# 48/38 Chainrings?



## GadgetGuy (Jun 22, 2006)

Hello,

I've just spent the last 2 hours reading all the posts on standard versus compact cranks. I live in Davis California where 80% of my riding is in flat farmland, and 20% is fairly steep and mountainous. I am currrently running a standard 53/39 crankset with a 12/27 9-sp cassette. Although I'm originally a singlespeed mountain biker and am happy to stand up and stomp at low RPMs, I prefer to spin @100 RPM on my road bike.

I find that I tend to have 2 speeds: casual and aggressive. When I'm in casual mode, I average 14-18MPH, and aggressive mode is 16-22. The fastest I will pedal is in the 30-32MPH range, and that's for sprints only.

Because my cadence is 100, I currently find myself living on the small chainring, and on the lower half of the cassette. The big chainring is only for downhills and tailwinds, which amounts to 20% of my riding.

What are your thoughts on running a 48/38 chainring setup (FSA rings). The way I see it, the 38t would be for my casual riding and hills, and the 48t would be for when I'm feeling energetic. And the 10t difference would make shifting smoother, too. Using Sheldon's gear calculator, it seems like I would be spending a huge percentage of my time in the middle of the cassette, too.

Questions:
1. Is 48/38 a good idea, or too weird?
2. Should I save some $ and stick with my current 39t and just get the 48?
3. How about a 50t instead of the 48t?
4. Should I just get a 50/34 FSA Energy Compact crankset instead? (I don't think the gearing would work as well for me)

Thanks!

View attachment 65420


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## rruff (Feb 28, 2006)

GadgetGuy said:


> 1. Is 48/38 a good idea, or too weird?


Not really... if you *really* wouldn't miss having a bigger gear, then it should be fine. It would cut down on the front shifting and cross chaining. I'd probably keep the 39 though and just replace it with a 38 when it wears out.


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## C-40 (Feb 4, 2004)

*other options...*

The 38T little ring won't improve your low end gearing much; it's only about 1/4 of a normal cog change.

If you don't ever use the 53/12, then buy a cassette that starts with a 13T. If you were a campy user, you'd probably find a 13-29 (10 speed) to be perfect. With Shimano, I believe you could replace the 21-23-25 group of cogs from a 13-25 with your 21-24-27 group to produce a 13-27. Then you'd pick up the important 16T cog that you're missing now. To be sure, see if the 21-27 cogs are all pinned to a common carrier. Shimano is poor when it comes to keeping tech info available for older components.

http://sheldonbrown.com/harris/k7.html


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## Al1943 (Jun 23, 2003)

If your frame has a braze-on type front derailleur hanger you could have a real problem getting the derailleur low enough for the 48t big ring. I put a 49-39-28 triple set on my wife's bike and had to cut the slot in the derailleur hanger deeper, and there wasn't enough metal to go any farther.
Not a problem if derailleur is a clamp-on.
Al


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## Dale Brigham (Aug 23, 2002)

*48/38 works fine*



GadgetGuy said:


> Questions:
> 1. Is 48/38 a good idea, or too weird?
> 2. Should I save some $ and stick with my current 39t and just get the 48?
> 3. How about a 50t instead of the 48t?
> 4. Should I just get a 50/34 FSA Energy Compact crankset instead? (I don't think the gearing would work as well for me)


Gadget Guy:

Most of us need a 53 tooth big ring like we need another hole in our skulls, meaning not really. Reducing the big ring to 50 or 48 teeth (or even, gasp, 46 teeth) makes it much more usable for everyday (i.e., non-racing) cycling. Here's my take on your questions:

1. Not weird at all. 48/38 works fine. I've had that same combo on several bikes.

2. As others noted, not much difference between a 39 and 38. I'd just change the outer ring and see what you think. Leave the 39 on until it wears out (unless you have a cheap 38 tooth ring handy).

3. Although a bit bigger than the 48, the 50 tooth ring will be fine, too, and might work better for your front derailleur adjustment, which can be a problem (as others noted) if it's a braze-on. My calculations show that for every fewer tooth on the big ring, the front derailleur will need to be lowered about 2 mm. So, going from 53 to 50 teeth equals 6 mm lower, and going from 53 to 48 teeth equals 10 mm lower. Choose the big ring based on what your front derailleur mounting will allow (not a problem for clamp-on front derailleurs).

4. I have an 50/34 FSA compact on one of my road bikes, and after riding it for a couple of years, I changed to 48/36 chainrings. I found the 34 too low for my needs and the 50 a bit big for my normal big-ring cruising with a 12-26 cogset. Also, even with an FSA compact specific front derailleur, the shifting across that 16 tooth chasm was never very pretty (actually shifted better for me with a plain-old Ultegra front derailleur -- go figure!). Playing around with chainrings on your present crankset will be cheaper than getting a new crankset.

