Ultegra rear derailleur and 34t cog...it works ( for me)

[the mayor]

I have seen a lot of questions about rear derailleurs and bigger cogs here.

I just picked up a Ridley X-Fire disc with Ultegra.
Just tried a 34t XT cog set on it. Worked fine....no adjustments needed.
The front ring is a 36t
Your mileage may vary....

[ericm979]

Which model Ultegra? It makes a difference.

[cxwrench]

Which model Ultegra? It makes a difference.

how's that?

[ohiorick]

I just put a 32-11 on my Stevens that has Ultegra DI2, but I had to reverse the "B" screw. It works fine. Not sure how a 34 would work. Like to hear about that.

[cxwrench]

reversing the b tension screw is always a great idea to make a derailleur that's spec'd for a max cog of 28 sort of work w/ a 32 or 34.

not.

when you reverse the b screw you're reducing the number of teeth the chain wraps. this might not make much difference on the large cogs, but on the smaller ones you could get some skipping under power. it's also not helping shift performance either. a hack job at best.

[ohiorick]

reversing the b tension screw is always a great idea to make a derailleur that's spec'd for a max cog of 28 sort of work w/ a 32 or 34.

not.

when you reverse the b screw you're reducing the number of teeth the chain wraps. this might not make much difference on the large cogs, but on the smaller ones you could get some skipping under power. it's also not helping shift performance either. a hack job at best.

Funny, Velo news does not agree with your opinion Ask Nick: Proof that running an 11-32 on Ultegra Di2 is possible

[cxwrench]

Nick is an old friend of mine and i completely respect his mechanical ability. the Di2 derailleurs do seem to work better w/ big cog cassettes than mechanical derialleurs, but i'm going to stick w/ what i posted. it may work ok, but it's never ideal.

[ohiorick]

Nick is an old friend of mine and i completely respect his mechanical ability. the Di2 derailleurs do seem to work better w/ big cog cassettes than mechanical derialleurs, but i'm going to stick w/ what i posted. it may work ok, but it's never ideal.

I will agree with that. It is outside the design of the derailleur, but it works and when my legs can develop enough power to make it skip on the small cogs, I'll put the 28-11 back on and not need the 32 .

[the mayor]

Which model Ultegra? It makes a difference.

It's 6700 standard/short cage.
I get good chain wrap on all the cogs.
No b-screw hack need on the X-Fire frame....
I could stand and stomp uphill..
All the parts are brand new ( except the cog set)...so wear and tear my change this.

[tihsepa]

I love this stuff.

Who cant climb anything paved on a 34 up front with a 28 in the back?
Get a mountain bike. Or a moped.

[the mayor]

I love this stuff.

Who cant climb anything paved on a 34 up front with a 28 in the back?
Get a mountain bike. Or a moped.

Well....apparently....a lot of people can't.
Even Pro Tour guys are going for some small gearing when needed.
Some guy named Contador ran a 34/32 combo...
I'm using this bike on a few dirt road rides that have 14K feet of climbing.
But I'm sure you could do it all in your big ring

[tihsepa]

Well....apparently....a lot of people can't.
Even Pro Tour guys are going for some small gearing when needed.
I'm using this bike on a few dirt road rides that have 14K feet of climbing.
But I'm sure you could do it all in your big ring

Nope, i have a moped.

I am just blown away by this constant push around here for a 1:1 ratio and no triple. Just run a triple. Problem solved. No need to jimmy rig it.

[FTR]

36/34?
You climbing walls?

[tihsepa]

36/34?
You climbing walls?

Exactly. There is a reason nobody does this stuff.

[the mayor]

36/34?
You climbing walls?

Well...there is one section of the D2R2 that causes a lot of people to get off and push...so yeah.
And if Contador raced on a 34/32 last year..and I hear that guy can climb pretty fast....I don't feel bad about a 55 y/o guy wanting a bail out gear.
I plan on running a 36/32 combo...but I had the 34 cog, so I tried it

[tihsepa]

Well...there is one section of the D2R2 that causes a lot of people to get off and push...so yeah.
And if Contador raced on a 34/32 last year..and I hear that guy can climb pretty fast....I don't feel bad about a 55 y/o guy wanting a bail out gear.
I plan on running a 36/32 combo...but I had the 34 cog, so I tried it

I hear Contador eats alot of steak though.

[the mayor]

Nope, i have a moped.

I am just blown away by this constant push around here for a 1:1 ratio and no triple. Just run a triple. Problem solved. No need to jimmy rig it.

What is jimmy rigged about a cassette that fits?
And why install a new crank and shifter if a cassette does the same thing?
Especially if I only run that cassette at a few events.
I may only use the 36 front/32 rear once or twice a year....but it's nice to have.

The bike is my primary cross race bike....and it will have a 42 single front ring and a 28 cog.
But I use it for dirt road events in the summer. At the hardest event....I did the biggest climbs in 38 front/ 28 rear...I made it, but it was a leg breaker.
Going with a 36/32 low this year....because the new bike came with a compact crank...and even if I only use the low gear once or twice all year...

[the mayor]

I hear Contador eats alot of steak though.

No...just trace amounts of steak....

[Jay Strongbow]

Well...there is one section of the D2R2 that causes a lot of people to get off and push...so yeah.
And if Contador raced on a 34/32 last year..and I hear that guy can climb pretty fast....I don't feel bad about a 55 y/o guy wanting a bail out gear.
I plan on running a 36/32 combo...but I had the 34 cog, so I tried it

yeah I know that ride, and Mt. Washington, Lincoln Gap and few others around here.

I think the guy giving you crap rides in the mid-west so you should probably just ignore those comments.

[the mayor]

yeah I know that ride, and Mt. Washington, Lincoln Gap and few others around here.

I think the guy giving you crap rides in the mid-west so you should probably just ignore those comments.

But he has rep power of 37....so he must know all about climbing....on a moped.

[crossracer]

Thanks for sharing, nice to know it works, even if it isn't ideal.
And I don't care what you are riding or why, just that you are.,
Bill

[the mayor]

Thanks for sharing, nice to know it works, even if it isn't ideal.
And I don't care what you are riding or why, just that you are.,
Bill

Hey ....knock it off with the being nice crap. This is the interwebz and there's no place for that. If you aren't going to argue...keep it to yourself...or you'l get negative rep :^)

[ohiorick]

Thanks for sharing, nice to know it works, even if it isn't ideal.
And I don't care what you are riding or why, just that you are.,
Bill

crossracer has said it best. There are some supermen here that can't understand why anyone wants some easy gears. Since I am close to 60 years of age, I won't live long enough to give these 20 something super racers any crap when they get old, I hope someone here will. The rest of us will do what we need to to keep putting in the miles.

[Fred 853]

Just in case anyone is interested, there is a new mechanical Ultegra short cage rear derailleur for road bikes that is designed to take cogs up to 30T. It is the Shimano RD-6700-A-SS derailleur. The "A" in the model number is what differentiates it from the regular model that maxes out at 28T.

[the mayor]

I checked the stamping on the back of mine....looks to be the standard unit.
hanger length and a few other things will be a determining factor on what works on your frame.
I was pretty happy that it works on the XFire....I'm going to be real happy at about mile 88 in Deerfield this summer....