bblair

Currently running a Shimano Ultegra 11 speed with a 11-32, but considering a mountain century later this summer. My setup is about 4 years old and I think model 6800.

Will my shifters work? New chain with new cassette? Or just swap and ride?

(I found a few in stock and I am tempted to grab them while I can and worry about the other stuff later.)

DiabloScott

It will almost certainly work, assuming the 34t is also 11-speed Shimano. You can check to see if your derailleur and chain have enough capacity by putting it in big-big and see if there's still some slack in the idler pulley.

34t isn't going to buy you much in the way of gearing over a 32t though.

CliffordK

Unless your chain is brand new, it is always recommended to start with a new chain when you get a new cassette. The chain is the cheap part.

I'd look at your current setup to see what you think it will look like with 2 more teeth.

Circumference = πD = 2πR

So, add 1" to the circumference, and the diameter will increase by about 1/3", and the radius by about 1/6"

So, unless your derailleur is absolutely at its max in stretch, or riding right on the sprockets, you'll be OK.

The new cassette will likely come with an extra spacer that you'll need to use.

It is hard to say if you'll benefit. That is a mighty large cassette. But each rider, as well as each ride is differnt.

DiabloScott

I have a 34x27 on one bike and a 34x34 on another bike and I only use the granny gear on one steep section of my regular ride: 275 meters at 15%

I count the pedal revolutions going up this beast.
34x27 = 101 revolutions
34x34 = 127 revolutions

34x32 = 120 revolutions.

Bill Kapaun

But sometimes you only need a tiny bit more.
About every 4th trip from the grocery store with a heavy load I wish my 27T largest cog was a 28T so I didn't have to shift to the granny ring.
OP is asking about a 6% change vs my 4%.

shelbyfv

Another option would be a GRX 46-30 crank.

Barry2 

I went 11-36 on my Shimano 8000 using PG-1170 SRAM 11-36
It's outside Shimano specs for the 8000 You'd have to check it for yourself on the 6800

Barry

Badger6

For the difference the OP is looking for, a few weeks of training for going uphill on his current setup would be sufficient, with a whole lot less hassle and whole lot more benefit.

bblair

You are probably right.

I am thinking about doing the Mountain Mama ride in Virginia and some big climbs there. A few years ago, I did Bike Virginia and a couple of the long climbs were very tough. But, 2 more teeth might have been almost equally tough, but more time.

(I can't believe that "back in the day" I rode a 52/42 and 13-26). How did I get up anything?

70sSanO

Years ago I was running a 13-30 Sachs Aris freewheel. I saw a 32t cog on eBay, bought it, installed it, and rode for years.

Did the 2t really make a difference? Physically, maybe in a rare situation. Psychologically, you bet.

John

bblair

My decision may have been made for me. Took a while, but found cassettes at Biketiresdirect and Excelsports. But chains, no luck. I have been running Shimano Ultegra cassette and SRAM chain.

I will keep looking, but perhaps I should spend that time training instead?

sch

Looked at Biketiresdirect and noted that the HG800 11-34 cassette is a nominal 50% higher than pre covid prices, must
be a lot of Shimano containers floating around off LA or sitting on the docks. FWIW IME a 10 spd KMC, SRAM or
Shimano chain works fine with 11 spd cassettes on three different bikes over the past 4+ years.

Diff between 32 and 34t cassette cog is small but on longer hills can make a difference. My last rebuild included
a chainset swap from 50/34 to 48/32 along with the 34t cassette so the final drive ratio dropped from 1.06 to 0.94
which is noticeable on steeper (>8-9%) or longer hills. Can't believe I once thought a 38/24 was a good hill
climbing gear for riding from Gatlinburg to Cherokee and back in the Smokies 25 yrs ago or Seattle to Billings
in the '70s both on 5 speed freewheels.

zandoval 

I am in agreement that in most cases a two tooth change is not worth the trouble, but if its all you can get without having to make major changes to your drive train, go for it...

