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-   -   R11xxGS subframe reinforcement (https://www.horizonsunlimited.com/hubb/bmw-tech/r11xxgs-subframe-reinforcement-33408)

Doubledown 26 Feb 2008 17:17

R11xxGS subframe reinforcement
 
I am prepping an 1150 Adventure for a S.American / African trip. I am concerned about the subframe. I have read too much about frame fractures on the road. I will be riding solo, and don't plan on carrying a ton, but while I have the time and resources, I would like to do as much prevention as possible. Question: where are the points on the frame that commonly need reinforcement? Also, is there any reason not to weld on the Touratech pannier frame- at the bolted attachment points, to the frame? Thanks a bunch

Margus 26 Feb 2008 18:47

For solo and not carrying a ton - you don't need to IMHO. I'm currently adding additional welds on my 1100s subframe (same as 1150), but only because I'm two up and loads of luggage. I wouldn't do it if I was going solo, they're very strong - see the carrying capacity of R11xxGSes, which is over 200kg. Of course, this is measured w/o long term potholes and vibrations in mind. If you go around half as that, it'll keep up even with the worst of road conditions IMHO.

Just DO NOT use any top box. Leave it home. Shaking-vibrating solid top boxers are one of the main reasons of broken subframes.

If pannier's aren't enough then use a waterproof luggage roll instead, and place it on pillon's seat - more close to the centre of mass, less stress on the rear subframe, better maneuverability of the bike too.

Happy travels! :)

Doubledown 26 Feb 2008 20:43

Thanks, definitely no top box. I have heard that when adding the pannier frames, that you have altered the integrity of the original design in the way the subframe is meant to flex, thus redirecting the forces to weaker spots on the frame (?) Maybe I am overthinking things. At the very least, this will keep me from over packing. Thanks.

Margus 27 Feb 2008 08:03

Yes, better not to overthink things.

I reckon decent rebuildable suspension, decent hand guards, maybe light cylinder protection and Hard Parts (for telelever only on 1150) are higher priority than the rear subframe in your case :)

Ride safe, Margus

fernan_ci 3 Mar 2008 00:31

anyway if you want to reinforce the rear subframe, I recomend this and will be bombproof:

http://img84.imageshack.us/img84/1350/22329585pb1.gif

http://img220.imageshack.us/img220/8846/22449554ld4.jpg

http://img215.imageshack.us/img215/4650/62843379tz8.jpg

http://img215.imageshack.us/img215/1037/27672615hr7.jpg

http://img220.imageshack.us/img220/8442/90926190ml7.jpg

Margus 3 Mar 2008 07:01

Now that is tough :)

But maybe a bit of an overkill from the sideframes side, since if you reinforce the sideframes, the "weak spot" of the chain in comparison will be the suspension upper support in the center of the frame. "A strong chain is no good when it has even only one weak link".

I'm using an analogy from Hame's blog: http://www.horizonsunlimited.com/tst...em/2007_12.php

They're 2 up full of luggage and taking loads of dirt roads. They've reinforced their subrframe on the road, but then the upper suspension support gave up. Here's their cracked suspension support:

http://www.horizonsunlimited.com/tst...s/crrrrack.JPG

Looking at their blog indeed they take LOADS of dirt roads. More than any average 2 upper would ever risk IMHO, and that 1100 takes huge beating with all that mass and the bad roads below. But that's a proper adventure IMHO too. :)

I'll try to post the pics when I've got my frame done and repainted. I'm reinforcing a more minimalistic compared to that. Going as light as I can - also replacing stock exhaust with aftermarket, which will give me about 6-7kg weight saving compared to stock. And IF it does brake even with those mods, I'll reinforce it more massively (probably something close as the pics you posted), but then also I'd need to reinforce the suspension upper support, so that there's no weak spot in the "chain".

Ride safe, Margus

gsworkshop 3 Mar 2008 18:51

If you have watched the Long Way Round you will see that the sub frames on these bike do pose a real problem.
They all did have heavy top boxes fitted though.
You will also see how not to fix the problem when it does happen.

Preparing your bike before hand is wise though and the suggestions by fernan looks good except that the gussets looks big and heavy and welding is done right through.
A seemingly insignificant little plate added in the right place with TIG welding only every 2cm for 2cm long will make the frame near unbrakeable in that area.

AliBaba 3 Mar 2008 19:34

The guys from LWR carried far too much stuff, it would have broken the subframe of any bike. To use a top-box is close to the worst thing you can do to any bike; both for handling and for the subframe itself.


