Adventure Cycling Association Forum

Bicycle Travel => Gear Talk => Topic started by: fastrog on August 06, 2017, 02:15:36 am

 
Title: front gears
Post by: fastrog on August 06, 2017, 02:15:36 am
I'm thinking about having a Surly frame built up locally because I do not like the stock bar-end shifters. My mech thinks I would do well with an electronic 11 or 12 in the rear and zippo in the front, partly because I have never been one to be a stickler and use all  my gears. Have done tours in Oregon, Washington, Montana and other hilly places. Plan to do Transamerica next year. Can I survive with such a gear setup? 68 years old and in moderate shape. Hope to be better by next year's ride -- well, better condition but not younger. Supported, by the way.
Title: Re: front gears
Post by: John Nelson on August 06, 2017, 05:49:21 am
It's all about gear inches. If the gear inches on your new bike will be as low as the lowest gear you used on the biggest hill you've climbed on a tour, then you're good. As long as you don't plan to get any older, of course. I don't think, however, many of us would like a bike without a front derailleur. But it sounds like you're not many of us. And you're touring supported.

Does your mechanic tour?
Title: front gears
Post by: RonK on August 06, 2017, 07:13:59 am
A Sram 1x11 setup with the right chainring would yield a workable gear range and would give the option of using hydraulic disc brakes. I'd stick to mechanical rather than electronic shifting.
To the best of my knowledge the only 12-speed system is Sram Eagle which is only available with trigger or twist grip shifters for flat bars, although Paul Components do make an adapter to mount the trigger shifter to a drop bar near the stem.
Title: Re: front gears
Post by: misterflask on August 06, 2017, 08:35:06 am
I thought 2 things about the grades on the TA when I set out: That grades would max out at about 6% and that western grades would be shallower than eastern grades.  I was about 1/3 right.  Western grades maxed out at about 6% (riding West to East), but grades in Kentucky and Virginia would commonly hit 10% and in Missouri reached something ridiculous like 17%.  So west of the continental divide, I never dropped down to the low ring on the triple, which would have given me about 31 gear-inches, but come Missouri, I was glad for my bottom gear of 21 or so (24 chainring to 32 rear sprocket). 

Fun fact - an inclinometer on your bike is the poor man's power meter.  For a 250 lb bike and rider on climbs where aero losses fall off, your power output = %grade x mph x 5.  And please no flames for my riding with an inclinometer; I'm data-driven.
Title: Re: front gears
Post by: RussSeaton on August 06, 2017, 03:09:14 pm
Nothing wrong with a 1x system since we now have 10 to 14 gears in back.  If you look at a normal 2x or 3x crankset, you will discover that you really only have about 10 to 15 different gears.  All the others are duplicates of each other.  Rohloff is an internal gear hub system.  It was the most common way to go with 1x until recently.  Now a few different companies make wide ranging cassettes that can give you high and low gears on one cassette.  SRAM offers 10-42 and 10-50 cassettes.  With the right front chainring, you should get a low enough low gear and a high gear that is workable.  A minor, or major, problem is the jumps between gears may be large and you will wish for much closer gearing.  People forget that having a triple crankset allows you to have sort of closely spaced gears on the big and middle rings where you ride 99% of the time.  Closely spaced gears that are enjoyable to ride.  AND still have a little inner ring that allows you to get really low gears when needed for that 0.1% of the time.  Having a 10-42 or 10-50 cassette with a single ring means you have no close spaced gears and will always be wishing you had closer gearing.  Not something I want.  But others may be happy to ride in the wrong gear 90% of the time.

You mention not being a stickler and not using all your gears.  That may be true.  But think about which gears you use 90% of the time.  Are they 3 or 4 gears that are all close together?  With a 1x system you may discover that you now have only one gear to replace the 3-4 gears you used to use.  You might discover that bicycling now sucks because you don't have the right gear and are always geared too high or too low.  Never the right gear to pedal happily along.
Title: Re: front gears
Post by: indyfabz on August 07, 2017, 09:39:09 am
You mention not being a stickler and not using all your gears.  That may be true.  But think about which gears you use 90% of the time.  Are they 3 or 4 gears that are all close together?  With a 1x system you may discover that you now have only one gear to replace the 3-4 gears you used to use.  You might discover that bicycling now sucks because you don't have the right gear and are always geared too high or too low.  Never the right gear to pedal happily along.

That is my biggest concern whenever I think about a 1x. I abhor being geared too high or too low, especially since I have never been a "spinner."
Title: Re: front gears
Post by: RussSeaton on August 07, 2017, 02:03:16 pm
That is my biggest concern whenever I think about a 1x. I abhor being geared too high or too low, especially since I have never been a "spinner."

Yes.  For fun I will put some math to the situation.  My touring bike is a 3x10.  44-33-20 crankset and 11-32 ten speed cassette.  My high gear is 108 gear inches.  My low gear is 17 gear inches.  Pretty darn good.  But I do have to deal with a triple crank and front derailleur and shifter.  Lets try to duplicate my setup with a 1x setup.  Lets use the SRAM cassettes I mentioned above.  SRAM makes an eleven speed 10-42 cassette and a twelve speed 10-50 cassette.  Lets use the twelve speed cassette.  To get a low gear equal to my low gear of 17 gear inches, you must use a 32 tooth single chainring with the 50 tooth cog.  Your high gear ends up as 86 gear inches.  Kind of a medium gear, not high at all.  Not high for paved road riding, maybe great for off road trail riding.  The 10-50 SRAM cassette has cogs of 10-12-14-16-18-21-24-28-32-36-42-50.  So your highest gears are 86, 72, 62, 54, 48 gear inches with the 32 ring you need to get my low gear.  I would be very unhappy riding with gears not too high and that far apart.  With the SRAM 1x system you can get higher overall gears by increasing the single chainring.  But then you have a higher low gear too.  And you still don't get closely spaced gears.  The cassettes made for 1x systems do not allow closely spaced gears because they have to cover such a large range.  10-42 or 10-50.  1x systems REQUIRE you to give up closely spaced gears AND one of the following, low gears OR high gears.  You can never have closely spaced gears and you must choose either low gears or high gears, never both.

Some day we may have 20 cog cassettes.  Then you can get closely spaced gears and high gears and low gears.  Everything with a single chainring.  No triple crankset needed.  And 20 cogs on the cassette.
Title: Re: front gears
Post by: DaveB on August 08, 2017, 10:34:00 am
1X gearing seems popular with MTB riders since it eliminates the sometimes problematic front derailleur and the wide gaps in gearing aren't that much of an issue off-road.   For road riding the situation is quite different.  Front shifting isn't that difficult or tricky under road conditions, even with a triple, and close gearing is far more appreciated. 

My road bike (not touring) gearing is a 50/39/26 triple crank and a 12x27 10-speed cassette.  My high gear is 112 gear-inches and my low gear is 26 gear-inches which is more than adequate for most road riding and my cassette is a "straight block" from 12T to 17T with small steps below that.