am8117

So I have just noticed as "trickle down" got us the 4-arm crankset design all the way to Tourney (FC-TY501), when looking at Sora there's still the 5-arm design specifically for the chainguard models.

But even more intriguing, the CX crankset (FC-CX50) of 46/34 is ONLY available in the 5-arm design.

There seems to be little difference in weights between the two designs (best comparable on the R3000 offering, but 3rd party weighted since - oddly - Shimano does not publish this for R3000.

1) Ignoring the GRX for now (which has different chainline and specific FD because of the small chainring), what could be the reason Shimano did not "update" the CX crankset?

2) Why is the CX crankset not the most popular for average riders? It seems everyone wants to save weight, which smaller FC clearly accomplishes and looking at BikeCalc it's very hard to spin out 50/11 (recreational cyclists rarely have 30mph tailwind or pedal hard on such fast descents) while instead marketing is going to sell us bigger cogs that - counterintuitively - add weight to the whole setup, not to mention need for SGS RD and less crisp shifting with larger jumps between the gears especially with 50 chainring.

shelbyfv

The CX-50 has not been in production for a number of years. It came with 50-36 and most riders seem to prefer a 34 small ring. As for "nobody needs a 50t chainring...."

delbiker1 

For the second time, the point is?

Iride01 

Maybe that is the last of a dying breed, not a big ticket item for sales, and Shimano just hasn't seen fit to change up the tooling and machinery for the manufacturing of it's replacement yet. Or maybe that's the product they chose to let their remaining stocks of parts that can't be used for any other purpose get sold from inventory instead of being scrapped from inventory.

What are you asking?

Moisture

I think you are missing two key points here.

1. We are talking about grams here. Not even close to providing any sort of performance gains/losses.

2. Shimano most likely looks at gearing from the perspective of, what sort of cadence would the average rider be maintaining, multiplied by the speed we can expect said rider to reach, with that bike.

If i understand correctly, you are asking why more bikes don't have a 46/48t outer chainring vs. the standard 50-53t found on most road bikes? if so, that is a valid question, but it has absolutely nothing to do with such a tiny difference in weight, or very little to do with what cadence the average rider will be spinning out at.

Iride01 

Well, it's a 10 speed crank. While the average joe among us won't be able to see a difference between a 10 and 11 speed crank, there are differences.

As for weight, it's heavier than the current road group Shimano 105 by almost 85 grams when you compare to the smallest ring offerings of 50/34T rings in the 105 group and its still heavier than the largest rings offered of 53/39 by 41 grams.

I'd think the big market for Shimano is 11 speed, soon to be hot for 12 speed stuff. You seem to only look at the 50-11 combo for the maximum and somewhat unattainable top end performances they give. However for even us lower level riders, the 50-11 or my 52-11 allows me to pedal at a comfortable cadence at times I'm actually resting and only pedaling 70 or so rpm. And I use my 52-11 many times on every ride. Even on the few relatively flat parts.

The FC-CX50 is only made in the 46/36T version today. Possibly a great choice for those needing lower ratio gearing on their road bike. But please don't tout it as the crank for the people. And don't imagine all of us as needing a volks-crank.

Moisture

36/46 absolutely is a ratio which would work great for most people.

Your preference for using 52/11 on "relatively flat paceement" indicates to me you've still got some ways to go when it comes to finding efficient cadence / gear ratios.

Iride01 

You have to realize that I'm in pretty much constantly rolling terrain. So I'm coming off a hill and the speeds I attained down the hill pedaling hard that 52-11 at 110 rpm allow me to slack up somewhat and pedal easy the 52-11 for a while.

I don't maintain a constant speed when I ride. My speed constantly is changing to adjust for the demands of the terrain and whether I'm in a section that I expend energy on or a section I pedal at a power I can rest.

70sSanO

Being a product of decades old high cadence efficiency, I’ve come to the conclusion that it is an extremely limiting approach.

When I started mountain biking I discovered my lower cadence power suffered. You can’t always get out of the saddle and not spin the rear tire.

If I were to do it over, I would have mixed it up more years ago and developed a 60-110 power range.

John

am8117

I am in Europe and was looking for a 48T or 46T double. For some weird reason both the CX50 and R460 can be bought online new and they even COST MORE than the 4-arm ones. There's no other than 50T available for Sora R3000 and Tiagra 4700 silently added 48/34. What do I do when I currently have the 4-arm 50/34 FC, but would like a subcompact and why isn't this the most popular choice for most riders out there? Do they think the GRX will eventually take over the subcompact market?

FastJake

1) My guess is that they just haven't bothered doing it yet, for whatever reason.

2) Ironically it is typically the least experienced riders setting their bikes up with the biggest gears. On the first new bike I ever bought I remember spinning out 48/11 (downhill of course, flat-bar hybrid) and thinking I "needed" taller gearing. Now my road racing bike's tallest gear is 52/13 (equivalent to 44/11) and even that rarely gets used, including on group rides in the high 20s - low 30s MPH range.