"back in the day"... Man... I am so glad to have had those... It brings me a smile when I see some young guy mashing up a hill with minimal effort as I puff along in my 34T Bailout Gear...

CliffordK

I went to a wide crank on one bike. 34/52, I think, precisely because of a wicked hill climb ride I did a few times.

Barry2 

What FD did you use for 18t capacity?

Barry

Badger6

I know that I am. I am not being arrogant, I am being matter of fact. The gains by adding teeth to the low gear mean you can more easily spin the crank, BUT for the given cadence (assuming you use the same cadence), your forward speed will be slower. It feels easier because it requires less power in the moment, but overall could require more effort. Knowing a thing or two about power (aka, watts), from 32t to 34t you are looking at a 1-2% lower power output required to achieve the same cadence in your lower gear to move the bike at a slightly slower forward speed. Because power is really a way to express work over time, despite the lower power required to spin the same cadence, it'll take slightly longer to go up the hills due to the lower speed, and thus any gains achieved by exerting less power on the cranks will be wiped out in that you will have to do it over a longer period. In other words, your specific output in watts may be lower, but the overall KJ expended could end up slightly higher. So, counterintuitively, you may be setting yourself up to actually expend more energy.

As stated by another above, there might be some psychological advantage, but physically you probably won't see any. As I said above, a few weeks of focusing on climbing hills AND building up endurance, I think you'll find that your 11-32 cassette is just fine.

CliffordK

Sorry, that was Stronglight 53/34, 5-bolt rings on Campagnolo Chorus Cranks. Chorus 11 speed Front Derailleur.

I've been off the bike for a little while. I need to get it back on the road. The biggest issue was with the 1st gen, super record 11 speed rear derailleur which gave me a little slack on the small/small combo. Just a touch more range would be nice.

14T range rear.
19T front
========
33T total capacity.

Looking at the Campy specs.. they are listing 34 capacity rear, 16T for front derailleur, I think.

Your front derailleur capacity will be somewhat dependent on the seat tube angle.

===================================================

Another note. The smallest 110bcd 5-bolt chainring for Shimano is 33T. For Camapgnolo 5 bolt it is 34T, I think. One may be able to get the 33T with 4 bolt Campagnolo.

JaccoW

Not the person you asked but I run a 48/28T x 11-32 setup with a Shimano Ultegra FD-R8000-F with this KREX chain catcher for a fun 20T capacity. But I do run friction + index/friction shift bar ends. Deore 11-speed in the back.
Works perfect because of the shaped cage.

Barry2 

I thought I was bad using R8000 rear with 11-36 breaking Shimano’s blessings
You’ve done better using R8000 front with 48/28 breaking the 16t spec with 20t !

Do you actually need the chain catcher? Did you try without?

Barry

zacster

I went from 50/34 and 13-26 to 13-29 and 3 teeth with smaller cogs made a big difference to me, but I'm also 66. 32 vs. 34 I'm not so sure would make nearly as big a difference. I would definitely have gone up to 34 myself but my bike is a Campy 10 setup and I think the 29 is the largest rear cog available from Campy. Besides, I don't foresee any long climbs in my future. The combo I have now is slightly out of spec but works just fine. Sometimes I think the specs are only for the bike manufacturers so they aren't building bikes prone to problems. For an individual though it frequently doesn't matter because you are aware of the limitations (like don't ride big/big or small/small). But even with that knowledge I ride big/big to make it over the last hump if I didn't go to the small ring in the first place.

bblair

Well, I am only 65, so you are one of the older guys that I look up to for advice and inspiration.

JaccoW

I think it might even work with a 22 tooth difference but by that time the front derailleur starts getting way too fiddly with the chain sitting in the narrow part of the cage.

Yeah the chain catcher is necessary. It's a pretty big drop and on a 11-speed chain the distances between the two chainrings starts to become pretty narrow. I even needed custom washers that were made by a forum member to enable the vintage Specialites TA crankset to work with 11-speed chain.
Besides it's a 17 gram piece that makes sure you don't drop the chain and damage your frame. I'm putting them on all my bikes from now on.