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-   -   The KTM Duke 390 Ownership Experience Thread (https://www.team-bhp.com/forum/motorbikes/138082-ktm-duke-390-ownership-experience-thread-168.html)

As man_of_steel mentioned, normal air is 78% Nitrogen, 21% Oxygen and rest are other gases and moisture. So topping an N2 tyre with normal air (in case if you don't find any N2 stations) does not make much diff in the short run. before that let me put forward something.

Nitrogen is an inert, non combustible and non corrosive gas. compared to this oxygen is corrosive (oxidation), aids combustion and is relatively unfavorable with regard to the rubber (read tube and tyre).

Oxygen (read normal air) permeates through the rubber pores. that is why our tyres tend to lose pressure when not used or generally over a period of time. Nitrogen on the other hand does not permeate through rubber and so a tyre filled with nitrogen will hold the pressure for a longer duration in comparo with normal air filled tyres.

Humidity (moisture) is a big culprit here. Normal air contains humidity (moisture) more so with salt content in our coastal areas. so when you put normal air in your tyre you are essentially putting some moisture / water vapor in your tube. Now with increased temperature water vaporizes or condenses and this directly effects your tyre pressure ( tyre pressure increases with temperature, though not extremely but still to the effect that your tyre pressure is different from what you wanted it to be). then water vapor comes in contact with metal and corrodes the same too ( ever wonder when you take a tyre to puncture shop, you see corrosion in the edges / inside of the rim?) so moisture with oxygen corrodes / permeates and this leads to reduced life of the rubber ( remember how a rubber band left unattended after a few months becomes placid and sticky and loses its elasticity). Now nitrogen filling means dry nitrogen and it does not have any moisture in it. so all the ill effects mentioned above are taken care of. further Nitrogen molecules are larger than oxygen molecules and hence does not permeate through rubber which essentially means that once your tyre has a certain pressure, it remains the same over a long period of time and also over an temperature increases ( during long rides or hot days)

So when nitrogen is filled in a tyre for the first time, the normal air inside is purged many times so that only pure and dry nitrogen replaces the space in the tube ( else the whole exercise is wasted right?) and if you top up nitrogen with normal air your tyre now has oxygen, perhaps some moisture and nitrogen and you are back to square one.

So if you are sticking with nitrogen it is great, but mixing with normal air (though it does not make any immediate impact) in the long run it is as good as running normal air as temperature changes, pressure changes, corrosion etc keep occurring.

In racing Nitrogen is used because for them tyre pressure is extremely important and the tyres get up to very high temperature and even slight change in pressure could mean win or loose situation for them.

Ride quality wise it does not make any difference as technically when you are riding, the compressed air in the tyre takes the load and hence should not matter though ride under constant pressure tyre is better than a varying pressure tyre. but with nitrogen filled the life of the tyre increases as normal air tends to reduce the life of the rubber and as nitrogen is inert gas, the tyres run cooler than normal air filled tyres.

For all the positives, the drawback lies in finding nitrogen filling station every time you need it, when ever and where ever you need it and then pay for it every time and then some day you put normal air you got to start all over by purging the whole gas out and refill it with pure nitrogen and the cycle starts. that means maintainability, availability and cost goes against the benefits.

I on the other hand check the air pressure every time I fill petrol. I tank her up fully always and most of the time the tyre pressure is same or a tad lesser. so that works for me.

Hope that helps. :D

I agree with this. It surely increases the maintainability and costs among others. However, this is purely on a trial basis. I'm waiting for it to last for a few days. I've also heard that tyre pressure in N2 filled tyres decreases when you're at a high altitude. This weekend, we're planning a ride to a hill which is around 70 kms from here (Not Nandi. Boring) and I want to see if it all the altitude creates a difference in the behavior of my tires.
That being done, and if there is no change in pressure, I'll stick with N2.

Fellas, came upon something weird this morning. Until the run-in period expires, I always idle the bike for 2-3 minutes before starting her day and idle it for 2-3 minutes before putting her to sleep. During these minutes, I check my fuel gauge, reset my trip-meter, and other things. Now, since I'm an amateur in terms of understanding the digital aspect of the D390, I observed that the 'fuel range' reading was blank as in '_ _ _'. My fuel gauge is on one bar above the reserve level right now and the yellow light might come on any moment. This fuel range reading was not there yesterday as well, when there was a red light at the traffic junction and I was exploring the digital display. Solutions, anyone?

Mate, can I have your contact details? Can't PM you.

