What RPMS do you run while cruising? Most Fuel Efficient?

[Sensfan]

Yeah Avon is the stock tire size AVON COBRA AV72 240/50-16 (84V)
and compared with Bridgestone Exedra EA1R 240/55-16

The touring model has a smaller rear,180 stock,I'm running a 200.

 

[Ishrub]

For a touring

Just redo calculations with Touring final drive ratio and check other figures using Touring tire size
Front/Rear 150/80R-16 / 180/70R-16 in:
180/70-R16 vs 200/70-R16 Tire Comparison - Tire Size Calculator | Tacoma World

Is your 200 still a 70 profile?

Touring specs Do not state final drive ratio but figures below are identical to R3 Std and Classic
from Rocket III Touring


TRANSMISSION:
Primary Drive Gear 1.034:1 ratio, with backlash eliminator
Final Drive Shaft
Clutch Wet, multi-plate cable operated
Gearbox 5-speed constant mesh

Gear Ratios
1st 2.929:1
2nd 1.947:1
3rd 1.435:1
4th 1.160:1
5th 0.964:1

 

[Ishrub]

@Sensfan Touring with 200/70 R-16 compared to stock 180/70 R-16

Yes, 5th gear but all figures calculated and based on Triumph published final gear ratios for Std and Classic rocket from page 104 of online .pdf manual posted by members on R3Owners.
I then used the final gear ratio/RPM @65 Mph table
Gear Ratio / RPMs for New Tire (@ 65 mph)
2.35 2.73 2.94 3.07 3.21 3.31 3.42 3.55 3.73 3.91 4.11 4.27 4.56 4.88 5.13 5.29 5.38 5.71 6.17 7.17
899 2206 2376 2481 2594 2675 2764 2869 3015 3160 3322 3451 3685 3944 4146 4275 4348 4615 4986 5795

to calculate an averaged ratio:RPM factor for the 200/70 R-16 tire of 1.0:808.2 and with same Final Drive Ratio of 2.846:1 as the R3Std/Classic gave RPM @65Mph = 2300 RPM.
Therefore 1.0 Mph = 35.3846 RPM
65Mph x 1.6093 = 104.60 Kph.
Therefore 1.0 Kph = 21.9885 RPM

As stated in data from 180/70-R16 vs 200/70-R16 Tire Comparison - Tire Size Calculator | Tacoma World the difference in circumference between stock tire and 200/70 R-16 is +4.3% and Rolling difference is -4.1% .
2300 RPM / 95.9 x100 = 2398 RPM @65Mph with stock tire.
2300 RPM @ 65Mph (104.60Kph) = 21.9985 RPM/Kph with 200/70 R-16
2398 RPM @ 65Mph (104.60Kph) = 22.9254 RPM/Kph with Stock 180/70 R-16 tire

Mph
2000 RPM 57/54 @Peak torque
3000 RPM 85/81
3200 RPM 90/87
3500 RPM 99/95
4000 RPM 113/108
5400 RPM 152/147 @Stock Peak power (I don't think it will pull it in 5th though)

Kph
2000 RPM 91/87 @Peak torque
3000 RPM 136/131
3200 RPM 145/140
3500 RPM 159/153
4000 RPM 182/174
5400 RPM 245/236 @ Stock Peak power (I don't think it will pull it in 5th though)

 

[Ishrub]

2750 - 3000rpm

Bingo @mr hunt
Having done all that, the best fuel economy is usually obtained close to Peak Torque.

Roadster 2750 RPM = 73 Mph/118 Kph with stock tires
Touring 2000 RPM = 54 Mph/87 Kph with stock tires

Triumph 2015 Roadster claimed factory
Fuel Consumption
Urban * * 28.6 US MPG
Constant Speed 56mph/90kph 44.7 US MPG
Constant Speed 75mph/120kph 35.9 US MPG

 

[mr hunt]

..all you had to do was ask .....the point of my rambling before (Annexure 1: I had been awake for 40hrs and had been at work for 24 of them, including a 16 hr double shift and had also been sampling a cheeky little SSB) was that there are too many extraneous variables that affect throttle position and therefore fuel efficiency at those rpm/kph ratios.

