Contrary to the opinion that manufacturers weights are hopefully optimistic thats not true of all components.In my experience,Schwalbe tyres have been to the quoted weight to the nearest 5g,Shimano weights are noramlly pretty accurate too.
My RS Reba forks were only 5 g over what RS claim.
Wheels however seem never to be light as I think/want them to be,must be the weight of stuff like rim tape and spoke nipples I forget……..
Saddles though,in my experience do tend to be lardier than advertised.
Agree weight off tyres and wheels is noticeable,other components less so,but if you think of all the individual components that make up a bike and the cumulative effect of all those 10g savings it begins to add up.
When doing a spread sheet tally I wonder how many people forget cables,hoses,rotor bolts,fluids,little bits like their computer,bottle cage mounts,etc?
Very often these add up to 1lb.
Quoted weights tend to forget pedals too.Thats another 1/2 to 1 lb……….