BobbyG

Last year I bought a 2006 Felt F-65 with its original 2x10 Ultegra gear set. I and my 61-year-old knees live in hilly Colorado Springs and have added lower gear ratios to three of my other bikes while retaining or increasing the high ratio.

On my'84 Nishiki International road bike I first simply swapped a smaller cog in the 2x up front, then years later swapped the rear 6-speed gear set for a wider spread. I also added wider rear spreads on my 2015 2x9 Charge Plug and 1x7 2007 Dahon 20" folder. The folder and the 26" winter wheel set for my 1997 Nishiki Blazer MTB have those big, low bail-out gears with a pronounced drop from 2nd to first...and I don't mind that at all.

The Felt has a relatively narrow rear gear spread, and the front double is wide, and I don't necessarily want to put a smaller cog up front, but would if that is the most expedient choice. I want to keep everything light-weight, as this is the theme of the bike.

Also, is it possible to replace just the lowest rear gear sprocket? I know that mat be a silly question, but if that is practical and inexpensive, that would be my choice.

Although I trust my 3 main local bike shops, I just want to know my options and maybe a best course of action before I begin contacting them.

Thanks!

Kontact

You have to decide how much lower you want. 2 teeth, or like adding a triple granny.

DiabloScott

This is one of the most common questions people ask in here. You should find dozens of previous replies that will help.
But briefly:
1. You can put on a bigger cogged cassette. You'll be limited by derailleur capacity and other factors.
2. You can put on a smaller crank. You'll be limited by selection and derailleur capacity and other factors.
3. You can put a smaller chainring on your existing crank - not usually many options there though because reasons.

Converting to a triple is likely to be way more involved than you'd expect - lots of new components. Unless you've got huge resources of parts, probably not going to be satisfying.

Russ Roth

Need more info, what is the current gearing, without that its hard to say. If a compact crank with a 50/36 might be able to change the 36 to a 34, if a standard road 53/39 not many option without a crank swap. What is the current cassette? An 11-23 or 25 cassette can easily be swapped for an 11-28, depending on the crank an 11-30 can sometimes be made to work but may require a new chain to mesh it and will also require testing in the stand to made sure the der won't rip off. But if the previous owner already put a 34 chainring and an 11-28, you might just be out of luck. If you're worried about your knees you also just might want to look into a shorter crank which is easier on the knees.

Germany_chris

Why not a White Industries VBC

andrewclaus

Post #3 covers the issues I've run into. You need to get the part number of the rear derailleur and get its max cog size and chain wrap capacity. That should be easy with the Ultegra.

I just looked at increasing the range of a 2x9 Ultegra, and found a 28 tooth max cog limit. As I recall, with the range of an 11-28 cassette, the front would be limited to a 16 tooth difference. And the front crank had a minimum cog size of 39. 39/28 isn't quite low enough for my 66 year-old knees on my climbs around Golden. My other 2x9 bike has 34/32.

Chinghis

I'm one of those people who asked this common question, so for me and my Centurion Ironman, I ended up replacing my small chainring, going from a 42 to a 38. Along with a 28t sprocket in the back (biggest that my 1988 Shimano 105 can take, I gather), it allowed me to do the July 4th GMR climb last year (5700' of climbing, 45 miles RT). Honestly I was actually a little surprised I was able to make it as far as I wanted to.

On my sons modern gravel bike, I ended up having to do the Wolf Tooth RoadLink thing with a bigger cassette.

Iride01 

On a 2006 bike with a 10 speed rear, IMO, your best option is to put a 3x on it. A 3x Shimano Tiagra group set can be had new and for not much money. So you can buy all new components designed to work together, or you can do mix and match with some of it. Just depends on your budget. Or you can hunt for used and NOS 10 speed 105, Ultegra, DuraAce or other brands. But IMO, the Tiagra shifts well enough. Though it will be notably heavier in the hand than Ultegra or DuraAce, it won't be so much added weight on your bike to slow you down or make your mountain climbs harder.

And for certain you might not even need that. As another ask, how much lower gearing are you needing? Just a couple teeth more on the big rear cog or what?

