The cogs (gears) at the front of your drive chain, connected to the cranks.

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26
votes
14answers
29k views

Triple vs Double chainring?

I'm bike shopping for my first road bike, and I've asked for a lot of advice from my father who was a serious cyclist once upon a time. After showing him one prospective bike, he dismissed it with a ...
15
votes
6answers
14k views

Does this chainring need to be replaced?

Here is a closeup of my triple: All three rings are Shimano Ultegra and have never been changed. They probably have at least 12000+ km on them. I've been pretty good about changing the chain ...
15
votes
2answers
2k views

Is there a practical gain from elliptical/oval chainrings?

I have seen competitive (amateur) cyclists with oval chainrings (front). What is the deal? Are they just for showing off, or is there a practical gain from it (different force transfer).
11
votes
4answers
5k views

Differences between Biopace and Rotor cranks

On mountain bikes of a certain age, "Biopace" chainrings are ubiquitous. These chainrings are (purposely) not circular. It seems that most people today agree that Biopace rings didn't live up to the ...
10
votes
4answers
445 views

Why use multiple materials on chainrings?

Why is it that on a typical mid-level road triple crankset, the outer rings (larger rings) will be aluminum, while the inner ring (small ring) is chro-mo? It seems to me that if aluminium was good ...
8
votes
3answers
11k views

Do cassettes and chains need to be replaced at the same time?

Someone recently told me that if I replace my cassette I need to replace my chain (and vice versa) so that they wear evenly. Is this true? And, can anyone elaborate on the reasoning for this a bit ...
8
votes
4answers
8k views

Mysterious case: chain falling off large chainring, how to fix?

On my commuter bike I decided to rid myself of the small inner chain ring (which is almost never used) and front dérailleur (now redundant). However, I have come across an unusual problem. Whilst ...
7
votes
4answers
3k views

How to fix front gear taking 2 shifts just to move onto next cog

I was out on a ride yesterday and several times when I was changing up and down between big chain ring and little chain ring (I only have the 2 rings up front) it required 2 gear changes. The gears ...
7
votes
1answer
245 views

Do I need to get a replacement bike for this broken chainring?

I wanted a cheap commuter bike, and just received this bike from Amazon. I have little knowledge about bikes, but looks like the middle chain-ring is broken to me. Is this indeed broken, or is it ...
7
votes
3answers
7k views

How do I calculate the diameter of a chainring from the number of teeth?

Simply knowing the number of teeth on a chainring can we determine an accurate diameter?
7
votes
2answers
7k views

if I replace chainset and chain should I replace back cassette as well?

I am replacing my chainset and chain, as its totaly worn and causing the chain to jump off when I pedal. The cassette is fairly worn too, but is not causing any problems. If I buy a new chain and ...
7
votes
2answers
4k views

Is a 7 speed chainring compatible with an 8, 9 or 10 speed cassette and chain?

Currently I have a 7 speed cassette (13-23) running with a spacer on a new Tiagra hub. After I changed my chain, the wear has made two of the gears unusable. I am considering changing the cassette to ...
7
votes
1answer
4k views

What physically makes chainrings have a specific speed compatibility?

Chainrings are sold as having a specific compatibility for only certain speed setups, some overlapping across many. What physically makes this the case? From what I understand, 5/6/7/8/9 speed chains ...
6
votes
4answers
4k views

How much distance can I put on drivetrain components?

I figure the jockey wheels on my derailer will last nearly forever, but what about the rest: cassette, chainrings, and chain? How many miles, kilometers, or furlongs do they normally last? I know ...
6
votes
3answers
5k views

What is the impact of changing to a smaller chainring?

My road bike has a Campagnolo Veloce gearset. It's running 53 and 39 tooth chainrings. I have a 13-25 10sp cassette. I find that a lot of the time when I'm cruising, I'm on the big chainring and in ...
6
votes
2answers
3k views

How can I keep my chain from falling off the inner chainring? (specifically, from getting stuck in the bottom bracket)

I've got a mountain bike which occasionally drops the chain off the lowest gear, and then the chain gets stuck in the bottom bracket. This happens while pedalling. Once the chain is there, it takes ...
6
votes
2answers
313 views

At what point does one need to replace a chain ring on a mountain bike?

