Carbon bike with Alloy 40 M.M. deep wheel rims.

[Doug.]

Hello.
I have recently built a carbon frame,fork and handle bar road bike,so far covered over 700 K.
Very pleased with it.......apart from at higher speed (above 40 k.p.h) the handling becomes rather "uncertain" that is it feels very light and vague.
This is even more so on slightly roughly surfaced roads.
The speeds mentioned are usually down hill,
On a particularly long down ward hill I achieved 60 plus k.p.h and that was not a pleasant experience ,
Could it be the wheel rims ? .
The wheels I fitted (they are alloy, carbon look alike !) and are 40 m.m. deep making them rather heavy compared to the rest of the cycle.
I am also prepared to accept it could be my imagination as I am relatively new to fast road bike cycling,the previous 40 years the bikes I used have been touring type .
Advise most welcome.
Thank you
Doug.
If it is considered the wheel rims to be the problem I am prepared to change them for conventional (about 20 to 24 m.m. deep) alloy type of rim.

 

[alecstilleyedye]

try putting different wheels on (if you have them on another bike) and see if it makes a difference. if not, it may be positioning that may be the problem; sometimes small adjustments to the bars and seat position can make big improvements.

 

[RedBike]

I don't see why it would be the wheels, are you sure it's not the fork?

In my experiance heavier wheels tend to have more of a gyroscopic effect so, which means the bike is more reluctant to change direction.

Racing bikes tend to have less 'trail' in the forks/frame than touring bikes which gives them a quicker more lively ride.

Try googling "Fork Rake" or "Fork Trail".

Have you used the recommended headset and fork?

 

[amaferanga]

If there was a crosswind then you'll notice it more with deep section wheels.

 

[02GF74]

the handling should change at speed but can - all objectgs have natrual frequencoies of vibration and it may be that something is resonating - similar to motorcycle tankslapper.

check that everthing is adjust and fitted correctly; then try again and then try a different set of wheels.