Go Back   Horizons Unlimited - The HUBB > Technical, Bike forums > BMW Tech
BMW Tech BMW Tech Forum - For Questions specific and of interest to BMW riders only.
Photo by Daniel Rintz, Himba children, Namibia

The only impossible journey
is the one
you never begin

Photo by Daniel Rintz,
Himba children, Namibia



Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 9 Apr 2005
Registered Users
Veteran HUBBer
 
Join Date: Nov 2001
Location: Paris, France
Posts: 655
R80G/S front forks

hello,
i saw the interesting messages on r80g/s rear shock.
i wonder how to make the r80g/s front forks better, if possible to change them ?
i ve heard we can put wp springs which is a good start, put r100gs front forks which are much better than the r80g/s original ones.
what else is possible ? wp ohlins etc ... ? any ideas, experience ?
cheers
happy trails ?


__________________
--
Vincent Danna

* www.va-project.com
Sept 2008 - dec 2009 : Voyage et art contemporain en Amérique du sud.

* http://vincent.danna.free.fr/
2002 - 2004 : Un tour du monde en moto.
Reply With Quote
  #2  
Old 9 Apr 2005
Grant Johnson's Avatar
HU Founder
Veteran HUBBer
 
Join Date: Dec 1997
Location: BC Canada
Posts: 7,216
You can significantly improve the stock forks with good springs, ND use 7.5 w quality fork oil.

Next step is R100GS forks, bolts straight in BUT you must also change the front wheel. Not a bad thing, you get a tubeless front tire then. Again use good springs, and oil, and you can also put an upgraded valving in, which makes a big difference I'm told - haven't tried it myself. I think it's a worthwhle upgrade. Note the stock G/S forks are weak, and have been known to snap just below the lower fork yoke. Exciting...
The stock fork legs should never be straightened if bent, just replaced.

Next step is WP or almost any dirt bike fork - BUT you then should lengthen the swing arm and rear shock to balance the ends. For long distance travel not worth it. For turning a G/S into a desert bike, that's the way HPN went with the BMW Dakar bikes. If that's what you want, go for it!
__________________
Grant Johnson
Seek, and ye shall find.

------------------------
Inspiring, Informing and Connecting travellers since 1997!
www.HorizonsUnlimited.com
Reply With Quote
  #3  
Old 9 Apr 2005
Gold Member
Veteran HUBBer
 
Join Date: Mar 2001
Location: British Columbia
Posts: 246
Scroll down the previous posts, as there has been lots of discussion about improving the front forks. R100GS forks are an easy and decent upgrade: both Grant and I (and several others) have gone that route with good results.

Lots of different forks can be added, with varying amounts of work required to make them fit and operate properly. HPN fits bolt on WP forks that feature longer travel. I have also heard of someone who used a Showa fork off a Suzuki RM 125 that bolted on with minimal work (of course he had to change the brakes, and springs).

I have heard of poor results adding a long travel motorcross fork without increasing the rear suspension. HPN lengthens the rear swing arm/ drive shaft to achieve this (now you have a tall bike!).

Personally, I think the R100GS forks offer a decent upgrade that will(coupled with a good quality rear shock) raise the handling ability to the limits of the rest of the stock chassis. If you want to go further then you might want to think about sending your bike to HPN for a fully integrated upgrade to the frame and suspension.

As a word of advise, if you do look for a R100 fork, try to get the front wheel, axle, and brake setup as well. This makes it an easy bolt on otherwise you are in for lots of work converting the old wheel to the new forks.

Good luck!
Reply With Quote
  #4  
Old 9 Apr 2005
Gold Member
Veteran HUBBer
 
Join Date: Mar 2001
Location: British Columbia
Posts: 246
I think Grant and I must have been typing at the same time!

