digibud

I'm 59 with a host of fun issues like bad knees that keep me from standing up much for power, a torn rotator cuff in both shoulders and I'm overweight at 220 (down from 278 last year because of riding). I ride a mtn bike with skinny tires in the summer on pavement but would really, really like to get a road bike just for the fun of moving a few mph faster. Due to other health issues I can ride strong aerobic speeds but it would be stupid for me to push my heart rate to the max so racing is never going to be important to me, even in an age-group setting. With that in mind, I have settled on a Specialized Roubaix triple. What I'm unsure about is the gearing. I don't want the Apex group. The 105 group doesn't go down far enough for me. I live among big hills and bigger mountains. Occasionally I use all of my mtn bike gears...and while I don't expect to get QUITE such low gears on a road bike, I really need something more than stock 105. I'd like to get something down in the area of 24 inches. I know that's absurd for a road bike but it is what it is and 95% of my rides are alone and I could care less if my cassette is silly. I'd prefer small chainrings with tighter clusters. My big ring is now 44 and I'm confident a 48 on a road bike would be fine but I'm unsure of how to best proceed if I'd like a new carbon fiber bike with what amounts to mtn bike gearing. I don't live in a place where I can find used bikes locally. What I am most interested in is recommendations for how to get the lowest gearing with the tightest cluster (I'll go a wide cluster if I have to) on a Specialized Roubaix. I think the standard 105 cluster might work if I could put a 26 tooth low on my chainring with a 27 rear that would sound great in terms of numbers. I could keep the stock 105 rear. Anyone know if a 26 inner chain is possible on a Roubaix and what would be involved in swapping the crank/chainrings? I will be working with an LBS but wanted some input here for a broader perspective. I'm fairly set on a 105 Roubaix triple. Hopefully this is stop-gap in the sense that when I hopefully drop another 20 or 30lbs I may be able to change gearing...but in terms of helping me get those lbs off I need gears for the hills with me as I am. Thoughts?

BluesDawg

Should be no problem to swap the 30 tooth inner chainring for a 26. your LBS should be able to handle that easily for minimal cost.

10 Wheels

I have a 50-39-24 on my 105 road bike.
With a 11-34 cassette. Didn't have to change the dérailleur.

stapfam

If you have a mountain bike- you probably have a crankset with 44/32/22 rings fitted and an 11/32 or 34 cassette so your lowest gear could be 22/34. But mountain bikes are heavy and you need those gears on the steep road hills. I know I did. I live in a hilly area and used to ride the Road up the 15% hills and I needed that lowest gear. 4 years ago I went road and got a triple on that 1st road bike. 52/42/30 crank and 12/26 casette. Those hills on the MTB I Struggled up in 22/34 were still hard on the road bike with 30/26----but no harder. They were a lot faster though.

2nd bike and I got a compact crank with 50/34 and 10speed 12/27 cassette. Those hard hills on 30/26 were no harder with 34/27. One years road riding and I had improved a lot so I don't think you opught to worry about a triple on a Roubaix. That depends on your hills though.

I went to the Alpes a few years ago with my first bike. I did adapt the gearing- I replaced the 30t Granny ring with a 28. But these were mountains.

If you are still worried about getting a low enough gear- Then get the Roubaix with a triple---but look at the MTB 10 speed XT or SLX cassette.

https://www.merlincycles.co.uk/Bike+S...-+MTB/list.htm

These are 11/34 but to use them you would have to change the rear derailler and a longer chain. This could be done by the LBS at purchase with some reimbursement for the new parts taken from the bike. You could also look at the SRAM XXX cassette but this is 4 x the price of the Shimano ones.

But to be honest- I think you could get by with just changing the Granny on the 105 crank to a 28t. 28/27 will get me up any mountain and I only do those once a year on holiday.

Barrettscv 

I have a 26t "granny gear" on my 105 triple crank and it does work well with a 12-27 ten speed cassette as long as two cautions are considered;

The chain has to be shorter (two links, if the chain was correct) and a "dogs fang", "jump stop" or "chain watcher" needs to be be installed near the 26t chain ring. See: https://sheldonbrown.com/harris/derailers-front.html and scroll down.

The front derailleur will want to place the chain on the inside of the 26t chainring. A guide is needed to keep the chain from dropping during down-shifts.

stapfam

I had this problem on the Tandem when I replaced the 26 granny with a 24. The original chainrings were Sugino and I only replaced the granny- but with a Shimano. Nearly every change and the chain was well and truly locked between the granny and middle chainring. The chain rings were different thickness and it was the wrong way on my set up. I finally changed all the rings to the same make and never had the problem since.

BlazingPedals

Most recumbents use a 'road triple' of either 30/42/52 or 30/39/53, along with a mountain bike cassette such as 11-32. On a road bike, 30/32 would yield something like 24.3 gear inches, depending on your tire size. For that gearing, 105 stuff works very well.

Barrettscv 

I'm using a 26t from Harris in MA and it fits correctly and does not allowing the chain to fall between the 39t and the 26t. The smaller diameter 26t granny gear creates a step & and a half that the indexed shifting does not adjust for. The cage design on the 105 triple FD, combined with the index shifting, wants to place the chain between the granny and the seat post. The dog fang, or any of the other guides, is positioned to solve this problem.

Dchiefransom

I had the same problem putting a 26 tooth little ring on my triple. The drop seems just too far, and I was dropping the chain onto the bottom bracket. N-Gear Jump Stop for me.

Shimagnolo

What crankset is this?

