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Tyre mileage on nc750

Can you quote the statement that you should rarely use the engine for slowing?
Because on page 13 of the NC700 manual, under "Engine Braking" I'm seeing the following (emphasis mine):

"Engine braking helps slow your motorcycle down when you release the throttle. For further slowing action, downshift to a lower gear. Use engine braking with intermittent use of the brakes to reduce speed when descending long, steep slopes."

I am interpreting this to mean always engine brake, downshift for better effect, and make sure not to cook your brakes during prolonged braking periods.



I'm not sure the heating up/compressing of the air contributes significantly to the energy dissipation. Depending on valve timing, the pressure differential is going to be very small or even zero. Remember the same mass of air is decompressed to (approximately, based on valve timing) the same volume on the power(less) stroke, most of the energy put into the compression is regained during the expansion. The majority of engine braking is correctly noted above as coming from the pump force required to draw in the air from the manifold with a closed throttle, as well as the small component coming from friction in the drivetrain.
This is different from big trucks that have actual engine brakes ("jake brakes"), where the exhaust valves are opened before the power(less) stroke to vent the compressed air to atmosphere.


Assumptions:
Compression isentropic
Air represented by an ideal diatomic gas, therefore Cp/Cv = K = 1.4
Ambient air temperature is 293K or 20C
Intake air conservatively assumed to be ambient temperature. In reality, due to reduced pressure through closed throttle, intake temperature is below ambient.

Known:
V1 / V2 = 10.7 (Compression Ratio)

T2 / T1 = (V1 / V2)^(K-1)
T2 = 293 (10.7)^(0.4)
T2 = 756K or 483C

Considering the heat of combustion is generally 700C or greater, and usually above 1000C, you're reducing the thermal load on the cooling system.


And no no no no no, the engine doesn't have to absorb "the heat that would have gone into the brake pads from using brakes only." The brake heat is the dissipation of kinetic energy as thermal energy due to friction. No friction, no heat. Engine braking relies on pump force to transfer energy, not friction. Different processes, different energy conversions.
FWIW, I enjoy reading your posts. :cool:
 
Engine braking relies on pump force to transfer energy, not friction. Different processes, different energy conversions.
Yes, this is a very succinct way of putting it. BTW, I wasn't suggesting that all of the energy of motion was dissipated into heating up the air; it was more of a secondary comment that pumping the air will result in heating. My main point was that engine breaking is NOT using your clutch plates as break pads, like some people seem to think!!

Considering that only about 25-30% of an engine's power goes into kinetic energy, and the rest is waste heat that either soaks into the cylinders and is pulled away via coolant or dumped as heat out of the exhaust, the small contribution of heat from engine breaking is negligible.
 
FWIW, I enjoy reading your posts. :cool:
Thanks man. I tend to get one of two reactions from people, either they quite enjoy the discussion, or they absolutely hate it. The hazards of being an engineer, I suppose.

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Yes, this is a very succinct way of putting it. BTW, I wasn't suggesting that all of the energy of motion was dissipated into heating up the air; it was more of a secondary comment that pumping the air will result in heating. My main point was that engine breaking is NOT using your clutch plates as break pads, like some people seem to think!!

Considering that only about 25-30% of an engine's power goes into kinetic energy, and the rest is waste heat that either soaks into the cylinders and is pulled away via coolant or dumped as heat out of the exhaust, the small contribution of heat from engine breaking is negligible.
It was clear to me you had a solid understanding, I was mostly trying to clarify for those who seemed to think that compressing air somehow caused more heat than compressing air and gas and ten setting it on fire.
At work, I often have to "distill" a relatively complex topic into a form that most people can follow easily.

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So...

What is your original tyre mileage everyone?
I got 2000 miles out of the stock Dunlop tires on my '21 model. Trying Avon Trailrider tires now. They have a state-of-the art dual compound rear tire. Seems to be holding up much better.
 
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Back to the OP's question. Pictures are with almost 4200 miles on the original times. Not near the wear bars yet.
 

