Commuting - using 48t (or your big chain ring)

Preface: sorry for all the numbers. You might need to read it twice but I really think this is an issue enough of us have, bikes that are geared higher than is useful.


My CC is spec'd with a 48/36. The cassette was 12-25 but I replaced it with a 11-32. That gives me these gear inches on the 48t: 115.1, 105.5, 90.4, 79.1. On the 36t, I can get these gear inches on the high end: 86.3, 79.1, 67.8, 59.4.

I hardly ever spend any time on the 48t. It really seems like an under-utilized chain-ring. I'm making an effort to exploit my bike to its full potential and use the 48t. I mean, someone must use it, right?!

I rode about 4 mostly uphill miles to the LBS to have my bar tape replaced. I used the 79.1 and 90.4 of the 48t. I noticed I was able to pick up and maintain speed better than on the 36t but my cadence was also in the low 60s range. Once I got rolling, though, I might have been able to get it up to the low 70s.
My average speed was between 14 and 16mph. Spinning instead of mashing would have topped at around 13 or 14.

On the way back from the LBS, mostly downhill, I used the same to gears, the 79.1 and the 90.4. My cadence was in the high 60s. With some effort, I could get the cadence up to the high 70s, but never above 80. My speeds were between 17 and 20mph. I did enjoy standing in my pedals on flats and gaining speed quickly but still the two highest gears, 115.1 and 105.5 were not used. Keep in mind it's gentle downhill. The thing is if it were more of a downhill which means work uphill, I wouldn't mind coasting.

65er has said repeatedly anything over 100 on a non-racing bike is a waste. Could I take it down a 44t maybe, would that give me more gears I can use more often? or is there a technique I can use to make better use of the 48t?

If you rarely go faster than 20mph, I'd agree that you have some wasted range there. Is it hurting anything, though?

Do you have a double or a triple?

no, nothing hurts but I rarely take it to the 48t. I'm usually spinning. If I mash, I can take it the high teens.
I have a triple, 48, 36, 26.

I used Sheldon's gear calculator for a 44t big ring and figured I'd be getting 105.5, 96.7, 82.9, 72.5 on the 48t and still 86.3, 79.1, 67.8, and 59.4 on the 36t. That seems a little more useful.

If you rarely go faster than 20mph, I'd agree that you have some wasted range there. Is it hurting anything, though?

my bike is also a heifer with a Brooks Flyer and some heavier stock components. Pedals are flats, also. Definitely not a racing bike.

Those high gears are used mainly for going downhill, huge tailwinds, or pacing behind a really strong rider or a friendly motor vehicle.

Sorry if that sounded confrontational. I've got a 48-38-28 triple on my bike and use the middle gear 95% of the time. The big and little gears are nice to have that other 5% of the time, though. ;)

Sorry if that sounded confrontational. I've got a 48-38-28 triple on my bike and use the middle gear 95% of the time. The big and little gears are nice to have that other 5% of the time, though. ;)

yea, that's how I feel about the granny gear and I'm always glad I have it, but that 5% is usually going up a mountain or down a mountain. I'm not okay walking up a hill but I am okay coasting down one. I just wish the big chain ring were more useful. I could use the 2 lower ones on the 48t but the 2 high ones, at 105.5 and 115.1 are just....not practical. I think I'm going to cross post this in the Bicycle Mechanics subforum. I want to know if I can do a 44t or lower.

Don't worry about what others are riding, and especially not vague rules to ride by. Ride what works for you.I have a 48t single with 12-27, but we have no idea how my commute compares to yours.

you don't need that 11 or a 12 , a 13/48 should be high enough..

Cross Racers , on the turf, are commonly using 46 and 44t outer chainrings ,
so they are on sale.

then maybe the 12-27 cassette is practical, again.

myself 90 is plenty high a GI size.

FWIW. "Standard" road triple is 52(or 53) 42, 30. Back in the day the 'standard' road double was 52/42 now it is usually 52/39. See a pattern? You have a mountain triple and most people using that on the road would not find it over-geared, rather the opposite. The problem as I see it is not with the 48 up front, but with the 11 out back. Back in the day that 11 would have been a 13, or even 14. With a 52, a 14 is a perfectly reasonable top gear for a commuter that will be ridden outside of the Netherlands. As another poster asked, "what's the harm"? You are not obliged to use every cog/chainwheel combination on every trip but it sure is nice when you are ready for anything. My advice is to change out the rear cassette for a 13 - 28. I'm guessing that is what that bike came with. No one puts together a Mountain triple and a Road cassette as a stock setup. No one I know that is.

