bark_eater 

I'm looking to do some longer rides on a couple of 6 and 7 speed classics. Locally I have variety of flatland century's to start off with. After that the DC Randonneurs brevets are the closest events, and I assume more likely to include some hill climbing. Right now I have a 700c 12 speed to work with, road double up front, 6 speed freewheel in the back. Next year hopefully I'll have a 650b with a road triple up front and 7 speed cassette in the back. So I'm sort of looking for some gear inch theory to get me started. Thanks, Woody

rhm

What's the crank; what chainrings does it have now, and what's the smallest you can fit?

The number of gears doesn't really matter; the important things are what's your lowest gear, and what's your highest gear.

The bike I rode on the Vermont 400k earlier this month has eleven distinct gears, ranging from 28 to 106 gear inches (1 x 11). The other bikes that I usually ride on brevets have similar gearing (2 x 9 on one, 2 x 10 on the other). With that gearing I can get up pretty much any hill, and I don't generally spin out on the descents.


Now and then I'll ride one on a three speed (49, 55, 86 inches, if I recall correctly) or a single speed bike (69 inches or so).

Obviously, when I ride the single speed my cadence varies a lot, from very fast on the descents to very slow when climbing, and occasionally walking the steep parts. The same goes for the three speed, but it's less extreme. As you add more gears, you can keep your cadence in an increasingly narrow range. That has some advantages, but I wouldn't overstate them.

ThermionicScott 

+1 on Rudi's thoughts.

When I started randonneuring, I stumbled across an article by Clifford Graves that passed along this advice: "Velocio himself advocated wide-ratio gears for touring: from 35 to 85. His normal riding gear was 72." So when I built up my rando bike ahead of PBP 2015, I followed suit: a 35-100" range, provided by a 50/38 crank, 13-28 cassette (7-speed ) on wheels roughly 26" in diameter. I've since changed it to a 48/34 crank and 13-26 cassette, but the overall range is about the same.

Jan Heine has some good thoughts here: https://janheine.wordpress.com/2012/...ur-chainrings/ I especially like this part: "Put the base gear [the gear I mostly use on flat roads when spinning along] in the middle of the rear freewheel/cassette, so that I can adjust to changes in speed and terrain with a simple shift or two in the rear." I've found that I prefer a 65-70" gear when riding at rando pace on flat ground, so the 48/19 in the middle of my cassette is perfect for that.

P.S. I like this website for dinking around with virtual gearing: Bicycle Gear Calculator

P.P.S. My first brevet season was on a different bike with a 52/42/32 triple crank and 14-28 6-speed freewheel. That worked pretty well, but I noticed after a few brevets that I never (well, hardly ever) left the middle ring, and that there was a lot of duplication, so I decided to pare it back.

bikemig 

I pretty much agree with everything in posts 2 and 3. I run 6-7 speeds on my long distance bikes. There is no denying though that it is harder getting closely spaced gearing on a 6-7 speed than when running 9 or more in the rear which is why I think that a triple makes a lot of sense for older bikes.

Here is a good piece on the topic:

https://www.bikehugger.com/posts/the...compact-crank/

clasher

My miyata 1000 had a 48/38/24 and a 14-34 freewheel and it worked well for loaded touring with the low gears,. For rando I can by with 27 gear-inch on the low end now but used to run a bit lower. I have no use for anything beyond the 112gi I have currently. For a 7 spped setup a 110/74 crankset gives a lot of choices for chainrings a d they are fairly easy to find.

bark_eater 

I got as far as getting my bike off the ceiling and onto the stand. It will be another week before I get to overhauling it for the the "Fall Campaign".Hopefully I will get out in the shop this week to get a tooth count on the present gearing. I did ride the bike on the small chain ring last year, predominately small to small and then usually only shifting down one or or two cogs for wind and terrain. That was mostly to keep my self from hurting my knees as I was upping my mileage pretty quickly. Mashing felt good in the moment, but I overdid it quickly. I'll be a month out of summer touring/fighting weight when I get back on the road so I plan on spinning for a while.

I found this training and ride log of a couple guys who took their classics across Pennsylvania the wrong way. I'm assuming their animals, and that I would gear down a bit. Scroll down to Bike specs.

bark_eater 

The bike is set up with 52 and 40 130BCD Biopace chainrings and a 14-28 6 speed free wheel. I've a low mileage Suntour Superb 14-30 on top of the pile and couple more of unknown history buried in various spots but I kind of like indexing with the down tube shifters. Different 130BDC chainring's might be stolen from from other bikes. I could set up a 48 and 38 110bdc road triple as a double pretty easily. A triple as compact double would need a new bottom bracket. A triple would need a new bottom bracket and front derailleur? Race day is Oct 5......

rhm

With a 110 mm bcd crank you can get down to 34t. With the 130 mm bcd the smallest one sees is 39t though I have heard 38t is an option.

