donhaller 

I'm new to the 10 speed cassette and double chain-ring, coming from an eighties 5-cog freewheel.

On my new Giant TCR C1 - Ultegra setup, I noticed that on my 12-25 rear cassette, when on the big front chain ring and the three largest cogs out back my chain is skipping a bit inside the dérailleur cage as it feeds through the rollers. It is of course worse on the 25 tooth cog because of the greatest angle and little slack of the chain, but still does this little skipping thing on the other two cogs as well. Is this normal? will it get better as the chain stretches and I get more miles on the bike. It only has about 45 miles on right now. I just picked it up last weekend and we are still getting acquainted.

The old girl is really pissed and looks at the new one from across the room!! Hates sharing a trainer and water bottle cages too!!

voltman

The sound is normal, but the procedure isn't. You really don't want to be cross-chaining like that.

WheresWaldo

Should have 18 real usable gears, if not it is an adjustment issue. The 39/12 and 53/25 (34|36/12 and 50/25 on a compact), although you may be able to shift into them and ride that way, puts too much side load on the chain and accelerates chain cassette and chainring wear.

donhaller 

I figured that Cross chaining on the big rear cog was not wise because of the angle. But I felt that not being able to use the other two is a little more than I expected. So is it normal to not use those top three cogs with the Big Chain-ring?

donhaller 

Ok - I just go to get better aquainted with the bike. My LBS adjusted them a smidgen (the best he could to pull off some of the skip, but the two largest one's still skip. (mental note: Don't use those gears) find other similiar ratios on the other chainring.

Thanks guys

WheresWaldo

No it is not normal. They are there to be used. There are times you will want to use them to prevent a double shift. It is an adjustment issue. Take the thing back to your LBS and have them make a very slight adjustment.

WheresWaldo

Sometimes, it is a combination of chain and adjustment. It shouldn't really skip in any gears. Something small like this could be a simple matter of swapping chains. If you have a Shimano chain on there, swap it for a KMC, or visa-versa.

UmneyDurak

You should be able to use those gears. It's not really a good idea to do it very frequently, but you still should be able to "cross chain". It's an adjustment problem. Take it back to the LBS to get it fixed.

donhaller 

I can use the gears. It just sounds like a "click....click....click....click" as the chain runs through the rollers. Kind of irritating, but a good reminder that I'm on those gears for sure.

aprilia4life

I try not to use 52/25 and 52/23, 39/12 and 39/13. I find both 39/12 and 39/13 drag on the side of the 52 chain ring so I steer clear of those gears and I steer clear of 52/25 and 52/23 because the chain is so damn tight from the big gears AND it's stretched from cross chaining.

I find I can get a good variation of speeds around the middle (where a shift down/up is required on the front), even from missing those 4 gears.

G60

are you trimming? there should be a small click of the little STI lever that moves the FD inwards for these situations.

either way, you should be in the small chainring for those gear ratios, but trimming may help. also, if this is a brand new bike, the cables may have stretched a little, requiring adjustment.

donhaller 

My LBS owner showed me that today. I wasn't sure about that. Good Point.

8Lives

+1 for the trimming feature, works a charm. Just like the small lever one detent and all will be quiet. It should work completely crossed over, though not recommended as above...

And what the heck was your LBS thinking to a)not tell you when you left the shop originally and b) not mention it when you brought it back in?

donhaller 

NO - today was the first time I took it back to him. He adjusted the bike, and then went over the shifting with me and showed me the angle of deflection as the chain went through the dérailleur cage and how the chain tightens as it goes up on the bigger gears. I can't put any blame on him, cause he has been great. It's just my first time with a really modern bike. I still worry about the carbon fiber and think it will crumble, and I'm just figuring out the new gearing and shifters etc. I'm pretty happy with my LBS!!
I started this thread today because I like to bounce information off of you guys to make sure I'm getting the straigh dope!!

donhaller 

Update - Last night after this discussion I put my bike back on the trainer. The adjustments made at the bike shop earlier in the day must have done the trick because it is running smooth now with no skips on 23T and just a slight ticking on the 25T.
Thanks for all the replies.

rha600

I've gotten that on every bike I own. when it's on an extreme angle like the big one in the front and the big one in the back it will rub the cage just a tad. If I click the shifter once as if i'm going to shift into the smaller front cog it moves the cage over a tiny bit but not enough to actually drop the chain. that stops it from rubbing and then when I get going and the chain is back on the smaller rear cogs I can shift the front derailer back to the right again so that it doesn't rub the opposite side. Does THAT sound more "normal"? I've never been able to adjust any of my bikes to where it never rubs.

edit: G60's post is what I'm doing...

bvfrompc

I hope your not thinking of riding that carbon fiber bike on the road, those things will fall apart just looking at them!!

I had the same problem with the shifting until I figured out the "trim" quite by accident and on my own. I have 20 useful gears on my 10 speed try as I might not to use the severe cross chains.

donhaller 

Yeh - I'm still worried about tightening the skewers too tight, or stresses from my weight and having it mounted on the trainer, putting in the bike carrier, or just about anything else I could worry about a "plastic" bike.

derath

Don't worry about the CF. Trust me it is strong. I have whacked some potholes accidentally that I though would cause me to need a surgical extraction of the saddle, and it held up fine. (the bike at least)

And look at NoRacer. He has put on at least 12k miles on his TCR in the last year. And he rides it in stuff that probably half the people on the road forum would consider "beater bike" conditions.


-D

jit5

The short chainstays on the Giant TCR cause the chain to be at a greater angle in some gears than other bikes.

The click...click...click, will be continue. I know from to much experience with TCRs.

SaddleBags

New bike - new cable. The cables need time to break in on new bikes or whenever your replace them. That barrel adjuster on your downtube or on the RD is all it should take to remove that 'click'.
Hang out in the mechanic's forum and/or read up on these references below:
Sheldon Brown
Park Tools

SaddleBags

Interesting. I just did a Giant Aero TT build (noticable shorter chainstays). I will throw it in big/big to see if it clicks on the road under pressure. I don't get any noise while switching gears to big/big on the stand.