H

FWIW. "Standard" road triple is 52(or 53) 42, 30. Back in the day the 'standard' road double was 52/42 now it is usually 52/39. See a pattern? You have a mountain triple and most people using that on the road would not find it over-geared, rather the opposite. The problem as I see it is not with the 48 up front, but with the 11 out back. Back in the day that 11 would have been a 13, or even 14. With a 52, a 14 is a perfectly reasonable top gear for a commuter that will be ridden outside of the Netherlands. As another poster asked, "what's the harm"? You are not obliged to use every cog/chainwheel combination on every trip but it sure is nice when you are ready for anything. My advice is to change out the rear cassette for a 13 - 28. I'm guessing that is what that bike came with. No one puts together a Mountain triple and a Road cassette as a stock setup. No one I know that is.

H

Surly's Cross Check comes stock with a 48/36 and 12-25 cassette. I'm not the only person running a 48x12.

EDIT: I just checked the Surly website and the stock cassette is now 11-32 like I put on mine.

I use a 48/38/28 Chainring combo on my 7-speed folding bike. The freeweel is 14-28T and I am currently looking for that elusive 7-speed 11-28T freewheel. I consistently spin out on the last gear.

.........28T.....38T.....48T............................................................
........................................
14 :....36.9....50.0....[63.2-->MPH@120RPM->>22.6]
16 :....32.3....33.8....55.3
18 :....28.7....38.9....49.1
20 :....25.8....35.0....44.2
22 :....23.5....31.8....40.2
24 :....21.5....29.2....36.9
28 :....18.4....25.0....31.6
..............................................................................................
Approimately @ 63 gear inches I suspect most people on here would.

Calc using Sheldon Brown's Gear site

My main ride has a 1x9 setup w/ 42t front and 11/28 cassette; I could easily make do w/ a 7 speed cassette w/ the same range.

Surly's Cross Check comes stock with a 48/36 and 12-25 cassette. I'm not the only person running a 48x12.

Mea culpa... see, I'm old school. These compact doubles and triples make it hard to talk intelligently about gears in mixed (generation) company. But, post #13... when you lay it out like that. I know what a 66" gear 'feels' like cuz I had one on my fixie (ok, single speed) back in the day. Single speed being the operative word... A triple is practically overkill on a bike with a top gear of 63" but most folders roll like that. My folder has what I think is a 48T/14-28 and I would kill for a few less teeth on the top cog (and a few more on the bottom...).

H

you don't need that 11 or a 12 , a 13/48 should be high enough..

Cross Racers , on the turf, are commonly using 46 and 44t outer chainrings ,
so they are on sale.

then maybe the 12-27 cassette is practical, again.

myself 90 is plenty high a GI size.

The 11-32 allows me to stay on the middle 36t ring 99% of the time (I actually use most of those), but maybe I could put the 12-25 again now that my bike is back to commuting duty. (summer tour is over) The 48t can be matched with an 11, 12, 14, and 16...So I guess today I used 48/16 for 79.1 GI and 48/14 for 90.4 GI. Incidentally, 79.1 GI is what 36/12 gets me. 36/11 GI gets 86.3.

I agree that 90 GI is good enough, I like getting up that high for some speed, but then I can only get down to 79.1 while still on the 48t. I wish I could reach up to the 90 and still have the option of getting below 80 GI. Because the 11 and 12 are not practical and I can only use the 48/14 and 48/16, I can pretty much only toggle between 90.4 and 79.1. Great for speed, but the elevation changes more than that. I'm surprised I'm the only one with this problem. The 11-32 cassette only introduced the 11 on the high end...I'm going to keep experimenting with the toggle 48t.

How about a 38t? That would put your high gear at 91.1 and give you a classic half-step-plus-Granny setup, so if you're willing to shift more often you can have both good range and pretty close gear ratios. If you do many long, low-traffic rides, you might appreciate having closer ratios to more easily maintain your preferred cadence.

