Final drive weigth reduction

Dmaster · 01-28-2013, 05:22 AM

I've searched the internet and this forum but couldn't find any info I'm looking for.
Did anyone ever tryed to get some weigth out of the final drive?
Does anyone know of someone doing it? Any picturs available?
What could you take away, drill/machine/whatever?

JonnyCash · 01-28-2013, 05:35 AM

I've seen people put holes in the aluminum housing, but i think that's more for the look than anything else. I'd imagine that one could pare some weight from the ring gear, like you would with a flywheel. That said, when I pick up a BMW final drive, I feel like it is pretty light, for what it is. Go pick up one from a Guzzi, it's much heavier, and then you'll be happier with the weight of the BMW part!

Big Bamboo · 01-28-2013, 11:29 AM

Jim Roche aka "Dr. Curve" did some lightening of his White Dog racer. Not a huge weight savings, but it is some...

Dmaster · 01-28-2013, 02:02 PM

The housing (is that the right name?) isn't the heavy part its the "gears"
why not cut the red parts?:

this isn't gonna help much but why is it here anyway?

I'm sure I can get some material of the small gearing but how much will it be.

Someone must have tried this before.
I know about "lightweight gearboxes" (drilled holes in anything) why not the final drive

chasbmw · 01-29-2013, 02:42 AM

The later final drives look lighter.

Just think of what would happen if your final drive locked up......declutching won't help.....

chollo9 · 01-29-2013, 04:52 AM

Like chasbmw says, transmissions are risky places to lighten.

Weight savings is always about the sum of little bits (bites?), but in some places reliability and maintenance aren't good tradeoffs. I would want to talk to a rear end specialist prior to removing any metal.

There's weight to be saved in the hub, I think.

Airhead Wrangler · 01-29-2013, 05:34 AM

The gears are heavy, but out of a total weight of 17 pounds they only account fo about 6 pounds, so theres a lot of metal just in the housing.

disston · 01-29-2013, 04:41 PM

Leave off every other nut, bolt or stud.

Leave out the rear brake shoes and other parts of the brakes.

Leave off every other spoke on the rear wheel.

Buy a skinny tire.

Of course you could also buy a Honda?

RonZacapa · 01-30-2013, 09:43 AM

The sum of parts is all in the unsprung weight. When I went from a tubed tyre to tubeless and junked the heavy duty tube on the rear wheel on my 1985 R80 monolever I threw away 3.65 lbs of weight. I would rather look at weight savings elsewhere on the bike, it can be done.
R80 Monolever roadbike = 175kg dry with an empty tank (385lbs for you imperial guys) I got another 6kg to go - 169kg no fuel. However I will not be reverse engineering important mechanical bits & pieces I know not much about. If you are obsessed with weight reduction (so am I) lets start with the easy bits.

Airhead Wrangler · 01-30-2013, 10:16 AM

The point here though is that it's not JUST weight reduction, but suspension performance as well.

Prutser · 01-30-2013, 01:11 PM

Quote:

Originally Posted by Airhead Wrangler

The point here though is that it's not JUST weight reduction, but suspension performance as well.

I know that the suspension performance is his main purpose.

supershaft · 01-30-2013, 02:13 PM

I believe the later FD's are heavier. Dr. Curve's modification is about all you can do. The gears are too hard to work with. I would leave the internal oil baffling alone. If I know Dr. Curve, that's a magnesium wheel. THAT's the solution. I wish it wasn't such a pricey solution!

Dmaster · 02-12-2013, 01:39 PM

Quote:

Originally Posted by supershaft

I believe the later FD's are heavier.....

Later? twin shocks vs mono arms vs para levers?
Tell me more, i wanna know all

Quote:

Originally Posted by supershaft

....that's a magnesium wheel. THAT's the solution. I wish it wasn't such a pricey solution!

I'm into offroad,. somehow I want spoke wheels in a offroad. Don't know why either.

AliBaba · 02-12-2013, 02:09 PM

Gjendem's bike has a lighter final drive and gearbox (and loads more). There are some pics here but they don't show the details: http://advrider.com/forums/showthread.php?t=30044

HPN has also done the same thing, there is a crappy picture of a modified gearbox somewhere at www.hpn.de

jackass dave · 02-12-2013, 03:03 PM

how about the rider going on a diet ,that would lighten the overall weight !!!

01-28-2013, 05:22 AM	#1
Dmaster ^OP Adventurer Joined: Apr 2012 Location: Netherlands. Oddometer: 68	Final drive weigth reduction I've searched the internet and this forum but couldn't find any info I'm looking for. Did anyone ever tryed to get some weigth out of the final drive? Does anyone know of someone doing it? Any picturs available? What could you take away, drill/machine/whatever?

01-28-2013, 05:35 AM	#2
JonnyCash turd polisher Joined: Jan 2011 Location: Midcoast, Maine Oddometer: 774	I've seen people put holes in the aluminum housing, but i think that's more for the look than anything else. I'd imagine that one could pare some weight from the ring gear, like you would with a flywheel. That said, when I pick up a BMW final drive, I feel like it is pretty light, for what it is. Go pick up one from a Guzzi, it's much heavier, and then you'll be happier with the weight of the BMW part! __________________ I wouldn't bring her home to Mama, but Mama ain't home tonight.