Great work on the numbers btw

 

[1olbull]

Was the rolling radius measured or considered and what was used for transmission efficiency?
I have read most bikes are around 90%.
I also wonder how much variation there would be between each bike?
Good ciphering BTW!

 

[barbagris]

As a point of interest. Just fitted an E-Max. Indicated is now so close to GPS I can't really see a difference. And I'd rather keep my eyes on the road. It was in the 3-4% fast region before. No real surprise though.

 

[Ishrub]

Was the rolling radius measured or considered and what was used for transmission efficiency?
I have read most bikes are around 90%.
I also wonder how much variation there would be between each bike?
Good ciphering BTW!

I would guarantee that the data used was generic as it came for the tire size calculation website
180/70-R16 vs 200/70-R16 Tire Comparison - Tire Size Calculator | Tacoma World
which is for both car and motorcycle tires and within the site clearly states the basis for their calculations i.e stated size from manufacturer and aspect ratio as a % of tire carcass width etc.
As we know there can be heaps of variation between and within manufacturers so called same tire sizes, so take it all as guide.

Their website explanation of tire size nomenclature also states:
"NOTE:
It should also be mentioned that different manufacturers' tire sizes will slightly vary from these calculations. Its usually a very minor amount but it's still there none the less. For this reason I recommend everyone looking at tires to go to the respective Manufacturers web site and look up the exact specifications they list for the tire before buying a set, or to compare tires between different manufacturers."

Once you start mixing averages of data such as the gear ratio and RPM tables to make an estimate you are really only working to accuracy (significant figure) of 1 decimal place at most despite the fun delusional illusion of accuracy by using 4 decimal places for some inputs like I did, but I did round the final speed figures to exclude meaningless decimals.
See Significant figures - Wikipedia, the free encyclopedia
"Spurious digits introduced, for example, by calculations carried out to greater precision than that of the original data, or measurements reported to a greater precision than the equipment supports."

The first set of calculations (post#27) for the Roadster comparison of stock 50 and Exedra 55 just used the calculated diameter and circumference from the generic tire size, although I did not re-do them at the end, I explained I should have used the rolling Revolutions per mile (km) estimate and the 'bee's dick' significance it was. (+3.7% circumference vs rolling Revolutions per mile (km) -3.6%) Again figures rounded by them to 1 decimal place.

The 'Touring' figures (post#43) do use the rolling Revolutions per mile (km).
(+4.3% circumference vs rolling Revolutions per mile (km) -4.1%) .
Ironically I just checked their calculation and they should have rounded the +4.3% to +4.2% (3.46"/81.43" = 4.249048) unless they used metric mm (87.96/2068.42 = 4.25252) quibble, quibble!

Transmission efficiency is completely irrelevant for our purposes and only effects power/torque which will also vary a little Rocket to Rocket due to manufacturers tolerances and shimming etc.

Chain and sprockets are much more efficient than shaft drive and in good condition are usually 10-12% loss from crank to wheel measured power/torque. They can vary with chain design, internal friction and tension; sprocket width, tooth design, the number of teeth on each sprocket in contact with the chain any one time and even the angle the chain leaves the sprocket. Racing chains are still often plain without O or X rings etc as they have less friction and do not need to last long for racing purposes. Racing sprocket sets and chain are often thinner and lighter as well which also reduces power/torque losses.


Often quoted for Roadster is stock wheel 120-122 bhp from 146-148 bhp at crank stock.= 16-19%
Shaft final, crank to wheel is always less efficient I have seen figures quoting 16-18% (but also only 6% which may have just been the shaft as I have also seen figures that the chain and sprockets alone is only 1-2%), as there is at least an extra 90 degree re-direction of power / torque and more friction and rotational mass losses with shafts, multiple bearing, uni-joints and enmeshed gear sets etc.

The amount of variation from all this only leads me to repeat the conclusions of Post #44 with a kicker in italics.

Having done all that, the best fuel economy is usually obtained close to (but probably not exceeding) Peak Torque.

Roadster 2750 RPM = 73 Mph/118 Kph with stock tires
Touring 2000 RPM = 54 Mph/87 Kph with stock tires

Triumph 2015 Roadster claimed factory
Fuel Consumption

Urban * * 28.6 US MPG
Constant Speed 56mph/90kph 44.7 US MPG
Constant Speed 75mph/120kph 35.9 US MPG