Friction on bicycle climbing a 5% grade at constant speed

[Lalaland]

Homework Statement

A man deals his bicycle up a 5 percent road at constant speed. Man+bicycle mass=90 kg with mass centre G. 1)Access direction of frictional forces 2) explain why frinctional force in front wheel can be neglected having a const. speed taking front wheel as FBD 3) Find normal forces

Homework Equations

Fy=0 Nf +Nr =G
Fx=0

The Attempt at a Solution

Direction is upward
Fy=0 Nf +Nr =G
Fx=0
M= 0. 0.46G= 1.08Nf.
Nf= 375.67N

Now I don't know how to show that friction in front wheel can be neglected

 

[CivilSigma]

I'm not 100% sure, maybe someone else can pitch in, but:

The normal forces in the front wheel can be neglected because F = ma and since the front wheel is at a const. speed, a = 0 which implies summation of Fx = 0. Therefore friction force must be zero.

This should also apply to the back wheel, ( but I'm not entirely sure if it will have a=0 since it is connected to a gear...)

Also, your calculations are unclear to me in (3), so I can't provide feedback there.