[This message has been edited by Timo (edited 08 April 2005).]
Reply With Quote
  #5  
Old 10 Apr 2005
Registered Users
Veteran HUBBer
 
Join Date: Jul 2002
Location: Alexandria
Posts: 426
thanks alot vencint fot your info
can you tell me do you still have the rear susp.for the g/s???
or any where i can buy used susp.in france??
thanks alot ,i did coverd most of the places in fracne on bike few times ,its great ,if no rains
Reply With Quote
  #6  
Old 10 Apr 2005
Registered Users
Veteran HUBBer
 
Join Date: Nov 2001
Location: Paris, France
Posts: 655
omar, i replied to you on the r80g/s rear shock forum
__________________
--
Vincent Danna

* www.va-project.com
Sept 2008 - dec 2009 : Voyage et art contemporain en Amérique du sud.

* http://vincent.danna.free.fr/
2002 - 2004 : Un tour du monde en moto.
Reply With Quote
  #7  
Old 10 Apr 2005
Registered Users
Veteran HUBBer
 
Join Date: Nov 2001
Location: Paris, France
Posts: 655
Thanx for your replies.
I ve heard about changing oil (put a thicker one) and putting stronger springs like WP ones : that s what i did actually with my R100 GS PD when i was travelling around. And you do feel the difference.
Now about my R80G/S : the easiest would be to put R100 GS front forks, change oil and put stronger springs. What are the brands, models, lengths, diameters of the R100 GS and the R80G/S forks ?
A friend of mine (I met him in India : pictures on http://vincent.danna.free.fr/surlaro...decembre.html) is driving now a full HPN : he gave his R80G/S, ordered, waited for 2 years at HPN, he paid a big bill to get it transformed into a HPN: he has now a 300 mm Marzocchi M1 front forks, the rear swing arm was transformed (made longer).
Those top end forks, like Marzocchi, WP, Ohlins can be found second end quite cheap, when they come from KTM bikes or other cross/enduro bikes, which can be really exciting. But to put them on a R80G/S, as you wrote, there are a lot of modifications to be done (wheel, brakes, bearings, …) and when they are much longer than the original BMW forks, you need to make the spring arm longer to balance the bike and avoid damaging the gearbox, driveshaft and final drive. Also, I have the feeling that only a specialist or professional can do this.
I d like to know if there could be an alternative with short (like the original BMW length or just a bit longer) top end forks, like Marzocchi, WP, Ohlins : which models could be used ?
If anyone has done this before, any experience to share …
Thanx
Happy trails

NB : this friend with the HPN told me about other companies that can prepare/change your bike :
http://www.wuedo.de/menu_main/menu_main.html
http://www.witec-motorsport.de/
and SCHECK : but couldn t find the website
__________________
--
Vincent Danna

* www.va-project.com
Sept 2008 - dec 2009 : Voyage et art contemporain en Amérique du sud.

* http://vincent.danna.free.fr/
2002 - 2004 : Un tour du monde en moto.
Reply With Quote
  #8  
Old 1 Jun 2005
Registered Users
New on the HUBB
 
Join Date: May 2005
Location: Dubai UAE
Posts: 13
Im also very curious to hear about the above question, as here in Dubai I'll find motocross forks mutch easier than R100G/S forks. Id like a taller bike but am woried about the complications/cost of raising the rear.
Reply With Quote
  #9  
Old 1 Jun 2005
Registered Users
Veteran HUBBer
 
Join Date: Nov 2001
Location: Paris, France
Posts: 655
the best would be to find a bike already equiped :-)

otherwise, the most reasonable would be to put r100gs forks, but then you need to change the front wheel, the front brakes : so already pricy.

for the famous front forks like marzocchi (magnum model), ohlins (couldn t find which model ?)and wp (couldn t find which model ?) :
- amazingly pricy (something like 3 000 euros even more with wheel, brake, all the accessories !) unless you find a good second hand one
- because they are longer than the original, you need to make the swing arm / driveshaft longer, otherwise bike balance / driving problems, if you don t you damage the rear (final drive, driveshaft, gearbox).

so, for an old bike like a r80g/s (worth around 3 000 euros let's say), it s a lot of money for those improvements + then after you ll may want to improve all the "weak" rest : chassis, etc ...
it s like putting a ferrari engine in a citroen 2cv car :-)


__________________
--
Vincent Danna

* www.va-project.com
Sept 2008 - dec 2009 : Voyage et art contemporain en Amérique du sud.

