[Tom Schmitz]

You made a fairly extreme assertion that motorcycles can’t hydroplane under any rideable condition. Not sure exactly what that is, but motorcycles can and do hydroplane under rideable conditions as I’ve had hit happen. It dodsn’t take 6 inches of water. 1” will do fine at 70 MPH on the interstate....

I think you are being deliberately obtuse. Most, I think, would not consider riding a street bike (a reasonable assumption, given its travel on the interstate) at 70mph into 1" of standing water to be a rideable condition. The very amount of water put up would preclude seeing where you are going.

I am happy that you survived, though I doubt you hydroplaned. If you had hydroplaned you would have gone down immediately, as there is no way to keep a bike upright in a situation where there are forces at work on the tires, yet they have no traction. Once traction is lost and the bike begins to roll, yaw, or both, it's going down. If it decelerates enough to come back into traction it will high side.

...F=ma is a fundamental concept in fluid mechanics. Even Wiki knows that....

I think you are being deliberately obtuse. The Second Law of Motion is fundamental, yes. However, there is more at work in the field of fluid mechanics than the simple formula 'f=ma'. Beyond explaining fundamental concepts there is not much in FD that will be solved with that equation.

 

[Voyager]

I think you are being deliberately obtuse. Most, I think, would not consider riding a street bike (a reasonable assumption, given its travel on the interstate) at 70mph into 1" of standing water to be a rideable condition. The very amount of water put up would preclude seeing where you are going.

I am happy that you survived, though I doubt you hydroplaned. If you had hydroplaned you would have gone down immediately, as there is no way to keep a bike upright in a situation where there are forces at work on the tires, yet they have no traction. Once traction is lost and the bike begins to roll, yaw, or both, it's going down. If it decelerates enough to come back into traction it will high side.



I think you are being deliberately obtuse. The Second Law of Motion is fundamental, yes. However, there is more at work in the field of fluid mechanics than the simple formula 'f=ma'. Beyond explaining fundamental concepts there is not much in FD that will be solved with that equation.

You will have to talk with the highway designers in NC which is where we (three of us) hit a patch of water probably 1-2” deep while riding in a heavy downpour. The water was probably 10-15’ across and the wake from my front tire pushed my feet off the pegs and the front wheel hydroplaned which is easily felt as the bars feel like they became disconnected momentarily. And, no, you do’t instantly crash as it takes time for a bike to yaw and roll and the time spent in the deep water was thankfully quite brief.

Conservation of momentum is a key concept in hydroplaning, which certainly is only a small part of the field of FD. Given your expertise in FD, please explain which other FD fundamentals are relevant to a tire moving through water at high speed.

 

[pdwestman]

May I suggest, that we all should get back to the basic fundamentals of dual-sport tires at real world speeds on dual-sport type routes on dual-sport type tires?

 

[Damocles]

tread·lex·i·a


/tredˈleksēə/


noun

Unable to distinguish tire tread orientation. (q.v., dyslexia).



DISCLAIMER: I may myself suffer from BOTH maladies mentioned!

 

[patroy75]

I just want to chime in here and say that my Mitas 07's rock in the rain and on North Carolinas shtty roads to boot!

 

[Tom Schmitz]

@Damocles, the CTA tires follow the convention that I have always thought was correct in tire mounting, which is as Paul describes. This convention is also found on the sport bike tires that I have had; my Michelin Pilots work this way and all of the directional tires I that have seen do as well. The mnemonic, for me, is "when yer sittin' on the bike and lookin' at the tars, the "V"s are pointin' atcha".

I had always thought that this convention was universal, but I think I am going to have to go in search of proper tires that defy this convention. There may be a learning opportunity.

I know that the Kenda K761 front doesn't follow this convention, but after communicating with Kenda and thinking about the who, what, where, and why of Kenda, I've come to believe that it is an error on their part*. I think it falls, at least somewhat, into the category of 'buying forks from people that eat with sticks'.

 

[Damocles]

In the learned discourse on this forum, Newton's SECOND LAW OF MOTION has been mentioned.

I now share an event involving Newton's FIRST LAW OF MOTION . . . avert your eyes NOW, gentle readers, if you wish to avoid the narrative!

