K60 Tire Pressure Questions

[squarebore]

I've had my k60s for about 1000kms now and have been waiting for them to settle in and become more comfortable. Grip is fine but I thought they were quite harsh with that very stiff wall and this caused vibrations on rough road or on what we call "chip seal" roads. These are the rougher asphalt compared to hot mix. Anyway, got sick of it today so I pulled over and dropped the pressures from 33f/42r to 27f/32r. Wow, what a difference. More grip and the bike is back to normal. I was going to get rid of them but am happy now.

My question is will the lower pressures really cause any issues? I've read a lot and have significant 4wd experience and understand the low pressure could cause over heating. I don't think the pressures I've set will cause any issues but you guys have a ton of experience and I'm happy to listen. Cheers

 

[Bikedude987]

Very interested in this too, especially since we do a lot of two up and don't want to shorten tire life...

 

[squarebore]

Forgot to mention the lower pressure makes the ride so much more comfortable. At the higher recommended pressures, the windshield actually vibrated loose and I was considering reducing the pre-load on the suspension as well.

 

[Mark R.]

I think 42 pounds is too high for the rear, and on K60's always ran 32 front/ 34 rear. I do the same with the Mitas tires I have now also.

 

[Maxified]

While on paved roads I've been running my K60's @ 36/42 for 13K+ miles with no vibe issues. Most of the roads I choose are in good shape, no interstate, not much of the coarse stuff.

 

[~TABASCO~]

38 /40 24/7/365

 

[tomatocity]

38 /40 24/7/365

Jaxon, I like those numbers. If I remember correctly you have been through multiple sets of K60's. Have you tried other tire pressures? If so, what were the results?

I ran 36F / 41R for half a set of K60's and they wore well. I usually had luggage mounted when the K60's were mounted. They are sitting in my garage waiting for the confidence and trip that needs such a tire.

 

[Checkswrecks]

Nobody outside of Heidenau can give you a definitive answer to this. And no tire manufacturer would.


Tire manufacturers establish their minimum and maximum tire pressures so that the sidewalls will have a certain amount of flex. The pressure range given will also be within a wider range of pressure where the tire can have over-pressure damage on the high side. Most people for some reason ignore the MAX and miss the point that the sidewall pressure is a do not exceed pressure, not a target pressure.


In low pressure, damage can be rim and sidewall cuts, unseating the tire bead, and tire heating. You were smart enough to ask about heat build-up and it can be a real concern in tires with thicker sidewalls. The molecules rub each other and create heat with each tire rotation causing sidewall flex, which is why tire pressure measurements are so inaccurate after the first mile of the day. Rubber is a lousy conductor, so thicker sidewalls can actually heat enough for the rubber to lose strength.


The range of allowable sidewall flex is based on the goals of a weight rating and a speed rating. Heidenau shows the ratings here and you can get the codes off your sidewalls: http://heidenautires.com/specifications/



So you preserve your safety margin by trading your desired reduction of pressure against limits on top speed and gross weight. In a guess and for common-sense riding around your home area, you probably are fine. But this really is a guess.

 

[~TABASCO~]

Jaxon, I like those numbers. If I remember correctly you have been through multiple sets of K60's. Have you tried other tire pressures? If so, what were the results?

I ran 36F / 41R for half a set of K60's and they wore well. I usually had luggage mounted when the K60's were mounted. They are sitting in my garage waiting for the confidence and trip that needs such a tire.

I still run the same pressure.. Because if im loaded, im probably hitting the high way for many hundreds of miles. Because of the speed the tire will heat up and the pressure will go up. I still tend to get great wear at 38-40 all the time... I can get about 20K out of a front and I pulled my last rear off at 13.5K but could go further if I were to stay on the road.. It was to slick feeling off road.
I see customers all the time with K60's that are wearing funny or with extra wear at relatively low miles, I can see the tire with my eyes... I check the pressure and they are always low... Keep these puppy's pumped up and you can get great miles out of them... Of course, this is MY EXPERIENCE, and certainly will not fit everyone's criteria.. I have to add that caveat for some folks.

 

[squarebore]

Thanks for all the advice and experiences. I guess it is now time for some objective testing. I'll draw up a test plan where I can test the temperature and then keep reducing the pressure and see what effect it has. I'll post the results when done. Cheers

 

[~TABASCO~]

This is not really fair or far from scientific, but this is an extreme case. A few years ago I got done riding a few days in Arkansas on a relatively new K60. I got a nail sometime the last day and didn't notice it. I then at the end of the day I got onto I-40 W and headed to Oklahoma City, OK. After two hours, I stopped at a gas station and when tried to leave, the rear was so hot it came off the bead and rim. After two plus hours of doing 75 fully loaded the SOB was boiling. I got it back on and a silly string installed. Point being, riding on a flat or really low probably burned off many thousands of miles of rubber in about two hours. The side walls are so stiff I never knew it was flat. Even after that day, I beat on that tire for about another year. These tires are pretty amazing.

 

[Smellyhound]

I'm new to my K60s, and they seem to be pretty smooth. The thing I did notice seems to be some sort of harmonic vibe between 25-32 mph. Only way I can describe is a buzz that sounds (feels?) like it's going "rom rom rom rom rom". It only does it in this speed range, more noticeable as I'm slowing down. Anybody else have this going on? Still rides smooth, just that weird vibe. Actually at highway speeds the ride is very smooth. Running pressures at recommended sidewall rating.


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[joneil]

38 /40 24/7/365

Ditto. I'm no expert, but Jaxon is. I just today ordered a replacement for my rear K-60 from Jaxon. Kept it at 40. 12k miles. No problems. I've ridden in Jaxon's dust. He knows of what he speaks.

 

[joneil]

I'm new to my K60s, and they seem to be pretty smooth. The thing I did notice seems to be some sort of harmonic vibe between 25-32 mph. Only way I can describe is a buzz that sounds (feels?) like it's going "rom rom rom rom rom". It only does it in this speed range, more noticeable as I'm slowing down. Anybody else have this going on? Still rides smooth, just that weird vibe. Actually at highway speeds the ride is very smooth. Running pressures at recommended sidewall rating.


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Normal.

 

[Smellyhound]

Thank you very much!


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[Checkswrecks]

Thanks for all the advice and experiences. I guess it is now time for some objective testing. I'll draw up a test plan where I can test the temperature and then keep reducing the pressure and see what effect it has. I'll post the results when done. Cheers

You are planning the wrong type of test. The heat builds up between plies in the carcass of the sideway and the only way to know would be to cut the tire apart or build in thermocouples.

 

[squarebore]

You are planning the wrong type of test. The heat builds up between plies in the carcass of the sideway and the only way to know would be to cut the tire apart or build in thermocouples.

I got the PM and thanks. I understand the principles and issues you are relating to however I will only be looking for the first signs of a significant change in the temp at the centre of the tire or on the side wall. Although this won't be a true indication of the temp between the plies, it should provide an indication of when the temps are starting to build. I'm guessing the temps that will lead to catastrophic destruction will be associated with very low pressures below 20psi and riding at highway speeds. I will only be testing down to 25psi as it is the lowest pressure I would plan to ride at.

 

[VgnSTRider87]

About to mount these this weekend or next. Any advice on whether to change tire pfessure for on and off road for the k60s? Also, recommendations for good pressures for a lighter rider (less than 160 with gear)?