For commuting with bar-end shifters, I prefer wide ratios so I shift less often and keep my hands on the brake hoods more of the time. But you could get that with half-step by riding "new style" and using only one chainring.

-Peter

Ever since I discovered SunRace offers 7 speed indexed thumb shifters(the old School on top kind) I started making plans of switching to a 14-32 7 speed cog for my ride. I really hated it when shimano quit making those old style shifters, and Paul's Thumbies + Ultegra bar ends are quite expensive. I don't use my 11 or 12 cog on my 8 speed, I find my 48 X 14 gear is great with my 700 X 32s.

I was looking for 44t chain rings 110mm and all I can find is chain rings for single speed/fixie use, that it without pins and ramps for smoother shifting. The first one that kept coming up was Salsa's (http://salsacycles.com/components/chainrings1/). Then, I found Surly's (http://surlybikes.com/parts/stainless_steel_chainrings). They come in every size under the sun: BCD x 34t, 35t, 36t, 38t, 39t, 40t, 42t, 44t, 46t, 47t, 48t, 49t and 50t. The variety might be just what I'm looking for to find the perfect gear range.

Mea culpa... see, I'm old school. These compact doubles and triples make it hard to talk intelligently about gears in mixed (generation) company. But, post #13... when you lay it out like that. I know what a 66" gear 'feels' like cuz I had one on my fixie (ok, single speed) back in the day. Single speed being the operative word... A triple is practically overkill on a bike with a top gear of 63" but most folders roll like that. My folder has what I think is a 48T/14-28 and I would kill for a few less teeth on the top cog (and a few more on the bottom...). H

My 2010 Kona Dew Drop has a 52/40/30 so you aren't crazy. Cross bikes tend to have more MTB like chain rings. My Dew, though MTB component based, is asphalt geared. :-)

I use my middle ring for starting, accelerating and climbing, but for cruising on level or near level ground, I use my big ring. (cassette is 11-34, if memory serves). I definitely maintain a higher cruising speed with the bigger ring engaged and using a middlin' cog (say 15, 17 or 20) than with the middle chain ring and a smaller cog (like the 13 -- the 11 has some weird chain interference issues right now, that I haven't had time to figure out, anyway).

Likewise, I can accelerate or climb far better using the middle ring, and an appropriate cog for conditions (say 23 for starting on level ground or climbing most hills, 26 for slight inclines or climbing bigger hills. The 34 is for really big hills, and is almost useless for starting, except up a steep hill)

My 2010 Kona Dew Drop has a 52/40/30 so you aren't crazy. Cross bikes tend to have more MTB like chain rings. My Dew, though MTB component based, is asphalt geared. :-)

I use my middle ring for starting, accelerating and climbing, but for cruising on level or near level ground, I use my big ring. (cassette is 11-34, if memory serves). I definitely maintain a higher cruising speed with the bigger ring engaged and using a middlin' cog (say 15, 17 or 20) than with the middle chain ring and a smaller cog (like the 13 -- the 11 has some weird chain interference issues right now, that I haven't had time to figure out, anyway).

Likewise, I can accelerate or climb far better using the middle ring, and an appropriate cog for conditions (say 23 for starting on level ground or climbing most hills, 26 for slight inclines or climbing bigger hills. The 34 is for really big hills, and is almost useless for starting, except up a steep hill)

Well said, sir! That is how I use my middle ring, also...but I want to be able to use my big ring for faster riding than is possible on my middle ring. When you say "cruising on level or near level ground, I use my big ring", do you mean your cadence is pretty mellow but your speed is good for the energy being put out?

I'm pretty sure I'm going to get a Surly 42t chain ring. At the 42t, I can get 100.7, 92.3, 79.1, and 69.2;...and the 36t would stay at 86.3, 79.1, 67.8, 59.4, 52.8...and so on. I'm really happy with the 36t/11-32 cassette. A 42t big chain ring would give me the range I want above the 86.3, maxing out at a fair 100.7 for real down hills which I'd most likely coast anyways, but still managing to be able to drop as low as 69.2. As things are with the 48/11,12,14,&16...I'm pretty much stuck at 48/14 and 48/16, the terrain simply demands more versatility. With a 42t, I'd be able to stay on the big chain ring for extended periods and the middle ring as I've been doing. I'm excited! Now where to get the money, haha...

