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MPG - The Bike Or The Rider?

Thought Date - Tuesday, February 12, 2019

By Rod

M.P.G. Which makes the biggest difference. The bike or the rider?

In the world of cars it seems the customer can get a rough comparison between the models that they are interested in for fuel consumption, but in the biking world there does not seem to be any reliable information.

Do we look at 'fuelly' for comparisons? The figures between different riders vary greatly, but it does give rough figures if there are enough riders logging their figures.

A fuel gauge on a motorcycle dashboard

Do we look at road tests? Ren has commented more than once that he feels the testers thrash along the motorways and do not find a gear higher that 3rd!
 
I try to be more forgiving of the test riders as they have a difficult job to please all. If a punter is looking at a particular bike and they want to know how many miles per gallon to expect does the test rider ride gently and miss-lead the punter in thinking they will get this figure, or do they try to give a more realistic mpg figure?

This may involve trying to give direct comparisons between bikes on a given test route that they use. So when they test a 600cc bike and ride the back roads at 50, the A roads at 60, and the dual carriageways and motorways at 70 this would seem reasonable right? But then the next test bike may be a 125cc bike, and to give a comparison to the 600cc bike they would have it flat out just about everywhere and hence the fuel consumption would seem very high.

This still is not a direct comparison as the bikes would need to do the same route at the same time, as the wind may be stronger on different days, and preferably the 125cc bike would lead so the 600cc bike accelerates at the same rate, and does not leave black lines when coming off of the roundabout.
 
So lets forget for a moment what we all know, small 125s do 120mpg plus and big bikes do less than 50mpg, and ask the question "is it the bike or is it the rider which has the biggest effect on the miles per gallon we achieve?" It is obviously a mixture of both but to what extent?

Ren has posted that taking it easy he has achieved 79 mpg on a 95bhp Yamaha Fazer, and 97mpg on his CB500X.See CB500X miles per gallon http://bikesandtravels.com/biker.aspx?ride=1156

I myself have achieved 110mpg taking it easy on my 250 Zuma. This figure was achieved when trying to compare the 250 with a 125, and my conclusion was that the 125 would probably do more to the gallon at 125 speeds but not a lot more. I say probably because it is very difficult to get a direct comparison as the 250 would accelerate quicker and not slow down as much on hills ect.

Rod's smart clean and fully faired GW250 Inazuma

I will typically get 70 - 73mpg from the Zuma when used on fast A roads / duel carriageways, and if I did not have mechanical empathy it would be under 70mpg so the 110mpg is only representative if the bike is used like a 125.
 
I would like to hear any thoughts you have. Have you tried riding a 1000cc plus bike like a small commuter? How many miles per gallon did you get?


If you'd like to contribute your own guest post contact ren@bikesandtravels.com

Reader's Comments

CrazyFrog said :-
It would take somebody with a far greater knowledge of the physics of infernal combustion engine than me to give definitive answer, but I would have thought that burning a given volume of fuel/air mix (ie 125cc for a 125 at full throttle and a 250 at half throttle) will release the same amount of energy and therefore the only differences in efficiency will be due to the overall weight of the bike, and the weight of the transmission components, rolling resistance of tyres etc.

The trick as you suggested would be to entirely mimic the on road performance of a 125 whilst riding a 250, which will be very difficult (even more so for a 500 or 750). If you were able to do this I wouldn't expect there to be much difference in MPG. One of the reasons I've never had a bike with more than 50bhp is that I know that I wouldn't use the extra performance, and therefore for me personally, the increased costs of consumables and petrol means it just isn't worth it. If you're going to ride a 1000cc bike like a 500, you're much better off getting a 500!

Interesting article.
13/2/2019 12:32:28 PM UTC
pocketpete said :-
Ah zuma......... My only regret in selling my Inazuma was that wonderful seat. So comfy - fitted my fat arse perfectly.. I must admit my 250 was giving me better MPG than my 500x but my 500x has averaged 75mpg since I purchased it, sometimes a touch higher or maybe a touch lower depending on traffic but not by much.
13/2/2019 2:39:08 PM UTC
Ian Soady said :-
All the bikes I've had that I've bothered to check have done around 55 mpg. From the Velo Venom, through the Norton Commando, to the Triumph Tiger 955i. As Pete Frog says, for a similar performance envelope you're going to use much the same amount of fuel - give or take depending on efficiency.

The Commando was a lovely easy ride especially cruising at 60 - 70 which is where I'd generally be; the Velo needed its neck wrung to keep up similar speeds; the Tiger did it on a mere whiff of throttle.

The Commando and Tiger were used largely for touring in France and elsewhere - both had decent sized tanks so I would normally only need to fill once a day unless aiming for some serious mileage.
13/2/2019 2:42:54 PM UTC
Rod said :-
I am thinking along the lines of CrazyFrog about the fuel energy equation, and the differences being Bike Weight, Transmission Efficiency, Rolling Resistance of the Tyres, and I would add where the engine is tuned for maximum efficiency.
Although it is not just the bike weight. My bike weighs in at around 187kg and a big tourer weighs in at around 265kg, this shows the tourer 42% heavier than my bike, But in the real world if the weight of the rider and pillion (say 160kg kitted up) and touring luggage (say 40kg) are added the difference is reduced to 20% heavier.
This is born out by my own experience touring two up on a 1000cc bike which returned over 60mpg. The Inazuma will do more mpg at similar speeds, but not a lot more, and this was on a 1000cc bike with carbs, and inefficient shaft drive.
Your thoughts on riding a 1000cc bike like a 500cc bike I will have to think more about. If you ride the 500cc bike on the redline all of the time you may be better with the 1000cc bike.
13/2/2019 6:25:55 PM UTC
Rod said :-
Yes pocketpete, the seat is very good on the Zuma.
You say that the 250 gave better mpg than the 500, but as I recall you sold the 250 because it was not powerful enough, so surely you are using more power than the 250 hence poorer mpg on the 500.