Cant PM you either! Just do 4 more quick posts and get out of the 'Newbie' status. :)

4 posts? That's it? ON IT! :D

Completed a ladakh ride yesterday on the 390. Have previously used different bikes (CBR and the 220) and I can vouch for it - the 390 makes ladakh look so easy :)
Tyres - Ralco knobbies (very tough to fit the fronts on though)
This combo dismissed all kinds of terrain with ease. This bike will bring forth the motocrosser in you :D

Also, saw atleast 10 different 390s on the route. Looks like lots of 390ers are hitting the ladakh circuit this year.

The best part was the mileage. On tarmac sections i consistently got 40kmpl. On climbing chang la it dropped to 27kmpl. The best I saw was 58kmpl when I was cruising down a pass at 70kmph@6th gear. On a tankful to empty basis I logged around 370km on the karu - pangong - chushul - hanle - tso moriri - chumar stretch.

Could you describe the suspension and engine response during the ride from North Pullu to South Pullu, if you travel on the route to Nubra?

We didnt do khardung la and nubra this year. But in general- based on the experience in Chang la -- engaging first gear would be a rarity. There is a loss of power experienced but nothing too drastic. I charged up Tanglang la at speeds close to 60/70 kmph. Suspension is a definite and literal pain in the a**

Congrats Mik for your Leh ride, Can you share the picture of your ride specially the tyres setup (front+back) and one with full luggage. I am also planning to do it on 390 :)


- Sudhakar

Hate to go *bump* but would solicit some feedback here please. Am I chasing the unicorn? Have not seen anything on the net around this.

Thanks for your comments. I believe the seating position is the bigger fish to fry as opposed to the backrest. I have gone through the wonderful thread by Sridhu in great detail. I like how he has set up his bike but no way can I pay so much for a luggage box.

Sorry, wanted to respond to you earlier recommending installing a luggage box. In fact the Givi has an optional backrest you can install on the box (I did not).

Quick feedback - both my kids & wife like the ride better with the box on. They are not hanging on for dear life. Even I do not like the looks of the bike with the box but needs must ... :-)

If you do not want to spend a bomb, I would suggest that you steal the subframe design from my photos & get it made locally. If you are in Bangalore, THirumala (& other JC road folks) have a cheap knock off box which will suit your pocket better. It is not as big but will serve the purpose. Nasirkaka had one on his Bullet, I think.

I did not want to compromise on the sturdiness of the frame & I happened to be in Malaysia. Hence the Givi

For a start, you don't have to practice idling the bike before and after a ride. Just get on the bike, fire up and ride. Idling the bike is a waste of fuel and time. Besides; your bike will warm up faster with a load on the engine than no load when idling.

Is there a purpose behind resetting the trip meter for every trip you make?

No need to panic for the "____". With the fuel level you mentioned, start riding and a number will show up in a short while. I will not rely on that number though. Ride a little and observe the behavior of fuel related read outs. No need to panic. I would start worrying about low fuel only after my trip meter registers >200km from a tankful.

Take it easy on yourself.

I come from a place where it's so cold, that every automobile in our garage has this ritual of idling for 5 minutes, before the day begins and before the day ends. Maybe it has stuck on me. Ha!

Yes. The purpose is to note down my daily trip readings in my own log book. Helps me in maintaining my fuel expenses and daily readings, considering that I'm a student and sustain on a limited budget.

Well, the fact is, that even on a good amount of fuel on the bike (3-4 bars), the range doesn't show up and all I see is '_ _ _'. Even though I won't rely on this number either, it's weird to see all of my screen digits loaded up except this. Gives rise to a thought that it might be some kind of electronic failure, perhaps? I'm getting decent mileage figures as of now, especially since I shift below 4-5k rpm, and occasionally let her burst to life.

Two pictures of my setup. I was using the regulation cramster saddle bags as spares+petrol-can carriers. Both the sides had 10 liter plastic cans.
The dirtsack tailbag was used for carrying rest of the stuff.
The viaterra tank bag was used for carrying the cam+other misc. stuff.
Two bungee cords are mandatory to ensure that the dirtsack stays in place. The bungee cords can easily be hooked upto the swingarm.

The tyres -- Ralco 110 front (handling became heavier) and 120 rear. The set available at Master Tyres in karol bagh for around 4.5k.
If you install this front tyre, do get a little 'patti' added on the front mudguard otherwise it will graze against the tyre as in my case.

P.S: The 220 in the picture is the same 7 year old war-horse we did our Auli ride in 6.5 years back :) Good to connect again.