10 Wheels

Tiagra

CHAS

Was living near Moab. 19% grades at the end of the drive.
Put a 26" chainwheel and cassette to 34t on my Roubaix. Switched to a XT derailleur.

doctor j

I have a 105 triple 50/39/28 with a 12/27 cassette, and it works well. The original chain rings were 50/39/30. I replaced the 30 with a 28 and did the work myself. The 28 is a TA chain ring, which I bought from Harris Cyclery. I have not had to use a chain watcher. I believe I've only dumped the chain down to the bottom bracket once. Just make sure the inner limit screw on the front derailleur is adjusted properly.

This is a good configuration for climbing hills/mountains.

badamsjr

I run 24/34/52 with 11/34 9spd on my road bikes, and really appreciate the low gears on hills.

Doug64

I believe you get more bang for your buck (lower geraing) changing the rear cassette. We run a couple of our road bikes with the 50/42/30 and an 11-34 rear cassette. I like the plain Deore rear derailleur because the cage is a little shorter than the LX or XT, and looks a little beter on a road bike. I believe that combination also shifts smoother than a wide range triple crankset. My favorite bike is set up with a 48/36/26 and an 11-34. We ride a lot of hills

24 F---27 R*= 23.3 gear inches
26 F---27R= 25.7
28 F---27R= 27.2
30F---34 R= 23.1
*27 teeth is the largest rear cog for a stock Shimano Ultegra cassette.

I tried keeping the 105 RD on my bike, but just could not get it to work.

oilman_15106

Check this out: Sram Apex road group. I know riders with Sram Red setups that have gone to the Apex rear der. with an 11-32 10 speed cassette. Combined with a compact front this offers quite a bit of low gearing.

https://www.bikeradar.com/news/articl...p-review-25053

Barrettscv 

I've used the Sram 11-32 ten speed cassette on my road bike with a compact crank, see: https://www.bikeforums.net/showthread...t=ultegra+apex

My Cyclocross bike has a triple crank with 50, 39 & 26 chainrings in combination with a 12-27 ten speed cassette.

This provide close gearing on flatter rides but still offers low enough gearing for difficult 15-20% climbs. Very tight gear spacing is available from 16 to 31 mph. Frequent changes on the front chainring are avoided, the 39t chainring is good up to 23 mph and covers most flat terrain riding. The 26t chainring can cover all of steeper climbs, up to 18% or more.

My road bike has a compact double with 50 & 34t chainrings in combination with an 11-32 ten speed cassette.

This provides low enough gearing for the steepest climbs. Tight gear spacing is available in a limited range from 18 to 22 mph. Gearing spacing is twice that of the other cassettes, larger changes in cadence are required with almost all gear changes. Frequent changes on the front chainring are required on flat terrain, the 34t chainring is good up to 21 mph. Steep climbs are possible for all riders.

The Sram Apex 11-32 ten speed cassette in combination with a compact crankset performs on rolling terrain perfectly. I'm able to use 34t chainring and the nine of the rear cogs (12-32) for any uphill situation at speeds less than 20 mph. Steep hills are easy, with a smooth 60 rpm cadence @ 5 mph. That's a real knee saver and makes a long, hilly day much easier. I'm also able to use the 50t chainring and nine of the rear cogs (11-28) for any downhill situation at speeds over 15 mph. As long as the terrain is rolling, up or down, the gearing is golden.

The problem is on flat terrain. Even small changes in speed create the need for shifting of the front chainrings and double or triple shifts at the rear. It's too easy to cross chain on the small chainring or to be on the 17 or 19t cog while on the big chainring.

Now that I'm riding the flat routes near my home in Illinois, I've pulled the 11-32 and put a 11-23 cassette on the wheel. I've also put a standard crankset with a 50 & 39t chainring set on the bike. I'll be able to stay on the 39t chainring up to 25 mph. This will reduce the need to shift to the big chainring to a few times an hour. I'll have a few hills that I'll have to grind out on the 39 & 23 combo, but these are less than 10% and less than 1/2 mile in length.

There is no one-size-fits-all in gearing, but if I had to use just one drivetrain it would be a triple crank with 50, 39 & 26 chainrings in combination with a 12-27 ten speed cassette.

stapfam

This says it all and the triple crank with 50/39 --but for me it would be a 28- coupled to a 12/27 cassette would do most just fine. This would be for the hilliest of areas but will still work on the flatter areas.

jackb

I bought a Novara Randonee touring bike in May but didn't like the gearing: shimano 105 RD with 11-28 and Tiagra FD with 50-39-30. I swapped the 30 for a 24 with no other changes and now have a granny gear of 23 gear inches, plenty low. the shift from the 39 to the 24 and back again works smoothly, though it's a jump. did the swap for the price of the new chainring (23.98) plus postage and the price of a bottom bracket wrench for Octolink (15.95)

ciocc_cat

Sure makes me glad that I presently live in flat-to-rolling terrain where the steepest climbs are usually interstate highway overpasses!

Age: 55. Bike: Early 1980s Ciocc San Cristobal. Gearing: 47/41 chainrings with a 13-23 "cassette" (i.e., Suntour Winner 6-speed freewheel). I very rarely ever need the 41-23 combo.

My advice: if you live in very hilly country, get the lowest "granny" you can get. I used to live in Fayetteville, Arkansas and there's no shame in having a "bail-out" gear that keeps you in the saddle as opposed to walking.

digibud

I really like the 50/39/26 with a 12-27 (12,13,14,15,16,17,19,21,24,27) and I really like the balance of that setup. If all it took was to swap the 30 for a 26 and the FD would still work well, that would be so excellent. The discussion at https://www.bikeforums.net/archive/in.../t-505018.html also seems to indicate this should work.