DiabloScott

If you get a little lucky, you can find a MTB derailleur that will work with your road bike shifters - and then you can put on a cassette with much bigger cogs.

Here's my example:



This is connected to 9-speed downtube shifters. I have no idea what is available for OP's system.

SoSmellyAir

To determine feasible lower gearing, you got to first identify the existing 2x10 Ultegra drivetrain: what chain rings and cassette are on the bike?

Without that information, I randomly guess that an Ultegra 12-30 cassette may provide lower gearing.

Shimano Ultegra CS-6700 Cassette (Silver) (10 Speed) (Shimano/SRAM) (11-25T) - Performance Bicycle (performancebike.com)

Bill Kapaun

According to this-
https://www.bikepedia.com/Quickbike/...spx?item=12117
You have a 50-34 crank and an 11-23 cassette.
The RDER-6600 has a wrap capacity of either 29 or 38T, depending if it's the SS or GS and a max rear cog of 27T. (you can "usually" fudge another tooth or 3, but no guarantee)
Your bike wraps 28T currently and I'd venture to guess you have the SS.
IF you have a GS version, you could go to a ??-27/28 cassette.

IF you were 9 speed, you could just toss on a "mountain" RDER, but 10 speed changes the rules.
Now days, things are a bit more confusing with the introduction of >10 speed and changing shift pull ratios.

BobbyG

Thank you all for your answers.

I will also mention that when I added a wider gear set in the rear of my 7-speed Dahon, the original Neos derailleur eventually broke, and I replaced it with a more conventional, more capable unit. But with the Felt I still want to keep it light if possible.
Success! Neos Derailleur Replacement with Adapter

Bill Kapaun

So for a couple oz. you want to struggle up hills?
BTW- in your other thread, that's an 8 speed SIS. Shimano Indexed System. It's a rather low level RDER, but it shows even their cheaper stuff can work fine.

MikeWMass

I faced the same question with my 2006 Lemond, I had 10 speed 105 5600 with50/34 and rear 12/28 (I think).
I ended up getting a 5700 triple front derailleur and triple crank. I was lucky that the 105 shifter was triple compatible, so I didn't have to get a new shifter.
I subsequently got a 12/30 cassette and a mid cage 5700 rear derailleur, brakes and shifters on closeout.. (so now I have a 5600 drivetrain for a spare!)

I would vote for the tiagra triple setup (or NOS 105 or Ultegra if you can find it)
With the 30/30 it would be faster to walk with any lower gearing, and I find the front shifts better than the compact double setup ever dreamed of.
I understand your concerns with weight, but truly a couple of pounds will not likely be noticeable.

Whatever you decide, good luck!

BTinNYC

Or...a 105 5701-GS rear derailleur and a 11-32 cassette. Mine works perfectly with a 11-34 cassette, which is 2 teeth bigger than the RD spec.

cyccommute 

A Shimano Mega 9 rear derailer will shift a 10 speed cassette with road shifters. You can find an old Deore, XT or even XTR for reasonable prices that will work and allow you to run an 11-34 cassette. 10 speed Shimano rear derailers with medium cages can also handle 32 tooth cassette.

downtube42

I'd put the biggest cog the rear der can handle, which per post 11 is technically 27 but 28 is probably ok. So 12-28 which is available. Now your wrap is too big by 4 teeth again per post 11. Then I'd replace that pointless 50 tooth chainring with a 46 and you're golden. 46/34 with 12-28.

If 34-28 isn't low enough (and it isn't for me) then either reduce both chainrings (depending on your BCD maybe you can get down to 30), or get a longer RD and a bigger cassette.