There are some square taper double cranks that allow considerably smaller rings.

clasher

I picked up an FSA 48/32 crank and they are also available in 46/30 for under a 100$. They are black 4 arm modern looking things but could be made nicer if you wanted to deanodize and polish.

bark_eater 

The two options I'm considering based on time, money and parts bin are to buy a 38t 130bdc chainring and scrounge a round 52t from another bike. that would give a range of 36.6 to 100 gear inches.
I have a 50t chairing but with the freewheel (14-28) The 50t and 38t set up seems to have a lot of redundancy's. If I can scrounge a 48t ,that would be an option.

I have a 110BDC RSX road triple crank and a set of 46t and 36t chain rings. This would give a gear range of 34.6 to 88.5. I am assuming that if I do not use a triple cog I can use the same bottom bracket.
The gear calculator makes a 48t and 34t looks pretty good with a range of 32.7 to 92.4. If I can keep my bottom bracket with the RSX crank this seems like a good set up, but I will be throwing money at a theory...

rhm

Redundancy is annoying when looking at the numbers on the screen, but when I'm actually riding the bike I pay no attention to it at all.

My suggestion would be to put the bike together with the best setup that can be achieved with parts on hand, and give it a try. It may not be perfect, but you'll get a much better idea of your needs than you can get in the abstract. If you don't have a gear low enough for the hills, you will be forced to go up them faster than you like, but it probably won't kill you; if you think the end is near, get off and walk. I mean, if it came to it, you could ride 200 km on a fixed gear (trust me!).

bark_eater 

I can admit to staring at the gear calculator a bit to much. A couple of the combinations had an exact match at around 70 gear inches. That seemed like a good spot to be able to shift between chain rings with out changing cadence. My touring bike is geared 46, 36+26. Day 3, after 150 mile of melted tar heatwave, I was riding the granny gear. So I think the a 46+36 would be a safe choice. Present bike go's back on the road next week, one way or another. This week training starts with pulling a 50 pound kid in a trailer with a single speed...

bark_eater 

Well I'm back at it with the gearing puzzles, and having started another thread over the summer:

https://www.bikeforums.net/classic-v...reewheels.html

I figured I'd update this thread instead of starting yet another...

I ended up spending the spring and early summer on 700x28 bike with a 48-36t and a 6 speed 14-28t.

With current events I didn't do any century's or have the time to "train" but I did manage to get a good run of consecutive 100 mile weeks as proof of concept, for my riding at least.

Now I'm collecting parts for a 650b conversion of a 86 531 Trek 400T. I have a 165mm Sugino 110 BCD triple crank set. The plan is to run 48-34T chainrings and a 13-30T 7 speed cassette and 650bx38mm wheels.

The gearing is visually appealing on the calculator.

Gear-Calculator

Any thoughts? I'm making up the 7 speed cassette from available 8 speed cogs, so I could shift some of the cogs depending on what's in production right now.

Thanks, Woody

xroadcharlie

With a 7 speed cassette I think keeping the 5 gears you use most reasonably close ratio, perhaps 16, 18, 20, 22, 25T. And have one extra low gear at 32T, and one extra high gear at 14T.

I used to think evenly spacing them was best, But with only 7 rear cogs, Going too close ratio will make climbing some hills a chore, and will hamper your ability to take advantage of a tailwind or slight decent.

Going wide ratio means I can seldom find the most comfortable gear to use. While this may be more perception then reality, That is I doubt we actually loose an appreciable amount of time, Or are likely to injure ourselves I find it more satisfying to have the gear that feels right.

The same principle applies with a double or triple chainring unless you enjoy having to double shift for a single step. Tge only thing that changes is the selection of chainrings.

bikemig 

I responded to this thread in 2019, . If you have a triple crank, I'd use it. I really like the way mountain bikes were set up BITD. You can run a 46/36/24 up front and get an 11-28 7 speed cassette for the rear.

bark_eater 

I've got 46/36/26 with a 11-28 on my 700x38 touring bike. I have to remind myself to us the 46t ring to keep from wearing out the 36T. Its got pretty upright seating, and a heavy wheelset, but I feel like the triple with the 36t ring also really effects how I ride it. The Trek I want to ask me to "push" a little. I have a good selection of 110 and 74 bcd chainrings, so It will be easy enough to try it out as a triple.

