max wear out of it, for your weight/bike and riding style. With 11k on the bike yes I ride every day to work and on weekends I ride alot. Am I riding safe?? I think so..
I have brought up that I lowered my pressure in several threads. No one has come back and said NO!! NO!!