msu2001la

Currently riding with a triple that has 52/42/30 tooth rings and I NEVER use the 30 and only use the 52 when I've got a tailwind or a downhill, or I'm really hammering. (My rear cassette is a 12-25 10-speed) Otherwise, I ride almost entirely in the 42.

I'm going to upgrade my crank and will probably switch to a double, since I ride flat roads in Illinois and really have no use for a triple.
Having a hard time deciding if 53/39 or 50/34 makes sense. The 50 tooth seems right, but 34 tooth seems way too low. Is there such a thing as a 50/39 or a 50/42? Would this result in just a bunch of overlap in gears?

I mostly want to avoid having to constantly switch between big/little up front when riding, and I'm afraid the 34 will be way too low, and the 50 will be too high. Thoughts?

AEO

50/39 exists.

50/42 can be done by switching the 39T for a 42T from your triple.

check out https://www.chainreactioncycles.com/ they have a sale going on for cranksets in the gearing you want.

alcjphil

I used to use a 50 tooth big ring on my road bike with a 39 tooth small ring. I liked the smaller gap in size between the two rings. There are various companies that make 50 tooth rings to fit 130mm bcd cranks, the one I used was made by FSA. You could also buy a compact crank and buy a 38 or 39 tooth ring to replace your inner ring and keep the smaller ring in case you ever need to do some hills

RT

WOW! THAT'S A LOW PRICE! (sorry, had to)

Just picked me up a 105 50/39 for $32!!!

shark2000br

Wow, I'm really wishing I hadn't just bought that same exact crank for 3 times as much USED on ebay last week.

droobieinop

The 50/34 compact crankset has been used on many recreational road bicycles to create a lower and wider range of gearing for the average club type cyclist.

I live in Florida, which is mostly flat, and my Jamis Xenith Comp came with a FSA compact crankset of 50/34. After accidentally dropping into the 34 a few times I swapped out the 34 for a 40 (one tooth larger than the more common 39). I later changed the 50 to a 52, but I'm kinda limited from going any bigger due to the 110 bcd of the crankset.

My suggestion would be to check the sheldonbrown.com gear calculator and play with the range of gears that can be created by swapping out chainrings. Then visit your LBS to find your solution

scirocco

50/36 with an 11-23 is a good flatland combination for solo riding (assuming you change to a compact crank). Small ring into the wind, big ring downwind. Shimano don't make a 10-speed 110BCD 36T but SRAM do and they can picked up cheaply.

If you change out an inner ring from what came with the crank it pays to stick with 10-speed specific ones. There are lots of other brand 9/10 speed rings available but the shifting is not always as good as it could be.

ericm979

You can get 110mm BCD chainrings up to 54t.

ptle

I run a 50/39 on my commuter. I don't think there is too big of a difference between 53 and 50.

droobieinop

I do realize that, however, matching rings for the FSA crankset that I have stopped at 52. And, fwiw, I am kinda silly about aesthetics.

If the bike is only for commuting, then I'd agree. I like to ride fast and long and often found myself spun out while trying to hang onto the group. When I started to do a few races I found the extra effort from being spun up killed my chances of contention. My first race this season I was out the back in the first few miles (not a 10th of the way in) when I couldn't accellerate enough down a short-steep hill because I didn't have enough gear.

So, not much difference for commuting, but every little bit helps when racing.

kayakdiver

Then I'd suggest cutting the steer tube.

kudude

srsly

RT

I don't mind a small ring above the stem, but not a stack. Tube cutter, stat.

droobieinop

oh, ow, stop stop....

This was an older picture, sorry I didn't state that when posting my pic. That was pre-final set-up, I couldn't find a more recent picture showing the crankset.

The point being that I like the black ring with the silver cutaways. Of course, now that I've been called out I had to double check and my newer FSA ring is all black with silver teeth.

oh well. And before you get started, the seat angle is more of an optical illusion.

msu2001la

Thanks for the input, and the link. The price of that 105 crankset is ridiculous, even if it is an older model.

AEO

I think last summer you could buy the 9sp octalink 105 cranksets for $30 off of ebay and the ultegra ones for $40.

The real deals are the 10sp 105 cranksets. $117~$130 for most double, compact or triple, black or silver.

msu2001la

What is the difference between a 9 speed and a 10 speed crank? From what I've read, a 9 speed crank can be used with a 10 speed setup. (In fact, I am currently running an 8 speed triple crank with a 10 speed cassette and chain, and it seems to shift fine)

Would there be an advantage to paying 4 times as much for a 10 speed model vs. a 9 speed model?

clink83

How about fc-r700(ulegraish compact) cranks w/ BB for $95? Sounds like a better deal..
https://www.jensonusa.com/store/produ...kset+W+Bb.aspx

Longmont_Tom

Back a few years, most road bikes came with 53/42. Then 53/39 came along and I think it was mainly for those riding more mountainous areas. I have been riding a triple and, like you, find I often ride all day in the 42 ring if on flatter terrain (love my 28 small ring for really big climbs). My friends with compact doubles are finding (when riding on flatter terrain) they are often switching between rings and the ends of the cassette (big - lttle cogs) trying to find the right gear. I suggest you stay with the 42 and pair it with a 52 or 53 for those tailwind/downhill situations. I don't think 50/34 makes sense for your riding.

merlinextraligh

What's wrong with the current crank? If you don't like having a triple, you can always take the inner chainring off, adjust the front derailleur, and you have a double.

msu2001la

Is an FC-R700 really an "ultegra level" crank?

Thanks. The more I think about it, the more a 50/39 probably makes sense.

I think you're right about the 34t being too low to be useable in most riding, and I don't think I need a 53t (or even a 52t) big since I'm rarely on the small half of my cassette while riding in my 52t now. A 53/39 might work, but the jump between the small and big seems unnecessarily big when I don't need the extreme ends of either gear and sounds like I'd just be cross-chaining a lot.

Nothing is wrong with the current crank. I have a little money to spend on upgrades, and getting a new higher-end double crank seems like it would be lighter than my current entry-level spec triple crank and possibly give me better shifting and gear ratios.

Taking the small ring off doesn't accomplish anything other than removing a tiny amount of weight and getting rid of 10 gears. It also seems like the centerline of my drivetrain would be pushed to the outside too much with this setup, whereas a double keeps things more centered on the rear cassette. The cross chaining on a triple 10-speed is pretty crazy if you're trying to ride 52-25 or 30-12, for instance... but on a double it's probably more reasonable to ride the bigger cogs while in the big chainring, right?

AEO

R700 is more like 105 level (in terms of weight) with DA looking chainrings.
and they don't come in black, standard double or triple options.
or any other size than 172.5mm

so if you don't want a 172.5mm compact crank, then the CRC offer is better.

merlinextraligh

Fixed.

In your own post, you said that the 42 tooth middle ring covers most of your riding. There's little reason, other than vanity, to change. And if you're riding in the middle chainring the vast majority of the time, cross chaining is not an issue.

But it's your money.

msu2001la

So, is your advice that I should buy a new triple crank? I'm buying a new crank either way, or did you miss that part of my post too?

clink83

Of course it doesn't come in a standard double or triple size, it was introduced as an ultegra level compact when there was no compact in the ultegra line. There is a reason there is also an r600, and that was to fill the 105 slot.
FC-R700 comes in 165, 170, 172.5 and 175mm lengths, Jenson just has the 172.5.
It also weights only twenty grams more than a standard ultegra crank, which isn't a big deal at all.
So, I don't know what that your reasoning for that was, but if you want a compact, the r700 crank is a much better deal.