Motorway cruising speeds


Carioca

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Hi All,

Just joined the forum as test rode a MT09 Tracer yesterday and wanted to ask you long termers a question about cruising speed and engine speed.

I had a good hour on the bike, including A roads, B roads and motorway.

I won't go over throttle or screen issues as they have been done to death. I wanted to ask about what speeds you guys all typically cruise at and why?

Why do I ask?

I saw on Fuelly that a load of guys get 60mpg out of their Tracers, and this is because they do mostly highway miles.
Once I took the Tracer demo on to the highway, I saw a massive drop in the "current" mpg between 70mph and 80mph (let alone 90mph).
This is because the revs had to climb much higher for a small incremental increase in speed.

So basically I didn't get the feeling that the engine could sit happily for hours on end revving that high to sustain 85mph. And if it did, fuel consumption would be low fifties (which means high forties when you do the actual maths at the petrol station).

Again, screen issues aside, this is more a question of the engine speed and fuel efficiency.

I really enjoyed the ride. I was surprised that an 850cc could almost match my old KTM990SM for power. Handling was never going to be quite as sharp, but stille excellent.

My only concern is that the engine needs to be revved quite high to sit at 85mph for motorway munching. And I have a 65 mile commute each way!!

So what do you cruise at with your Tracer?

thanks all,
H
 

bobh

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It doesn't matter what the vehicle is, or what gearing it has, the square law of air resistance can't be beaten. You need to use nearly 30% more energy to cruise at 85 mph than at 75. All the gearing can do is to get the engine to run at its most economical revs (usually at, or close to, max torque) at the selected cruising speed.

Is it worth it for the time saved? Do the math, as the saying goes.

65 miles @ 75 mph = 52 mins
65 miles @ 85 mph = 46 mins

So in theory you could save 6 minutes. But that assumes you can keep up a constant speed for the whole distance (which is unlikely, if not impossible). On a busy motorway you can really only go with the flow, even on a bike (at least, if you want to carry on doing it year in, year out, without time off in hospital or worse). And it also assumes that the whole 65 miles is motorway.

A year or so back I was talking to an ex-dispatcher in Swindon, who used to make regular runs up the M4. One time three of them all had deliveries to make in London, so they decided to do a bit of an experiment. They all set off together, and arranged to meet up again at Heston services, which is not far short of your 65 miles. One was to go as fast as possible, one went pretty much with the flow and the third stuck rigidly to 70 mph. They all arrived within a couple of minutes of each other.
 

Carioca

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Good answer. And I love the maths!

But it still doesn't quite answer the question.

The engine feels very "busy" at motorway speeds. Anything over 70, and it feels like it is revving quite high. Much more than I expected.
It doesn't give me the confidence that it could sit for hours on end at that rate.


I totally agree with your maths and the futility of going faster. But I will still do it. I will do it because I want the sensation of progress, regardless of the realities. I think most people are like that.

What do you sit at on the motorway?

I have done similar distance commuting on both bigger biked (Pan European 1300cc) and smaller bikes (v-strom 650cc), and both felt like they could sit at 80-90mph all day long.

As you suggest, maybe it is simply a question of gearing, rather than the engine, which is how they have made an 850 so perky and torquey...?

Also - how do you get this forum to work on Tapatalk? I keep getting the verification request, which is impossible on the app...

Thanks!
 

Shaun64

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I recently did leeds to Oban in 8 hours and got 60 mpg,only 100 miles out of 760 miles on a1 but rest on quick roads at around 80-90,the tracer will sit at these speeds all day long,why you would want to sit on motorways all day long at a 80-90 is beyond me.
 

chump

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The bike will sit at any speed all day long. If the revs are at 5k or 7k it makes no odds, surely. It's not going to fall apart. 100mph is about 7k isn't it?
 

bobh

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But I will still do it. I will do it because I want the sensation of progress, regardless of the realities. I think most people are like that. Agreed - we'd all sit in cages if we didn't think the same.

What do you sit at on the motorway? Usually just go with the flow, which is normally between 75-80 indicated, a bit less on variable speed sections e.g. M25, M42 (some of the cameras are still live on those, even when not showing a reduced limit).

As you suggest, maybe it is simply a question of gearing, rather than the engine, which is how they have made an 850 so perky and torquey...? I have to say, when I got mine (it's the basic MT-09, not the Tracer) I thought it was actually a bit OVERgeared, as I was only using 6th at higher cruising speeds. I guess it's what you're used to - a big tourer like a Pan is hardly turning over, and V-twins always feel longer-legged than they really are. I know it's not really relevant, but I've recently geared my Fazer8 down one tooth at the front, so it's happy at 30 in 3rd. And it's still only doing <6000 on the motorway (just over half-way up to the redline). No idea what effect it's had on fuel consumption, though!
Sorry, I can't help you with Tapatalk, though.
 

LewFZ1

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I have the MT09 and if touring I just keep it in B Mode and about 70 mph, the instrument cluster has an ECO symbol and as long as you do not ring the neck of the thing to get to 70 mph you will stay in the ECO setting more or less.
 

highlander

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You can raise the gearing using a smaller rear sprocket to give lower revs at a given speed. I did this on an old gpz500 which improved fuel by about 10% and more relaxed revs when cruising.

Small compromise to acceleration of course but that never bothered me.
 

LewFZ1

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Or as I said ride it in B mode(Boring mode) at least you still have the option when you want to wring the neck off it and ride it as it was designed to be which was fun.
 

chump

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Or as I said ride it in B mode(Boring mode) at least you still have the option when you want to wring the neck off it and ride it as it was designed to be which was fun.
and your speedo will still be as accurate as it was.
 

LewFZ1

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The speedo is about 6% out anyway when compared to a GPS. Not sure were the speedo pickup is on the MT-09. I altered the gearing on my Z1000SX from a 15 th front to a 16 th and that had the pickup from the front sprocket, the speedo was then bang on.

Here is a good site as you can play around with gearing and see what does what to the bike. Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator To find the MT-09 you may have to enter it as the FZ9.
 

Unfazed

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On the Tracer it's still on ECO at 80

I've been commuting between London and Medway and I'm getting 59 to the gallon and that's not taking it easy either
 

Carioca

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Thanks for the responses guys.

If I can replicate 59mpg at 80mph I will be happy.

I am now looking at screens and side luggage... I've always fancied an MRA X-creen, as at least that is transferable to any future bike. Plus I quite like how they look!!
Luggage will impact the fuel eff'y, but hey-ho. If I could afford metallic ones I'd go for that, but a used set of givi plastics will prob be the way to go. Just need to decide size.

NOTE - for anyone starting from scratch - someone out there is doing a mad bargain on a full SHAD set. Around £400 for the full mounting and 3 boxes. If I didn't have the givi top kit I'd consider going down that route.
 

bobh

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I think the ABS bikes take the speedo signal from one or other of the wheel sensors, so if you change gearing the speedo remains as (in)accurate as before.
 

V8legend

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I've just been around France, Andorra, and Spain. Cruising at 80 - 85mph gives about 56mpg. Backing off to about 75, gives over 60. All figures off the wildly inaccurate speedo. I've no idea how far out the mpg figure is. Anyone checked it? Oddly, the speedo isn't so far out when you change it to kph!
 


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