01-28-2013, 11:29 AM	#3
Big Bamboo Studly Adventurer Joined: Sep 2010 Location: Big Island of Hawaii Oddometer: 824	Jim Roche aka "Dr. Curve" did some lightening of his White Dog racer. Not a huge weight savings, but it is some... __________________ "No hour of life is wasted that is spent in the saddle." =Winston Churchill=

01-29-2013, 02:42 AM	#5
chasbmw Beastly Adventurer Joined: Feb 2006 Location: Bath Uk Oddometer: 1,010	The later final drives look lighter. Just think of what would happen if your final drive locked up......declutching won't help..... __________________ Charles http://i46.photobucket.com/albums/f1...ps6e61ae2e.jpg R90s 1070 replica, R90/6 1971 Commando Fastback

01-29-2013, 04:52 AM	#6
chollo9 Screwed the Pooch Joined: Jul 2003 Location: Silk Hope, NC Oddometer: 496	Like chasbmw says, transmissions are risky places to lighten. Weight savings is always about the sum of little bits (bites?), but in some places reliability and maintenance aren't good tradeoffs. I would want to talk to a rear end specialist prior to removing any metal. There's weight to be saved in the hub, I think. __________________ If your gonna be dumb, you gotta be tough When you get knocked down you gotta get back up, I ain't the sharpest knife in the drawer but I know enough, to know, If your gonna be dumb, you gotta be tough

01-28-2013, 02:02 PM	#4
Dmaster ^OP Adventurer Joined: Apr 2012 Location: Netherlands. Oddometer: 68	The housing (is that the right name?) isn't the heavy part its the "gears" why not cut the red parts?: this isn't gonna help much but why is it here anyway? I'm sure I can get some material of the small gearing but how much will it be. Someone must have tried this before. I know about "lightweight gearboxes" (drilled holes in anything) why not the final drive

01-29-2013, 05:34 AM	#7
Airhead Wrangler More tacos than you Joined: Mar 2008 Location: Manzanillo MX, occasionally Seattle Oddometer: 5,127	The gears are heavy, but out of a total weight of 17 pounds they only account fo about 6 pounds, so theres a lot of metal just in the housing. __________________ R80ST Gets The HPN Treatment Ducati Pantah 500SL Rebuild Seattle to TDF on an airhead WTB R100R Mystic sidestand and mount.

01-29-2013, 04:41 PM	#8
disston ShadeTreeExpert Joined: Mar 2011 Location: Silver Spring, Md Oddometer: 5,027	Leave off every other nut, bolt or stud. Leave out the rear brake shoes and other parts of the brakes. Leave off every other spoke on the rear wheel. Buy a skinny tire. Of course you could also buy a Honda? __________________ Never memorize something you can look up. ---Albert Einstein

01-30-2013, 09:43 AM	#9
RonZacapa Adventurer Joined: Mar 2011 Location: Durban - East Coast of Africa Oddometer: 28	The sum of parts is all in the unsprung weight. When I went from a tubed tyre to tubeless and junked the heavy duty tube on the rear wheel on my 1985 R80 monolever I threw away 3.65 lbs of weight. I would rather look at weight savings elsewhere on the bike, it can be done. R80 Monolever roadbike = 175kg dry with an empty tank (385lbs for you imperial guys) I got another 6kg to go - 169kg no fuel. However I will not be reverse engineering important mechanical bits & pieces I know not much about. If you are obsessed with weight reduction (so am I) lets start with the easy bits.

01-30-2013, 10:16 AM	#10
Airhead Wrangler More tacos than you Joined: Mar 2008 Location: Manzanillo MX, occasionally Seattle Oddometer: 5,127	The point here though is that it's not JUST weight reduction, but suspension performance as well. __________________ R80ST Gets The HPN Treatment Ducati Pantah 500SL Rebuild Seattle to TDF on an airhead WTB R100R Mystic sidestand and mount.

01-30-2013, 02:13 PM	#12
supershaft because I can Joined: Sep 2010 Location: San Francisco Bay area Oddometer: 6,082	I believe the later FD's are heavier. Dr. Curve's modification is about all you can do. The gears are too hard to work with. I would leave the internal oil baffling alone. If I know Dr. Curve, that's a magnesium wheel. THAT's the solution. I wish it wasn't such a pricey solution!

02-12-2013, 02:09 PM	#14
AliBaba Gnarly Adventurer Joined: May 2005 Location: Norway Oddometer: 298	Gjendem's bike has a lighter final drive and gearbox (and loads more). There are some pics here but they don't show the details: http://advrider.com/forums/showthread.php?t=30044 HPN has also done the same thing, there is a crappy picture of a modified gearbox somewhere at www.hpn.de AliBaba screwed with this post 02-12-2013 at 02:49 PM

02-12-2013, 03:03 PM	#15
jackass dave Adventurer Joined: Jan 2008 Oddometer: 66	how about the rider going on a diet ,that would lighten the overall weight !!!

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