Groundhog2

I wish I had a 52 tooth chainring. My bike is a Gary Fisher Mendota which specs like a "fast commuter" but the gearing is 48/36/26 front and 11-26T 9 speed rear. So I would like to have a larger front ring than 48 tooth for the many times going downhill or easy levels. Problem is that the Fisher has a mountain bike heritage and uses 4 bolt holes and odd spacing compared to most road bikes. Cannot find a 52 tooth ring gear to fit it.

TricycleTom

I use a triple, so I'm usually on the 47 t middle ring. I use the 52 for a half-step higher in the four high gears, to fine-tune cruise RPM. The original block was 13-16-19-23-28, which gave extremely even steps to divide by. The original granny gear was 28t, to give a half-step down from regular low, but I soon switched to a 26, for a full step down. I have spent more time in bottom gear than top, but have fonder memories of the fast bits. Here on the flats, a more efficient 14 is cheaper and better suited. Pros with their 53s may be shifting a bit later on the back - there's no control on that. Their point is that the body is slightly more efficient at a cadence that is a bit lower than may be comfortable.


BTW, vintage folk - aluminium has no set fatigue limit. I have broken both the original TA cranks, and the handlebars during sprints. The crank went during the first stomp of a stoplight grand prix, leaving me standing on the pavement with one pedal clipped on. The handlebar was particularly surprising, as I'd hung a touring bag on the brake hoods for thousands of miles. A failure downward would have been more dangerous.

SlowJoeCrow

When I was a teenager with a circa 1980 10 speed I used the big ring all the time. Nowadays my biggest chain ring is a 46 which gets used on flat pavement and descents, although I spend more time in the 36 ring.

Artmo 

You either have a very low cadence or ride very fast with a 52X11, i.e. a 127 inch gear!! I wish I were as strong as you:-)

Happyday

Yes I do use my 52T when I go downhill, whether I pedal or coast.

When I am coasting downhill, the big chainring enables me to pedal faster when I start pedalling on reaching the flat.

I will pedal downhill if there is a small uphill. The big ring helps me to climb the slope much faster and faster.

hermanchauw

joesch

Same for me, especially in the DFW area.
When in CA I will use the smaller ring on longer steeper hills.
105+ is not what my knees prefer.

jimmuller 

When I was younger I wasn't as old as I am now. But I never actually needed a 52T ring. When I had one I used it, but (almost) never on the small sprockets.

Groundhog2

I'm low cadence for sure and do NOT ride all that fast. I want the 52 tooth to replace my 48 for use in downhill sections and easier flats.

radroad

A 38 or 39 is a fine spinning chainring. I'm completely baffled by the standard 34 ring spec. It's too low for regular use on flats on lighter bikes. It's too easy to run out of gears. Is a 34/32 or 34/30 bailout gear valuable enough to give up 2 or 3 higher spinning gears? A 36 tooth ring seems to be a practical minimum for slightly faster than average recreational road riding, at least to prevent constant double shifting.

I wonder if a 52/36 or even 53/39 might come back in vogue when 12 speed cassettes become standard? A 12 speed 11-34 or even 11-36 would cover maybe 95% of road riding scenarios.

Or how about 50/36 or 50/39? 52 or 53x11 probably isn't going to be used very often.

jimmuller 

This note prompted me to think (never a good thing). At any given time there are only four links bending, one each at the top and bottom of the ring and sprocket. The others are stationary w.r.t. the adjacent links. Now, it is true that for any given ratio a smaller-smaller combination will mean more total bend per link. But the total amount of bend from top to bottom is independent of the number of links around the ring or sprocket, 180 degrees. In other words, the same 180 degrees at each end is just distributed over fewer links. With smaller rings and sprockets the pedal and wheel rotation rates are the same though the speed of the chain is lower, so each link bends through its allocated amount in the same amount of time. Hence it needs a higher rotation rate w.r.t. the adjacent link to obtain its greater allocated angle in the same amount of time.


