Shimano 11 speed road to XT 11-40 use question.

I recall a discussion about a spacer needing to be added or removed if you swap an Ultegra group's 11-34 with XT 11-40. I'm overall fine with gearing still having Fargo while getting the Route 45 set up for speed and more road use. With an invitation to a mountain trip and barely used XT 11-40 in the box I'm wondering my best steps to get the Routt 45 gearing deeper.

The context is a trip where a friend's not a rider wife wants to do sag wagon duty. Thus, my brain says why not have someone's car that will be present anyway carry stuff and ride the Route 45 instead of the Fargo set up as a full on tourer.

The 34-50 front stock Ultegra is otherwise perfect for most riding I do from home or cabin. Some tell me just put the XT cassette on and a chain with two more links.

I thought about different crank but then I'd lose that high speed gearing I use on rides from home. Yes I know about GRX crank differences but the Ultegra group is why I got a new bike in June vs who knows when. The Fargo and a hard tail MTB address deeper gearing.

There's also putting smaller, lighter faster tires on the Fargo, and Wolf Tooth link options but a cassette and chan swap seem easiest.

Thank you.

mtbnut87 wrote:

^^^   Came here to post this.  I run 11-34 on my "road" wheelset with the spacer.  The thing that confuses a lot of people is the word "Ultegra" on the cassette and then they automatically assume "road".  In this case....  sorta.  Shimano designed this cassette for MTB hubs.  So you should already have the spacer behind your 11-34 OR you have an MTB hub with no spacer....   either way, you should have to make no changes.  Just swap the 11-34 for the 11-40 + longer chain.

 

"Shimano has created gear ranges in the Ultegra line for the most elite road cyclists to gravel grinders, and everything in between, so riders can achieve the sweet Ultegra feel no matter what they ride. In this particular iteration, Shimano creates the Ultegra CS-HG800 Cassette to fit on a mountain bike hub, so those running big touring setups or cross-bikes can now run the smooth shifting feel of Ultegra, and with the huge 11-34 tooth range you won't have issues finding the sweet spot to pedal your way through any adventure."

I'm used to 2x Shimano shifting now after riding Campy and SRAM and the brakes are maybe better than my Rival brakes so in all honesty it seems like Ultegra is great. I'm glad I put priority on frame and wheels over higher end drivetrain stuff.

What's going on is the Routt 45 is just so fantastic, comfy and fast that I want to ride it where I thought I'd choose the Fargo.

Thanks again.

dangle wrote:Assuming you're on the newest 8000 series GS (mid cage) rear derailleur, that's a bit beyond the spec for chain capacity. The 50/34 crank (16 tooth) difference and the 11-34 cassette (23 tooth difference) is the max spec (39 teeth) for that derailleur. Shimano is notoriously conservative so you might be able to get away with the 11-40 cassette (29 + 16 = 45 teeth), but you will have to be awfully careful with your chain length. There's no room for error.

Thank you.

I have the Ultegra RX that I'm certain has the max front 16t and rear 39t you mention thus being concerned. An XT 40t max I took off a new bike some time ago reminds or pokes at my brain for the deeper gearing but for most of my use the stock drivetrain is perfect. We have a Fargo perfect for where my Moots is not but I'm admittedly addicted to pedaling the Routt 45.

As much as people say it will work being at the max for those specifications probably asks for what the Wolf Tooth links do.

dangle wrote:A Wolf Tooth adapter won't improve chain capacity. All it does is move your derailleur further from the cassette. 

mtbnut87 wrote:

@dangle is correct.  The Wolftooth part just helps you clear larger cassettes.  I have a buddy that is running the 11-42 with 50/36 Di2 Ultegra on his 3T Exploro and no Roadlink, so I'd be surprised if you have issues.  If you DO have capacity issues, you can either add a longer cage (not available for this RD) or do what I did...  add a larger lower pulley to eat up some chain length.  I run an 11-46 Sunrace with GRX 46/30 that way with the Ultegra RD8050-GS. 

dangle wrote:Assuming you're on the newest 8000 series GS (mid cage) rear derailleur, that's a bit beyond the spec for chain capacity. The 50/34 crank (16 tooth) difference and the 11-34 cassette (23 tooth difference) is the max spec (39 teeth) for that derailleur. Shimano is notoriously conservative so you might be able to get away with the 11-40 cassette (29 + 16 = 45 teeth), but you will have to be awfully careful with your chain length. There's no room for error.

John wrote:

I tried and could not get this to work over the full front chainring range (46).  Ultimately, what did work with the 11-40 cassette was an XT derailleur with a Wolftooth Tanpan, to index with the Ultegra shifters

In my case the missing piece was a 15t bottom jockey wheel, but it would not have worked in a non-Di2 setup, due to the fact that in Di2 the two smallest cogs are locked out in the small ring.  I simply would not have been able to take up that much slack without a longer RD cage.

Dan wrote:Anyone try an 11-40 or 11-42 with a 105 rear derailleur?  I have a triathlon coming up in Western Maryland where parts of a climb include grades over 30%.  I'd like to put an 11-42 on my 105 equipped road bike to avoid walking on the super steep sections.

mtbnut87 wrote:

I'm not super familiar with the 105 line.  What is the exact model #?  It needs to be the longer cage and "direct mount". The RD-R7000-GS appears to be Direct Mount, which is compatible with the Wolftooth Roadling DM, which they designed for just your need.  You should be able to run the 11-42 with that combo.

I had to buy my wife a GX810 RD, because the RD-6800-GS is "Conventional Mount" which is incompatible and the best I could get hers to work with was an 11-40.

Dan wrote:

I can't figure out what model # it is.  I read that the model number is usually stamped on the outside face of the inner parallelogram plate, but I don't see any model number anywhere.  

Can you post a pic?  Need to see cage length and hanger type.

fourfa wrote:I've got a 11-40 running OK on my RX800 derailleur, no RoadLink, just lots of b-screw.  Also a 16T front difference (46/30).  I write "running OK" because it's basically at its limit, and seems more sensitive to throwing the chain around while backpedaling than I'm used to.  It's far enough out that I need to back the b-screw out when switching to the 36 tooth cassette on my other wheelset or the shifting gets pretty slow.

My GF's bike is 105 (RD-R7000-GS) and the same 11-40 is working fine.  She's not had any backpedal issues for whatever reason.  Also a 46-30 front.  

Lately I seem to see lots more people saying they got 11-40 to work with stock shifters, than needed a Roadlink.

fourfa wrote:Yes, I can use 46 front and 40 rear with no damage, and 30 front and 10 rear with still a little chain tension.  Both make enough noise to make me notice and stop doing it.  This is mechanical shift - if I had Di2 I would for sure lock out these combos and rest a little easier