How do I convert my Glock trigger from a 5lb pull to a 3.5lb pull?

Do I only need a 3.5lb connector?

Yep

actually the 5# connector in a stock glock results in about a 5.5# pull.  the 3.5# connector will be about 4.5# (these are what i have measured on one of my new glocks using a Lyman guage)

with some work, you can get it down to 2# using stock parts.

here's some info from Glockmeister on differnt trigger combos:
glockmeister.com/triggers.shtml

With a polished 3.5# connector you can get in the 3#-3.5# range. The fit of the trigger bar makes some difference. I always buy a few trigger bars and swap the out till I find the best fit.

After that you can respring the gun with a glockmeister competition trigger spring, and a reduced power striker spring. With this combination you will still be able to reliably light any primer including small rifle. Now you'll be in the 2.25-2.5# range. If you go one step further with a skeltonized striker you will need to use federal primers only.

Quoted: actually the 5# connector in a stock glock results in about a 5.5# pull.  the 3.5# connector will be about 4.5# (these are what i have measured on one of my new glocks using a Lyman guage) with some work, you can get it down to 2# using stock parts. here's some info from Glockmeister on differnt trigger combos: glockmeister.com/triggers.shtml

I added a 3.5 connector from Lone Wolf to my 21 & I really can't tell the difference.

I use a 3.5 and I can tell a difference.
Trigger pull is right where I like it.

My competition gun has a 3.5# connector and a stock trigger spring. My carry gun has a 3.5# connector and a NY1 trigger spring. I have tried a reduced power striker spring in only one gun but I did have reliability issues with it. YMMV.

Quoted: Quoted: actually the 5# connector in a stock glock results in about a 5.5# pull.  the 3.5# connector will be about 4.5# (these are what i have measured on one of my new glocks using a Lyman guage) with some work, you can get it down to 2# using stock parts. here's some info from Glockmeister on differnt trigger combos: glockmeister.com/triggers.shtml I added a 3.5 connector from Lone Wolf to my 21 & I really can't tell the difference.

try using a stock 3.5 connector.