This Sunday I did the West Point Tri and had a old problem return.
The first decent is a long 2 mile hill that I had reached over 35mph on and suddenly my front wheel started to vibrate.
This vibration increased in frequency and magnitude and I was sure I would loose it. Slowing down to 30mph or lower brought things under control and I finished the race keeping it below that speed. I have had this problem in the past and the correction was to tighten the head set. When I checked after the race everything was real tight.
A few extra facts:
The wind was blowing up hill at about 10 - 15 mph. I have been using high pressure tires. 140 psi rear and 125 psi front. I was riding in the drops and not the aero bars. Several weeks before I had no problem going 43 mph on a 1 mile hill near my house.
I love going real fast down hills but this really scared me. Any suggestions??
Check to see if your frame is aligned. Otherwise check the geometry on the frame. You might have crappy fork rake. Plenty of resources on the web about this. If it is no good then you just need to buy a new fork.
cheers
Bob
"Alan and Paula Levin" <[email hidden]> schrieb im Newsbeitrag "]news:[email hidden]...
Quoted message said:
This Sunday I did the West Point Tri and had a old problem return.
The first decent is a long 2 mile hill that I had reached over 35mph on and suddenly my front wheel started to vibrate.
This vibration increased in frequency and magnitude and I was sure I would loose it. Slowing down to 30mph or lower brought things under control and I finished the race keeping it below that speed. I have had this problem in the past and the correction was to tighten the head set. When I checked after the race everything was real tight.
A few extra facts:
The wind was blowing up hill at about 10 - 15 mph. I have been using high pressure tires. 140 psi rear and 125 psi front. I was riding in the drops and not the aero bars. Several weeks before I had no problem going 43 mph on a 1 mile hill near my house.
I love going real fast down hills but this really scared me. Any suggestions??
"Bob Creasote" <[email hidden]> wrote in message news:<[email hidden]>...
Quoted message said:
Check to see if your frame is aligned. Otherwise check the geometry on the frame. You might have crappy fork rake. Plenty of resources on the web about this. If it is no good then you just need to buy a new fork.
cheers
Bob
I agree that these are classic symptoms of improper fork rake (angle) or other frame alignment issues. If you are lucky ($$$), it is limited to the fork. I presume you have also already checked to see that the headset is properly adjusted and tightened(?).
1. When it happens they say to clamp down on the top tube with your thighs.
2. Sometimes the wobble is caused by the rider. That was the case with me. I had some wobble and someone told me that, then the next time I consciously willed myself to be more relaxed as I gripped the handlebars and there was no wobble.
"Alan and Paula Levin" <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
This Sunday I did the West Point Tri and had a old problem return.
The first decent is a long 2 mile hill that I had reached over 35mph on and suddenly my front wheel started to vibrate.
This vibration increased in frequency and magnitude and I was sure I would loose it. Slowing down to 30mph or lower brought things under control and I finished the race keeping it below that speed. I have had this problem in the past and the correction was to tighten the head set. When I checked after the race everything was real tight.
A few extra facts:
The wind was blowing up hill at about 10 - 15 mph. I have been using high pressure tires. 140 psi rear and 125 psi front. I was riding in the drops and not the aero bars. Several weeks before I had no problem going 43 mph on a 1 mile hill near my house.
I love going real fast down hills but this really scared me. Any suggestions??
a friend of mine does heaps of riding and he told me this story where he was tailing a car and going down a hill (reaching speeds of 60-70kmh) and cuz he had an aluminium frame, there was something about the resonance of the tube that made his frame vibrate and start to 'hum'.
i think this is based on wind instrument/sound resonating through hollow pipe physics. all i can remember from high school physics is that if air flows thru a pipe such that it can create standing waves so that it starts to resonate, then it creates vibrations of the tube so that those vibrations impact on air particle to cause sound transmission.
so maybe your bike turns into a musical instrument over certain speeds!! this is just my (possibly physically incorrect) explanation.
"Alan and Paula Levin" <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
This Sunday I did the West Point Tri and had a old problem return.
The first decent is a long 2 mile hill that I had reached over 35mph
on
Quoted message said:
and suddenly my front wheel started to vibrate.
This vibration increased in frequency and magnitude and I was sure I would loose it. Slowing down to 30mph or lower brought things under control and I finished the race keeping it below that speed. I have
had
Quoted message said:
this problem in the past and the correction was to tighten the head
set.
Quoted message said:
When I checked after the race everything was real tight.
A few extra facts:
The wind was blowing up hill at about 10 - 15 mph. I have been using high pressure tires. 140 psi rear and 125 psi
front.
Quoted message said:
I was riding in the drops and not the aero bars. Several weeks before I had no problem going 43 mph on a 1 mile hill near my house.
I love going real fast down hills but this really scared me. Any suggestions??
