soom

Hi all,

I'm rather new to road cycling and I built up a bicycle with a complete Shimano 105 group set. Everything seems to be fine and internal cable routing was a sheer test of patience for me. I've been riding and getting used to the shifting dynamices of having multiple gears.

My question in particular is referencing the left shifter (front derailleur) where if I shift the entire unit then it goes onto the big chain. Now sometimes I decide I want to go into my smaller chainring and I click the small tab. I notice that sometimes it appears that I am able to click it a total of two(?) times.

[Currently in large chain ring]
*click small paddle*
Click
[Looks down and see small movement of FD]
*click small paddle again*
Click
[Chain drops to the small chain ring]

Now my confusion is that sometimes it takes one click to just drop it down and other times it takes two and when I see the small movement of the FD it seems there is a little chain rub perhaps. But this could be attributed to my gearing; 53x39 & 12-25. I strongly suspect that it is a matter of cable tension for the gearing that I am in. If there is too much tension the FD will be unable to release all the tension resulting in the small movement of the FD. Am I right on this thought?

I haven't been out riding much to test things out and just try to understand basic mechanics but somewhere online I heard the mention of the high trim / low trim of the FD?

Was wondering if you guys had any insight on this matter. Thanks!

HTupolev

Positions on the FD sometimes have "multiple positions" that you can budge between. Typically this is used for trimming, so you can move the derailleur around to avoid rub while in that ring. If your setup isn't great, though, you could potentially have to use the farther position (as a second shift) just to get it to shift at all, but usually this isn't necessary.

Solutions:
1. Deal with it, or
2. Mess with the FD's barrel adjuster until it works (probably needs to be tensioned to stay closer to the inside) or
3. Just give up on indexed front shifting, stick an SunTour ratchet on your left drop, and never worry about it again (but suffer slower shifts and inconsistent bicycle aesthetics).

Lazyass

The shifter has a trimming adjustment for when you get chain rub. Download and read the 5800 user manual.

macca33

Correct - the 11-speed Shimnao front derailleurs are a little bit more involved in setting up. This is because they have an upper and lower trim setting .For them to work correctly, the instructions need to be followed.

cheers

loimpact

In short......here's a steal from an article I found back when I first got my Ultegra 6800. (Note......The 105 5700 and Ultegra 6700 handled trim differently than 105 5800 and Ultegra 6800 do, so even within lines of shifters that *do* trim.....there can be differences but being that you have 5800.....this should help you understand)

If you’re in the large chain ring, there’s a 'half’ click down to trim. A full press on the downshift lever will drop it onto the small cog. When in the small cog, another half click will take the FD to the maximum inward position. Small to big again takes it to the maximum outboard position.
A piece of plastic on the inside of the cage plate reduces the rasping sound. It’s a nice touch, though I do wonder whether it would increase the range of chain lines before rub if it wasn’t there.

Read the above about 3 times.....then go to your bike and play with it. If your brain doesn't go...."Aaahhhh, I get it now!!"......then re-read the above 3 times again & go back & test it on your bike. It'll sink in soon. Keep in mind, and just as this author says......it doesn't *completely* heal FD rub, but you'll be able to use it more to your advantage and have better control over your shifting when you want it. HTH!

aubiecat

It's fun watching the kids discover the joys of trim.

datlas 

Yup. I know some supposedly experienced cyclists who don't "get" trim.

UnfilteredDregs

We like trim.

rms13

This and set up for the 11 speed Shimano is actually a little different than other front deraileurs so you should be following the manual if you want proper shifting performance

Pirkaus

Get your trim set properly and it opens all the cross chaining you will ever need without FD rub.

rjones28 

This is a pretty good demo.

smarkinson

And make sure you've got the cable routed the right way around the cable bolt.

Technical FAQ: Shimano 11-speed front derailleur cable setup - VeloNews.com

goenrdoug