Another thing different with smaller rings and sprockets is chain tension. That means more force on the bushing of the link being bent, hence more friction. More friction and greater link rotation rate would certainly produce more drag in the chain. But the angle of each link's bend is just an incidental detail, an innocent bystander.

Phamilton

I have one bike with a 52 and one with a 50. I very seldom take it off the big ring, and I very seldom shift. Indiana is pretty flat. I usually use the 21 or 18t cog in back, depending on wind. Sometimes if I'm feeling spunky I'll pedal down a hill in 16t but I'll usually just spin out and coast on a bigger cog. It's a large step between 18-21, but I've grown accustomed to it. My riding is nearly all commuting, I usually plug along between 15-18mph, cadence around 80-90. Whenever I used the small ring, the chainline was goofy and drivetrain seemed noisier. I've been thinking a lot about SS/FG lately. I think I'd like to live somewhere hilly for a while, just to see what it's all about. All that said, last week had 3 quite windy days. I did use my 24t cog a couple times, but not the small ring.

Naildgod

I love reading how differently everyone approaches cycling. My MTBs don't have larger chainrings, but my hybridized road bike has what can only be described as a, "comically large chainring."

I built my road bike for 2 reasons: build muscle mass and cardio exercise. It's geared as a 1x7 with a 68T chainring and a 34-14T Shimano Mega Range. I burn through cassette teeth, so the cheap freewheel is a quick and dirty option. I rarely hit 25mph and it DOES NOT CLIMB, but, on the flat asphalt lanes and trails in the Twin Cities, it's a fun way to put on lots of lean mass.

Salamandrine 

Interesting analysis. I'll have to think about when I'm more awake. My initial thought is the links may rotate in space 180º, but they amount that they pivot around their pins differs in relation to ring size. At the top and bottom of the cogs and chainwheels, they rotate more with smaller rings, less with bigger rings. Anyhow this stuff has all been tested empirically. IIRC, cross chaining was actually the more significant source of increased drivetrain friction.

fietsbob

More likely , as I still use 6 speed Freewheels with 13t top cogs,
not a new Freehub wheel with 11t..

jimmuller 

Spot on, but that's only half the answer. Between the link at the top and the link at the bottom they must accumulate 180 degrees. A larger ring or sprocket means there are more of them around the half-circle, so the angle of rotation for each link is less. Each link does its share then stops moving w.r.t. its neighbors while the next link picks up the rotation process. For example, I'll move 5deg then you move 5deg then the next guy moves 5 deg, etc. as compare to we all move 10deg when our turn comes.

With, say, a ring twice as big you'd have twice as many links to share the 180 degrees of rotation so each would rotate half as much w.r.t. its neighbors. The time for the ring to do one half-revolution would be the same, assuming the same gear, same cadence, same bike speed. With that larger ring each link would have to move twice as far around the half-circle but the total time would be distributed across twice as many links. So the rotation total time per link would be the same. Hence each link would be rotating w.r.t. it neighbors with only half the rotation rate on the bigger ring. Combine that with the higher tension on a smaller ring and you get the likelihood of more drag on the smaller ring.

Pilot321

1987 Cannondale SR500 (Shimano 105) Biopace 52/42 chainrings, 13 - 28 freewheel. YES, I use the 52 a lot, on flats, and downhill. I can't imagine not. I would like to reduce the inner, 42 ring to something smaller due to all the hills in which I have to navigate, but like having the 52 for the speed.

SlowJoeCrow

Have you considered replacing the crankset with a road triple? That would give you a 30/39/50 or possibly 52 out of the box and you can easily find all sorts of of chain rings to fit the 130mm bcd middle and outer positions. These cranksets are getting hard to find new but used takeoffs and NOS are out there. The only tricky part would getting the MTB front derailleur to shift cleanly, or replacing it with a road part and a matching front shifter. Shimano used to make a 3x9 flat bar road shifter set that had the correct cable pull.

