thebluesky

Hi,
My bike is a Di2 Ultegra mid cage with chainrings 52/36 and actual cassette 11-32. I am 70 years old and I have gone through a severe heart operation. Despite of that I have my routine is to bike 30-35 kilometers in fast pace almost daily. In this manner I have succeeded to gain puls at 51-52 b/m . Recently I feel that I need little more help from bigger sprockets such as
11-36 and or 11-40, and I wonder which to choose.
I appreciate any help and advise in this respect.

martianone

BlueSky:
not sure of your terrain.
how much hill climbing is in your ride, wind or rough road ?
i am just a year or two less experienced in life, than you are.
riding in a pretty hilly area, often on dirt gravel roads.
set my road bike up as a 1x, a few years before this was trendy to do.
ride with 39 X 11-36.
if possible, I would swap front chain rings to something lower ?
30 X 44 perhaps ? Not sure what works with your shifter ?

thebluesky

Well I am living in an almost hilly region of Sweden combined with lots of flats and the roads are admirably clean and good. Some climbs are very long and as usual Sweden is very windy two times in the year and each time it blows for 6 months. I would happily change chain rings to 30 X 44 but the another problems come around as you already mentioned.

Bald Paul

You can switch out to compact crankset chainrings (50/34) with an 11-34 cassette.

Troul 

if the 11-40 has the same top end & mid range cogs, opt for the 40T.

VegasTriker

Don't forget to consider the range of your existing rear derailleur. I have a recumbent trike that came with an SRAM X7 rear derailleur and an 11/36 10 speed cassette. When I wanted to duplicate that with a Shimano rear derailleur instead,, it was very difficult to find one that would span that large a difference. 11/32 is no problem to find a number of suitable RDs for Shimano. I found the answer at the Sheldon Brown website where they suggested a suitable wide range RD but with the addition of changing the "B screw" to a longer one.

cxwrench

Doesn't work with his rear derailleur. You should know the specs of the OP's drivetrain before throwing out advice like this.

And for the OP this thread should be in 'bicycle mechanics' not GD.

70sSanO

I have no knowledge of Di2 compatibility, so this may be bunk, but can an XTR Di2 FD operate with Ultegra Di2 shifters?

If it can, you might be able to use smaller chainrings to get there.

John

Troul 

I gave my opinion to the question that the OP asked.

In general, for someone with a health condition, it's not our place to tell the OP what is safe for there needs. Too high of a heartrate can bring about a bad situation when the concern is a compromised organ as such.
The doctor they generally see should be able to referral them to a sports medicine doctor, one that specializes in cycling, that would likely be best in helping them to determine what gearing could be safest.

Advice from a forum is a shot in the dark for what might put them in a risky situation.

cxwrench

You have got to be kidding. The OP's derailleur won't work w/ a 40+ tooth cassette. I don't know anything about his physical condition and this thread has nothing to do w/ that. He asked if he could use a larger cassette w/ his current derailleur. You incorrectly advised a cassette larger than the derailleur is spec'd to work with. Maybe you should read the OP a few more times so you understand what is being asked.

Ogsarg

I have Ultegra DI2 with a compact double and 11-34 cassette. While I admit to never actually trying, I don't think it will handle anything bigger.

urbanknight

Play around with Sheldon Brown's gear calculator and find which ratio matches your desired cadence with the speed you are able to maintain on those climbs.
https://www.sheldonbrown.com/gear-calc.html

And as mentioned above, consider your derailleur's capacity, but you can always change components as needed. It just takes $$$.

70sSanO

I would guess this discussion will eventually turn to an extended derailleur hanger like the Wolf Tooth RoadLink.

I have them on my mountain bikes to run up to a 40t, within rear derailleur capacity.

There are mixed opinions, and I haven’t used one on a road bike, but I think they do as advertised at the expense of some shifting performance at the high end. I have no idea if there are issues with Di2.

It all depends on the priorities and what compromises someone is willing to accept.

John

Bald Paul

It won't.

Troul 

I agree, after rereading, but the op brought up a heart condition that grabbed my attention which took my attention. I never said it it would work with the current der setup.
Have a great day!

PeteHski

This is the obvious solution.

guachi

I'll 2nd or 3rd the 50/34 and 11-34 cassette option. It's readily available and definitely will work (may need a long cage derailleur).

thebluesky

Thank you all for your time and your concern in my question. The specs of the bike in question as follows.

Ultegra Di2

Chainrings: Shimano Ultegra 52/36

Cassette: Shimano 11-32

Derailleur: Shimano GS (Long Cage)

I am just back with changes to the bike Recommended and made by local bike dealer.

-Installed Wolf Tooth Road Link DM for Shimano 11-speed-Ultegra R8000/Dura Ace R9100
-Installed Cassette SRAM Rival PG-1130 Cassette 11-speed 11-36
-Got Shimano Deore XT CS-M8000 cassette 11-speed 11-40 to try if the 11-36 was not suitable
-No changes made to chainrings (the reason mentioned was to prevent high cadence because of health condition)

Maelochs

Ummm ....

CAT7RDR

I had a similar issue with wanting a more user friendly cassette.
On an older Ultegra 6600, I went from a 53/39 to a 46/30 GRX crankset paired with an 12-27 10-speed. The gear gaps are tighter and shifting is smooth.

Maelochs

I honestly don't see why changing the chain rings would be any worse than changing the cassette. Either way the guy wants to spin more.

I have a friend who is a heart-attach and leukemia survivor who just put an 11-40 on his bike because he still wants to ride up hills but he is 70 and fresh out of chemo. He also has strict doctor-imposed limits on heart rate---which he meets by watching his heart rate. He rides the same cadence but more slowly.

Maybe it would be cheaper to add the 11-36 and wolf tooth than to change the chain rings, but what matters is overall ration, not how big the sprocket is. I have to think a 50-34 could be had pretty cheaply .... and that 11-40 (should he ever use it) must weigh a ton.

70sSanO

My vote is a GRX 48-31 crank with the 11-36, maybe an 11-40 if really necessary.

A 48:11 should be enough for a lower cadence at a higher speed.

I would think 31:36, or 40, should be low enough.

There really isn’t an issue with spinning in the 31:36/40 as I’m sure there are a lot more gears available to prevent high cadence.

John

Edit added: There is a possibility that the 31 is so low that it will be necessary to shift between chainrings a lot more if the current 36 is the primary ring being used.

Cyclist0108

thebluesky I have a 2014-vintage Di2 Ultegra setup with a mid-cage rear derailleur officially rated for 32T max.

I'm using an 11-36T (sram) cassette and a 46/30T GRX crankset and it works flawlessly. No need to change anything except the B-screw.

mtbikerjohn 

I'm using an 11-40 cassette with a RX800 gs derailleur...Officially,its not supposed to work,but it does. All I had to do is dial out the b screw.

DaveSSS 

Changing gear ratios doesn't force a rider to spin too fast. That's at the rider's discretion. I'm 68 and I've used a 46/30 and 48/31 with a sram axs 10-36. Having a 40 tooth largest sprocket only creates larger jumps between the sprockets. I've gained enough strength in my 3rd year of my return to cycling to use a 10-33 cassette if I choose, but all that does is add a 14T sprocket. I've logged over 15,000 miles on replacement knees.