kedward778

Hello,
I just test drove a Giant TCR Avdvanced Pro 1 2018. Love the ride, but while the chain is on the the large front chain ring, I experienced chain rub on the front derailleur for the 3 lowest (largest) cassette gears. I went to engage the trim to relieve the chain rub, but there was little if any trim affect. I asked the bike mechanic to adjust, and he tried but then said "that is just the way it is".

I **know crossing chaining is not ideal** for long periods, but every other bike I have ridden allows you to simply engage the trim to eliminate chain rub.

Thoughts? Anyone experience this on their TCR? Or is it time to find a new mechanic?

'02 nrs

could be the FD cable has too much slack in it? is the cage inline with the chainrings?

Andrew R Stewart 

Since we don't know the bike's shifter spec unless we do a search some might not want to offer advice yet. If the shifter does have a trim feature then a too tight cable is a very common reason to not have much trim happen when engaged. Do know that some tolerance exists in all parts and the exact same brand./model # part can work slightly different in the fine aspects from another same part. There are times when the mechanic is faced with the choice as to what combo will rub. Small cogs with the big ring or big cogs with it. Andy

Bill Kapaun

Was "every other bike" an 11 speed with exactly the same drive train?

kedward778

Pretty similar, I have an older giant TCR with ultegra 10-speed and it had a great trim setting that relieved chain rub on all gears. I might expect a little chain rub on the newer giant TCR advanced pro ultegra because it has one more gear but why am I getting chain rapping all three high end gears and why is there no chain rub relief when I engage the trim?

I find it hard to believe they can't design a bike that doesn't have chain rub, especially when it cost $3,000

tomtomtom123

If you look up the shifter model on the internet, then you'll find out whether it not if it has rim. We cannot tell you since we don't know what it is.

You could replace the shifter with a compatible model that has trim.

Also, SRAM YAW FD don't need trim, usually. On my bike I had to expand the cage a couple of millimeters. The FD had a convenient bolt to open the cage and insert some washers. I then used my old Shimano shifter which had trim, but I set up the limit screws so that the trim did nothing. So essentially I only had 2 absolute positions on the FD.

HillRider

They can. It's called "friction front shifting" and can be trimmed exactly as you wish.

More seriously, the electronic groups (Shimano Di2, etc.) automatically reposition the front derailleur to center it over the selected chainring for every rear shift.

freeranger

Looked up the bike specs, which calls for an R8000 Ultegra groupset, so looked up the specs and the info I found states it does have trim. So I guess if the groupset is R8000, it should--found the info re:trim under the pic of the front derailleur -- https://cyclingtips.com/2018/09/shim...g-term-review/

Steve B.

The shop mechanic is a lazy idiot and I'd then question whether I'd want to buy from this shop. This bike and according to the website, has a mechanical shifting system, which can ALWAYS be adjusted. It sounds like the factory chose to not install inline barrel adjusters on the housing from the front shifters to the cable stop on the frame. These would allow a bit of adjustment to the derailleurs. The rear already has a barrel adjuster on it, fronts never have.one.

The alternative is to simply pull in a slight amount of cable onto the set bolt on the derailer. That'l have the shifter pull a bit more cable and will eliminate the rub.

My new Cannondale Topstone has no inline adjusters either. If and when I change out the cables (next year likely), I'll add them.

https://jagwire.com/products/small-p...line-adjusters

UKFan4Sure

I'm thinking that any $3000 bike should have upper-crust components. They should not have chain rub as long as they are adjusted properly. Any late model bike I've owned that was 105-Ultegra never has had any problems with it.

sirjag

i have the Giant Contend SL1 (highest tier al frame) with 105s and had same issue. manually adjusted the FD until the problem went away. Just takes some time to dial in...

jag

bpcyclist

I run 105 on one of my newer bikes and I have a bit of rub when fully cross-chained, but only with those two combinations--which I never use, anyway. As mentioned above, it really is worth having a hard look at that FD to be sure it is really, exactly aligned and straight. Last time I noticed rub in some other gear combos, that was it. Somehow, that FD angle (with respect to the big chaingring) was way off. No idea how that happened. But realigning it solved the whole deal.