Well said, sir! That is how I use my middle ring, also...but I want to be able to use my big ring for faster riding than is possible on my middle ring. When you say "cruising on level or near level ground, I use my big ring", do you mean your cadence is pretty mellow but your speed is good for the energy being put out?

While I'd love to say I keep a steady cadence at all times, I acknowledge that I often let my cadence drop off some when I am using the big ring to cruise (or climbing gentle hills), say from 85-90 down to about 75-80, and possibly even below 70 sometimes (I don't have anything to indicate my cadence, and I've only recently realized I can count cadence using my Garmin's timer). This works out to 16-18 MPH-ish (my observed speed, and consistent with Sheldon's gear ratio calculator). I don't think in GI very well, so I tend to focus on my cruising speed in a given combination, at my comfortable cadence.

While I'd love to say I keep a steady cadence at all times, I acknowledge that I often let my cadence drop off some when I am using the big ring to cruise (or climbing gentle hills), say from 85-90 down to about 75-80, and possibly even below 70 sometimes (I don't have anything to indicate my cadence, and I've only recently realized I can count cadence using my Garmin's timer). This works out to 16-18 MPH-ish (my observed speed, and consistent with Sheldon's gear ratio calculator). I don't think in GI very well, so I tend to focus on my cruising speed in a given combination, at my comfortable cadence.

TBH, my riding style would probably be really different if I wasn't constantly reminded of my cadence by the bike computer.

Meh.. my Via Nirone has a 50 big chainring, I hardly ever use the small ring. Seriously, only on huge steep hills on weekend rides. My fixed has a 46x16.. no issues.

I don't get it.

You're happy with the low range that your gearing provides. You're also apparently happy with the spacing because a smaller "large" ring won't change that. So why mess with it?

I don't know which front derailleur your bike uses, but it is possible that it won't work as well with the 42.

Who knows? At some point down the road you may want to be able to pedal down some of those bigger hills or take advantage of a strong tailwind. If you decide to get a cassette with closer spacing that doesn't have an 11 cog or even a 12, you may wish you still had the 48.

On my commute I don't typically use the top several gears on my road bike either and could happily spend most of the time on the small ring even though I don't, but there are times that I do want those taller gears.

I kind of like the fact that there's fairly big jump between the small and the large chain rings. When I'm cruising along and need to come to a stop, I can just drop it into the small ring. That usually puts me in a gear I can easily start out in.

Meh.. my Via Nirone has a 50 big chainring, I hardly ever use the small ring. Seriously, only on huge steep hills on weekend rides. My fixed has a 46x16.. no issues.

haha, all right, tough guy. I'm settled on what I'm going to do. =]

I don't get it.

You're happy with the low range that your gearing provides. You're also apparently happy with the spacing because a smaller "large" ring won't change that. So why mess with it?

I don't know which front derailleur your bike uses, but it is possible that it won't work as well with the 42.

Who knows? At some point down the road you may want to be able to pedal down some of those bigger hills or take advantage of a strong tailwind. If you decide to get a cassette with closer spacing that doesn't have an 11 cog or even a 12, you may wish you still had the 48.

On my commute I don't typically use the top several gears on my road bike either and could happily spend most of the time on the small ring even though I don't, but there are times that I do want those taller gears.

I kind of like the fact that there's fairly big jump between the small and the large chain rings. When I'm cruising along and need to come to a stop, I can just drop it into the small ring. That usually puts me in a gear I can easily start out in.

Why mess with it? Because I know what I ride and I never use the 48, never. Why? Because I can only use the 48/14 and 48/16. If the
elevation increases, I shift back down to my middle ring. I don't experience tail-winds, no really huge hills unless I'm looking for them. I'm happy with the low end of the range, I want the high end to be more useful. Even on tour, I'd use the 48 sometimes but I wouldn't need it. I'll ask my LBS if a 42 would work. Or maybe I'll put ask the Mechanics forum. I don't see why it wouldn't. It's a Tiagra Triple btw, with a 48/36/26...42/36/26 doesn't seem like much of a jump. I'll ask around anyways, though. Thanks for the tip. As far as future cassettes, I'm really satisfied with the 11-32. If I changed it, it would be for the 12-25 stock or maybe a new 12-27.