* http://vincent.danna.free.fr/
2002 - 2004 : Un tour du monde en moto.
Reply With Quote
  #10  
Old 5 Jun 2005
BCK_973's Avatar
Registered Users
Veteran HUBBer
 
Join Date: Mar 2005
Location: Buenos Aires,City of good sex,mate and asado!
Posts: 539
Vincent
I had in Germany a G/S 84 build.After a few months decided to upgrade my bike.Put a Acerbis 43l Tank,Whithe Power shock, and removed the useless fork!
Baugth a newer GS forkbridge and installed a DR 650 wheel and fork with the complete brake.
It was easy installed and worked perfect for many years.I sold the bike with 280.000!
The parts where used ones!
Bye
KH
__________________
http://vientoderipio.blogspot.com/
America is a nice continent,not a country.All people who lives in this continent are americans.Discover it in peace!
Reply With Quote
  #11  
Old 5 Jun 2005
Registered Users
Veteran HUBBer
 
Join Date: Nov 2001
Location: Paris, France
Posts: 655
thanx for your post, good to hear about alternatives, adaptations, creativity :-)
other working doable experiences ?
__________________
--
Vincent Danna

* www.va-project.com
Sept 2008 - dec 2009 : Voyage et art contemporain en Amérique du sud.

* http://vincent.danna.free.fr/
2002 - 2004 : Un tour du monde en moto.
Reply With Quote
  #12  
Old 11 Jun 2005
Gold Member
Veteran HUBBer
 
Join Date: Mar 2001
Location: British Columbia
Posts: 246
As I mentioned before, there was a post about this a year or so back....
I believe that someone had put a late model RM125/ RM250 (Showa?) inverted fork on a G/S. This was a bolt on modification, or close to it, with the major work being a change to heavier fork springs (due to the extra weight), and of course wheels and brake.

Again, I would follow Grant's suggestion that substantial front end and rear end modifications be done as a package. going to 300mm of travel on the front end while keeping the stock rear shock and swing arm setup could really upset your bikes handling. HPN sells a longer monolever for this setup.


[This message has been edited by Timo (edited 11 June 2005).]
Reply With Quote
  #13  
Old 11 Jun 2005
Registered Users
Veteran HUBBer
 
Join Date: Nov 2001
Location: Paris, France
Posts: 655
sorry, for being lazy and not searching in the past posts :-(
as usual, there s a lot on the hubb and it s worth doing a quick search before posting :-)

i found this, among other posts (20 all together) :
http://www.horizonsunlimited.com/ubb...ML/000057.html
http://www.horizonsunlimited.com/ubb...ML/000203.html
http://www.horizonsunlimited.com/ubb...ML/000158.html

definitely, if you put a 300 mm top end forks for on a r80g/s, you ll have a kind of "chopper" riding style, which is not what you want when travelling around especially, if you don t modify the rear (make the swing arm longer, put a longer shock absorber etc ...), hpn style.

would it make sense to put a 300 mm top end forks (if you find a cheap one!) and install it (if possible ?) with the same length as the r80g/s forks, meaning that the tubes of this 300 mm top end forks would top or go beyond the upper t plate (because they are much longer than the original ones) ?

also, is there a length difference between the r80g/s forks and a r100gs forks ?
for the moment, i ve read :
r80g/s : wheel axel diameter = 17mm, forks tubes diameter = 36 mm, brake disk diameter = 260 mm
r100gs : wheel axel diameter = 25mm, forks tubes diameter = 40 mm, brake disk diameter = 285 mm
therefore if you put a r100gs forks on a r80g/s, you need to change also the front wheel and the front brake system

thanx
__________________
--
Vincent Danna

* www.va-project.com
Sept 2008 - dec 2009 : Voyage et art contemporain en Amérique du sud.