You'll go faster down the hill if you tuck rather than pedal at 40+ MPH, but to each their own...

am8117

Fair enough, but I was trying to compare the comparable in that the CX50 and the R460 seem to be common design of the last 5-arm cranksets. Since the most recent 105s do not even offer that, I needed to compare the compact 5-arm Sora with the subcompact 5-arm above and see there's 100g shaved off when going 50 to 46 (on the same design crankset). And comparing inbetween the 50T but within same line (ie Sora), there's litereally no weight saved between 4 and 5-arm design. It just seems the weight savings never really came from going 4-arm to begin with.

If one runs modern Tiagra or above, they always have the logical conversion to GRX, but there seems to be limited subcompact chainrings available otherwise and previously there was the CX crankset which is now kind of disappearing. I can't see 105/Ultegras subcompacts on the offering.

am8117

I am constantly having to shop around for cassettes staring at 13 or even 14T (used with 50/34) and was wondering why not simply go subcompact and be able to use the most popular cassettes while saving 100g but the market does not seem to cater for that. Needless to say, with every cassette starting at 11T the chainline of how it's ridden *most of the time* is not ideal and the gaps around the 20T cogs feel uncomfortable to choose from at times.

I do understand I am not a racer, but this is a CX bike with wide tires and I rarely have "average" riders overtake me - I do not care for how others ride but some of them I am overtaking are riding 53/39s ... smh

FastJake

If you have specific gearing preferences, consider stepping out of the box of what Shimano (and the other big names) are offering right now. Do they even make cassettes that start with 13T anymore? I don't know, but I have a bunch of 8-speed cassettes that do...

As far as cranks go, there tons of options. "Vintage", new, cheap, expensive, take your pick. If you're counting grams, the Rene Herse crank is one of the lightest and offers chainrings from 24-52T.

Iride01 

I'm really confused. Why are you mixing GRX in the same conversation as your needs for a crank. Do you need a crank with the 47mm chain line of GRX or do you need a crank with a chain line of 43.5mm which most road bikes are and some cyclocross. Though I think the trend in cyclocross is going to the wider chain line bikes. But I don't know, I don't follow that closely.

The FC-CX50 is a 43.5 chain line crank not in the GRX line up to my knowledge.

Iride01 

I don't have a hill steep enough or long enough around here to tuck and get to 40+ mph. I live in rolling terrain, not overly hilly or mountainous terrain. I have to pedal to get myself over 40 mph. When I go to CO to visit my son, I do find some places where I can simply tuck and let it rip down the backside.

am8117

Ok so this particular setup I have is made-to-last 9-speed setup. The bike can converted, of course, but pretty happy with that. So in that sense the GRX has not trickled down to 9sp. But anyhow, even the current FC on the bike is 4700 which was meant to be 10sp (FD is 3500) and shifting is crisp.

The reason I mention the GRX is because they offer way smaller chainrings. There was no GRX before, but we had CX cranksets. They seem to have since been abandoned.

In any case, I do not want to make this topic to be of "too low-end" components because the problem of the right gearing is universal and has always been - just the CX cranksets are disappearing.

NB If GRX didn't have a different chainline I would have given it a try, but I am actually pretty happy with 34T in the front, I do not really need smaller chainrings.

shelbyfv

Call me obtuse but I still don't understand what your problem is. If you want a 46-34 you can get the R460. If you want a 46-36, apparently you can still get the CX-50. What doesn't suit you about those choices?

am8117

Sorry I should have mentioned this particular setup is 9sp, but wanted to avoid the discussion to be lineup specific. So yes, for 9sp there's still cassettes starting at 13 even 14T. The more I look at the more I see there was nothing wrong with running a standard road cassette with comfortably small gaps between gears with a CX crankset for a non-racer, but the CX cranksets are disappearing.

kek

There are 46-36 and 48-34 option with 4-arm design:

Shimano FC-R8000 46-36T - 4-arm 2x11 crankset
Shimano FC-RS510 46-36T - 4-arm 2x11 crankset
Shimano FC-4700 48-34T - 4-arm 2x10 crankset

am8117

I do not care for the "old" design, but I am concerned if some time later I will still be able to buy a 5-bolt replacement chainrings if I buy the "obsolete" R460 now.

am8117

Thanks I actually arrived at this conculsion later on yesterday after posting my question, but - and it might make me look unreasonable - I wish I could find 46 with 34 4-arm one for 10sp (since my setup is 9sp and that has worked fine so don't want to push it).

shelbyfv

I wouldn't fret so much about future proofing. Chainrings last a long time and the cost of a complete crankset isn't much more than a pair of replacement rings. Get something and ride your bike.

am8117

Sounds right.

kek

5x110 is as good as 4x110 for future proofing, because it is still being used by other companies

if you really want future proofing, you can find some direct mount cranks with replaceable 5x110 spider