Ryan_M

Ok I know this is going to be a lot like asking you what my favorite flavour of icecream is but... I'm strongly considering building a road bike and I have to (more or less) blindly pick gearing when ordering the groupset so I'm hopeful some input will give me something to go on. FWIW I'm likely going to go with an Ultegra R8020 groupset.

Currently I have what started as a Giant Roam 1 but I've done a lot of work to it including a full Deore XT drivetrain 38/28t rings and a 11-42t cassette and that works well for me on that bike for the trails and light offroad we do. I definitely use those lower gears because the GF lives in escarpment country and my knees don't like standing and grinding up hills so I sit and spin, however a road bike is going to be lighter and more efficient so maybe I don't need as low? Also my natural cadence is 95-100RPM and I like a close ratio cassette. I wouldn't say I'm a particularly strong rider and I'm 183cm 85kg, more of a fitness rider. Our short rides are about 40km with better rides being 70-110km.

Again I know it's nearly an impossible question to answer but I'd appreciate anything to go on.
Thanks!

cpach

If you don't care about being able to sprint in a group ride, paceline down a slight incline with a tailwind, etc, or just pedal downhill really really fast (so fast, in fact, that you'd probably be faster focusing on tucking rather than pedaling) you will probably have plenty of top end with a subcompact crankset, 46/30, 48/32, or (GRX only pretty much) 48/31. I'd probably do the GRX 48/31 for the crazy range in addition to matching the rest of the groupset better visually. Aside from "gravel", these make a ton of sense for mostly noncompetitive mostly solo road cyclists. Start with an 11-34 cassette and get a smaller one if you actually find you don't use the 34t very often and/or find the ratios insufficiently close (very much not a big deal with an 11 speed cassette for me personally, but your mileage may vary!)

Lazyass

I'd just run an 11-28 with a 50/34 compact crank. With a 28mm tire and a 100rpm cadence you'll riding less than 10mph in the lowest gear combo. You really going to go slower than that?

BTW standing out of the saddle to climb takes pressure off your knees. And you'll be going faster than sitting and spinning at 1000rpm in a super low gear.

ZHVelo

You could just get 50-34 and 11-34 cassette. Still have the 50-11 for downhill and you have the 1-1 ratio as your lowest gear.

PeteHski

+1
I have this setup on my Giant Defy and it's great for climbing and still reasonable on the flats. Certainly suits a spinning style.

Bob Ross

Y'know how I know you don't have any long >12% grades where you ride?

PeteHski

LOL, was thinking the same. I'd love to be able to hit 10 mph on some of my local steep climbs.

Lazyass

I see the road section hasn't changed much aside from much fewer people visiting.

Lazyass

Generally, when someone has a question about gearing and they live on the Alpe d'Huez they tend to include it in their post.

Reflector Guy

Well, sure, of course. Isn't that where everyone lives?

PeteHski

If you read the OP's first post you will get the impression it is fairly hilly where he rides and he's a fairly big guy with a modest level of fitness. Plus he likes to sit and spin. A lot of people really do ride slower than 10 mph up hills - in fact most people do. It doesn't have to be Alpe d'Huez, they can just be short, steep hills. I don't think there's a lot of point in running an 11-28 these days, when 11-32 or 11-34 is now pretty standard issue on new road bikes with a compact crankset.

escarpment - a long steep slope.....

Kimmo 

If it's too steep for my 39/25, I'm not interested.

Iride01 

Isn't this the road bike sub-forum?

Which to me is endurance bikes on paved roads. I can't imagine using a 38/28 front on the pavement.

mstateglfr 

Currently using a 28-42 bailout and you say run a 34-28.

mstateglfr 

28/42 bailout gearing you have right now is 18.52 gear inches(on a 40mm tire).
30/36 bailout gearing gives you 22.94 gear inches. That is about equal to 28/34 on your current drivetrain, for reference.

30/36 is about the best you will get for a road bike gearing without getting into expensive or wonky options.

A 46/30 crankset mated to an 11-36 cassette can be handled by an Ultegra GS rear derailleur. The Ultegra RD has an official 39t capacity and the drivetrain I mention would be 41t. 41t total capacity drivetrains are commonly seen on gravel bikes. My gravel bike uses an Ultegra RX RD and 41t total capacity- it works fine.
Any smaller for the crankset though and the FD may not shift as well as its designed to.

Lazyass

A 34T is a tiny chain ring. It doesn't take an advanced level of fitness to go up some hills in a 34/28. I would have suggested an 11-32 but he said he likes a close spaced cassette.

surak

If you're going Shimano then get a medium-cage (GS) rear derailleur. You can run 28, 32, 34t max just fine, change it up if whatever you pick doesn't work for you.

I have a decent level of cycling fitness and am light, but vastly prefer a 32t or 34t around here where there are real hills but nothing H.C. I've definitely been overgeared riding my CX bike up the Cat 1s and 2s on equivalent to 34:30 gearing. People using taller gears than that are definitely not spinners.

PeteHski

He also mentioned a natural cadence of 95-100 rpm and steep hills. 11-34 has got to be the best bet for a spin climber. Sure it makes the spacing a little more lumpy, but only flat-landers would complain. I would even consider an 11-36 SRAM cassette on that setup if I wanted to make the climbs an easy spin at that sort of cadence.

terrymorse 

50-34 chainrings and 11-34 cassette seems to be a common gear setup around here, where the Santa Cruz Mountains offer some long and fairly steep climbs.

While grinding up West Alpine Road last weekend in my 34/24 and 34/28 gears, I caught up with a few riders spinning in what looked like 34/32 or 34/34.

They were working, but they had a relaxed pedaling cadence.

SoSmellyAir

Close ratio cassettes generally do not provide sufficient range, especially on the low end.

The current setup of your Giant Roam 1 offers much lower gearing (28T:42T) than even the Ultegra GRX groupset (30T:36T). Perhaps before ordering your new Ultegra groupset, you ride your current bike (as lightly loaded as possible) to your GF's location and see if you can get make it there and back without using, for example, at least the (physically) largest (42T) cog, and preferably the two (physically) largest (37T and 42T) cogs in your current 11-42 cassette. If yes, the math shows that a 46/30 chain ring set and a 11-36 cassette should work.

Or you can just order a 46/30 chain ring set with a 14-28 cassette and (a) hope for best or (b) ask your GF to relocate to somewhere less steep.

PeteHski

It's pretty common everywhere on new road bikes, especially endurance road bikes. It's a good setup for most general riding and certainly my choice for hilly GFs etc. I find it's not so much the length of climbs, more the gradient that matters for gear choice.

HTupolev

What is "some hills"?

guachi

50/34 front and 11-30/11-32/11-34 rear.

The biggest issue with the 11-34 is weird spacing. There are no one tooth gaps. They are all two or more.

SoSmellyAir

Given my meager power output, none of these are close ratio cassettes; I need single tooth jumps from 12T through 17T. Fortunately I do not live in escarpment country; learned a new word today.

genejockey 

I like the 52/36 x 11-34 I have on my Canyon for all around use. The 36x34 is low enough that I often find myself not using it on climbs where I'm in the lowest gear I have on any other bike. And the 52x11 is nice for when I'm descending and want to speed up between corners and don't want to spin like mad.