 |
|
17 Jan 2008
|
|
Registered Users
Veteran HUBBer
|
|
Join Date: Sep 2003
Location: Estonia
Posts: 787
|
|
Quote:
Originally Posted by oldbmw
This is not a fixed thing Margus. On the diesel bike forum where bikes often run with a max of 9hp, transmission loss can be substantial. For instance the old Enfield gearbox when filled with grease as recommended consumes over 25% of the crankshaft power. Switching to 90 grade oil halves this, with a further decrease of power absorbtion when using 50 grade oil. The new (since 1995 or so) 5 speed gearbox on 50 grade oil will often allow a bike to go an extra 10mph, as it absorbs very little power.
Many modern bikes run the gears in the very thin synthetic engine oils which reduce drag to a minimum, wheras the bmw's use separate gear oil of 75/80 weight. Worse for BMW's is that the gearbox is directly coupled to the engine, so there is no primary reduction. This means the input shaft turns 2-3 times faster. to compound this problem, the output shaft is offset to drive the shaft. This forced BMW to use a gearbox that not only spins fast but final drive is via transverse cogs, all of which conspire to drain power. Old Gearboxes and most car gearboxes usually lock the input to the output on the same shaft, so in top gear power is not trasferred by energy wasting gears at all. This normally can easily be checked by looking to see if top gear is shown as a 1:1 ratio. Final drive ratio should always use the least amount of intermediaries for highest efficiency ( and probably component life).
|
Hmmm...
I did dynoed my GS and guys who've dynoed most of the bikes and have extensive experiences on this field said the BMW-spec gearbox/paralever drive-train is within the power loss spec of most of other modern shaft-drived systems (or my over 60Kkms done GS performed well above factory performance specs to "cheat" the dyno machine results calculation), including japanese bikes with wet clutches and gearboxes floating in the crankcases in a very thin engine oil. I use spec oils only: usually 75W-90 GL5 both in gear- and bevel box.
The pro for BMW engine+gearbox system is all the shafts rotate parallel, which, at least in theory, should give the best mechanical efficiency and longevity - i.e. lot of unusually high mileage BMWs, Honda STs & Goldwings, some Guzzis. Engines where 90-degree turns are done have their own "uneffective" losses. So maybe that's why on dyno the BMW specs the same as other shaft-drived bikes that have all the friction going on in the thin engine oil, but with 90 degree turn at one point before it's transferred into shaft(?) I.e. bikes like Yamaha Diversion, Suzuki GS or VX, Honda XLV etc.
I agree the power loss ratio does vary, that's why I use the word "approximately" anyways. Depends on the temperatures of oils, mechanical details (i.e. Klingelnberg-Polloid spiral pattern in BMW paralevers), ratios, oil viscosity etc. But with modern shaft drived bikes the power loss is around 18% range running in common transmission oils in bevel boxes. I'm sure Enfields etc with different oils (even full of grease variant as you said) have different results and probably have more power loss than the modern siblings.
Last edited by Margus; 17 Jan 2008 at 08:18.
|
17 Jan 2008
|
|
Registered Users
Veteran HUBBer
|
|
Join Date: Mar 2007
Location: UK
Posts: 4,343
|
|
How much do they weigh??
Quote:
Originally Posted by AliBaba
The weight issue is funny. As always people think that the traditional BMW-stuff is heavy. I compared the weight of swingarm, beveldrive/sprocket, driveshaft/chain on a R80GS and a F650GS Paris Dakar:
R80GS shaft 12,4kg
F650GS 9kg
That’s not to bad is it? …… Well if you need to carry a spare set of sprockets and chain the weight for the chain-bike will be 12.3 kg! Still 100 gram lighter but you need lubricants, a few chainlocks and maybe some tools.
Conclusion: Shaftdrive is not necessarily heavier then chain and sprockets!
|
Hi Alibaba,
I just cannot imagine what it is about a couple of sprockets and a chain that adds up to 9 Kg.
Can't say I have ever weighed suchlike though.
I would "imagine", again I don't have weighing scales to hand, that the current crop of BMW shafties are heavier than the earlier models - they just look bigger and, therefore, heavier.
So, is it a useful comparison to take an old bike alongside a current production model (including the next generation of F650GS)?. I quite understand that you are riding one, so you have a personal interest!