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I'm thinking I got about 5000 miles out of the original Dunlops that came on my 2015. Not as much as the 8000 or so on the Metzeler Z8s that came on the 2012.
 
In the picture shown, it is interesting that the blocks are so large that they do not seem to wear thin at the corners where the grooves meet.

With a lot of tires with more grooves, the tread wears thin where the grooves meet along the middle of the tire. This is usually a vulnerable area where nails, rocks, and other road debris slip in and puncture the tire.

These tires you had shown have a nice road pattern, good life, and offer some trail capability. That was a great post. The pictures helped.

To everyone else… Attach the pictures of your worn tires. It really helps make purchase decisions. Don’t forget to tell us what tire it is. Thanks for doing that.
FYI; They're the Dunlop Trailmax. I assume they're standard on the 2020 bike.
I also don't do any off road. I'm probably 80% freeway, 10% highway, 10% surface streets.
 
I got about 4500 US miles out of my stock ones. Could have probably gotten 5000 but it was starting to slowly lose air from a plug I put in the rear tire...plus I didn't really like them. I have almost 8000 on my current Shinko 009's with plenty of tread left to go. Might try Road 5's next just to see if the price difference is really worth it for me or not.
 
i was watching FortNine on youtube talking adv tyres and he made an interesting comment
he says that new bikes hit the showroom floor with tyres that we cannot buy
they are made especially for new bikes and are nothing like the tyres(same numbers)on the shelf
one reason for this is to keep the weight down
so that crappy dunlop may be fine when we replace it with the same tyre

i fitted 705's when my oems wore out at 8000kms(bought bike second hand)
 
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I replaced my crappy Dunlops on Friday. Only had 1700 miles on the bike and was well into the wear indicators. I have never had a set of tires wear that quickly in 46 years of riding. I was checking wear every time I stopped and could see the tread disappearing. I don't ride them down to the cords, when they hit the wear indicators I start shopping. This time it was a rush buy so I would not miss out on the end of the riding season.
 
i was watching FortNine on youtube talking adv tyres and he made an interesting comment
he says that new bikes hit the showroom floor with tyres that we cannot buy
they are made especially for new bikes and are nothing like the tyres(same numbers)on the shelf
one reason for this is to keep the weight down
so that crappy dunlop may be fine when we replace it with the same tyre

i fitted 705's when my oems wore out at 8000kms(bought bike second hand)
This is sort of an open secret that many manufacturers use. For things like bike tires, the tires may have the same tread pattern as the tires we find available for sale, but the OEM tire may have thinner tread or sometimes even have different compound.

My NCx bikes both had tires that were changed fairly early in the life spans. Both the Bridgestones and Dunlops were cupping oddly on the front. The rears were just wearing out.
 
i was watching FortNine on youtube talking adv tyres and he made an interesting comment
he says that new bikes hit the showroom floor with tyres that we cannot buy
they are made especially for new bikes and are nothing like the tyres(same numbers)on the shelf
one reason for this is to keep the weight down
so that crappy dunlop may be fine when we replace it with the same tyre

i fitted 705's when my oems wore out at 8000kms(bought bike second hand)
That is certainly true in some cases, OEM using specially made tires. However, the 2012 NC700X had two potential tire brand/models installed by Honda. One was the Metzeler Z8. It wasn’t a great tire but it had a reasonable life. One could get 8500 miles from the rear tire, if ridden gently, and the same tire was available for purchase elsewhere, not that you would probably want one.
 
i was watching FortNine on youtube talking adv tyres and he made an interesting comment
he says that new bikes hit the showroom floor with tyres that we cannot buy
they are made especially for new bikes and are nothing like the tyres(same numbers)on the shelf
one reason for this is to keep the weight down
so that crappy dunlop may be fine when we replace it with the same tyre

i fitted 705's when my oems wore out at 8000kms(bought bike second hand)
What F9 said is not universally true. OEM fitment tires are available for some bikes and in some countries the bike cannot pass inspection for annual registration unless OEM approved tires are fitted.
 
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