This post addresses bicycle crankset compatibility in terms of mixing various speed cranksets with other components. For example: an 8 speed crankset on a bicycle with 10 rear sprockets and a 10 speed chain (a), or a triple chainring with a front derailleur (FD) constructed for double chainrings (b). It will also address mixing road cranksets with MTB FDs and vice versa (c).
Before you start, to avoid any misunderstanding:
please take the 5 minutes needed to read the compatibility articles use instructions.
Separate posts explain: standards of bottom bracket (crankset) bearings (and axles), as well as bottom bracket compatibility). That will not be taken into consideration in this post, but when acquiring a crankset, make sure that it’s bottom bracket (BB) standard is one that can be mounted on the bicycle frame.
In the post about FD compatibility, other factors important when matching FD and crankset are described. So, even if number of speeds and type of crankset and FD are the same, those factors should also be matched. In short: FD cage shape and number of large chainring teeth it is designed for should match the teeth number of the largest chainring on the crankset it is combined width. Detailed explanation of things one should pay attention to and try to match are listed in the post:
Compatibility – front derailleurs
1. Different number of speeds for crankset, and the cassette
Typical example: can a crankset for 9 speeds be used with a bicycle that has 11 speeds (rear sprockets) and an 11 speed chain (for 11 sprockets)? Or vice versa: can a 10 speed crankset be used on a bicycle with 8 speeds?
All the “speed” chains have almost the same inner diameter (roller width). Despite the fact that chains for more speeds have thinner plates and are therefore narrower (on the outside) than chains for less speeds, the inner width is the same. For detailed explanation look here: Compatibility – chains.
Because of this, teeth thickness of crankset chainrings doesn’t vary much. Also, adjacent crankset chainrings have great difference in diameter and are not as tightly spaced as rear sprockets. So there is no risk of chain, being to wide, to get stuck between two chainrings.
All this enables crankset chainrings to be freely combined with all kinds of chains (and, over the chain, various numbers of rear sprockets). The only complication is the thinner cage of the FDs designed for more speeds. This means, if using a (wider) chain for less speeds, chain will rub the cage with less cross chaining then if a wider cage FD was used. Cross chaining is not advisable anyway, so one can consider this and early(er) warning. Explanation of gear changing and cross chaining is here:
Bicycle gear ratios
Exceptions to this are single speed chainrings, made for wider, 1/8″ thick chains (they won’t work with multi-speed chains) and Shimano IG chainrings (that work only with chains for up to 8 speeds).
2. Mix-matching various types of cranks (chainrings)
2.1. Combining double chainring cranksets with triple FDs
Explanation of important attributes and differences of FDs can be found in these posts:
Front derailleur
Compatibility – front derailleurs
Triple FD has a longer cage (than a double FD), with inner part of the cage being a bit lower, to catch the chain off the third, smallest chainring. If the two chainrings of a double don’t have a big difference in number of teeth (14 or less), triple FD should work just fine on a double (with correct setup of the limit screws and cable, of course). Typical examples are standard road doubles 53-39 (14 teeth), or 46-36 (10 teeth) – a typical cyclo-cross crankset.
If using a popular “compact” crankset, with a large difference in number of teeth between the big and the small chainring, like 50-34 (16 teeth), or 46-30, shifting will be slower, with more possibility of dropping the chain when shifting onto the smaller chainring.
However, even if chainring difference is large, front shifts are usually quite rare (compared to rear shifts), so even then it might work acceptably well (depending on one’s criteria).
2.2. Combining triple chairing cranksets with double FDs
The biggest problem with this combo is that double FDs don’t have a long enough cage, with inner part lowered enough to catch the chain off the smallest, third chainring.
The quality of this pair functioning is affected by the following two factors:
- The lower the difference in teeth number between the largest and the smallest chainring, the better.
For example: 48-38-28 (20 teeth difference) is better than 44-32-22 (22 teeth difference).
Or: 50-39-30 (20 teeth difference) is better than 53-42-30 (23 teeth difference). - The number of large chainring teeth the FD is designed for should match the number of teeth of the largest triple chainring, or be slightly lower.
For example: FD for 50 tooth chainring on a 50-39-30 triple.
Or a FD for a 46 tooth chainring on a 48-38-28 double.
Bad idea is a FD for a 53 tooth chainring on a 44-32-22 triple.
2.3. Combining MTB cranksets with road FDs and vice versa
Road and MTB cranksets have slightly different chainring spacing. Still, this doesn’t cause much problems even to shifters and FDs when mixing them, as is explained in these two posts:
Compatibility – front shifters
Compatibility – front derailleurs
Difference definitely doesn’t bother the FDs. If the shifter, cable and screws for limiting movement are properly set, there won’t be any problems.
