MrWasabi

I have a 2014 Fuji Traverse 1.3 that has three chainrings up front. I want to go to one chain ring up front and eliminate the front derailleur/shifter. Can I just add a different chainring to my existing crank/BB setup or is that not possible with the Acera Octalink?
https://bike.shimano.com/en-EU/produ.../FC-T3010.html

I'd rather just change out the chainring and not have to get a new crank/BB and change everything. I guess I could possibly just take off the other two chainrings and use the one left but I want to change the gearing to something like a 40-42T at the same time. The existing 9 speed cassette is 11-32T. I also have another Tiagra cassette I could use which is 9 speed 11-25T. I'm biking in FL, mostly on paved trails with some hard pack at times. Not much if any hills/inclines.

Thanks for any advice on a chainring change and gearing.

AU Tiger

I have a 1x11 drive train with a 40T chain ring and an 11-46T cassette. I really like the simplicity compared to the 3x9 that was on my previous bike. I never have to think about what chain ring I'm on or if I need to shift chain rings - I simply shift up or down.

Having said that, I don't know that you're going to gain anything by going to a 40T or 42T cassette. Riding in Florida, you can probably just stay in the middle chain ring on your current bike almost exclusively. Which means you can treat it like a 1x simply by ignoring the other two rings, and the front derailleur wouldn't even be a factor. I live in a very hilly area and use every gear I have pretty much every ride, so I couldn't get by with a narrower range cassette. But I suspect you can.

The 11-25T you mentioned makes more sense to me for Florida riding. That would give you more options in the range that you actually use, and you wouldn't have to worry about a major change. Swapping a cassette is very simple.

hokiefyd 

I'd recommend riding your usual rides a few times and take note of the gear combinations you actually use. Do you or could you stay in your middle ring up front and do all of your riding on your 11-32 cassette? If not, do you think you'd need just one or two more big gears in the back and that would take care of it? If so, then an 11-40 or 11-42 cassette might work well for you. You could then just take the small and large ring and derailleur off and have a 1x drivetrain that way. Note that you'll very likely need a different rear derailleur if you go this route, as your current one may not clear a 40T or 42T large sprocket. Sticking with 9-speed, Sunrace make an 11-40 cassette and Microshift make an 11-42 cassette that might work well. The Microshift Advent derailleur and shifter would likely round your drivetrain out nicely at a very reasonable cost (non-clutch derailleur is $40 and the shifter is $20). The cassette, either brand, will be less than $40, so you could probably do the whole deal for under 100 bucks.

It would take a little more maths, but it would be instructive to determine the gear inch range you use on a regular basis and then you can evaluate how other drivetrain options would work for you. This may involve a different sized ring up front to get the range or high/low gear you want, but gear inches is sort of a "no kidding" approach to looking at different drivetrains. If you know the high and low you use and where you typically ride, you can usually determine with some confidence whether or not a new drivetrain will work well.

DorkDisk

I read this another way: that OP is considering a 40-42t chainring and he has two cassettes to choose from.

1x conversion by definition is always a crankset issue; specifically from triple to single. Removing two chainrings from a triple is a mathematical solution, not a bicycle one. On shift-y chainrings, your chain will not stay in place. You will need a single speed chainring at least or other retention mechanisms to keep the chain in place.

So, it appears that your crankset can have its chainrings removed. Ideally you'd want the new chainring in the middle position for chainline, but certain sizes may not fit in there as at a certain tooth count the ring will hit the stays; YMMV. Since your bike is a triple derived from MTBs, 40t rings are not that common for that BCD; they seem to top out at 38t.

Many new chainrings will use shaped teeth for chain retention. If they require a specific chain, keep that in mind before you buy. Running a 10 or 11sp chain will not be an issue on 9sp rears but will run up costs. Remember to size the chain correctly, as the shorter chain is one of the biggest benefits of a 1x.