On another forum, an inmate rationalized the KLR650's modest power output to some extent by claiming, "The doohickey (counterbalancer system) alone uses TWO HORSEPOWER!"

I disagreed, invoking Newton's FIRST LAW OF MOTION:

An object at rest will remain at rest unless acted on by an external force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an external force.

(Or, words to that general effect.)

I reasoned (?), if Mr. Newton isn't FUNNING us, after the balancer system (shafts/weights/chain/etc.) is in MOTION, the only power used sustaining the motion is that used to overcome bearing friction, chain friction, and air resistance. I doubted this compensatory power expended by the balancer system approached anything near two horsepower.

I was branded a heretic; accused of creating a fantasy, "perpetual motion" machine; and pilloried by many unkind words from loyal supporters of the inmate who posted the two-horsepower budget operating the doohickey.

Still, I could think of no external forces acting upon the doohickey (balancer system) than those of bearing friction, chain friction, and air resistance. Thus, my heart and mind remained unchanged. If Mr. Newton withstood the criticism, so can I!

 

[Tom Schmitz]

I think what you have not factored in is Iron Butterfly's Second Corollary to Newton's First Law.

"Any contraption of a Rube Goldberg Nature having two or more bellcranks, entrapment levers, escapements, eccentrics, weights, or other booger-brained mechanical contrivances designed to do a job of work more easily done in a manner designed by an Estonian (or not at all) shall be declared to consume 5% of the power provided by the unfortunate mechanism saddled with its existence".

I'm sure that is where the two horsepower figure came from...

 

[Damocles]

I think what you have not factored in is Iron Butterfly's Second Corollary to Newton's First Law.

"Any contraption of a Rube Goldberg Nature having two or more bellcranks, entrapment levers, escapements, eccentrics, weights, or other booger-brained mechanical contrivances designed to do a job of work more easily done in a manner designed by an Estonian (or not at all) shall be declared to consume 5% of the power provided by the unfortunate mechanism saddled with its existence".

I'm sure that is where the two horsepower figure came from...

Premise seems valid!

As to, "two horsepower," that's close to 1100 ft-lb/second, IIRC. That much power seems excessive to me, even for one of Rube Goldberg's contraptions within the confines of a KLR650 engine!

EDIT: But . . . two horsepower is indeed about 5 % of the optimistic output of the KLR650 engine!

 

[pdwestman]

I think what you have not factored in is Iron Butterfly's Second Corollary to Newton's First Law.

"Any contraption of a Rube Goldberg Nature having two or more bellcranks, entrapment levers, escapements, eccentrics, weights, or other booger-brained mechanical contrivances designed to do a job of work more easily done in a manner designed by an Estonian (or not at all) shall be declared to consume 5% of the power provided by the unfortunate mechanism saddled with its existence".

I'm sure that is where the two horsepower figure came from...

Premise seems valid!

As to, "two horsepower," that's close to 1100 ft-lb/second, IIRC. That much power seems excessive to me, even for one of Rube Goldberg's contraptions within the confines of a KLR650 engine!

EDIT: But . . . two horsepower is indeed about 5 % of the optimistic output of the KLR650 engine!

And what do these thoughts have to do with, "My KLR feels loose on gravel"? Other than driving up all of our post counts?

 

[motoskycle]

I have an '18 KLR with 1800 miles on it. I've done about 600 miles on gravel and I just cant get over the fact that it feels awful. Front tire is constantly sliding and feels loose. I have to take corners really slow. The front tire is at 21psi and its stock. I've ridden dirt bikes for the past 15 years in all sorts of terrain and never ridden a bike that feels so loose and squirly. It gives my an uneasy feeling and I have no confidence.

Any ideas? Is it the tires?

I just rode most of the WABDR which included a lot of gravel road sections. I tried the Shinko 804/805’s for the first time. When I first hit the gravel I had 32/34 psi from riding the highway and it was all over the place. Pulled over, set the psi to 20/24. I didn’t want to go as low as my dirt bike cause I was carrying a weeks worth of camping equipment etc. Reminded myself to stay on top of the bike in corners and let her rip. It felt awesome. (I have a gen 1, stock suspension and devide my gear between small panniers and small tank panniers for weight distribution.)

