Triumphrat

Gurthang

Today on the way to work some guy passed me in what, all I could tell, was an old Honda. Of course, I accelerated and the chase was on. After 90+mph the weaving in between lanes got a little unsteady and wobbly for my liking. I know the lane changes I made were more violent than perhaps intended for the bike, as equipped, which is where my question comes in.

It sounds to me that as far as function goes, the dampener and brace both offer stability, but each in a different way, and each a different kind of stability. For the described issue above, is one better than the other? Also, is both a waste of money? I seem to recall reading someone noting that they noticed no difference in going from one to both.

Let's hear it!

Aussiematt

There was a good thread on the Thruxton front end instability a while back which tried to address the effectiveness (or otherwise) of the fork brace, damper, fork mods, tyres. I have progressively done all these and I am happy with the results. For me, the fork brace stopped the tendency for the bike to hunt on rain grooves on highways around SF whilst the damper provided confidence when hitting a pot hole whilst leaned over. My gut feeling is a damper is not so much needed if someone has wide handlebars. I have clip-ons so less leverage and the damper therefore helps. Also at high speed the damper does make travel on the highway more stable. I have heard others say that dampers just disguise a poor front end set up. At the end of the day both seemed to be effective in improving the front end stability on my 04 Thruxton

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2004 Thrux, FCR39's, Uni filter, 813 cams, Works shocks, Ricor fork valves, progressive springs, Pieman ignitor, green clutch springs, GT501s, Beringer caliper, predators, fork damper, fork brace, Corbin gunfighter seat, custom tinware etc

roxythruxton

You say wobble ? Hm . Check the spokes and headstock bolt . Might need some tightening . I know mine does . The wobble will go away .

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Yep. I've got some mods .

Gurthang

Thanks for the info. I'm also sporting the clipons so it sounds like I could benefit from both of these mods.

Yeah I experienced a wobble while slinging into a different lane but my elevation was changing due to a raised/lowered slab of concrete so I think that's what did it. I'll check the spokes though to be sure nothing is loose.

FYI I'm running stock sized AM26's. I also have stock shocks/springs set at the stiffer preload settings (maybe this has something to do with it as well).

ocguyocguy

In my opinion if the stock fender and steel support for the fender is still in place on your bike you do not need the fork brace, that stock fender support acts like a fork brace...the intiminators do have a subtle improvement over stock...the biggest improvement is when you need tires I would suggest the Avon Road Riders. I found the Avons will make more of an improvement than all those other things.
This has been my experience with my Thruxton.
The Metzlers are squirley compared to the Avons.

Coroja

Generally, a fork damper resists the side-to-side oscillation that results from unbalanced forces on the wheel. These are typically problematic when the fork is unweighted due to acceleration, bumps in the road, etc. The wheel can literally bounce from one side to another, which if it occurs at a resonant frequency of the fork assembly, results in the dreaded headshake. No width of bar variations will allow a rider to counteract a real headshake, simply because it occurs too quickly. A steering damper minimizes headshake by offering progressively greater resistance to fork motion depending on the speed at which the fork is turning. In other words, the resistance is relatively low at the speed of rider steering inputs, but high at the speed of bump inputs.

A fork brace resists the tendency of the fork legs to be twisted by cornering (or other) forces. Depending on tire width, compound, bike speed, fork diameter, etc., the fork legs can be twisted so that the wheel axle is not aligned 90 degrees to the steering axis. The amount of misalignment changes with cornering force and results in imprecise steering. This is more commonly a "steady state" condition, rather than a rapid transient condition, such as headshake. However, it can certainly be exacerbated by bumpy pavement. The Bonneville has 41 mm conventional forks, which are not nearly as stiff as a GSX-R 750's 41 mm upside-down forks, but a lot stiffer than the spindly forks fitted to classic British twins. I suspect that a fork brace would have little impact on a modern Bonneville's handling, but I haven't tested that theory myself.

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The people who talk the most generally have the smallest results. Results speak for themselves. - Matt Mladin

sbpark

i have a brace, damper, progressive springs in the front with 15w oil and my front end is very solid/planted. the damper is awesome on the freeway. raingrooves are not even an issue anymore and the front end doesnt feel as light/twitchy as before, especially in the twisties. before the damper my front end was twitchy and unsteady in hard turns. then i added the fork brace which didnt seem to make that much of a difference, but i like the way it looks! lastly, i did the springs and this make another noticable difference. more planted and confident in hard turns. i would say damper and progressive springs in the front with a slightly heavier oil in the front really firms up the from end on these bikes, and the brace would be on the bottom of the list as far as the order i'd do the mods, especially if you are on a budget. also noticed getting rid of the crappy stock metzlers and switching over to sport demons made a huge difference. they may wear out fast, but they are very stick and confidence inspiring. used to feel the rear tire skip out in the back on hard turns, and after new rear shocks and sport demons, brace, damper and progressive springs up front my bike is solid all the way up to 125mph indicated.

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'07 Thruxton, Caspian Blue Checker, FCR's, 813 cams, Pieman ignitor, Predators, ported & polished head...

beemerrich

I have cartridge emulators and fork brace on my thruxton. After installing the emulators, I noticed the front end tracked much better over road imperfections/holds lines better in corners on less than perfect pavement. Front end diving and/or topping out has been eliminated as well. The bike still wanted to wobble in high speed sweepers at that point...

The fork brace helped in that regard, with only the hardest-hit high-speed sweepers now producing any noticable wobble. I was running avon roadriders throughout the above changes. I'm not planning anything further on the suspension for now...I already ride faster than I should, so no need to further facilitate that sort of thing!

YMMV,

--Rich

retroracer

Rich,
Are you using Ricor Intiminators? If not, then what brand are you using? Also, did you keep the stock fork springs or upgrade those too?

Retro-Racer

Don't take this as ballbusting, but at 90+ on the LIE, I don't think any bike on this planet is going to be all that stable.

You're right about a brace and a damper working in different ways but achieving similar results. The stock steel fender brace is better than no brace, or say, just a MAS fender. But a proper fork brace will triangulate the forks and will vastly improve handling especially when the bike is leaning into corners and you hit a bump and/or grab a handful of front brake. A damper will help quell some wobble that is introduced due to areodynamic buffeting... and of course has that cool boyracer look. IMHO, if you have to start somewhere, get a brace.

/Mike
"That's just my opinion folks. I could be wrong." - Dennis Miller