Edit: yeah if you have that FSA 120/90 crank, you could drop to 46/30 and get down to 30-28. 90 rpm at that gear range goes from 7.7 mph to 27.7 mph. Around $150 for a new cassette and two chanirings.

grumpus

How attached are you to your current top end? I'm a fan of close ratios on the back and smaller rings on the front because I'm not racing so I don't need to push a knee-crunching big gear. Stronglight 86 mm BCD cranks can be assembled as a double with a 28 tooth small ring and whatever your derailleur can handle for a large ring. I've used these in 32-44 on touring and dirt bikes (because they were available cheaply as 32-44-50 old stock triples) they worked fine for me with 12-26 on the back and short cage rear mechs.
That depends what cassette you have and the maximum sprocket capacity of your rear mech. If the cassette has separate sprockets you can fit whatever large one you can get, but if your rear mech has a 26 t limit you probably won't gain much.

Kontact

A mountain 9 speed Shimano derailleur works correctly with road 10 shifters.

Camilo

Find a regular old Shimano 8 or 9 speed long cage mountain bike rear derailleur - Deore, LX, XT, etc.. They will all work with Shimano 10 speed shifters (10 speed MTB RD will not). Put a 11-32 or 34t cassette on (some will even work with 36t, but aren't spec'd that way) on the rear wheel and Bob's Your Uncle.

We've used that set up with 9 and 10 speed road shifters and both triple (30 and 28t small ring) and compact double (34t small ring) cranks. No problems. Easy set up and not too expensive.

Bike Gremlin

Your 10-speed Ultegra shifters will work with Shimano MTB rear derailleurs for up to 9 speeds. Either get an old 9-speed Deore, or a new 9-speed Acera RD, with a long cage (SGS).
Then, you can mount a larger ("MTB") 10-speed cassette, like 12-34 (or 11-34, whatever you can source).

If a 34T cassette doesn't cut it, you could swap the cranks for some 46-30 Shimano GRX. They might not shift perfectly with your existing front derailleur, but only you can say if that is good enough. Apart from triple, I'd say that for most riders, 46-30 is a lot more reasonable gearing compared to 50-34. Sure, you will lose some top-end speed (as in pedaling even faster when already going pretty fast down hill), but you will get a pretty easy climbing gear for when you get tired. And yes, going from a 34 to a 30 T small ring is not a huge difference, but it adds up (if you also swap the cassette).

BobbyG

Update: the original is a 11-23. I went to the co-op and am having them put a used 12-28 which the tech said is about the limit for the original short cage draillieur. $10 parts, $15 labor. If it needs a new chain that's about another $20 to $25 but a can do the labor on that. I will lose a little on the top end (11 vs 12) but rarely end up in high on this bike, and my hard core mashing days are over.

If this Isn't satisfactory i will look at adding a smaller front cog. It may only be a couple teeth smaller, but with the larger rear it may be enough for now. If not, I'll look at a longer cage deraillier for a wider spread gear set. After that if necessary a compatible mtb bike derailleur/component setup may be necessary. Going used at the co-op and wrenching myself makes it work budget-wise...but I'm not so fond of doing it myself anymore.

I'll update next week after I get the bike back.

Bill Kapaun

A wide double & 11-23T cassette is also the "theme" of the bike.
Lower gears change the "theme" of the bike.
Quit worrying about "theme" in one aspect to suffer in another.

You want to make the bike usable for your needs or you don't,
Pick one.

mirfi

I hate(love) to go all nerdy on y'all, but at 67 I knew I had to lower my Gear Inches, just too old and bad knees, lungs, heart, back, etc...

A special thanks to Sheldon Brown's Gear Calculator

Bike (700c tires) had come with 36/46 on the front and 11-32 on the back.
First went smaller on the smaller front gear 36 to 34 (the smallest that would fit the existing setup).
Gear inches went from 29.7 to 28
Second section I went bigger on the rear cassette from a 11-32 to a 11-36
Gear inches went from 28.0 to 24.9.

May not seem like much, but it was for me.

Note; If I thought the derailleur could have handled a 36+ I would have went there.

Bill Kapaun

+1
It's a situation where sometimes just a little bit more makes a world of difference. Like an inch ='s a foot.

If, as the OP stated "...I will lose a little on the top end (11 vs 12) but rarely end up in high...." with a 50T big ring, they need to up their cadence or join a racing team. Spinning a slightly lower gear slightly faster increased my endurance VERY substantially.