I do like the way that BMW are prepared to manufacture bikes with all 3 common(ish) drive systems; shaft, chain and belt. In the next few years, we may see more of the chain drive models appearing, or belts for that matter.
Apart from this, I would just like to remind the original questioner that the chain drive bike can have it's gear ratios changed pretty easily - I don't hear or read of shaft drive owners fiddling with their gear ratios.
That's why the "racers" will always have a whole pile of sprockets and gearboxes for the various circuits - lets see how BMW are going to deal with this when they go racing!!
__________________
Dave
|
18 Jan 2008
|
 |
Registered Users
Veteran HUBBer
|
|
Join Date: Apr 2001
Location: Norway
Posts: 1,379
|
|
Quote:
Originally Posted by Walkabout
Hi Alibaba,
I just cannot imagine what it is about a couple of sprockets and a chain that adds up to 9 Kg.
|
That's because the swingarm are included (for both shaft and chain). The swingarm are very different on shaft vs chain bikes.
|
18 Jan 2008
|
|
Registered Users
Veteran HUBBer
|
|
Join Date: Mar 2007
Location: UK
Posts: 4,343
|
|
Ah!
Maybe difficult to separate out the functions for a shafty, but I may look around for a single-sided swing arm/chain drive and weigh it!
A Duc or a Triumph perhaps??! 
__________________
Dave
|
18 Jan 2008
|
 |
Moderated Users
Veteran HUBBer
|
|
Join Date: Jan 2006
Location: DogZone Country
Posts: 1,218
|
|
Quote:
Originally Posted by pauldelft
Hi people,
new to the site and absolutely love it!
I'm planning to make a RTW trip or Amsterdam-Cape town within two years from now, depending a bit on budget, time etc.
The big question everyone faces is of course which bike to choose? Lots of info and pro's and con's on weight vs power vs reliability, but no one seems to talk about shaft drive vs chain driven bikes (at least, i can't find it, might just be me).
Here in Holland I drive a bashed up cx500 (due to budget and living in inner city), which is shaft driven and i love it. It has never let me down (nearing 90,000km) and the shaft is totally care free. This experience tilts me towards shaft driven bikes, but the only enduro bikes seem to be BMW's, which are not my type of bike (too expensive and too high tech) for a RTW.
What are the options on shaft driven enduro's? Or can someone convince me chain is just as good/better?
cheers
Paul
|
Hi Paul
I suggest that with a good chainoiler there is no longer a need for shaft drive. I've had fantastic kilometrage out of my chains (Africa Twin) since fitting a Scottoiler.
I think that this allows a much wider choice of bikes for you. Get a chain drive and fit that oiler.
Shaft drive is of course, still an excellent choice, but the oiler opens up possibilities.
|
18 Jan 2008
|
|
Registered Users
Veteran HUBBer
|
|
Join Date: Aug 2007
Location: Sax, Spain
Posts: 901
|
|
|
Cammys Old Bike......
Quote:
Originally Posted by Caminando
Hi Paul
I suggest that with a good chainoiler there is no longer a need for shaft drive. I've had fantastic kilometrage out of my chains (Africa Twin) since fitting a Scottoiler.
I think that this allows a much wider choice of bikes for you. Get a chain drive and fit that oiler.
Shaft drive is of course, still an excellent choice, but the oiler opens up possibilities.
|
Are you keeping the same theme with your AT then Cammy?
|
18 Jan 2008
|
|
Registered Users
HUBB regular
|
|
Join Date: Jan 2008
Location: Netherlands
Posts: 39
|
|
|
Never intended to get a discussion going on looks, but there you have it! Thanks for returning back to subject caminando, I had figured the same; either a shaft (limited choice of bikes) or a chain with oiler will do fine for most trips. Cheers for all the input!
Go ahead and have fun talking about looks, gear ratios and the weight of swing arms, i've got the info i need!
Paul
|
18 Jan 2008
|
|
Registered Users
Veteran HUBBer
|
|
Join Date: Apr 2001
Location: Norway
Posts: 1,379
|
|
Quote:
Originally Posted by pauldelft
Go ahead and have fun talking about looks, gear ratios and the weight of swing arms, i've got the info i need!
Paul
|
Hey! Don't run away we have more obscure details 
|
18 Jan 2008
|
|
Registered Users
Veteran HUBBer
|
|
Join Date: Mar 2007
Location: UK
Posts: 4,343
|
|
|
[quote=pauldelft;169261]Never intended to get a discussion going on looks,
Paul[/quote
But it is all part of the heady equation. So, as Alibaba says, don't stop reading this one!
