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Old 05-06-11, 04:51 PM
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Originally Posted by qmsdc15 View Post
badger, interesting info about "sag". I've heard about sag in reference rear suspension, but I did not know suspension forks were intended to sag. I don't have a lot of experiernce with suspension forks. I had a first generation Cannondale Headshock, that definitely did not sag, and what you'd probably describe as a silly/bouncy cheap toy fork (which does seem to sag a little bit) on my newest bike.
Hi, qmsdc15 ... yep, they is! I'm certainly no expert by any means, but I did learn a little about this the past few years. Kind of from necessity; until this past year my main/only bike has been a 'hybridized' hardtail, that I liked and still like very much using on-road, and I was always looking for ways to make it more efficient.

The idea, really, is that like any active suspension the fork (just like a rear suspension) will be more responsive if it 'sits' a little ways into its travel (all bicycle sus forks suffer from some degree of 'stiction' from their seals/bushings), and can 'extend' into depressions in the surface as well as compress in response to bump forces, thus increasing continuous contact with the surface and hence handling/steering.

'Silly bouncy things'?? I certainly didn't/don't have any particular brand or model in mind, but it is fair to say I think that good bicycle suspension is inevitably expensive. Consequently, the forks often supplied on relatively inexpensive bicycles are necessarily not especially good, and are almost always heavy -- there's just not enough margin to allow something decent even at OEM pricing. Weight apart, the usual most obvious failing is inadequate rebound control -- hence 'silly bouncy'! That in particular is what many people not familiar with really good bicycle suspension quite rightly are thinking of when they say that on-road suspension is unnecessary.

And that is to some extent true, although ... I think to be more accurate one might say that 'active' suspension is arguably not necessary; the fact is of course that all modern bicycles have and depend on 'suspension' -- pneumatic tires. The real question is not whether suspension is necessary, but rather how much suspension travel is necessary when riding on-road. Most cyclists who stick to relatively smooth surfaces find that tires are sufficient -- I now include myself in that group -- but some do prefer a little bit of additional suspension, especially re. bumps/cracks/potholes. And I have to confess that I do sometimes wish I could afford something like a Moulton -- I once had the pleasure of being able to take a beautiful Moulton road bike out for an hour or so ... the combination of light weight, quickness, and 'cush' was really quite something! Oh well!
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