Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 28 Post(s)
Tagged: 1 Thread(s)
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Originally Posted by FastJake
Your logic makes sense, but I thought the old steel forks were less rigid? I've ridden some older bikes where hammering the front brake makes the fork dive back. I thought they eliminated this (because people were scared of seeing their forks bend?) with the newer forks by making them stiffer.
It's not a matter of total rigidity, but the nature of flex. Steel forks tend to flex in the blades, where it doesn't affect braking. They're very rigid from the upper blades, through the crown and steerer.
Also the tops of the steel blades where the bosses are attached are very stiff. If you look at an older high quality steel fork with canti's you'll see less outward movement of the bosses when brakes are applied compared to many newer forks.
Then there's the effect of threadless headsets and stems mounted above multiple spacers, compared to threaded headsets with quill stems that buttress the steerer deep below the upper bearing.
Obviously you can't translate the general to specific bikes, so you have to deal with each bike as it actually is.
My commuter has an alloy fork, quill stem and locknut mounted brake hanger, and has zero modulation issues. I see others with similarly built forks, but with threadless headsets, and they have issues.
I believe the problem has multiple causes which work in combination, and while one or two might not cause shuddering, multiple ones will.
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Last edited by FBinNY; 08-24-11 at 10:28 PM.