 

[DPelletier]

I just rode most of the WABDR which included a lot of gravel road sections. I tried the Shinko 804/805’s for the first time. When I first hit the gravel I had 32/34 psi from riding the highway and it was all over the place. Pulled over, set the psi to 20/24. I didn’t want to go as low as my dirt bike cause I was carrying a weeks worth of camping equipment etc. Reminded myself to stay on top of the bike in corners and let her rip. It felt awesome. (I have a gen 1, stock suspension and devide my gear between small panniers and small tank panniers for weight distribution.)

Good plan; The KLR is too heavy to run dirt bike pressures AND it has no rimlocks like a dirt bike.....the lowest pressure I go is about 18 or so. I could see a bit less for a sandy section but I wouldn't run it there for long. I used to run 12-14 front and 8-10 rear on my KTM300.

Normally I run 22 front and 20 rear; I don't run 2 up or carry much of a load so there is no reason for me to run more air pressure in the rear (the larger air volume of the rear tire means it can carry a heavier load at less pressure than the front). My use is mainly off pavement except for my short, backroad commute (2 miles)

Cheers,
Dave

 

[motoskycle]

Good plan; The KLR is too heavy to run dirt bike pressures AND it has no rimlocks like a dirt bike.....the lowest pressure I go is about 18 or so. I could see a bit less for a sandy section but I wouldn't run it there for long. I used to run 12-14 front and 8-10 rear on my KTM300.

Normally I run 22 front and 20 rear; I don't run 2 up or carry much of a load so there is no reason for me to run more air pressure in the rear (the larger air volume of the rear tire means it can carry a heavier load at less pressure than the front). My use is mainly off pavement except for my short, backroad commute (2 miles)

Cheers,
Dave

Interesting, makes sense. I’ll have to try the lower pressure in the rear.

 

[Hagan]

I just rode most of the WABDR which included a lot of gravel road sections. I tried the Shinko 804/805’s for the first time. When I first hit the gravel I had 32/34 psi from riding the highway and it was all over the place. Pulled over, set the psi to 20/24. I didn’t want to go as low as my dirt bike cause I was carrying a weeks worth of camping equipment etc. Reminded myself to stay on top of the bike in corners and let her rip. It felt awesome. (I have a gen 1, stock suspension and devide my gear between small panniers and small tank panniers for weight distribution.)

Thanks, but both f/r tires were set at ~20psi. I tried with and without any of my camping gear and there really wasn't any change. More weight on the back made the front feel lighter as expected. I weighed my bike with myself and camping gear and I was 700lbs.

 

[motoskycle]

)

Thanks, but both f/r tires were set at ~20psi. I tried with and without any of my camping gear and there really wasn't any change. More weight on the back made the front feel lighter as expected. I weighed my bike with myself and camping gear and I was 700lbs.

I haven’t tried the stock tires.. the shinkos were so cheap I wanted to give them a shot. I think I might try the combo that KLR4ever recommended next!
“Try a Dunlop 606 on the back and a Pirelli MT21 on the front”

How did you weigh you’re bike/gear? I would love to know how much mine weighed for this last trip.

 

[pdwestman]

motoskycle, Do you own a bathroom scale & a couple of 2 x 4's?
2 x 4 under front tire, to be nearer level, scale under rear tire. Balance the bike vertically. Note the weight. 2 x 4 under rear tire & scale under the front tire, Note the weight. Add the two together, will be very close.

 

[motoskycle]

motoskycle, Do you own a bathroom scale & a couple of 2 x 4's?
2 x 4 under front tire, to be nearer level, scale under rear tire. Balance the bike vertically. Note the weight. 2 x 4 under rear tire & scale under the front tire, Note the weight. Add the two together, will be very close.

Very clever!!!

 

[KLRCraig]

Never mind... I was responding to a comment on page 6 and then found out the Thread is on page 8...

NEVERMIND!

 

[pdwestman]

Never mind... I was responding to a comment on page 6 and then found out the Thread is on page 8...

NEVERMIND!

"https://www.youtube.com/watch?v=OjYoNL4g5Vg

As long as you "Quote" the post, it is perfectly acceptable to arrive at to the party "late", KLRCraig.

Hey, I didn't get to watch that clip yet!!!!!!!!!! You made it disappear while I was pecking my reply.

 

[Hagan]

Finally installed my d606's and so far they have been great. No off road testing yet though.