McQz

Shimano 105 cranks and derailleurs, 11-28 & 50-39-30
Short of replacing the derailleur, can we go bigger than 28t on the cassette?

Is there a smaller chainring than the 30t for the 105 crank? It seems like I should be able to go to something like 46-36-26 or whatever the smallest chainring available would be.

We live 60 miles from the nearest bike shop and our transport is a 15mpg pickemup truck, so it isn't very convenient to pop over without having a good idea what I want to do when we get there.

Thanks,

McQz

My wife and I have Specialized Cross Bikes with Shimano 105 derailleurs & cranks, 11-28 cassette, and 50-39-30 chainrings. We use these bike as all-around bikes with rear racks / panniers, cargo trailer hitch, and Burley kid-trailer hitch (I'm the only one who pulls trailers). They are used for all of our around town riding to run errands. (For strictly fun riding my bride and I have road and mountain bikes.) We also take them on road trips as our favored mode of transport whenever we stop to sightsee etc.

In a year I have NEVER used the 50t ring. Much of the time I find myself quite comfortably in the 30t ring! It seems that I should be running different gears.

According to our mechanic the 28t sprocket is the largest that the 105 will accommodate. Examining the front derailleur and chainrings, it appears that there is a margin for change there.

Short of replacing the derailleur, can we go bigger than 28t on the cassette?

Is there a smaller chainring than the 30t for the 105 crank? It seems like I should be able to go to something like 46-36-26 or whatever the smallest chainring available would be.

We live 60 miles from the nearest bike shop and our transport is a 15mpg pickemup truck, so it isn't very convenient to pop over without having a good idea what I want to do when we get there.

Thanks,

10 Wheels

I changed mine to 50-39-24 and a 11-34 cassette. Didn't have to do anything else.

Barrettscv 

Going down to a 28 or even a 26t granny gear is the cheapest and best way to increase the range. Just add a Third-eye chain retainer since the chain might drop more readily.

You will find that the chain goes slack in the smaller cogs while on the 26t granny gear. Just be sure the chain is adjusted correctly, not too short on the big-big combination.

https://harriscyclery.net/itemdetails.cfm?ID=1776

https://www.cambriabike.com/shopexd.a...m=021850000100

10 Wheels

https://www.google.com/products/catal...ed=0CDAQ8gIwAw#

10 Wheels

https://www.google.com/products/catal...ed=0CDAQ8gIwAw#

Drew Eckhardt 

Obviously. You have a cassette with a tiny little small cog. 39x11 nets 27.8 MPH cruising and 36.1 MPH sprinting. 39x12 is still 25.3 and 32.9 MPH respectively.

I'd run 50-39-28 x 13-14-15-16-17-18-19-21-23-26. Tight spacing, plenty of speed on the 39 ring, low bail out gear.

I used 50-40-30x13-14-15-16-17-18-19-21 in the 8 speed era and eventually moved to 50-34x13-14-15-16-17-18-19-21-23 as parts wore out. Never need anything more than 50x13 (even living in Boulder, CO between the plains and Colorado Rockies for 15 years), although having the one tooth jumps to the 19 are wonderful.


You can run a 24 on a 74mm BCD.

When doing so a chain catcher may be prudent.

HillRider

Your 30T granny can be replace with as small as a 24T chainring and I have changed them out for 26T chainring on a dozen or more bikes with very good results. I would also try toi get a cassette with a 12 or better, a 13T small cog. An 11 is a waste of time for you and a 12x27 will certainly work and a 12x30T cassette should work despite Shimano's guide lines.

McQz

I appreciate the input. I really like the idea of a 24t CR. I also agree that the 11t sprocket is wasted on us, but the 10 speed cassette is already there and unless I change out the whole cassette for something like a 12 or 13-30, I'll probably stick with it. Back to the CRs, I REALLY have no use for the 50. I am perfectly happy coasting when gravity draws me down a hill over 30mph - I'm never going to pedal that fast.

With the stock cassette and the 24t small CR, what would you recommend as replacements for the 39 and 50?

CbadRider

The duplicate threads were merged.

McQz

Thanks, I tried editing the 2nd one away and had no success.
Fran

Barrettscv 

You could install TA Alize 130 bcd chainrings. A 46t and a 38t are available, but not cheap.

You could also install a trekking triple like this: https://www.universalcycles.com/shopp...5&category=380

The chainline becomes poor when using a trekking or MTB chainset, however.

Michael

motobecane69

first of all, your mechanic is probably wrong on 28 being the largest you can run in the rear. you definately have a long cage deraileur because you are running a triple and many of us are running 32 tooth rear casettes. Whenever this topic comes up there are those who say "it depends on the length of your deraileur hanger" which may be true yet multiple people post pics of their 105 and ultegra setups with 32 tooth cogs and nobody ever chimes in and says "I tried it and it didn't work" I also agree, if you can get a casette with a 12 or 13 tooth cog it would be worth while.

Since you mention that most of the time you don't even use your middle ring let alone your big ring, you may want to consider just getting a whole new crank. sounds like a MTB crank might be perfect, especially if you are loading up panniers. The 48/36/26 crank option from the post above sounds pretty ideal. A new casette with a 32 tooth cog is going to be $40-80$ depending on the level of casette and that only gets you a small improvement. Add to that the price of a single chain ring and your getting up over $100. Might as well buy the new crank listed above that includes the bottom bracket and pay $20 for your lbs to install it. Same cost as changingn casette and one chainring but this will get you a lot more flexibility.

well biked

I tried it and it didn't work.

McQz

What issue(s) kept it from working?