I use a 48/38/28 Chainring combo on my 7-speed folding bike. The freeweel is 14-28T and I am currently looking for that elusive 7-speed 11-28T freewheel. I consistently spin out on the last gear.

.........28T.....38T.....48T............................................................
........................................
14 :....36.9....50.0....[63.2-->MPH@120RPM->>22.6]
16 :....32.3....33.8....55.3
18 :....28.7....38.9....49.1
20 :....25.8....35.0....44.2
22 :....23.5....31.8....40.2
24 :....21.5....29.2....36.9
28 :....18.4....25.0....31.6
..............................................................................................
Approimately @ 63 gear inches I suspect most people on here would.

Calc using Sheldon Brown's Gear site

try one of these two options. I've no experience with either but had considered doing one or the other before just deciding to build myself a 26" wheel with 130 mm axle and a freehub (haven't actually started that yet, but it's in the plans for the winter).

http://www.comcycle-usa.com/Cassettes-and-Chains/Cassettes-24131/5904743-DNP-Epoch-7-Speed/ProductInfo.aspx

or

http://www.ebikessf.com/node/154

Quoting :
I use a 48/38/28 Chainring combo on my 7-speed folding bike. The freeweel is 14-28T and I am currently looking for that elusive 7-speed 11-28T freewheel. I consistently spin out on the last gear.

.........28T.....38T.....48T............................................................
........................................
14 :....36
.9....50.0....[63.2-->MPH@120RPM->>22.6]
16 :....32.3....33.8....55.3
18 :....28.7....38.9....49.1
20 :....25.8....35.0....44.2
22 :....23.5....31.8....40.2
24 :....21.5....29.2....36.9
28 :....18.4....25.0....31.6
..............................................................................................
Approimately @ 63 gear inches I suspect most people on here would.

Calc using Sheldon Brown's Gear site

if you convert to a hybrid hub like a dual drive , SRAM, Sturmey Archer both..
that top gear in high in the hub is 133% larger,
and perhaps the triple chainring set can revert to a double, since the low gear
in a 3 speed is 0.75:1 and then the low can be derived that way..


and there is a Caprio hub and cassette made for folding bikes , 11 is the 2nd cog
9 is on top , low is a 26..

Why mess with it? Because I know what I ride and I never use the 48, never. Why? Because I can only use the 48/14 and 48/16. If the
elevation increases, I shift back down to my middle ring. I don't experience tail-winds, no really huge hills unless I'm looking for them. I'm happy with the low end of the range, I want the high end to be more useful. Even on tour, I'd use the 48 sometimes but I wouldn't need it. I'll ask my LBS if a 42 would work. Or maybe I'll put ask the Mechanics forum. I don't see why it wouldn't. It's a Tiagra Triple btw, with a 48/36/26...42/36/26 doesn't seem like much of a jump. I'll ask around anyways, though. Thanks for the tip. As far as future cassettes, I'm really satisfied with the 11-32. If I changed it, it would be for the 12-25 stock or maybe a new 12-27.

The tech docs (http://techdocs.shimano.com/media/techdocs/content/cycle/SI/TIAGRA/FD-4403/5EW0B_EN_v1_m56577569830606953.PDF) for the Tiagra front triple recommend at least a 10 tooth difference between the large and middle chain rings, so you might run into some trouble.

There's no law that says you need to use the large ring x percentage of the time. If the middle ring is sufficient for 90% of your riding then that just means there's one less thing you need to fiddle with while riding. Just shift the rear.

By reducing the size of the large chain ring you aren't enabling yourself to more fully utilize the capability of the bike, you're just limiting its capability.

What would make sense to me is closer spaced rear cassette favoring the lower end of the range. That would eliminate the higher portion of your current range that you don't use while giving you something in return, - closer spacing.

fietsbob, you are looking for that elusive 11-28T FREEWHEEL? I think that's a cassette. My research on that shows a freewheel requires enough space for a tool to prevent anything smaller than 13T. One online retailer used to modify freewheels to 11T but they told me they stopped doing that.

