6

When 135mm-spaced QR and 142x12 thru axle disc road frames became the norm, a lot of what was written about bike chainline took on a hidden caveat that in many cases hasn't been corrected, which is that those bikes put the rear ideal chainline in exactly the same spot as their mountain counterparts. Many higher end road cranks are now offered in two versions ...


5

There are two measurements, given as pitch x width. The pitch is the distance between rollers and width is the width that the sprockets have to fit through. The pitch is generally 1/2" on modern chains, but some old bicycles (esp. old track bicycles) use 1" pitch chains (skip link or block chains). The width changes depending on number of speeds (so you'll ...


5

The math is easy to do. According to Sheldon Brown, fatbike chainline is 66 or 76mm for dropout spacings of 170 and 190mm respectively. Assuming a 100mm BB is used with a 170mm dropout spacing and 66mm chainline: a 5" tire is approximately 127mm wide so the tire would extend 63mm off the centerline of the bike. That's only 3 mm clearance if the chain is ...


4

I went to take pictures of the BB installation as @Batman suggested. After removing the crank arm, I actually noticed an offset of 1-2 mm on the drive side, like @mattnz anticipated. However, I also noticed that there was a gap of about 1 mm between the frame and the BB lid: After this observation I googled a little bit, and learned from this forum thread ...


4

As you have mentioned, the point of having a variety of spindle lengths is to allow selection of a BB which creates the proper chain line, while ensuring proper clearance from your frame. (Typically 51 mm from BB center to the center of the chain ring set. The assumption that using the Italian BB mandates a wider BB spindle is not correct. You should have ...


4

If you already adjusted the front derailleur, there is not much to do. As you wrote yourself, the distance between crank arm and chainring is too small for your derailleur. Ask Rotor about compatible derailleurs. The main reason to have derailleur not touch is not noise. The derailleur scratches the crank, which creates a starting point for cracks.


4

Freehub body spacer kits for positioning the rear sprocket include spacers of many different widths. The possible combinations of spacers on the inboard and outboard side of the sprocket to be adjusted to within a few millimeters, which is good enough to get good chainline.


4

There is no hard and fast limit. The farther off the cogs are, the worse vibration and wear you will get. My personal experience is that a couple of millimeters off is still smooth and at 5 mm the chain will be noisy but still work. On a singlespeed it's virtually impossible to throw a properly tensioned chain without breaking cog teeth, but bad enough ...


4

SRAM have emphasized the 1x configuration, but 1x systems can be built from Shimano components too. You are right that a 1x system is pretty much a wide ratio cassette and a single front ring. Double-wide chainrings are commonly used to help chain retention as there is no front derailleur cage to guide the chain. Clutch derailleurs are also used to tame ...


4

Looks perfectly safe to me. In fact, it looks like that crankset's spider arms were designed to also be used as a double crankset for a bike with a front derailleur, with chainrings mounted on both surfaces. Note how the support "fences" inside the bolt holes have the same curvature to clear a chainring that the outside supports do.


4

Yes, that's enough to create situations where you may have chain rub that can't be adjusted out in some additional gears on most road bikes. There are other factors, namely chainstay length - bikes with "pushed" chainstay lengths, i.e. 405mm-ish or less, are notably more finicky about this kind of thing. How important this is depends on your riding habits. ...


3

Random interference with the chainstays/seatstays/dropouts like this just happens sometimes. It's not really anyone's fault. If you added 3mm of spacer to the drive side and took 3mm away from the non-drive side, the wheel will be out of dish. That's fixable, at the expense of increasing the left-to-right spoke tension disparity, creating less total tension ...


3

No. And not only that, if you were to stay with square taper cranks you would find that the BB length for one crank does not necessarily match the BB length for another crank. In other words, if you use a 103mm square spindle bottom bracket A with crank B, it does not mean you would use a 103mm bottom bracket C with crank D, regardless of whether bottom ...


3

It will be 3.5 mm off, and that is quite bad. Square taper bottom brackets aren't that expensive or difficult to replace, just get a correct one.


3

Steel frame can be set out to accommodate a 135 mm rear hub without substantial effort (bear in mind that the dropouts will need to be realigned). With a rear derailleur the chainline is not an issue (in my opinion) as long as it is not kept on the most outside cogs in the rear. You can also play with the chainline by mounting another crankset (different ...


3

Not a specialist on this, but I assume that the 2303 (being a triple crankset) would have the chainline aligned to have the middle ring right on the center of the cassette, while the 2300 would probably have middle of the two chainrings in line with the cassette. You could probably get bottom bracket with a shorter spindle to move the two remaining ...