Happy Cycling!

Dale


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## MR_GRUMPY (Aug 21, 2002)

If you can live without the 27, a 14-25 "junior" cassette may fill the bill. The 14 will allow you to spin up to 35 mph, and the "block" type gearing will always keep you in a good gear.


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## The Flash (May 6, 2002)

I use the 14-25 on my TT bike for that very reason....very close gearing and you can always find a useful combination.....

Where is a good source for a decent 50T ring?

Flash


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## DIRT BOY (Aug 22, 2002)

*FSA makes them...*

I used for a while and loved it. It's now on the rain bike.


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## Dereck (Jan 31, 2005)

Hi Gadget
Your gear ratios are down to your needs of course, but mechanically, beginning of last year I realised that taking 30 years off cycling had 'improved' my form to where hauling a 53 ring around was mostly decoration.

So, what I ended up with on my 130mm Ultegra double cranks was a 38T Salsa inner ring and a 50T TA outer ring - I had a 13 - 25 or 13 - 27 on the back.

Shifting between these rings has been fine throughout the year or so I've run them - regular 9sp Ultegra shifters and front derailleur. I got my TA 50T outer from Branford Bikes, but after a devastating fire, they've gone out of business - Peter White Cycles is the only other source for TA I can recall, but there may be others.

My new bike has a 34 / 50 Shimano Ultegra compact 10sp - ugliest cranks on the planet, the skinny chain is a fussy thing to mess with and the gear size shift between the rings is a long drop or rise - wish I'd gone with Plan A and put the same 9sp gearing on the new ride as I have on the old one...

Hope that helps

Dereck


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## fmw (Sep 28, 2005)

I tried to switch my 110BCD cranks from 50/36 to 46/34 just yesterday. The bike has a braze on and I wasn't able to get the front derailleur close enough to the large chain ring. A 48T might have been doable but with a 4 or 5mm gap. If your bike has a clamp on derailleur then, of course, it wouldn't be an issue. I just went back to the 50/36 which works fine for me. I wanted to try the smaller large ring for reasons I won't go into here but it didn't work out.

Bottom line is that I agree with C40. It is easier to attack gearing issues at the cassette than at the cranks. Also gearing changes there are usually more noticeable. Years ago I had a bike with a 13/29 cassette. It felt like a mountain bike in low gear.


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## longlegs (Apr 18, 2002)

Just go with a compact crank(50/34) as others suggested. It gives you nice low gears and a decent big ring for downhill and pushing on the flats


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## balesmachine (Oct 5, 2012)

*39/53 makes no sense to me either*

Cycling has been my life for over 41 years. It has been the thing I do. I have raced, both mount bike and road bike, did ultra-marathon for 20 years, and now it seems I am trying to hang with the young fast guys.

I can totally agree with you on the 53 tooth outer chain wheel. I don't like the jump from 39 to 53 and back. It is so large that whenever you do it, you have to shift three times to get near where you were. 

For the first 15 or 20 years, I rode the beautiful Campy record setup with a 42/52 chainwheels, The jump wasn't so bad, but the 52 was too big, I thought, and the 42 was not low enough many times. 

I welcomed the new 39 inner chain ring, but thought the 53 was way too big. If I rode in it, I never got beyond the middle of the casset, so I basically was not using about half of the cogs, which made no sense to me. 

I had shimano durace cranks, and thought I was stuck with the 53 till I found Peter White. Google him and you will find that you can get almost any tooth chainwheel for almost any crank you want. I have been riding a 46 tooth for 10 years now and recently went to a 48 to keep up with fast young guys I ride with now-a-days.

happy cycling 
Steve


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## Drone 5200 (Mar 3, 2003)

Several years ago I replaced my 53 with a 50 to have 50/39 up front. Im running DA 7800 with shimano rings. This is a combo available with the 7800 (but not available from shimano in later iterations). In the back I mainly use an 11-23 for the flat and rolling rides that I enjoy most. I replace that from time to time with an 11-28 when I know I'll have some climbing. The shifting with the the shimano 50/39 type-B rings is flawless, as you would expect. 

I tried a 50/34 once and could never warm up to it. I found the large gap up front to be very annoying. Granted, the 34T is great if you have long step climbs, but its less than ideal for flat and rolling stuff. I prefer a 39. I find the the 11 tooth jump up front to be perfectly suited for my style of riding at my age. I'm mid-40s and just dont need the 53T anymore.


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## wim (Feb 28, 2005)

I like it. After many years of turning my old (6500) Ultegra 52/42 crank, changed the rings out to a new 48 and an old 39 I had laying around. I've always preferred a 10-tooth or so step in front and, like others, find the compact step too large for my liking. No longer racing or going on team training rides, so the 48 is perfectly adequate.


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