8 CABLE PRE-STRETCHING STEPS
With the handlebars unwrapped and housing unsecured to the bars, shift to the largest cog in the back and the large chainring in the front.
For an externally cabled bike, pull on the cables lightly, one at a time. Start at the down tube, and then at the right chainstay for the rear derailleur. Do not pull too hard. If you do, you risk breaking cable stops or frame inserts. If the bike is internally cabled, the process can be bit more difficult as there is no exposed cable to grab a hold of. Shift the rear derailleur to one of the middle cogs. Hold the derailleur at one gear with your left hand, while simultaneously creating tension with the corresponding shift lever. Do this ever so gently until you just about feel the shift lever click up to the next position. The same can be done with the front derailleur.
Shift the rear derailleur to the smallest cog and the front derailleur to the smallest chainring.
Turn all barrel adjusters in. Reset the cables by loosening anchor bolts and pulling out any slack before re-torqueing them.
Do your final tuning. Secure the housing to the handlebars (on a road bike) and wrap the bars.
For your brakes, squeeze them firmly at least five times to seat everything, and then readjust.
Once everything is tuned and the bike is on a stand, go through all the gears rather quickly and with more force than you’d normally use when riding. This step provides extra insurance that you’ve removed all the slack out of the system. Check your work again to see if you need to make any further adjustments.
Go for ate stride. Run through all the gears to ensure everythings hi ft swell. If you perform the above to aT, I guarantee you won’t need a followup adjustment after your first ride.