Richard Cranium

Oh - boy another "what gears are good" thread.

Well, the actual answer is " they ALL are." There is no secret, no grand scheme that makes some gearing setup the perfect answer to your cycling needs.

Being geared correctly for a ride is a function of the load it is shifting under - as well as the unique qualities of the power source being applied.

That means asking strangers on the Internet for advice is worthless. Asking someone who has already ridden the exact routes you intend to ride - and happens to know your current cycling abilities - could be of great benefit.

bark_eater 

Well there's something you dont see every day.....

Tourist in MSN

Looks pretty good if you are in an area without steep hills. That gearing still looks good if you do not use two or four of the most cross-chained gears.

I have an 8 speed 11/32 cassette on my folding bike, two touring bikes and a rando bike. Makes keeping the spares shelf pretty simple. Thus, I do not have a lot more than you currenty have, as I have only one more sprocket and only a slightly wider range in back.

My rando bike has a road triple crank with 52/42/30, cassette is 11/32. I have three higher gears than your highest, but I rarely use them. If I am going down a short valley with an equally steep uphill on the other side, I will use those three highest gears on the downhill to maintain momentum as I start up the uphill, but otherwise my highest three gears get very little use. And I have one lower gear than you have, I have bad knees and need to be careful on strenuous uphills.

To summarize my thoughts, your range of gears is pretty much the same range of gearing that I am using 95 percent of the time, and 5 percent of the time I have something slightly higher or lower than your range. That said, you might enjoy having a triple for wider range, but if you do not feel any urgency on that, then it could easily be a low priority.

shelbyfv

Since this doesn't have much to do with distance riding, you might ask that the thread be moved to "Mechanics" or even "C&V." IME, most riders who do significant distances don't obsess over gearing. They want a gear that gets them up the steepest climb they'll encounter and the rest falls where it may. Reliability is more of a concern.

Trakhak

By the way, relying on the smallest chainring doesn't wear only the small chainring, it also wears the smallest sprockets in back. The fewer the teeth engaged, the faster the wear. You'll get far more life out of your drive train if you mostly use the middle ring in front and the middle sprockets in back.

Classtime 

I've got a 48/34 on my Rando Bike but with a ten speed 11/28. The 14 teeth in front is an extreme jump but provides a good range. I really enjoyed my time on a Trek with 1/2 step plus granny 5 speed and put a less than ideal 6 speed on it. I only took it on hilly 50 mile rides but could see the benefit of 1/2 stepping with the granny for steep climbs. The two "large" rings would ask you to push it a bit. See what you come up with on the calculator.

Tourist in MSN

If you are looking for an example of a half step plus granny system, I built up my Lynskey Backroad for light touring three years ago, eight speed 11/32 in back (11,12,14,16,18,21,26,32), in front a triple with 46/42/24. I avoid using the two most cross chained gears on each chainring, thus only use 18 of the 24 possible gears.



The 24T chainring is almost invisible being silver on a titanium frame. And the 42 is hard to notice behind the 46.

I do not recommend half step to people that have grown accustomed to lots of gears on 10 or 11 speed bikes, but I had a half step bike in the 1980s, so I got very used to it.

I find half step not that useful when the changes in grade are frequent and large. But I did a two week tour in Florida which was totally flat, it was perfect there, a slight change of windage and I knew exactly where the next gear was.

unterhausen

It really depends on the rider.

The two bikes I ride on brevets have 34f/36r and 28f/32r low gears. I rode 34f/32r on PBP and was missing the 34/36 gear a couple of times. But I'm using a 10 speed system on those bikes so I have plenty of gears, not the case with a 5/6 speed freewheel.

My rationale for having low gears like that is that suffering over a steep hill causes problems that don't happen with lower gears. Lower gears mean you don't have to eat quite as much.

bark_eater 

Thank you all for the thoughts. I'm hoping to try a number of different set ups. As the bike is still a pile of parts I haven't found out whether I need to go with shorter 165mm cranks with the 650b. If 170mm cranks will work I'll be able to try a 46-30 up front. I hadn't realy considered running a half step and granny. That's how the bikes original gearing is set up. 50-45-32T and a 14-28t 5 speed. If I run a 7 speed cassette with a cog added on each end I can get a gear inch range of 24.4 to 118 which would certainly cover the range I would use locally.

1/2 Step+Granny