CosmoCyclist

Hi. I have a 9 month old Giant TCR Advanced Pro1 Dics 2020, medium size frame. I have some scraping marks on the inside of the frame next to the small cog. I have taken this up with Giant and they say that there is no structural damage and that they can do a paint touch up for me. I do know of two other bikes with the same problem, both medium frame sizes. I dont see the point of repainting it again if the same thing will happen again.

Has anyone else experienced this problem or know how to solve it?

cobba

Photo: https://bikeforums.net/g/picture/23481020

Trakhak

The pattern of paint scuffing suggests that the limit screw for the derailleur's outward travel might be backed out too far, allowing the chain to derail outward. If that's not the explanation, the practical solution would be to add a very thin washer to the hub axle on the drive side, followed by resetting of the limit screws.

Koyote

Add a chainstay protector.

CosmoCyclist

Thanks. Will check if that is the case.

70sSanO

I can’t believe Giant’s response or that this is normal.

If the high limit screw that far off, the rest of the cassette wouldn’t index correctly. The indexing is from the 1st position cog.

I suppose it could be a missing/wrong DS hub washer, but a chain should never run against a dropout.

How could it get out of the shop?

John

IceTee2

Because the LBS mechanic assembles "a bunch" of $479 entry-level bikes for every $2000 bike. With all due respect there ain't time or $$$ in being meticulous....

70sSanO

That’s not even close to being meticulous. I sure hope you don’t work in a shop.

John

Iride01 

So your chain is rubbing that stay/dropout all the while it's in the 11 cog? Or does something else have to happen like the chain comes off or something. I too have to wonder if the high limit isn't set correctly.

I assume you took it back to the shop where you got it since you got a statement from Giant on the warranty aspect. I might just take it to another shop and see what they say.

IMO, if the chain rubs the stay/dropout all the time when in the 11 cog and everything is assembled and adjusted correctly, then that might well be a warranty issue and mfr defect. However if it's just someone put it together wrong at the shop or didn't adjust it correctly, then that's on the shop or whomever futched with it.

freeranger

So, removing material from a frame is not structural damage (doesn't seem it could "just" remove paint without some material coming along with it)?! Does it have to break first to be considered structural damage? Did a Giant dealership or Giant Bicycle Corportation say it wasn't structural damage? If it was an LBS, I'd be contacting Giant Corporation directly. Might be a good idea to get a written opinion from whoever claims it isn't structural damage, if you don't already have it in writing. If you are friends with the other two bike owners who have the same problem, have them get the same opinion in writing. If Giant Corp. (not the dealer) dismisses the damage, I'd be contacting some consumer agency. This is, if the LBS doesn't seem willing to resolve it.

CosmoCyclist

Hi John. I was quite disappointed. There are however two role players in between myself and Giant; my LBS and the local importer for Giant. I am contacting Giant directly now.

CosmoCyclist

I am doing that right now. Asking for written confirmation from Giant Corp stating that they don't believe that its a structural and is due too poor assemble. The local importer tested and video'd the chain rubbing. They sent it to Giant and then I got bits and bites through my LBS.

cobba

Take a photo showing how much clearance there is when the chain in the big front / small rear combo.

IceTee2

I'm NOT a bike mechanic, just a 74 year old that was forced to choose riding a recumbent trike over a DF due to physical limitations. Bought a slightly used trike and had to learn how to adjust/maintain the components since the LBS wouldn't service what they didn't sell or drive 3 hours to the shop that did originally sell the trike. About every two months or so, I re-learn how to adjust the derailleurs and spend maybe an hour or so fiddling until it's "perfect". Not because I have to but because I want to. JerryBike maintenance keeps me occupied and I like the detail of it all. Jerry

CosmoCyclist

I suspect that its only rubbing when gearing down to the 11th cog. Never heard anything while riding. Local importer did some testing and sent video and photos to Giant in Taiwan

Iride01 

So then what exactly do you think the manufacturer is responsible for? Suspicion doesn't provide much help for your case if you aren't going to find out for yourself why that scrape to the paint happened.

To me it just looks like the chain came off the cog and you continued to ride it for a while or something got caught in there and scratched it up. Though they might do something nice for you just for keeping good customer relations, I don't understand why they should be responsible for what I'm seeing in the picture.

cobba

Looks to be plenty of clearance, when does the chain rub on the frame?

https://bikeforums.net/g/picture/23504533

TiHabanero

Good night, here we go again assuming there is a defect without proper investigation for determination of cause. If the importer has proven a defect, please send us documentation, ie visual proof, otherwise it looks to me like an over-shift either during set up or out on the road at some point during test ride after setup. From the pictures provided there is ample room for the chain to pass by the drop-out.
One other cause can come from installation of the wheel with the chain on the smallest cog while finagling the disc between the brake pads. I have seen it dozens of times and experienced it firsthand an equal number of times, albeit the mark is more like chipped paint than a rub.

Dave Mayer

Sometime in the past chain jumped off of the smallest cassette cog and rubbed the paint off of the inside of the rear dropout. This is very reinforced area of the frame, with little prospect of damage.

The derailleur adjustment may or may not still be off. This needs to be checked. Tools required are a 5mm hex key and a small flat blade screwdriver. It will take 5 minutes to go through the rear derailleur adjustment from scratch, which includes checking the high and low limit screws, or about as long as it took me to skim through this tedious thread.

70sSanO

Well with that picture, the chain obviously does not rub against the dropout, even prior to the damage.

Most of my bikes have less chain clearance.

John

Trakhak

The supplied photo taken from the rear of the bike suggests that the chain is on the small sprocket and the small chainring. If so, and if you ride the bike using that combination, it might be a contributing factor (the chain can bounce around more easily in that combination because the derailleur spring is at its slackest).