* http://vincent.danna.free.fr/
2002 - 2004 : Un tour du monde en moto.
Reply With Quote
  #14  
Old 11 Jun 2005
Registered Users
Veteran HUBBer
 
Join Date: Nov 2001
Location: Paris, France
Posts: 655
would it make sense to put a 300 mm top end forks (if you find a cheap one!) and install it (if possible ?) with the same length as the r80g/s forks, meaning that the tubes of this 300 mm top end forks would top or go beyond the upper t plate (because they are much longer than the original ones) ?

impossible : just took a look at the bike, there s not enough space because of the handlebars.
__________________
--
Vincent Danna

* www.va-project.com
Sept 2008 - dec 2009 : Voyage et art contemporain en Amérique du sud.

* http://vincent.danna.free.fr/
2002 - 2004 : Un tour du monde en moto.
Reply With Quote
  #15  
Old 11 Jun 2005
Gold Member
Veteran HUBBer
 
Join Date: Mar 2001
Location: British Columbia
Posts: 246
Well...

the reason for longer forks is to alow a softer spring (which can be softer because it has a longer stroke to absorb the energy from a bump). This means the fork can be soft enought to respond to small bumps, but still have the travel to take a big hit. If you reduce the length of the shock by lifting it in the triple clamps (which would be possible it you repositioned the handlebar - yes spacers are available) then you would need to reduce the travel of the fork by limiting the stroke with shorter/ stiffer springs. Dirt bikes that are converted to dirt track/ super motorrade (sp?) often go this route.

I think the main issue remains matching the front with the rear. Yes the R100GS forks are a bit longer, but not enough to upset the handling of the bike.

The way to do this conversion is to get a full front end, with brake, wheel, and forks. This way the only issues becomes matching a master cylinder to the new caliper. BMW sells lots of different sizes that bolt onto the stock lever. You might also run into problems getting the headlight, indicator lights, and guages to fit on, but this is all do-able. The advantage of the R100GS fork is that everything more or less bolts on in the right spot.

Reply With Quote
Reply


LinkBacks (?)
LinkBack to this Thread: https://www.horizonsunlimited.com/hubb/bmw-tech/r80g-s-front-forks-8209
Posted By For Type Date
airhead dirtbikes ??? - Page 16 - ADVrider This thread Refback 14 Feb 2007 11:12

Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


 
 

Announcements

Thinking about traveling? Not sure about the whole thing? Watch the HU Achievable Dream Video Trailers and then get ALL the information you need to get inspired and learn how to travel anywhere in the world!

Have YOU ever wondered who has ridden around the world? We did too - and now here's the list of Circumnavigators!
Check it out now
, and add your information if we didn't find you.

Next HU Eventscalendar

HU Event and other updates on the HUBB Forum "Traveller's Advisories" thread.
ALL Dates subject to change.

2024:

Add yourself to the Updates List for each event!

Questions about an event? Ask here

HUBBUK: info

See all event details

 
World's most listened to Adventure Motorbike Show!
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.

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)



Ripcord Rescue Travel Insurance.

Ripcord Rescue Travel Insurance™ combines into a single integrated program the best evacuation and rescue with the premier travel insurance coverages designed for adventurers.

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 travel protection is now available for ALL nationalities, and travel is covered on motorcycles of all sizes!


 

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!



Five books by Graham Field!

Diaries of a compulsive traveller
by Graham Field
Book, eBook, Audiobook

"A compelling, honest, inspiring and entertaining writing style with a built-in feel-good factor" Get them NOW from the authors' website and Amazon.com, Amazon.ca, Amazon.co.uk.



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.

Susan and Grant Johnson 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.




All times are GMT +1. The time now is 09:43.