3

Rear cogs on a 9-speed are about 4.5mm apart, center to center. A typical chainstay length is a hair over 400mm. The arctangent of 4.5/400 is about 0.65 degrees. At such a shallow angle you can simply multiply 0.65 times the number of cogs you're spanning to come up with the angle that is spanned when you shift that number of cogs. In other words, ...


2

Sheldon Brown makes a point about different spindle lengths being to do with seat tube diameter, when listing Shimano BB sizes. He says, Shimano sometimes specs two different lengths for the same crankset. This usually relates to the diameter of the seat tube. The shorter dimension is normally preferred, but bikes with fat seat tubes may require the ...


2

Why would the spindle lengths be different at all? Why wouldn't the Italian BB spindle have the bearing shoulders further apart by 2 mm while keeping the 113 mm length? No idea about this. The great thing about bicycle standards, is there's so many to choose from. I would guess it's to keep the same amount of spindle sticking out of the bottom bracket ...


2

The Steamroller has 120mm spacing (i.e. track hub spacing) in the back (based on the 2011 Surly complete catalog). A modern road hub is 130 mm spacing. My recommendation is to buy a wheel with a 120 mm track hub on it and thread the cog on it -- you could spread (i.e. cold set) the frame in principle (spreading can be done if and only if the frame is steel)...


2

We can make this easy... Lets assume your frame is totally straight and not bent in anyway. Measure front chainline. Chainline is the distance the chain is from the bike's centerline. You will need an inexpensive machinist's scale . A machinist scale is just a small 6" long ruler. On a machinist's scale the zero mark is exactly at the edge of the scale....


2

The Alfine has a chinaline of 42.7mm for a single crank and the Ultegra 43.5mm for the double and 45mm for the triple. For the double the chainline is measured halfway between the 2 rings so the outer ring will be even further out, but the inner further in. Sheldon says "With typical 5 mm chainring spacing, this puts the inner at 41 mm, the outer at 46 mm"....


2

Change into the middle gear in the cassette and check the chain is straight. Otherwise, you may need to remove a bottom bracket spacer (usually 2.5mm thick) from the drive side and move it to the non-drive side or vice versa. (Of course, make sure the chainring does not contact the chainstay on the frame to avoid damage) Failing that, you mention in the ...


2

Kind of a cheap-shot answer, but you could revert back to the original. That would certainly cure your noise problem. I'd be concerned on the follow-on effects of upgrades, where one simple change creates an avalanche of changes and new parts. Perhaps your choice of power meter needed more research? Is it too late to return the power meter and find a ...


2

32 teeth should be enough to clear the frame. Even using a 30 Tooth (pictured below) there is still plenty of frame clearance. That's a different frame, but still, it looks like there would be plenty of room on any frame. The following picture shows a 2010 Big Hit with a 32 tooth chainring, and you can see there is ample frame clearance. The chain device ...


2

I've done the chain-setting by hand for a couple days when I was waiting for a replacement front mech to arrive. It worked, but without a FD cage the chain could bounce around and fall off at bumps, like coasting through gravel. Also, setting the chain while riding was awful-risky because you're bent right down to reach your chain. It gets old fast, and ...


2

Since the front derailleur moves up when shifting out and the outer ring is smaller, the chain will most likely fall off. And shifting inwards will wear the bigger chainring since it is not made for changing gears from the bottom right. The bigger chainring has small pins that will make changing gears smoother but the other side doesn't, so you're basically ...


2

Yes, you need to consider chain line, but that does not mean you cant swap in larger rings on the middle and outer positions. Sounds like right now you are are using the middle and outer chainrings exclusively on your triple crank. If you put two larger rings on the middle and outer positions, there's no actual difference in how you are treating the chain. ...


2

There is a paper on bicycle chain efficiency from John Hopkins that discusses this issue along with others. Basically, cross-chaining being "bad" is a myth with relatively modern chains and cassettes. As long as the angle is shallow enough to prevent the chain catching on the next cassette cog, I think you should be just fine. Even back in the bad old days ...


2

I can give an explanation of what is going on with the setup you have, and why the chainrings seem offset from the cassette. I think that perhaps there is not any problem and you don't need to adjust the chainline. An older bike with a triple drivetrain will have 73mm BB shell (as you said) and a 135mm rear dropout spacing. Standard chanline was 47.5mm. The ...


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