Conversion from SWB to LWB swing arm--is it worth it?

schrader7032 · Post by **schrader7032** » Fri Jan 23, 2009 7:25 am

There was recent discussion on the MOA board about this. It takes a few additional parts besides the swingarm itself. You'll need a new rear subframe plus a new brake rod. With the lengthening, you could also upgrade the size of the battery...needs a new tray and supports.

The LWB should provide more stability, but the SWB is more nimble when turning given the difference in geometry. If there's some straight line instabilities at speed, going to LWB would help that. However, if there's some instability, that should be fixed first rather than putting a bandaid on it with the new swingarm. Check steering stem bearing tightness, fork stiction, rear shocks, swingarm bearings for proper greasing and centering, tire pressures, etc.

I don't have any direct experience with this conversion. However, I have a /2 which is similar in its short wheelbase. The nimbleness of the /2 compared to my /7 is quite noticeable. I like the different feel...

Kurt in S.A.

drax · Post by **drax** » Fri Jan 23, 2009 11:41 am

Kurt, great feedback about the handling differences. I wasn't aware of the nimble factor/benefit of having a SWB.

I just acquired and haven't even haven't even ridden this toaster yet, so I don't even know how it handles at higher speeds. It doesn't even run! Maybe I'm getting ahead of myself with this MOD? Hmmmm...

I'm thinking I should just leave it be, since there are other things on the bike that are in more need of attention--carb overhaul, new battery, new tires, changing all the fluids, mufflers that aren't rusted out and a thorough cleaning.

I can get all the components you mentioned, so I'm still debating this conversion. Anymore feedback would be appreciated!

mearns4389 · Post by **mearns4389** » Tue Jan 27, 2009 6:13 pm

I have an old guitar. I brought it to a luthier one time for some upgrades. He looked in side and pointed at an old orange label and said "do you know what that label says to me, it says 'I am old, leave me alone' if you want that new stuff,sell this guitar and buy one with the stuff you want". The guitar is still original. There are pros and cons to the short wheel base, but they don't make them any more. It might be a shame for some one who wants one, to have one less in the world. I think many road racers prefere the SWB. I just bought a /5 SWB but only took it for a short ride before taking it apart (see wireing harness post) It felt great. Some day I'll ride it enough to compare it to my /6 and I'll report back to you. -Bill

thaemlitz3321 · Post by **thaemlitz3321** » Tue Apr 07, 2009 3:21 pm

For a naked toaster I'd think a SWB would be more desirable due said handling characteristics. Road many of miles on a '71 R75/5 loaded with Avon fairing, bags, trailer, etc. Handled way better than the same era Honda 750. I think guy's prefer the LWB for touring. A cool mod might be swapping the front drum for some later period disk brake forks. But I'd just get her running and figure out the wild stuff as necessary.

VBMWMO · Post by **VBMWMO** » Mon Feb 15, 2010 2:52 pm

I'm considering replacing my short wheel base (SWB) swing arm on my '73 75/5 to a long wheel base (LWB) swing arm. It would apparently add 2.5" to my wheel base. Anyone have any experience with the conversion and also the difference in handling? Should I go for it? thx

Vintage BMW Motorcycle Owners