For gearing, its personal. What I do is figure out my max speed whilst on the 11t cog; this means a max chainring of 46t on any bike I own. For the rear, I go with the tightest spread I can get while getting the low gear I need. 11-34 is classic 9sp MTB gears, and 11-25 is classic 9sp road gears. FWIW Im running a 32 front and 11-34 9 sp rear on my 1x conversion, which uses an SLX crankset for a simple conversion. If you can get away with 3x t, look into the new deore 1x cranksets; they are cheap.

MrWasabi

Thanks for the replies everyone,

Yes, you read that right, I'm considering just a single chainring up front and currently have two cassettes to choose from, an 11-32 that's on there now and an 11-25 Tiagra one I have in my stash. Sorry if my terminology is off. With the type of 90/10% paved/hard pack trails I ride on I think the 11-25 cassette might be best. Understood on being able to fit something properly on my middle chainring, I got some excellent advice on that in the mechanics forum. I'm wondering if I can just stay with my current 36 middle chainring and remove the others or will I be giving up too much speed with 36t? Should I just bite the bullet and get a new 1x crankset like in your link but do they make that in a 40-42T and for a 9 speed? I already have a new 9 speed Deore M591 rear derailluer, Deore M590 RapidFire Plus shifter(s) and a KMC X9.99 chain that I'll be getting installed at the same time. I also have a new Deore M591 front derialleur in my stash so I could just stay with what I have and scrap the single speed idea if I'm not going to accomplish too much with the change.

With the type of riding I do, I just don't need all those gears and the the single speed front with less of the right usable gears will make things more simple. I tried doing this a few years ago and riding just got away from me a bit with work and all. I'm ready to tackle it again now.

DorkDisk

Your chainring has ramps and shifty bits not meant for chain retention. You will need to buy either a single speed chainring or additional stuff for chain retention. The new crankset will be lighter and knock all your birds with one stone. As for gearing, thats up to you; no, 40t is not common in the MTB world.


3x9 to 1x9

MrWasabi

Thanks again for the great advice. Nice bike too.

Since it seems I may have a hard time finding a new single speed crankset in the 40-42T range and if I still want to do this, I might be better off just finding a new chainring that won't give me chain problems? I understand it will come down to clearance but any idea on what to target out there? I see a bunch of brands and options out there.

DorkDisk

Look at gravel cranks; SRAM, Shimano GRX; you could also get arms and rings from various brands.

Edit: check to make sure you have a 68mm bb shell; if not, you can only run MTB cranks

MrWasabi

Thanks again,

I have a Shimano Octalink BB and am unsure of what size? I think the Traverse would lean towards a MB? I'll do some more digging to figure it out. I'm still hoping I can just find and add a single 42T chainring to my existing crankset and be done with it.

DorkDisk

Measure the width of the BB shell to find out which one you have.

RaceFace make a 38t thatll fit your crank. 4 teeth at the high end is not that big of a deal IMO.

MrWasabi

Thanks again,

I'll measure it. That ring looks good. So if it says for another speed like 10, does that matter? I was looking at this one too in a 42T:
https://www.jensonusa.com/Shimano-SL...-SPD-Chainring

It's 104BCD. I put it on the middle ring, remove the others and just need to make sure I have clearance? I want to make sure I don't have any issues with the chain and things are smooth afterwards.

AU Tiger

I still don't understand what makes you want to go to a 1x since you can really just get away with using one chain ring on the setup you already have. In my experience, a 1x drive train is convenient for eliminating the need to shift between chain rings by trading multiple chain rings for a wider range cassette. But you don't need a wider range. In fact, you're considering a narrower range cassette. So what benefit will you get from throwing away the other two chain rings as opposed to simply not using them?

MrWasabi

Just looking to simplify things, I guess lose a little weight...tinker a bit. I'd agree keeping a wider range in the rear to make up for the single front if I were mountain biking and needed more range but I spend most of my time in just a few gears with the type of riding I do. If it's too much of a hassle I may just skip it all. Maybe just swapping for the new Deore front derailleur and getting things adjusted may have me using the other chainrings and extra range more since it will help smooth that part out more?