My guess is you'd need to change rear hub and may have to change spokes or even just build another wheel.

I use the big ring on my triple more now that I've been shifting using half step gearing, and like it. Use what works for you, and don't be afraid to experiment.

If you're never using your big ring, why not just replace it with a bash guard?

fietsbob, you are looking for that elusive 11-28T FREEWHEEL?

no I'm not , but if you, OP, give up, on finding
what was a rather short production run, item ..
It's an option.

I'd think for the high gear .. ( a little math)
if an IGH is 1.33 [ 4/3], then a 13t cog turned 1.33 [ x .75 inverse .. 3/4], ..
would functionally be like a 9.75 t

Myself, I have a Brompton with a simple Sturmey Archer AW3
currently have a 15/54, 3.6:1, a 13/47, will do about the same thing.

mine is turning a 349-37_ 16" wheel .. It goes down the road just fine..

http://www.velominati.com/blog/wp-content/uploads/2009/11/big-ring1.jpg

It's nice to see I'm not the only one who obsesses over gearing.

I've got my winter bike set up with a 46-34 compact double and 12-27 cassette. That gives me this range:

102.6 75.8
94.7 70.0
87.9 65.0
82.1 60.7
76.9 56.9
72.4 53.5
64.8 47.9
58.6 43.3
51.3 37.9
45.6 33.7

The high end is still more than I usually use, but I like the mid-range of the big ring a lot for my commute, and the 34T gives me a low enough gear to get up the 10-20% climb at the end of my commute.

Right now I've got a 38-36 double setup on my CX race bike. I've been using the 38T ring as a bash guard until my real bashguard got shipped (came in yesterday), but to my surprise, I can shift very well between the two rings.

You got a motor paced bike drive there,[#35] once the air is out of the way ,

in the suction behind another vehicle you can really get up to a good clip.

check out Schlumpf High Speed Drive, an internal overdrive planetary
gear turns the chainring 2.5X the crank arm speed.

that 48t becomes a 120 tooth, functionally..

I will preface this post by saying that I am relatively inexperienced. However, my Kona Dew has chainring's of 28/38/48. I rarely find the need to be anywhere other than the middle (38) chainring. The freewheel is 11-34, 8 speed. It's gotten to the point where I almost wonder if a ss would suffice as little as I shift. Then again, Phoenix is not very hilly or windy, which works to my advantage.

My CC is spec'd with a 48/36. The cassette was 12-25 but I replaced it with a 11-32. That gives me these gear inches on the 48t: 115.1, 105.5, 90.4, 79.1. On the 36t, I can get these gear inches on the high end: 86.3, 79.1, 67.8, 59.4.

I hardly ever spend any time on the 48t. It really seems like an under-utilized chain-ring. I'm making an effort to exploit my bike to its full potential and use the 48t. I mean, someone must use it, right?!




I have a CC and I never get off the 48 and wish I had a 52. I think my 38 small ring is nearly minty fresh.

haha, all right, tough guy. I'm settled on what I'm going to do. =]

Hah.. i'm not that tough, I just don't like spinning fast.

try one of these two options. I've no experience with either but had considered doing one or the other before just deciding to build myself a 26" wheel with 130 mm axle and a freehub (haven't actually started that yet, but it's in the plans for the winter).

http://www.comcycle-usa.com/Cassettes-and-Chains/Cassettes-24131/5904743-DNP-Epoch-7-Speed/ProductInfo.aspx

or

http://www.ebikessf.com/node/154


Not meaning to hi-jack the OP's thread but thanks for the link. I've been looking for a 11T freewheel. I've read bad things about DNP machined freewheels. Anyone chime in on these?

http://www.velominati.com/blog/wp-content/uploads/2009/11/big-ring1.jpg

Holy Drillium Batman !

It's nice to see I'm not the only one who obsesses over gearing.

I've got my winter bike set up with a 46-34 compact double and 12-27 cassette. That gives me this range:

102.6 75.8
94.7 70.0
87.9 65.0
82.1 60.7
76.9 56.9
72.4 53.5
64.8 47.9
58.6 43.3
51.3 37.9
45.6 33.7

The high end is still more than I usually use, but I like the mid-range of the big ring a lot for my commute, and the 34T gives me a low enough gear to get up the 10-20% climb at the end of my commute.

