jsm,
Can you ride no hands with 100% confidence? I’m guessing not… My opinion only, but I think you should do yourself a favor and get a bike that fits before you take a spill. 4cm of spacers with a 90 stem is a bad combo… Good luck!
Learn something new every day. Thanks!
Andy, I appreciate your opinion and recognize there is always something to learn. However, can you explain why? I am convinced my fit is not unique at all. Based on your input it sounds like you believe I need a larger bike with shorter top tube?
Thanks!
jsm,
I don’t think you need a larger bike at all but really can’t say from the limited knowledge I have of your situation from your posts. From your descriptions though, it sounds like you are in the exact same circumstance that I was in when I got into the sport 3 years ago. I bought a P3 because of the coolness factor. Theoretically, the size was correct. However, I have a short torso…so the top tube was just too long for me. I ‘solved’ this problem by building up the head tube with spacers and using a short stem (90). This resulted in a highly unstable/twitchy front end. In fact, it was so twitchy, that once I took my hands off the bars for a split second and the next thing I knew I was sliding across the pavement on my hip at 30mph. Again, somebody explained this to me once using an analogy…it is like you are putting the handling/responsiveness of a race car into a tractor trailer. If an 18 wheeler could turn on a dime, it would topple over because it is built up so tall and the center of mass is right on top of the wheels. Make sense? I’d have somebody with a lot of experience with bikes and fitting take a look at you and your set-up. Hope this helps and that in the end this isn’t your problem…just didn’t want you to go through what I did. Good luck!
Thanks Andy, appreciate your feedback.
Wow, I just read the post and I can imagine that shimmy at speed would be quite frightning.
I have a 2005 soloist and I have been 80+ kph lots of times with no issues. In fact it is dead solid at speed. Since you are looking at geometry/setup factors here are mine:
56cm frame, 110mm x 73deg stem (ie. no rise), 28mm of spacers (which I think a lot, not sure what the max is though), Easton SL90 fork. I have the stock Easton wheels and a set of 32 spoke Open pros - Both are fine at speed.
I am 6’ and weight 160lbs.
As for technique. I always hold the TT with my knees when I am going fast on a downhill. I stay seated with my butt as far back as possible (mainly to get aero). It is bumpy I will unweight my saddle but still hold it with my thighs. Not sure if this helps.
JSM,
Just to confirm Andy’s situation. I had the same thing happen. Nearly the exact situation with a P2 only I solved it with a seat shifter and forward post that moved me up. It was downright scary on downhills and you could not take your hands off the bars. Cervelos have very long top tubes. I compared them with other tri bikes and it was evident. They may work for some people, but others are better off on a better fitting bike.
My solution was exactly the same as Andy found. I could not be more happy with the result.
Chad
Finally solved. Thanks for all the input, went 40mph downhill and confidence in rider and bike is improving. Speed will increase as confidence grows. Changed the stem. I removed the old stem which was the same I had on my P2K when wobbling. However, the biggest issue is probably the hardest to admit, the more you relax upper body/grip the faster you can go. Also, pressing on the TT with your knees/tighs etc works wonders as well.
Stay relaxed!