R8000 front mech question

[yashcha]

I’ve been trying to finetune my front shifting(shimano rs685 and 8000. Front mech), but running into some issues. The shifting is perfect, and had it professionally installed and adjusted today, but the effort required to shift to the big ring seems much more than what is required on my friends bike.

Initially, I need a lot of effort to push the lever. It seems to be hard up to some point, and then it gets noticeably easier to push the lever. On My firends bike the pressure seems to be constant, and overall noticeably less. Is there any way to back off the spring tension?

I am not using the stock super slippery cables and housing. Could that really be the problem?

Thanks!

[yashcha]

Did not quite make it perfect, but I learned through tinnkering around for hours that the high limit screw has a very important role in determining how much effort it takes to shiift into the big ring. The sweet spot is the least amount that you need to screw in the high limit screw while still being able to shift into the big ring. I had to screw in the tension screw all the way to make this set up work, but now it shifts with about half the anount of effort as before, so that is a win.

[dddd]

Hi, I've installed a couple of these, both 8000 and 9001, over the past week.

The hi-limit screw is not a limit screw at all. It is a booster screw that causes the cage to get pushed out earlier and further when the screw is tightened clockwise (inward).
The travel limit is built into the shift lever.

I definitely noted the increased effort to initiate motion in the derailer in both installations, ...and also on my own Colnago CX-Zero with the previous 6800 model front derailer!

It seems that the leverage curve through the derailer's travel range is shaped to perhaps reduce effort as the upshift is nearing completion as your fingers are reaching their own travel limit, but at the cost of some ease in getting the thing moving.

I have occasionally attempted an upshift only to get no motion at all and be left thinking that I must have already shifted to the big ring, only to find otherwise a few moments later when I ran out of range on the cassette before reaching even a modest terminal velocity.

It's a minor quibble, but you'd think that with these new mech's space-age looking linkage (looking like the inside of a camera perhaps) that the shifting ease would be a touch more uniform.

I always use SRAM's Jonnisnot cable lube along the path of the cable near the bottom bracket, which generally makes shifting easier. Did you use Shimano's pre-lubed housing? That SP41 housing is a big help, and together with the sealed ferrules gives lengthy maintenance intervals.
A hundred break-in miles might also either smooth out the operation and/or strengthen your hand, so it won't seem like a problem. Some of the bb guide routings I've seen have sharp edges presented to the cable, and which need time to wear down.

[bigbill]

I installed a 9100 on my gravel bike by watching a youtube video and it works like a champ. I just followed the directions because the cable routing really isn't intuitive. I think the R8000 and 9100 are the best parts of the new groups. I'm using it with a set of 685 levers.

[oldpotatoe]

Originally Posted by yashcha

I’ve been trying to finetune my front shifting(shimano rs685 and 8000. Front mech), but running into some issues. The shifting is perfect, and had it professionally installed and adjusted today, but the effort required to shift to the big ring seems much more than what is required on my friends bike.

Initially, I need a lot of effort to push the lever. It seems to be hard up to some point, and then it gets noticeably easier to push the lever. On My firends bike the pressure seems to be constant, and overall noticeably less. Is there any way to back off the spring tension?

I am not using the stock super slippery cables and housing. Could that really be the problem?

Thanks!

NO

Most likely inner wire/housing drag somewhere...Under BB, if internal, somewhere. It should be consistent and pretty easy, even w/o the uber expensive, slick shimano inner wires. Maybe a broken strand somewhere or not clean cut at end of housing

[yashcha]

Originally Posted by oldpotatoe

NO

Most likely inner wire/housing drag somewhere...Under BB, if internal, somewhere. It should be consistent and pretty easy, even w/o the uber expensive, slick shimano inner wires. Maybe a broken strand somewhere or not clean cut at end of housing

Thanks Pete, the “high limit” screw was set too deep. Backing that off prior to reinstalltailn made all the difference, even with non optislick shimano cables. I assume it will be even better with the specialized cables.

[bigbill]

Originally Posted by yashcha

Thanks Pete, the “high limit” screw was set too deep. Backing that off prior to reinstalltailn made all the difference, even with non optislick shimano cables. I assume it will be even better with the specialized cables.

The routing of the cable on the FD makes the slick stuff peel off the cables. It's still where it matters, but kind of unsightly on the FD itself.

[dddd]

A lot of bikes, especially recent carbon-frame bikes, have the front derailer cable dragging over a sharp edge as it exits the bottom bracket guide and re-enters the frame.
No cable coating will help there, since the coating gets scraped right off.

Lubrication and time/usage (for the sharpest edges to wear down) seem to make the problems go away and without frequent cable failure at that location.

I find it odd that there is that freeplay between the actuating arm (which retains the cable and pinch bolt) and the greater linkage. I note a faint clicking noise and see some non-intuitive relative motion there which I have yet to figure out.

[zank]

What throws most people on the R9100/R8000/R5801 FDs is the high adjustment. They are used to adjusting traditional FDs so the the outer plate just clears the chain in the big ring/small cog in the top shifter position. With the toggle derailleurs, you adjust in the top trim position and big ring/big cog and get the inner plate to just barely graze the chain when cross chained.