I should know the answer to this by noon tomorrow, but I am curious, and if you are still awake, Thomas, having taken care of your girlfriends cats, and watered her plants (and probaly rummaged through her underwear drawer): my handle bars are spinning around the head tube (or at least the part that comes up out of the head tube), and they are as tight as I can get them. I don’t know bike terminology, so bear with me. This is a new P2k. On close examination, and comparison with my GF’s P3, I note that the Syntace stem completely closes around the “part that comes up out of the head tube” so you can’t make it any tighter. My GF’s P3 has a gap, so that when you tighten the allen screws it gets tighter. I went out to the garage and checked my Cannondale roadbike, and her Trek roadbike. Both have gaps. How can this be mis-sized on a new bike? I am lucky not to be in the hospital.
i had a similar, but not so extreme, problem with a Merckx Team Sc. I would tighten the stem (initially an Easton EA70, then a Thompson Road) around the steerer tube, only to have the clamp bottom out. It didn’t spin, but it also would not hold the headset in adjustment.
I first thought the Easton was out of spec, so I replaced it with a Thompson. To no avail, the problem persisted. The clamp on the Thompson stem is very powerful and I ended up crushing the carbon steerer tube.
I replaced the fork with a Reynolds Ouzo and the problem resolved. Both stems – the Easton and the Thompson – worked fine with the new fork. When properly tightened, I could measure a gap of about one centimeter between the edges of the clamp. I surmise that the steerer tube on the Merckx (AC made) fork was out of spec and slightly undersized.
The moral: get ye to a good bike shop with your bike and have it inspected by professionals. Don’t leave until the problem is resolved. Either the fork or stem is likely a little out of spec resulting in the slippage.
AND DONT RIDE UNTIL ITS FIXED!
Best of luck.
As luck would have it I am still up and still at work at 3:12 AM. I just dropped a client off at the airport. He flew in in his brand spanking new, Swiss built, jet turbine Pilatus PC-12. What a beautiful airplane. It was sitting there next to a bunch of Lears and Citations and it was so much more elegant. What a beautiful airplane.
Anyway.
I think you have a 1&1/8" diameter stem on a 1" steer tube. Or, the shim that sizes the 1&1/8" stem clamp down to 1" diameter is missing.
In any event, you need to get that back to the bike shop so they can square that away. And no, you should not be riding it at all.
Let me know how it works out.
Thanks for you time, Tom. I hope everything is sized right on the Pilatus.
Hmmmmm… Well on closer inspection, in the daylight, I see that the stem is cracked through behind the heads of the Allen screws–possibly stressed from over-tightening, since there has been no crash or falling over, etc. Since I have never tightened these myself until last night, I presume I am to sue my LBS owner, who assembled the bike, and his parents and grandparents for giving him life. First he is going to see if Syntace/Cervelo will replace it. Then I will sue! SUE! SUE! SUE!
Oh, that beautiful Pilatus fit me just fine. The damn thing was like an airliner.
Huge perk of this job when customers fly in for a fitting in their own airplane, take you out to dinner after then give you a tour of their plane.
That was a good day in the bike business. What a beautiful, beautiful airplane. Big and brand spanking new with a fresh coat of wax.
Tom
I saw one of those taking off from Benton Harbor while on the run course during Steelhead. Very nice plans. For a single engine plane they can cruise at over 250 knots. I understand that they are very forgiving from a pilots perspective.
Rocketboy
These guys recounted outrageous tales of high perfromance take-offs and landings. They used 600 feet of runway at metro.
When that Jet turbine spooled up I got goosebumps. It was prettier than any Lear or Gulfstream out thee. The cockpit was so beautiful. Huge cargo door, we just loaded there bikes up into the cargo door and off they went.
I’ve seen a lot of airplanes in my day, but that was the most beautiful airplane I’ve believe I’ve ever seen.
If I ever had a spare few million bucks (never) that would be high on the toy list.
Today’s word: Omphaloskepsis. (Adoration of the navel)
Mine, or yours?
Can they do a barrel roll on takeoff? I love that.
In this case, my girlfriend’s.
And yes, I believe the Pilatus PC-12 can preform a roll on take-off given enough speed.