Loose front end

[The_Break]

Edman, where do you still get geo charts for the Fuji? It was a 2005 model, I think. Size was a medium. Six13 is a 54. And interestingly enough, when I picked it up after the build, the comment was made that they put the frames on top of each other and they were remarkably similar ito geometry.

 

Fork: Had a look and the current fork is a "Slice Premium +". Old fork gone with frame. (Personally I'm wondering whether it's not the fork - I hope like héll, actually, since it's something that can be fixed... at a cost, but can be fixed.)

 

Stem: I haven't measured it, but it's a normal stem. My notes from Dr Swart states 100 - he did not change it. Actually, on my road bike setup he changed mm's, all was pretty close to what it should be. But the small changes made the difference.

 

Wheels: also normal ones - Mavic Ksyrium Elite. Taken from old bike.

 

Now for the interesting bit, the balance. Both Edman and The_Break alluded to it.

First off, yes, it does happen on flats as well. On the higher speeds of descends it's just much more noticeable and I feel I really loose out there. On the flats I do not get the feeling that I may be planting my teeth in the tar any moment soon - whether that's because of lower speed or because of descent vs flat I really don't know. But I presume you asked the question for a good reason, so I'd appreciate your comment.

Thinking of balance, what I tend to do is hover behind my saddle at times on the descends. Picked up the habbit from my limited mtb'ing. But I did that on the old bike as well... Will be buggering down some local mountain descends over the weekend - so if it's a technique-thing, I may be able to fiddle with it over the weekend. But like I said, I did not change anything in my technique between the bikes.

 

Hi Seebee

 

Not your stem. Length is fine.

 

I do however feel that it is your fork. My feeling is they have fitted a fork that has incorrect rake thereby reducing your effective wheelbase, i.e. the distance between the centres of your wheels. Reason I asked if it happened on the flats is to give me an indication of how much weight is on the front wheel when it happens. As it happens on the flats it indicates that it is fork related due to speed and not due to speed and a poor forward weight distribution.

 

So my advice is to check which fork should have been fitted to the bike according to the Cannondale USA specs. Contact there technical team and ask them. Also, if the forks differ you will probably find that the rake your current fork has causes a shorter wheelbase. Email the US guys found in the doc below.

 

http://www.cannondale.com/zaf/eng/CannondaleFiles/Manuals/2005_synapse_six13_geometry_comparision_technote_en.pdf

 

Actually I am almost willing to bet money on this one.

Edited February 23, 2011 by The_Break

[SeaBee]

...

One interesting thing is that the 2007 Six is specced with Slice Premium fork and not the Slice premium +.

 

The_Break, thanks will mail them... That is why I mentioned this above. I see on the site they say the 07 Six13's (all of the models) are fitted with a Slice Premium fork.

 

Mine is fitted with a Slice Premium Plus fork. I have tried to find something, but can't find exact specs for them and what the diffs are (ito rake, etc.), except that I think Premium Plus is a all-carbon fork.

[SeaBee]

They actually came back to me!

 

So just for info, for those interested:

Referred me to the local guys (think I'll chat to the LBS first) but regarding the fork - it is so that the Premium should've been fitted, but the Premium Plus is exactly the same, just all carbon. Same dimensions, the works.

 

Since nobody else came back and said it's a general Six13 or Cannondale issue, I suspect there's just something small on my bike. They suggested all kinds of interesting things - amongst others ensuring headset is properly adjusted.

 

Also asked if it may be shimmy I'm experiencing, but for sure I don't pick up a "wobble" - it just wants to wash away in crosswinds.

 

Think I'll take it to my LBS owner so he can have a quick test-ride and see if he picks up anything interesting.

 

Will also have a lot of time to evaluate my position on the bike over the weekend, getting some more serious climbing (and thus descending) done. It may simply be the case that because this is a more racey frame, my style of descending simply does not suit it that well. Will evaluate... hopefully without doing any harm!

[Reg Lizard]

Ok this may be a bit way off- but I heard a bloke complain about speed wobbles as a result of slime that had hardened inside the tube.

[Barend de Arend]

Since we've done the geometry and fit and headset...

 

Are the handlebars/stem loose? Stand in front of the bike, put the wheel between your legs, and pull on the bars.

 

Is the fork steerer cracked? Remove the fork. Check.

 

Is the front wheel stable? Is the skewer tight? Try and move the wheel by hand. You'll be able to make it touch the brakes, but past that should be difficult.

 

Any chance in trying a different wheel (maybe from a friend?)

[SeaBee]

Over the weekend I've tried getting a lot more weight over the front wheel. This symptom did feel better. Could feel the wheel wanting to move, but being more solid. Feared much more for my teeth, though, because if it did go at that point, there was nowhere else to go!

 

Only problem is that it feels very unnatural for me and that my hands and one shoulder really started aching. So much so that my hands are the only sore thing on me today after the ride. So maybe on my old bike I could get away with my technique, this one does not allow for it?

 

Same goes for flat areas - I don't lean on my hands very much due to a shoulder injury. So maybe that may declare the whole thing...?

 

Will still try to get the bike to the LBS owner for a test ride. If something is actually wrong with the bike, he'll pick it up. Before you ask, I work out of town and my time is slightly limited after work, so it's a bit of a mission...