Good stuff there AliB and Magnus; I do like your pics and the research that you guys have put into your preferred steeds.
__________________
Dave
|
|
Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
|
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Check the RAW segments; Grant, your HU host is on every month!
Episodes below to listen to while you, err, pretend to do something or other...
2020 Edition of Chris Scott's Adventure Motorcycling Handbook.
"Ultimate global guide for red-blooded bikers planning overseas exploration. Covers choice & preparation of best bike, shipping overseas, baggage design, riding techniques, travel health, visas, documentation, safety and useful addresses." Recommended. (Grant)
Led by special operations veterans, Stanford Medicine affiliated physicians, paramedics and other travel experts, Ripcord is perfect for adventure seekers, climbers, skiers, sports enthusiasts, hunters, international travelers, humanitarian efforts, expeditions and more.
Ripcord Rescue Travel Insurance™ combines into a single integrated program the best evacuation and rescue with the premier travel insurance coverages designed for adventurers and travel is covered on motorcycles of all sizes.
(ONLY US RESIDENTS and currently has a limit of 60 days.)
Ripcord Evacuation Insurance is available for ALL nationalities.
What others say about HU...
"This site is the BIBLE for international bike travelers." Greg, Australia
"Thank you! The web site, The travels, The insight, The inspiration, Everything, just thanks." Colin, UK
"My friend and I are planning a trip from Singapore to England... We found (the HU) site invaluable as an aid to planning and have based a lot of our purchases (bikes, riding gear, etc.) on what we have learned from this site." Phil, Australia
"I for one always had an adventurous spirit, but you and Susan lit the fire for my trip and I'll be forever grateful for what you two do to inspire others to just do it." Brent, USA
"Your website is a mecca of valuable information and the (video) series is informative, entertaining, and inspiring!" Jennifer, Canada
"Your worldwide organisation and events are the Go To places to for all serious touring and aspiring touring bikers." Trevor, South Africa
"This is the answer to all my questions." Haydn, Australia
"Keep going the excellent work you are doing for Horizons Unlimited - I love it!" Thomas, Germany
Lots more comments here!
Every book a diary
Every chapter a day
Every day a journey
Refreshingly honest and compelling tales: the hights and lows of a life on the road. Solo, unsupported, budget journeys of discovery.
Authentic, engaging and evocative travel memoirs, overland, around the world and through life.
All 8 books available from the author or as eBooks and audio books
Back Road Map Books and Backroad GPS Maps for all of Canada - a must have!
New to Horizons Unlimited?
New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!
Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80G/S.
Read more about Grant & Susan's story
Membership - help keep us going!
Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events all over the world with the help of volunteers; we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.
You don't have to be a Member to come to an HU meeting, access the website, or ask questions on the HUBB. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.
|
|
|
helps answer the question - Why Go? Inspirational stories by veteran travellers Greg Frazier (5 times RTW), Peter and Kay Forwood (193 countries), Tiffany Coates (Mongolia Mayhem) and Rene Cormier (University of Gravel Roads).
Get Ready! covers planning, paperwork, medical and many other topics! "Inspirational and Awesome!" See the trailer here!
What stuff do I need - riding gear, clothing, camping gear, first aid kit, tires, maps and GPS? What don't I need? How do I pack it all in? Lots of opinions from over 150 travellers!
Ladies on the Loose! For the first time ever, a motorcycle travel DVD made for women, by women! These intrepid women share their tips to help you plan your own motorcycle adventure. They also answer the women-only questions, and entertain you with amazing tales from the road! Presented by Lois Pryce, veteran solo traveller through South America and Africa and author of 'Lois on the Loose', and 'Red Tape and White Knuckles.'
Cotton or synth sweat-wicking t-shirts with the cool Horizons Unlimited graphic on the front and a snappy slogan (changing every year) on the back.
Show your route on your panniers. Great conversation starter when you meet people on the road!
Motorcycle and travel books to inspire and inform you!
The definitive guide to planning your motorcycle adventure! This insanely ambitious 2-year project has produced an informative and entertaining 5-part, 18 hour video series. "The ultimate round the world rider's how-to!" MCN UK.
How much do they weigh??
Hybrid Mode