Quote:

Originally Posted by gsworkshop (Post 177813)
Preparing your bike before hand is wise though and the suggestions by fernan looks good except that the gussets looks big and heavy and welding is done right through.
A seemingly insignificant little plate added in the right place with TIG welding only every 2cm for 2cm long will make the frame near unbrakeable in that area.

Funny I was thinking the same myself ;-)

Em and Hame 4 Mar 2008 02:05

Frame supports
 
Quote:

Originally Posted by Margus (Post 177694)

I'm using an analogy from Hame's blog: http://www.horizonsunlimited.com/tst...em/2007_12.php

They're 2 up full of luggage and taking loads of dirt roads. They've reinforced their subframe on the road, but then the upper suspension support gave up. Looking at their blog indeed they take LOADS of dirt roads. More than any average 2 upper would ever risk IMHO, and that 1100 takes huge beating with all that mass and the bad roads below. But that's a proper adventure IMHO too. :)

Thanks for the reference Margus. Below shows where I've reinforced the sub-frame. The above gusset was installed in Kununurra, Australia after numerous corrugated roads; the below gusset (cut from a shelf support!) was installed in Buenos Aires after Bolivian roads took their toll.

http://www.horizonsunlimited.com/tst...latestweld.JPG

I'd agree with gsworkshop, no need to go berserk with heavy plates and full welds, despite what I've ended up with.

Good luck,
Hamish

mother77 4 Mar 2008 22:41

If you have the time and access to a good welder, i would reinforce it. This is speaking from experience.

I have an R850GS in South america. I binned it in The atacama desert in north Chile and that didnĀ“t do the sub frame any good. Possibly starting a hair line fracture. But Bolivia and Peru with quite a lot off road finished it off. One side of the subframe snapped half way between arequipa and cusco on a mining track, 300km from any where useful. rode 100km to get back to the road with luggage straps to hold the frame together. then the other side went 100m from the tarmac Luckily a police man comandered a truck for me!. was riding solo , 2 Jesse panniers and a large role bag. quite a lot of stuff , weighing 35 kg in total + me at 90-95kg. but i have seen folks with more!

Got it repaired in Arequipa with help from friends for $10 but was a B****H to get the frame to fit again as it was bent and warped after riding it and welding it.

met 2 other riders down here with same problem. Bolivia and it corragations can kill anything!

cheers
mike

mother77 4 Mar 2008 22:42

Ps
and it is no where as neat as the photos above.

I would be embarrased to post the photos ;o)

Margus 7 Mar 2008 19:27

Hamish,

mine is basically the same as yours, just I have the rear brake line support attached still. Looks like welding guys think the same way :)

http://i104.photobucket.com/albums/m...S/DSCN1779.jpg

http://i104.photobucket.com/albums/m...S/DSCN1781.jpg

Let's see how it holds up.

Ride safe, Margus

desert dweller 22 Mar 2008 01:17

we are two up, on dirt all the time.

my subframe cracked as result of running on a pogo busted shock for about 1000km. tho no photos handy, the gussets i had welded are in the same places as the above photos, at bottom of subframe between the very bottom tube and the footpeg hangers. 3mm steel and about 22mm wide.

don't have the top gusset, about the join though.

cheers,
andy

Warthog 22 Mar 2008 22:27

Quote:

Originally Posted by Doubledown (Post 176838)
I am prepping an 1150 Adventure for a S.American / African trip. I am concerned about the subframe. I have read too much about frame fractures on the road. I will be riding solo, and don't plan on carrying a ton, but while I have the time and resources, I would like to do as much prevention as possible.

I think there are better ways to spend money on prepping you bike, or putting the cash toward the trip itslef. We were two up on an 1150GS. We also had two panniers, two roll-bags, a tank bank, a topbox (I know there are some who dislike them but, if you are two up, 15 kg in a rollbag across the backrack and 15 kg in a topbox are not that different in my book, except one is secure!) and a rucksack!!

Yes we did over pack, and got rid of stuff on the way, but the bottom line is the bike was weighing in at 450kg with us on board. The back wheel was trasnferring 300kg to the road!! We had not problems.

Admittedly, we did not do as much off-road as you are likely to find in Africa, but if you even manage to pack 50kg, which is a lot for one person, that is still the equlivalent of a light pillion and no luggage at all!! I reckon you'll be OK.

Enjoy the trip!


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