rear mech 5700 v 5701

[S-Express]

how do you tell if it actually needs replacing ?

Unless you have any specific reason to suspect it needs replacing - then it probably doesn't.

 

[Yellow Saddle]

ok, thats great, what i can do when i swap everything is take it apart at least i know what i'm actually looking to buy, thanks, how do you tell if it actually needs replacing ?
Because i'm upgrading to 10 speed on it i was going to do the cables etc thats why i was thinking it might be a good idea to put a new one in at the same time its not done massive mileage but has gone through about 7 winters

To find out if your headset bearings are good or not, do the following.
Stand next to the bike and hold it by the stem. Lift the front end by the stem and rotate your wrist left and right. It will simulate an exaggerated steering movement in fresh air. Feel for bearing roughness through your hand, but mentally (or physically) isolate cable rub. Bad bearings will be evident. If not, do the same exercise on a few bikes so that you establish a mental base-line. Using one new bike will give you a good indication of smooth bearings.
Once the headset presents as "rough", it doesn't mean both bearings are rough. The bottom bearing goes first and a 3/1 ratio of bottom to top is not uncommon. When replacing bearings, you can choose to replace just the one if you like. Most headset bearings are sold separately for top and bottom. You may be lucky and find that the bike uses the same bearing on both ends, but not always.There are plenty of quirks and silliness in the headset game.

 

[reacher]

great, thanks for the advice, i'l try that and check it

 

[cyberknight]

my road comp 2012 in white has a tapered steerer , if that's any help.