dippitydoo

Hi guys,

Odd question. So I just installed my ultegra lever and crank. When Im in the big ring up front and I need to go back to the small ring, I would press the downshift lever. It goes down perfectly fine but once it engages in the small ring, pressing the downshift lever half way still has resistance. Once I do press it halfway, all resistance is gone. Oddly enough though, the first click actually puts me in the small ring. When I press it the second time, it doesn't really do anything. Any ideas on what that second press is for?

datlas 

I think you have stumbled upon the "trim" feature. It tweaks the FD over a mm or two to avoid chain run when cross chaining.

BoSoxYacht

It seems like his front dérailleur is poorly tuned, and the trim feature isn't working the way it should.

loimpact

Yes, it sounds like it's not adjusted enough. If you want to play with it, find the barrel adjuster that should be laying somewhere in-line around our head tube or maybe just started down your downtube. Screw it both ways to play. (ride up & down the street so you can see what's happening)

I'm running out the door right now but if you search one of my recent posts I went into a detailed description of how the trim works on Ultegra 6800.

When I get back, I'll post about what I *think* I'm going to do going forward & why it might make sense for others.

RogueRadio

Front derailleur is off. Tighten your cables, they are stretched if you are not getting motion. Retune, recalibrate, and rejoice. This is the halfstep mechanism, it is used so you can stay in your small chain ring through the entire range of gears. It moves the front derailleur closer to the Big Ring, thus allowing you to avoid chain crossing in all gears on the small ring up front.

loimpact

To be fair, it's for the large ring too. (There are 2 trims for both rings) And while it *should* stay once you adjust it, I find it can come out of tune slightly by itself every now & then. No biggie, just don't think anything bad's happening if it does.....it just happens.

HOWEVER.......One of the things I think I've decided is to adjust the FD down to where the jump from small ring to large ring will not be to the outermost edge, but to the innermost. It wil still require a 2nd click to jump down to the small ring but I won't have to worry about a half-click when I'm going from say 34/15 to 50/19 cuz I've done that before, mid-acceleration & found myself back in the small ring just cuz I had to half-click in the first place. (no half-click, no worries as I'm speeding up)

I'm almost of the belief that there really doesn't need to be an "outermost" trim position for the large ring as I don't have any FD rub when I'm in 50/11 (my fastest combo) so really no need, at least for me.

(shrug)

trailflow1

dippitydoo are you using Ultegra 6800 ? on the 6800 front shifter there is a 2 step down shift procedure designed to stop the chain being thrown over the small ring and off onto the inside. Which sometimes used to occur on the older groupsets. Its works like a backwards trim. Click once to shift down,click it again to fully move the cage across. When properly set up the second click will move the cage again very slightly inwards and will also stop the chain rubbing on the cage when you also shift into the largest cog on the cassette.


The OP is talking about going from the big front ring to the small front ring. You are describing the trim function when moving up the cassette (to smaller cogs/higher gears). This trim function ALLOWS you to cross chain without the chain rubbing on the derailleur cage.

dippitydoo

Correct! I'm running 6800.

Im not gonna lie. All this trim talk has got me a bit confused. I miss the good ol days where pressing a button can shift you up or down.

Does this his mean that every time I need to shift from the large to small ring, I have to press the downshift twice?

trailflow1

Yes correct ,but you get used to it, it becomes second nature.

dippitydoo

So when I'm shifting down, do you recommend I click twice consecutively or should I click once, let it engage the smaller ring then click the second time a few seconds later.

trailflow1

Twice consecutively will be fine. I cant see waiting making any difference.

loimpact

Here's a short thread, easy-read thread where somebody else went thru all the same stuff.....(including myself so know you're not alone)

https://www.bikeforums.net/road-cycli...s-ultegra.html

I don't think I can type it much better than I did then so hopefully it'll make sense to you after you read it.