The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: slickster on August 03, 2011, 11:57:22 AM
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Would a fork brace help. When I pass a tractor-trailer my front end does some strange movements. 84 r65 with rt fairing.thanks in advance.
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If it's an aerodynamic effect I think a steering damper might help more than a fork brace.
A fork brace if needed helps when the forks are under stress in a fast turn.
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It is a light (Relatively) bike with a fairing and a rider on it, going through 70 MPH turbulence - some movement is going to happen. Pass the truck and get into the clean air again as expeditiously as possible. IF your tires are worn oddly, this can contribute to "twitchiness", but probably isn't the case with your R65.
Fork braces are only helpful for going around corners fast, and it is questionable whether the ubiquitous fork braces seen on airheads is actually any better than the brace/fender support that the bike's already have on them.
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Slickster I have an 82 R65ls with an S style fairing on it. I can tell exactly when I hit the "wake" of a tractor trailer rig because I get a slight side to side oscillation as soon as I hit the turbulence. Just roll on some throttle and get by as quickly as possible and it smooths out.
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Fork braces are only helpful for going around corners fast, and it is questionable whether the ubiquitous fork braces seen on airheads is actually any better than the brace/fender support that the bike's already have on them.
A few of the BMW High Gurus & Mavens on other forums and websites believe that an add-on fork brace can contribute to the problem of fork stiction.
Some non-R65 Airheads had a metal plate, rather than the sturdy cast and machined aluminum bit under our handlebars, used as the upper triple clamp. These bike may benefit from a very correctly installed fork brace.
On an R65, a fork brace adds weight and complexity. [smiley=2cents.gif]
Monte
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On those other airheads with the flimsy top plate, I've seen a variety of CNC-machiend aftermarket bits sold to help make things a bit sturdier there. I've also seen people with doubled-up top plates bolted together, as well as the "toaster Tan" upper fork plate. I do think that those bikes benefit from reinforcing the upper part of the fork tubes. Not sure if a fork brace on the lower sliders helps as much, but anything to help keep the fork tubes parallel on those bikes is usually helpful, provided they aren't installed in a manner to provoke stiction.
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I crouch down low and get on the gas. This is where Euro bars come in handy.
But I have no fairing of any kind.
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Would a fork brace help. When I pass a tractor-trailer my front end does some strange movements. 84 r65 with rt fairing.thanks in advance.
No. Your front forks are not large/ridged enough for the load placed on them by the additional weight of the RT fairing and bags. The 1.85" front wheel rim is not wide enough to support the 100/90-18 tire you must have on the front. The 90/90-18 is a poor subsitute for the original and now unavailble 3.25-18 tire that is the stock size. You need a 2.50 inch wide rim and stiffer larger forks.
A fork brace will be a waist of time and money and chances are that you will install it incorrectly. I tried the Telflex brace on my stock R65 forks. It did nothing for the wobbles. At best you can minimize the wobble you are feeling by making sure the swing arm pivot pins are torqued to the upper end of the range torques (but not any more).
I have installed a 1988 K100RS front end with its 2.50-18 alloy rim on the front of my 1980 R65 with its Luftmeister fairing and Givi topcase and panniers. The steering head bearings are the same part number. It cures all the ills you are feeling. The K100RS front end (forks, triple tree and wheel) are 41mm (?) in diameter and make the bike handle like a dream.
Good luck.
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In your situation no a fork brace wont help. But, I am here to say I noticed a huge difference in the handling of my 81 with the addition of my Fork brace(tubular, San Jose) So in the probably doesn't make a difference argument all I can say is it did for me, and it did it WELL.
I say your best bet slickster is to follow Gumby's advice and replace the forks.
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Your biggest problem lies in the fact that you are carrying an RT fairing.
They are heavy and prone to being affected by cross winds.
Sorry but thats just the way it is.
You have to beef your front end up to carry it. And even then it will still be prone to wandering in a cross wind.
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It was my impression that R 65s at some point got a better fork set up than older, larger airheads. The R 65 was not really designed for Autobahn (or freeway) use, at some point you might be better off with one of the bigger ones.
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It was my impression thatR 65s at some point gota better fork set up than older, larger airheads.
The new simpler type of fork fitted to R65's from inception and the same basic fork fitted to other airheads from 81 on is considered inferior in design to the /7 and earlier mainstream airhead forks. The damper valve assembly was the subject of several Service Instructions to fit modified components in the first few years due to complaints of noisy operation. From 85 on the R65 and other airheads were fitted with a different fork of improved design which had larger diameter stanchions.
In general terms the R65 was considered to have better (particularly quicker) handling than the mainstream airheads but that was mainly due to a shorter wheel base. The R65 forks although cruder in terms of the damper design did have less travel and significantly stiffer springs than the earlier airhead forks which will also have helped with the handling if not the comfort.