Noonievut

I’m building up a new frameset with an 11-sp 105 drivetrain I have on hand, the max cassette range on the lowest gear is, I believe 32. With my 34 small front chain ring I’m a little hampered in getting easier gears up big hills. What is an economical way to upgrade to get more gears on the low end?

Andrew R Stewart 

Can your crankset fit a smaller ring? If so that's likely the lowest cost method to reduce gear ratios. If not than the cost grow very quickly. Andy (who runs x3 cranks on most of his bikes to get BOTH low gears and reasonably small gaps between the ratios)

Bike Gremlin

Apart from using a triple crank with friction shifters, you could use an 11-speed Shimano MTB cassette (36 or more teeth on the largest sprocket) combined with an RD hanger extender if needed, to enable the RD to work with larger sprockets.

That's exactly what we did with my friend's bike and it works very well:

Andrew R Stewart 

I would avoid having to use a hanger extender (Wolf Tooth as example) as it will increase the amount of open chain between the cassette and the guide pulley IN ALL COGS. Often resulting in loss of shifting response when riding in the smaller cogs. One of the goals of Shimano using the slant pantograph parallelogram, a spring loaded B pivot and a pulley cage with the guide pulley axis offset from the cage pivot was to minimize this amount of open chain.

If you get a chance read "The Dancing Chain" by Frank Berto. He describes (among other things) the design elements that ders have used over the years and why some survived to today and why other elements lost out and left the market. Andy

Bike Gremlin

I agree. Even though it does work in practice (tried and tested on a "gravel bike" with a heavy rider and lots of miles).

My preferred course of action would be to use triple cranks, 7-8 speed cassette and friction shifters. It is quite budget, and an extra benefit is greater rear-wheel strength compared to 11-speed road bike wheels with the same OLD.

What you suggested is probably a better option - though I'm not 100% sure if it's cheaper (availability of parts and all). I suppose that switching from say 50-34 to a 46-30 double would probably work fine with the existing FD (it will have to be moved just a little bit lower).
But the above-described option is what my friend and I did on a budget (what was available at the time) and seems to work well.

Iride01 

Evaluate the range of gearing you need. Do you need the high ratio of the 50 front and 11 or 12 rear cogs? If not then look for a crankset with smaller rings altogether. A 32/48 or something there'bouts.

32 front and 32 rear will give you the same low gear as a 34 front and 34 rear.

However, depending your your series of 105 11 speed DR you might actually be in spec for a 34 tooth cog. RD-R7000-GS and you are good. RD-5800-GS and the spec says 32 max. If you have the 5800, then buying a R7000-GS might not cost too much more than the wolf tooth extender will.

Ride lots and long and those currently not quite low enough ratio gears will get easier without having to change them out.

Barry2 

I also needed lower gearing.
First in tried less teeth by replacing the chain rings.
That threw off the chainline and my FD would not adjust far enough to compensate.

So I purchased a R8050 GS (long cage) and a SRAM PG1170 11-36.
That, along with my 50-34, works great for me.

Barry

Feldman

Try the 34 tooth cassette anyway. In my experience Shimano road rear derailleurs are always good for more teeth than the official spec.

Frkl

You may even be able to go higher. I run a 600 Tricolor rated to 28 teeth with a 32 tooth cassette with no problem. It could probably handle 34, just looking at it, but i would need to tighten the B screw a bit more. i tried an extender right away when i installed the cassette, and it created all sorts of chain rub problems, since road bike spacing is tighter than mountain. then I tried it without and it worked just fine.

I think the limiting factor might instead be how much chain the derailleur can wrap. If it cannot handle the whole wrap necessary, you may end up with some gears (big-big combinations) you can't shift into, but you shouldn't be shifting into those anyway.

Frkl

Another thought, although I might be stating the obvious--going with a change on the cassette end can allow you to get an easier gear without affecting most of the other gear choices you have

Going to a smaller chainring will make all the gears (on that chainring) easier. Yes, you will still have the big ring to mash, but the entire range on the small ring with change.

So an important question is, do you want easier gearing in general or just one or two easier gears?

70sSanO

If your 105 crankset has a bcd of 110mm, you are stuck with that inner chainring.

You probably only have 2 choices.

Get a long cage road compatible RD, GRX?, that gets you to a cassette up to 40t. You’ll have capacity issues limiting how much of the cassette you can use in the small chain ring.

Use a Wolftooth RoadLink to get to 40t and maybe get a little worse shifting performance. You will still have capacity issues.

If you are struggling now, adding a couple of teeth isn’t going to make things that much easier. You need a significant change in the lowest gear.

It is just the way it is.

John

TPL

Smaller chainring

70sSanO

With a 110 bcd? Technically a 33t, I suppose.

John

mirfi

What are your gear inches?

Work out the math - https://www.sheldonbrown.com/gear-calc.html.

On all my derailleur bikes I've had to upgrade and Sheldon Brown showed me the way,

rosefarts

I still remember riding and racing on my 11-23 and would occasionally change to the 12-25 for steep days. I tried a 12-27 and hated it, too low. Of course that was on a 53/39.

I can’t do that anymore.

Frkl

There are triple-izer chainrings, so adapters that have tabs into which a third chainring can mount. Availability is patchy, and depends on your BCD.

Your front derailleur might have the range necessary, even if it only rated for a double. Shimano sometimes economizes on things like that by building one version but selling several as something different (see: front and rear V Brakes).

You may run into a front shifter problem, but you could get a cheap Sunrace downtuber or bar end shifter for the front.

But there is a cascade of issues for almost every "solution". A real triple with a proper bail out ring may be worth the money.

70sSanO

OP is building an 11 speed drivetrain. None of that exists.

John

cyccommute 

Not that this solves the problem for Noonievut, but you don’t need to use friction shifters on a triple crank. I’ve put many, many, many miles on triples with STI shifters…even using mountain bike cranks. I do use a Shimano road triple derailer and make sure it’s one of the cheaper ones that Shimano offers. Those work better with triples.

cyccommute 

You are the second person I’ve run across to mention this. However, in practice, I’ve never noticed any change in shifting response in any gear on either upshifts or downshifts. I have a Road Link on my touring bike and have never noticed any issues whether on the stand or on the road. Shifts remain crisp and quick.

Bike Gremlin

Yes, good point. Friction shifters aren't necessary.

In terms of "price to benefit" (as well as in terms of robustness), I think friction shifters are hard to beat. Stll, for those who prefer indexed shifting, what you suggested is the way to go and it's a perfectly good solution.

kek

most economical wide-range rear derailleur for 10-4700 and 11 speed road shimano:

RD-RX400

it officially support up to 36T (unlike R7000/R8000/RX800 with 34T spec), it can also do 40T without hanger extender
it uses 4700 cable pull, that is compatible with 4700, 5800, R7000, 6800, R8000, 9000, R9100 drivetrains 10-11 speed

Noonievut

Thanks for all the tips! There were also lots of questions but I’m going to think through all of this and take time to decide.