Interesting Ian, same rider at the same sort of speed three different bikes = same mpg.
13/2/2019 7:03:50 PM UTC
Pocketpete said :-
Yes I always felt the zumaz struggled on the motorway a bit. At the time I was doing 25 miles each way.

The 500 makes that trip easier less laboured. If I remember the 250 gave me 85ish to the gallon. Which wasn't bad.
13/2/2019 9:50:23 PM UTC
Upt'North said :-
Definitely Bike.
For me anyhows.
For long journeys on mixed roads with both bikes carrying the same load but one a much lighter bike. Both bikes also making approximately the same bhp.
Honda CBF1000 47 mpg.
Honda ST1100 52 mpg.
The CBF was a new to me fuel injected bike and considerably lighter.
The ST shows 63000 miles and is fitted with four carbs.
So the older heavier more worn bike is 10% more economical.
Other than witchcraft I would put it down to the ST sitting at around 4000 rpm most of the time on long runs,i can't remember what the CBF would be revving at but I expect around 5000 rpm.
Upt'North.


13/2/2019 11:34:32 PM UTC
Rod said :-
PocketPete, 85mpg sounds right for the Zuma on a mixture of roads.

Upt'North, I think the gearing makes a difference especially on larger bikes.
In my experience the shaft drive bikes tend to be over geared, which helps with the fuel economy.
14/2/2019 8:02:23 AM UTC
Steve said :-
As many others have observed,I also think its down to revs, my nc700 is very frugal but is never above 4000 rpm, once even recording an astonishing 100mpg on a slowish sightseeing day. The cb500x and nc700 are a good comparison, both make about 35kw so say going along at about 60 the nc700 is at 3000 rpm, what is the cb500 doing? if it is nearer 6000 rpm then there is twice as many induction strokes so twice as much fuel used if the induction rates are the same. Lots of variables though as others have mentioned, weight/rolling resistance etc.
I think the biggest improvement on modern bikes is FI, i never got anything like my present mpg on carb bikes, many carbed multis and twins i had last century barely able to get 40mpg and often in the 30s if "making progess"
14/2/2019 10:25:11 AM UTC
Daf said :-
I've averaged ~80mpg on my Inazuma over about 40,000 miles. It's actually dropped to ~75mpg since fitting an aftermarket exhaust though.

Riding the bloodbike (FJR1300) carefully (because blood) and not exceeding speed limits, and using the cruse control extensively on the motorway, I've been getting at least 70mpg... so I think rider technique has a lot to do with fuel consumption!
15/2/2019 3:29:07 PM UTC
Rod said :-
That is an impressive figure Steve! 100mpg from a 700cc bike.

Daf, your figure of 70mpg plus is confirming my thoughts, that the smaller bikes are more fuel efficient, but not by as much as the headline figures suggest.
I still feel the bikes we are trying to compare need to be tested together, at the speeds that we want to ride at to give a true comparison.
15/2/2019 6:51:48 PM UTC
Steve B said :-
Ive got an Aprilia Shiver 750. Road tests gave 45mpg
It has a digital dash that shows mpg as you go
Sat on the Italian autostrad at the 80 mph speed limit showed 50 mpg so i rolled the throttle back to 75mph and was showing 55-60 mpg
All excited arriving at the next fuel stop and filled up
Yes you guessed it 45mpg
Figure that one out as I cant
On this particular bike it makes no difference what speed or how it is ridden, always 45mpg
17/2/2019 8:39:32 PM UTC
Mike said :-
When I bought my fzr1000 new in 1996 I got over 50mpg running it in and around 27mpg after. But I didn't get a bike to save money on a run even when commuting, it was about not sitting in traffic, getting to the destination by having fun and if fun mentioned an extra £20 a week by going faster, accelerating harder, braking later that's what I did. I'm also old enough to remember when fuel went over £1 a gallon and saying I'm not paying that, and here I am 30 odd years later still buying my feel good drug called petrol. The only time I think about mpg is when the low level light comes on, which on the fjr1300 is after 175miles, and a petrol station is needed. I'm rambling a bit but the bike will always do more mpg, it's the rider that can't stay away from having fun.
18/2/2019 11:07:19 AM UTC
Steve B said :-
Fun is the factor for us Mike.
But those looking for economy would need to look elsewhere.
Each to their own I would like more mpg but I enjoy the Aprilia and I have a Honda 300 scooter that is good on fuel for shorter journeys so Im spoiled a bit
18/2/2019 11:32:41 AM UTC
Ren - The Ed¹ said :-
Fun? What is this thing called "fun" you speak of? I don't like the sound of it, we'll be having non of your "fun" here.
18/2/2019 2:37:40 PM UTC

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