Related post – Bottom bracket compatibility:
Compatibility posts are also available in eBook (printable and Kindle) and paperback editions on Amazon:
If you have any questions (or additions and corrections), please use the BikeGremlin forum’s compatibility section:
https://www.bikegremlin.net/forums/bike-compatibility/
The existing comments posted under this article (questions and answers) have been moved to this BikeGremlin forum thread:
https://www.bikegremlin.net/threads/compatibility-09-cranks-ets-article-comments.119/
Thank you Reija!
It took me years to finally move on from 3×9, there is no way 1×12 will have the same gearing options as a 3×9 but I understand the world is dumbing down and one shifter as opposed to two will make life easier to most people by limiting their options and like you said, solving a problem that doesn’t exist. I figure within 10 years or so someone will “discover” how cool is a 2×10 and God forbid a 3×9 lol
Haha. Yes. 🙂
They might even “discover” the friction shifters! 🙂
Hello, Relja!
Can I use a Shimano Mt210 (3x) with a Deore M4100 (10 speed cassette, 11-42T)?
Hi Jappy,
Do you mean if you can use “9-speed” cranks with a 10-speed cassette (and chain)?
If that’s the question, my answer is yes – it works quite well. That is: a 10-speed chain with 9-speed cranks is OK.
Relja
Will a campy triple crank, with the triple front derailleur work in conjunction with a campy cassette that has 12 cogs?
Hi Artie,
I haven’t tested that combo. I’d expect it to work, but haven’t tried it to be certain.
Great article! I have dilemma if the 9 speed system will work with 10 speed crankset. Technically it should, question is how. I have really old bike but really great components that i use for more than 17 years. The FC-M540 crankset needs to be replaced but I cannot see on market something similar. I’m not inerrested in Alivio but in Deore or higher sets. The Shimano FC-T551 looks like good alternative but it is designed for 10 speed system. I’m not a fan of 10+ speed system because of the durability of the material.
I use the old Deore LX dual control shifting system and it work without any problem since 2005. Didn’t had better equipment. The todays “equipment” last for one or two seasons and then it needs to be replaced. I have friends who replace the chains 4 times per season. My Durace CN7701 was replaced after 5 years and still it was usable for emergency purposes.
Cheers
Hi Patrik,
I would expect the 10-speed Deore cranks to work fine, as long as the largest chainring size matches your FD (i.e. is similar enough to your current largest chainring size, assuming that works well).
You might see some chain rub on the larger chainrings happen a bit sooner (when not severely cross chained), but if that is an issue, it can be fixed by using a 10-speed chain (with the 9-speed cassette, it should work fine), or by placing some shims between the chainrings and their mounts (0.5 mm or similar width) to increase their distance.
Another note, just in case it helps: FC-M540 chainrings can be replaced without replacing the cranks (unless there is some other damage).
Regarding component durability – I haven’t done any objective testing & measuring to confirm, but it seems that the more-speed-stuff doesn’t last longer (if not shorter, can’t confirm that 100%), while costing more.
Hi, I have a gravel bike with a 2x FSA crankset 48t/32t with a Sora 9 speed drivetrain. I wanted to switch my 32t to a 30t which has a 4 bolt 90bcd. I saw that the FSA Omega/Vera Pro Chainring has the same bolt pattern and bcd. The description says for 10/11 speed, but no mention of 9 speed. I went to my local bike shop that had the part to inquire and the person indicated that it would not work due to the different spacing. However, based on some forums that I’ve read, it appears that this chainring should work, at worst, it might require a 0.6mm chainring spacer. What do you think?
Thanks
Hi Glenn,
Unless your cranks have some very exotic chainring mounting system, I would expect spacers to do the job.
What worries me is the difference in chainring size. 48-30 combo is 18 teeth of size difference. Modern compact cranks, with 16 teeth difference, is already what I’d call “pushing it a bit.”
46-30 cranks still usually cost an arm and a leg, but that would be my first choice.
Having said that, my current “gravel” build is with 50-34 cranks, since those I got dirt-cheap and my old setup was 53-42, so I hope the gearing will be acceptably low, even though I find the 50T (and 48 for that matter) chainring to be a tad too large for the flats with some headwind, and 34 T way too small for the flats. Still, I went with bar-end friction shifters, so in case of any problems, I can always mount triple cranks with an MTB FD and call it a day. 🙂