Are cones specifically matched to bearing size

[giantcrs3.0]

Hi I need to replace front wheel cones, as they are very pitted , measured ball bearings ,they are 3\16"
have had a look on ebay ,amazon ect , the cones,or cones and axles available , seem to have the
length of axle,cone , but none seem to say specify what bearing size they are for , i would presume there
would be diffrent sizes for 1\4" 3\16" ect if so does anyone know where i could get 3\16" cones ?

 

[RebornBumbler]

I think they're usually 3/16" front and 1/4" rear.

 

[guitarpete247]

Make sure you check your cups, in the hubs. If they're pitted you need new hubs/wheels. What caused them to get pitted? I would suspect either water ingress from power washing or loose bearings. Also agree 3/16" front 1/4" rear.

 

[Gravity Aided]

How do the bearings look in the rear wheel ?