gadabout007

last couple rides I've noticed that changing from the small to big isn't as smooth as it used to be... almost like I'm feeling resistance before the chain is on the big ring. Yesterday I put it on the stand and found that when i turn the crank by hand and switch to the big ring it required a lot of force on the crank to get it into the big ring. I went through the process of recalibrating the fd and got bupkis for my trouble.

I took it to the shop today and they're telling me that my cassette and chainrings are toast. The chain is still good, it was replaced last October. They gave me quote of $550 for the rings or $675 for a new 7900 crank and $275 for the cassette. I'm thinking of going with an ultegra cassette as that's only $100, but I'm not all that enamored with the current crank and was already thinking of upgrading to a crank with shorter crank arms.

Any recommendations on a new crank in the $700 neighborhood? It must be compatible with the BB86 bottom bracket other than that, I'm open to suggestions.

rdtompki

Run, don't walk to another LBS. Better yet, find a bike-savy friend who can help you sort this out. These guys are trying to rob you blind in in Canadian coin.

Grasschopper

Rotor 3D+

ilovecycling

Wow $550 for chain rings? They better be made of some precious metal for that much.

Tip: Find a new bike shop ASAP. These guys are ripping you off.

merlinextraligh

What kind of crank do you have that the rings cost $550?

As for the cassette, Ultegra makes a lot of sense. Few gram heavier than D/A, but it will actually last longer (the TI rings on D/A which save the wieght wear faster) and the only difference you'll note is in your wallet.

ultraman6970

This guy has a sign in his forehead saying... "LBS, screw me up!!! I have money and i'm clueless, but i have a carbon bike tho..."

OP, i think you have to learn some mechanics to start with. Secondly probably you have a problem with worn chainrings or maybe the cables are stretched. If you are using sora dont complain... thats how it is.

Dude you should post this one in the mechanics thread, maybe is just a problem adjusting the FD, but if you are clueless... then any store will charge you and tell you whatever and you will agree to it.

KevinF

The bolded portion makes no sense. If the gears themselves were truly "toast" then installing a new chain would have created all sorts of problems. You'd feel the gears slipping every time you exerted moderate pressure on the pedals.

Find another mechanic. Somebody should be able to diagnose and fix this for cheap. If you want a new crankset, go for it, but there are much cheaper ways to resolve this.

tolik

Basic bike mechanics are essential. Like mentioned FD may need adjustment. Loosen right screw a bit and it will shift easier. Nope chain is not twisted.Nashbar and places like that sell chain for $ 30-50 and chainring you can find on e-bay for 50-80. Cranks don't have anything to do with it. Have to crash pretty hard to bent them. For miles I ride I find SRAM chaines and cassettes best band for the buck. Granted is compact with 9 speed. Have a cassette on it that has more than 14000 miles on it and still in good shape. Found a compact aluminum chainring once for $ 15 on e-bay. Should've bought the whole stock. Doesn't last for more than one chain. Still a good buy.

gadabout007

The drivetrain has about 20,000 km maybe 2,500 km on the chain... a few thousand of those kilometers have been in the rain and snow.

When compared to new crank, the big ring is significantly worn, with all the teeth coming to a sharp point. The small ring is arguably okay, not nearly as worn as the big ring and probably has more life left. The three center cogs on the cassette are worn as indicated by the Rohloff wear indicator.

the quoted price seems to be inline with what local bike shops are charging.

Big ring $479

https://www.labicicletta.com/componen...chainring.html

Small Ring $99

https://www.labicicletta.com/componen...chainring.html

Of the five road bikes I have, three of them were built up by me including the bike we're currently discussing. Bikes are not terribly complicated machines. From time to time I do run into an issue that I cannot resolve myself or do not have the necessary tools. When I do, I rely on a local shop that I trust explicitly. This bike has Di2 so it's not a matter of cable tension, Low & Hi limits are properly set and the font of the derailleur cage is exactly 4mm above the the large chainring. Myself and the mechanic put it in adjustment mode and went through the procedure of recalibrating the entire system. Lastly the shop put a newer ultegra 6700 crank on the bike and the problem went away. I appreciate everyone second guessing replacing the chainrings and my choice of shop, but my request was not a critique of my mechanic or their diagnosis. I was looking for ideas on a new crank to replace the existing crank.

qqy

Which store said this? Sportif?

Hiro11

Those prices are insane. DA chain rings should cost you a fraction of that, the large ring should be ~$170 (US dollars):
https://www.google.com/products/catal...d=0CIMBEPICMAA#

DA chainrings are overpriced even at that level, but that's a topic for another day.

An Ultegra cluster will last longer and cost about $75. Installing the chainrings should take about ten minutes, installing a new cluster takes about two minutes. You need an $8 tool to do the cluster, not sure what you need for 7900 chainrings.

With 25,000 K on the bike, is this even 7900 we're talking about? You must ride a ton if it is. At that amount of mileage, I might buy a whole new crank. An new Ultegra crankset can be had for maybe $250 and will work just fine (it's essentially indistingushable from DA, IMO).

Long story short, those are crazy prices.

TrojanHorse

Good lord, that big chainring shouldn't be any more than about $200 (if you can find one)...

Colorado cyclist lists them at 199 (out of stock) and amazon has them for a little more.

https://www.amazon.com/Shimano-FC-790...6668066&sr=8-1

KevinF

I couldn't believe the $479 price for the big chainring, so I typed "dura-ace 7900 outer chainring" into Google and found everybody else seems to sell that between ~$150 and ~$250. Is all bike stuff incredibly expensive in Canada?

At any rate... If you want to replace the whole crankset, then go for it. It would help to know what you don't like about your current one though that had you considering a replacement even before the shifting troubles started.

c_bake

You need to shop around more on-line. Those prices are crazy. For starters try these links.
https://www.coloradocyclist.com/product/display/15455/
https://www.excelsports.com/main.asp?...jor=1&minor=12

ultraman6970

Gada.... dude you put 20.0000 kms in a crankset already?? you ride a lot apparently

After seing how much is a di2 chainring, probably will be better to start thinking in campagnolo electronic... one more advantage apparently.

gadabout007

The only thing I buy local are consumables, clothing, and anything I have an immediate need for. I get everything else from wiggle, ribble, or pbk. Component prices are stupid in Canada despite the US and Canadian dollar being at parity or greater for a long time.

The only real complaint I have about the crank is the arm length. It's a 175mm and I'd prefer 172.5mm. The crank also has a lot of scratches on the face and gouges on the crank arms. It's purely aesthetics, but I'd like to clean that up a bit.

ultraman I was gifted a team bike with 5000km already on it and the groupset. I've put 10,000 km on it before it was wrecked in a crash. The group was transplanted to the replacement frame in February and it's seen another 5000km since then.

ultraman6970

You are a lucky man hehehe