Duo

i normally have triples on my vintage bikes, the big 52 is rarely used, as the middle front gear is preferable for using the small or big gears in back, no cross chaining.

however if the middle gear wears out, then i guess the 52 is gonna be good enuf. here in the flat midwest, most of these gears are useless anyways. about the only time they are useful is in the head winds, but dropping in a few low gears gets the job done.

mstateglfr 

I don't understand the approach some have where they ride bikes with gearing that doesnt work for them.

if a 52t ring isnt used, why not get a smaller ring? Swap the crank out entirely if needed and go with something thats 50/34 or whatever else that works.
no need for modern looking as there are tons of new classic looking cranks that have a 110 bcd. Or just pick up and number of Sakae or Sugino cranks from the 80s with 110 bcd if you want to keep the crank actually vintage in age and look.

to each their own and all, I just don't understand having a drivetrain that limits the rider.

this isnt just c&v related, though I see it a lot here because someone is 'thrifty' or wants to keep a bike original or period correct.
I ride with a woman who has a modern Sora compact drivetrain and never gets out of the 34t ring. It's absurd. Clearly the 50/34 11-28 drivetrain is not what she needs, but she won't change because she was talked out of it by a shop. Wat?!
she needs a 46/30 subcompact FSA crank so she can get out of the 34t to g all the time and use the smallest few cogs less.

Groundhog2

Thanks Slow Joe ! Yes, changing out the entire front crankset has been the only option found (so far) but is unrealistically expensive when all I am after is a bit larger big ring. I'll probably live with it as-is unless I locate a 4 bolt 52 or 53 tooth ring. With a little over 14,000 miles on the bike, trading bikes might get considered at some point.

MKahrl

Our bike group leader tries to talk all buyers of new bikes who are over 50 years old to get a triple. That way they can stay in the middle chain ring nearly all day using the granny for steep hills. Inevitably the bike shop talks them into a double because that's what they have.

What is wrong with doubles? Nothing. Especially for anyone on this forum. But go out riding in the general public and you will find people cross chained into big-big small-small combos everywhere. They shift the rear derailleur and pay no mind to what front ring they're in. My 70 y.o. step mother regularly climbs having left the chain on the 50t ring and arrives at the top and comments "That hill was tough!".

conspiratemus1

Maybe she's doing something right. After all, she did marry your dad....

jimmuller 

If you have a triple and ride the middle ring all the time except when climbing steep hills, why not dump the big ring and just go with a double anyway?

MKahrl

I agree, dump the big ring. Not easily done when shopping for a new bike.

This advice is mostly for new bike buyers unfamiliar with gear ratios and don't plan to learn. And that includes many friends who ride thousands of miles each year and have for decades. These riders are in the 50 to 80 years old.

Most new road bikes come with Compact (50-34) crank sets and what I'm talking about is using a 36 or 38 middle ring for all day cruising with a 11-32 in the back. The 34t small chain ring on a compact double when used with a 32t cog is low but many riders don't mind going lower, 24t or 26t chain ring for climbing 14% grades. So to get what you suggest the bike shop has to put 36-26 crankset on the new bike. Those types of doubles are not common. But a 46-36-24 triple that used to come OEM on new bikes.

RANT: Why can't bike manufacturers make road bikes for experienced recreational bike riders? People who ride 20 to 50 miles on a weekend and go on longer rides in the summer?

If I send a friend into a bike shop who has gray hair the clerk will try to sell them a hybrid, which comes close, but has flat handlebars and thick-rubber tires. If the buyer is able to explain that they are an experienced cyclist that wants road handlebars, they end up with a racing style bike with skinny tires, very low handlebars and no means of mounting a bag. I know it's possible to find the right kind of bike and some gravel bikes fit the bill but at this point you have to give them pretty detailed directions on what to look for because gravel bikes sometimes still have racing bike frame geometry.