Right now I've got a 38-36 double setup on my CX race bike. I've been using the 38T ring as a bash guard until my real bashguard got shipped (came in yesterday), but to my surprise, I can shift very well between the two rings.

are you contradicting what tjspiel said about needing a minimum of ten teeth between rings? I have a Tiagra Triple btw. What front derailleur, are you working with?

I use the big ring on my triple more now that I've been shifting using half step gearing, and like it. Use what works for you, and don't be afraid to experiment.

what's half step gearing? The range is good on the middle, but sometimes I just want to be able to push some high GIs without having to switch back down to the middle ring on an unexpected elevation change.

are you contradicting what tjspiel said about needing a minimum of ten teeth between rings?

Not exactly. As with most bike specifications, the specification means "this is what we intended the part for and what we've tested with." Things always work best if you stay within the specifications. However, there is almost always some gray area outside the specification where things will work acceptably. My 36-38 case is both ridiculous and extreme. I was surprised the thing shifted at all.

The line in the Tiagra triple front derailleur specification that calls for an 11-tooth minimum difference between top and intermediate rings probably means that with less of a difference the derailleur cage may scrape the middle ring teeth when you have the derailleur height properly adjusted for optimal shifting on and off of the top ring. You can get around this to some extent by installing the derailleur higher, but the higher you set it, the worse it will shift. A some point you may also have problems with chain scraping the cage when you're on the small ring.

I'm using a 105 double front derailleur in my 36-38 setup. It turns out the the height of the derailleur was dictated by where the bottom of the cage hits the chainstay. That would make for poor shifting, but since I'm actually just using it as a chain catcher it's OK. The chain does rub the derailleur a bit if I shift onto the "big" ring, but I don't intend to do that. In any event, doubles are much more forgiving of poor setup than triples.

Some numbers that might be useful:

100 GI, pedaling at 100 rpm = 30 mph
100 GI, pedaling at 80 rpm = 24 mph
80 GI, pedaling at 100 rpm = 24 mph
80 GI, pedaling at 80 rpm = 19 mph

The only time I'm going much above 20 mph is either down hill or wind at my back. In either case pedaling is easy and I don't mind upping the cadence. Like others I have low gearing on my bike (44/33/22 in front, 12-27 in back, 26" wheels). This is a beefy touring/commuting bike. If I had a light racing bike I'd probably up the gearing a bit.

Paul

I live in a mountainous area and therefore make good use of a triple. I use my 22t chainring only about 5% of the time, but I switch often between the 32t and 44t chainrings. I've got an 11-32 cassette. My low gears are lower than I really need. I don't think I've ever used the 22/32 combination, but on long climbs with lots of gear strapped aboard I have used the 22/28, which is my 2nd lowest gearing at about 23 gear inches. And my high gear is plenty high (about 115 gear inches), but I occasionally still find myself wishing I had a little more. On rolling hills, if you can power through the downhills it makes the uphills a lot easier. And you need those high gears to do that.

If you think that a 48t ring is too high, then I would step down with both chainrings rather than just the large one. I vaguely recall seeing a compact double that was something like 27/44t. I believe it was a Sram, but I'm not certain. That kind of front gearing, combined with a wide-range rear cassette would give you lots of high and low gearing, but it does leave you with fairly wide gaps between the gears. If you skip 8-10 gear inches between shifts, it becomes difficult to find that "perfect" gear for a given terrain. But if you can live with that, then you have a bike that is very capable in a broad range of conditions.

a 50t chainring was fine when the freewheels were no smaller than 13t.
now an 11/44 is higher.

a 50t chainring was fine when the freewheels were no smaller than 13t.
now an 11/44 is higher.

Yeah, but the pro riders have a 53-11. So I must need that.

If you think that a 48t ring is too high, then I would step down with both chainrings rather than just the large one.

Agreed.


I vaguely recall seeing a compact double that was something like 27/44t. I believe it was a Sram, but I'm not certain.

That was probably a mountain double, which are becoming more common. For the most part you can't go smaller than 34T with a 110 bcd road compact double crankset. Somebody makes a 33T 110 bcd ring, but it's not common.