The large chainring on my mountain bike is missing a number of teeth on one side (apparently the side I like to go over rocks on). Is it harmful to the drivetrain to ride without these if I'm not ...
6
votes
1answer
390 views

Is it safe to ride with one missing chainring bolt?

I have a double chainring on my road bike but one of my chainring bolts has broken so I'm left with only 4 out of the 5 I'm supposed to have. Is it safe to ride? (just until replacements arrive)
6
votes
1answer
101 views

Front derailleur rubbing against chainring

I'm trying to fix up my old (1999) Trek 4500, and I've run into a snag while adjusting the front derailleur. It's a Shimano FD-CT92 (bottom bracket mounted E-type), and it's rubbing against the ...
5
votes
5answers
2k views

Why would a manufacturer change chainring sizes drastically between years?

A friend was just showing me the 2010 Cervélo S2 specs, as well as the 2011 S2 specs, and the Ultegra line, at least, changes from a 53/39 chainring set in 2010 to a 50/34 set in 2011. This seems like ...
5
votes
4answers
1k views

Can I increase my highest gear ratio?

I have a modern bike (ridgeback meteor '13) and It currently has a 21 speed shimano chainset. I find that going down hills (which I do a lot) and on flats I need a higher gear. Can I do anything to ...
5
votes
2answers
1k views

Can I run a dual crankset with a chain guide tensioner?

We recently got a new mountain bike for my son via craigslist, it is a couple year old Transition Bottle Rocket and came with a E-Thirteen SS+ chain guide/tensioner. He would like a lower gear for ...
5
votes
2answers
161 views

Is the same effort required to maintain a set speed using different sized chainring / cog combinations with same ratio

If I have a bike with the same cranks setup with a 36t (chainring) / 12t (cog) ratio and the same bike setup with a 48t (chainring) / 16t (cog) ratio, would the effort required to maintain a set speed ...
5
votes
1answer
235 views

Chain Ring Bolts

Having a strange problem removing my chain ring bolt. problem is there is nothing to hold the back piece with because its perfectly rounded/flat, so when i turn the front the whole piece rotates. what ...
5
votes
4answers
1k views

What causes chain suck?

Specifically when changing gears from middle chain ring to smallest, the chain will sometimes get 'sucked' up between the inner chainring and chain stay. It seems to happen more often in muddy ...
5
votes
2answers
227 views

Can double chainrings be used with a clutch-type rear derailleur?

I've been reading up on Sram's CX1 1x11 cyclocross-specific group. It hinges on two technologies to minimize the potential for dropped-chains/chainslap. The CX1 clutch rear-derailleur keeps the chain ...
5
votes
1answer
306 views

Number of gears for a racer

I am looking to upgrade my racer, I currently have a Bottecchia racer from the mid-80s and it has 14 gears. While looking around for newer racers I noticed that a number of them had 20 gears while ...
4
votes
3answers
514 views

Chain slipping on middle chainring

I have recently replaced the chain and the cassette. Previous chain never slipped. I never had any problems with it at all. But I have made about 10 000 km on it and the wear was beyound any limits, ...
4
votes
4answers
5k views

Why are there almost no bikes with a single chainring?

Bikes with two or three chainrings are the norm, and then there are singlespeeds, but except for kids' bikes, you see almost no stock bikes with a single chainring in front but a cassette and ...
4
votes
3answers
2k views

Bent Chainring causing chain to attempt changing gears

I was riding my road bike last night when something strange happened. I stopped at a stop sign. (I didn't have time to slow down so I was in my highest (fastest) gear. When I started I had to press ...
4
votes
4answers
792 views

What's the correct position to assemble eliptic (Biopace, Rotor, etc) chainrings?

If you take a regular, "classic" road chainring (130bcd, five arms), you have five possible positions to assemple it in the crank arm. This can even be used to "rotate" between different positions ...
4
votes
2answers
597 views

Why does the chain tension vary as pedals are turned?

I have a new single-speed bike (after purchase this year, it was unused in a garage for a few months), but as I turn the pedals, the tension in the chain varies noticeably. What should I check, ...
4
votes
2answers
4k views

What are common causes of premature chainring wear?

My bike mechanic told me today that my front chainrings are starting to wear out and I should consider replacing it soon (with my next chain replacement). The cassette is still in good condition and ...
4
votes
4answers
781 views

Cruiser bottom bracket is clicking and grinding

My Trek Pure Deluxe 3-speed cruiser has been making a clicking noise when riding for some time. The problem is faint, and is more felt than heard. However, it's been getting worse; it now makes a ...
4
votes
3answers
6k views

Can I replace chainrings without replacing the rest of the drive train?

