Please specify which crank I need.
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Please specify which crank I need.
I have a 06 Giant OCR C2 with the factory triple crank. I have had nothing but trouble with it slipping gears and not getting to the granny gear under pressure. Several bike mechanics on 'Ride the Rockies' have stated it is a cheap crank.
I want to switch to a compact crank. I know nothing of the mechanics of switching over. Can someone tell me which crank and Bottom bracket I need for this model? I am bike lingo illiterate so please be specific when giving sizes, brands, etc
( I have searched this site but most discussions are non-bike specific).
I want to switch to a compact crank. I know nothing of the mechanics of switching over. Can someone tell me which crank and Bottom bracket I need for this model? I am bike lingo illiterate so please be specific when giving sizes, brands, etc
( I have searched this site but most discussions are non-bike specific).
#2
mechanically sound
Just get any modern outboard bearing design compact double crankset. It will come with the BB cups and spacers to fit your bike.
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If you're having shifting trouble it's almost certainly not the fault of the crank. Sounds like you need new cables and housing and a general tune-up. A new crank might make shifting a little faster, if better designed, but won't have that much of an effect.
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Balky shifting is the fault of the cranks This one is almost as good as the post over in Clydes where a mechanic told the guy that a the reason his rear wheel wouldn't coast anymore was because the cables were loose
Sorry to make fun of your situation, thenorthwoods, but these guys just crack me up
Let's start with the obvious. The crank on a bike isn't the problem. If the bike won't shift to the granny gear under pressure (not something that you should be asking it to do anyway), the front derailer isn't operating properly. My guess is that the cables on the derailer aren't sliding smoothly through the cable housing and/or the cable carrier under the bottom bracket. They need to be removed and lubricated inside the housing. A little dry lube on and around the cable at the bottom bracket will help things move more smoothly too.
But that may not completely fix the problem. I suspect that the front derailer may also be sticky from road grime. Clean up the pivots with some solvent. Boy! I hate to say this but...WD40 can actually work here Work the pivots a little and clean up any over spray.
You may not be done yet. Your limit screw may not be set properly. You want the derailer to move as far inboard as possible without knocking the chain off the inner wheel. I suspect that the bike was set up with the limit screw just a little too far out to work properly. You don't want to go too far inboard but you want the derailer to shift.
Technique is part of the problem too. Shifting to the lowest gear is always difficult. You are usually under high torque and trying to move the chain. This doesn't end well. When you shift to the lowest gear, you need to 'soft pedal', i.e. relieve a little pressure on the pedals, momentarily to allow the derailer to swing over far enough to knock the chain off. It's difficult because you are struggling up a hill and the last thing you want to do is easy up on the pressure...but you gotta!...just a little. As soon as the chain start to drop, you can go back to full pressure.
Finally, chain slippage is almost never the fault of the crank. If you chain is popping and skipping, it's the fault of the cassettes in the rear and the chain. They aren't mating properly. Either the rear derailer cable is a little loose or the chain and cassette are worn. A new chain on an old cassette is the usual culprit. If the bike hesitates when you shift on the rear, then the cable tension is the issue. If the chain pops on the gears when stand up and pedal, the cassette is the likely problem.
Go over to Park Tools for repair help.
Good luck.
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Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
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Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
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+1 Crank might be cheap, but it is a derailleur problem, not a crank problem. Are they saying cheap cranks don't shift? If so, walk around their shops, and ask them why they are selling bikes that won't shift (lower end cranks)?
#6
mechanically sound
The OP wasn't asking for a diagnosis, just which crankset would fit. -"I want to switch to a compact crank."
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He probably wants to switch to a new crank because some snot nosed kid told him that his crank is the problem when it isn't. Why spend money on something that won't fix the issue he is having? Even if he wants a new crank, he'll still need to address the underlying problem...a maladjusted shifting system.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
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Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
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Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
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Let's phrase it this way?
thenorthwoods: Your cranks can be made to shift just fine for very little cost. Do you still want to replace them?
thenorthwoods: Your cranks can be made to shift just fine for very little cost. Do you still want to replace them?
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Crank problems
I had my bike mechanic call Giant direct. They confirm that they have had problems with the Truvativ rouleur gxp crank. The front derailleur is an ultegra as is all the other components. The front derailleur works fine it is just that the chain will not always go where I need it too. I suppose that could be the derailleur but I have been told 4 times now that it is not.
Giant switched cranks the next model year to a compact crank. The bike was new when this started and has occurred ever since.
The problem is that under load (hill climbing) the chain comes off when dropping gears to a lower selection. It will never allow itself to go onto the granny gear without losing the chain.
Giant (the company) (unknown who)suggests switching cranks.
Giant switched cranks the next model year to a compact crank. The bike was new when this started and has occurred ever since.
The problem is that under load (hill climbing) the chain comes off when dropping gears to a lower selection. It will never allow itself to go onto the granny gear without losing the chain.
Giant (the company) (unknown who)suggests switching cranks.
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I'll take this as a "I want a new crankset."
Have you thought about going with Ultegra? It seems to be working for in other applications. The Ultegra is a very fine crankset - including the 30-39-52 triple. And the installation of the Hollowtech II bottom-bracket couldn't be easier really. And it's all very lightweight. I just put one on my own bike.
Have you thought about going with Ultegra? It seems to be working for in other applications. The Ultegra is a very fine crankset - including the 30-39-52 triple. And the installation of the Hollowtech II bottom-bracket couldn't be easier really. And it's all very lightweight. I just put one on my own bike.
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I need to install the 6603 crank myself. I have it sitting at home ready to go. One question Panthers007, does the spacer go between the left crank arm and the outboard bearing? That is the way it looks on my diagram.
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The Shimano website should help you. I believe it would be on installation of the crankset. On the Ultegra the spacer came with the crankset, not the bottom-bracket which was sold separately. It went on the left (non-drive) side between the outer-bearing and the left crank-arm.
Installation was a breeze, by the way.
Installation was a breeze, by the way.