I now ride a 60cm SurlyLHT with chain rings at 26/36/48t. Can I replace with a smaller set at 22/32/46t (or similar combination) without having to replace the entire drive train - cassette, rear ...
4
votes
1answer
1k views

Why does my chain keep jumping off the front chainring on my 1x9?

My chain has a tendency to frequently jump off the front chainring. I have a 1x9 so it's not a front derailleur issue. It generally happens when I hit something like the lip of a driveway or sidewalk ...
4
votes
1answer
2k views

Changing from Shimano Road Double Chainset to Triple Chainset?

Road bike setup at the moment is: Shimano Tiagra (9 Speed) Shifters / Front Derailleur / 52-39T Chainset / Short Cage Rear Derailleur / Casette 27-11T. Will I be able to do a straight swap and ...
4
votes
2answers
415 views

How do I tell if my cog needs replacing?

Two answers to this question gather that after 14335 km (8907 mi) of cycling with a single chain, the cog is at risk of being damaged. I haven't noticed anything unusual apart from the chain being ...
4
votes
3answers
934 views

Fixed Gear Chainring Centering

I have a fixed gear bicycle with a chain that gets periodically tight and loose as I complete a rotation of the pedals. How do I center my chainring so that the chain has even tension throughout?
3
votes
4answers
2k views

Bottom bracket with built-in internal hub - does this exist?

I've heard that one can install a bottom bracket that has what is essentially a built-in internal hub, giving one the ability to add a virtual double chainring where there's only one. This would be ...
3
votes
2answers
498 views

Replacement for 52 tooth chainring Ultegra triple ( 6503 ) 9 speed

Hello It seems that the stock 52t chainring for a road triple ultegra 9 speed is on back-order or has been discontinued. Is there a replacement that will fit and shift? This is for my wifes Trek and ...
3
votes
3answers
812 views

Chainring: cheap vs expensive

What am I getting out of a $55 chainring vs a $25 one? Are more-expensive ones longer-lasting, or more lightweight, ...? This is for a $700 single-speed, to give you an idea of quality of bike I'm ...
3
votes
3answers
359 views

Replacing a chainring - what did I do wrong?

TL;DR I thought I could figure out repairs myself but clearly I'm a moron. I replaced the chain and chainring on my fixie last Saturday, and this morning it got scary loose on me. I started to feel ...
3
votes
1answer
455 views

Chainring and cassette compatible?

I've got a 20 year old Cannondale mountainbike (model # scratched off long ago). It's been used as a daily commuter for a few years and for a couple long trips. I've been told that the original ...
3
votes
3answers
198 views

Chain falling off inner chain ring no matter how L screw is set

Bike is a relatively new Cannondale Carbon Synapse with the Ultegra 6800 groupset (although front chainrings are FSA). Has about 1000KMs on it. Bike has been great, but I went out on a ride today ...
3
votes
1answer
148 views

Why are chainrings 50T and larger five-bolt rather than four-bolt?

I've noticed that chainrings 50T and larger all use five bolt holes instead of four, invariant of BCD. How come? Is this simply due to tradition or is there a mechanical stress reasoning?
3
votes
1answer
430 views

Chainring offset - chainline - of Alfine vs. Ultegra/Dura Ace

I have a bike with Alfine 11 and belt drive. I think I could use a 175mm crank, certainly a 172.5, rather than the 170 Alfine comes in (height 6'1" frame size 60cm) and going a little lighter and ...
3
votes
2answers
499 views

What is causing noise/vibration high power input on right hand (drive side) crank?

I am getting a repetitive grinding sound/slight vibration while fully mashing on my Kona-humu single speed. Description of Problem This grinding is more similar to what you would hear from an ...
3
votes
1answer
195 views

Help me to attach inner ring

I have cranks with 4 holes for outer and middle rings attachment. There are no holed for inner ring attachment. On my other bikes crankset middlering has 8 holes 4 for cranks and 4 for inner ring. I ...
3
votes
2answers
323 views

How can you tell how far apart your chainrings are?

I just replaced my cassette and my crank with one from the LBS that the guy said would work. I've had no problems with the cassette, but the crank is too wide so that my front derailleur does not ...