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Gravel vs road gearing… less force to pedal?

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  • March 14, 2018 at 5:55 pm #28252
    kvert

    Completely unscientific question…

    I have a 42 front 10-42 rear setup on my gravel bike… for the last couple years I’m trying to convince myself to pull the trigger on a road bike with 52/36 front 11-30 rear setup.

    For a recreational and never will be competitive rider, is there any reason to let this stupid thought win out?

    It would certainly give me more top-end but would the gearing be any easier/more efficient to pedal? I have absolutely no mathematic principles to apply to it but I just feel like having more teeth up front (52 vs 42) would be more efficient since that force is pretty direct compared to having less in the back (11 vs 10) which takes more indirect force to spin.

    To answer the obvious–no I will not change my gravel bike gearing and no I won’t want to sell it to switch over–I’d want to keep both bikes. It actually came stock with a 50/34 11/36 setup but there’s something in my head that wanted to stick with a simple single ring setup.

    There’s also something in my head that really wants to go with a di2 setup and is trying to win over the other half of my brain that reasonably doesn’t want to drop 4 grand to get me there to do essentially the same type of riding anyway (I primarily use my gravel bike as a road bike).

    Thoughts?

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  • March 23, 2018 at 4:05 pm #914541
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    Miller
    kvert wrote:
    But, I ordered the road bike anyway (Canyon ENDURACE CF SL DISC 8.0 DI2) and it actually should be arriving within a few hours.

    Yay. Doesn’t matter what the question was, that’s the right answer, lol.

    March 23, 2018 at 2:36 pm #914539
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    kvert

    I guess I was approaching it

    I guess I was approaching it more from a tighter grouping being more efficient, angle.

     

    i.e. My gravel bike is 42;10-42 and the road is 52/36;11-30. So 11 gears to cover 1-4.2 vs 22 gears to cover 1.2-4.73. Not an exact range match, and I’m sure there’s some overlap in the big/small, but there’s still a slightly tigher grouping overall.

     

    Either way, nothing that would matter enough anyway… just trying fiddle with numbers to justify the purchase.

     

    But, I ordered the road bike anyway (Canyon ENDURACE CF SL DISC 8.0 DI2) and it actually should be arriving within a few hours.

     

    Faster/more efficient ponderings go out the window now… it doesn’t matter… I’m still excited about it.

    March 23, 2018 at 4:48 am #914537
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    Boatsie

    An advantage of a tall geared
    An advantage of a tall geared road bike vs a tall geared trail bike is topography. On the road during a descent there isn’t that need to have an accelerating gear ratio because roads aren’t weaving trees and bumps and such similar loves.
    Hence if you have a capable ratio selection to climb and motor along flats with; I ;not being a racer, you might be lazy like many of us and after a peak, hit top cog and regard less concerning acceleration because you’re underway and may input light or heavy stance on your crank and enjoy the distance. Ohh look a tree 🙂 whoo it’s the other side of the gutter.
    50/11 is pretty tall man. 53/13 similar. Both plenty enough to push wind coming down or slow crank and recover

    March 20, 2018 at 12:48 pm #914535
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    Daveyraveygravey

    jterrier wrote:

    jterrier wrote:
    I am not quite sure what you are getting at but just bear in mind that it takes a very very fit rider to sustain power through either a 50-11 or 52-11 combo for long periods. If you look at the wear on the average riders cassette, its all in the middle. You maybe spend 3% of your ride in that absolute top gear (50-11 with a compact, for example). So its barely worth having. More usable gearing in terms of front chainrings is 46/32, as you can easily envisage spending a good amount of time turning the 46-11 combo on a nice A road run, and the smaller ring means you can run a tighter block at back (11-28 maybe) which eliminates some of the indelicate shift action getting up to/coming off of a 32 tooth sprocket.

     

    Most of what you say is right, but I would argue you don’t have to be THAT fit to spin out a 46-11.  It wouldn’t be too steep a downhill or too strong a following wind to run out of gears with that set up.  In my opinion, of course!

    Another advantage of a front mech is sometimes the chain bounces off either ring, and if you are lucky you can use the mech to get it back on again.  Not something you want to make a habit of though.

    March 16, 2018 at 5:51 pm #914533
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    Nixster

    Advantage of a double over a

    Advantage of a double over a single up front is the smaller jumps in the cassette for the same coverage of ratios, which can help maintain cadence.  For the road that’s more important however not everyone is sensitive to it.  If you frequently find yourself running out of top end gears then go 52-36.  If not, compact or below will likely suit you better and give lower drive train losses as others have said.  Drive train losses are not insignificant but if you’re using knobblies then road tyres will give you the biggest benefit.

    Everyone has their preferred cadence and finding the gears that work for you and your type of riding is going to help you.  If it’s flat, you’re bigger and you like to pedal at 80rpm then larger chain rings, if it’s proper hilly, you’re Quintana-esque and you like to spin then smaller.  There is no right answer.

    March 16, 2018 at 5:05 pm #914531
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    Boatsie

    madcarew wrote:

    madcarew wrote:

    For the same ratio, ignoring utterly miniscule drivetrain efficiency differences, the pedalling effort is the same at the same speed. Overall your 42 chain ring set up is about 1-2 gears lower than your 52:36 would end up, so easier overall, but at any given cadence for the same speed, it is just as easy / hard to pedal on either combo

    I agree. Same power output.
    If we use 1cubic solid cube blocks moved 1 inch to demonstrate torque and further inches to demonstrate rpm of crank.
    We as humans can measure strength(torque) and as example. If I struggle to move a 100kg cube then I would view such as my peak strength. If I move 50kg 3 inches I have done so easier than 100kg 1 inch yet I have demonstrated 150% horsepower doing such.
    Theorically I could push 1kg hundreds of inches yet I know I don’t find comfort at either ends, eg busting my knees and back with 100kg nor losing control and tripping at more than 2-3 rp.second.
    Balancing power and strength is better with practice.
    Regardless of strength, it takes 4 times the power to push twice the speed. In reality I can comfortably cruise along at 30kmph in 6th cog whereas I exhaust faster sitting at 25kmph in 8th cog. A similar setup, I think the front is a 44t (or near) and the rear is an 8 speed.
    I agree with earlier regarding trying skinnier tyres on the gravel bike because you can feel your routes and decide better plus most bikes I see aren’t top shelf hence the front rear tyre combo becomes a front and a spare. Tyre liners are excellent..
    An advantage you might find with the very tall cogs is if your a lazy casual, in no rush rider that convexs a peak and just rolls using gravity, catching breath, into top cog where assistance isn’t hurtful to your stride and just poking her a bit to let you ride faster. Faster ma star faster. Lol
    Just reread your initial write. I’m going opposite way from 23-25-28 mm to 38mm. I’m guessing it will be much the same yet slower and heaps more ‘don’t care with concentration and want to protect rims’ on the nice cushiony fatties.
    Hence should enjoy either. 50 or 52 is honestly plenty of crank. To save some life more teeth on rear grip better when worn. 50-12 is pretty strong. Although no where near as high as 52-11, the bloke I bought a bike off was a multiple seasoned daily commuter and he rarely used 52-12. Much flat, slight continuous downhill of 10m drop 15 km roll. Something like that.

    March 16, 2018 at 10:23 am #914529
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    madcarew

    For the same ratio, ignoring

    For the same ratio, ignoring utterly miniscule drivetrain efficiency differences, the pedalling effort is the same at the same speed. Overall your 42 chain ring set up is about 1-2 gears lower than your 52:36 would end up, so easier overall, but at any given cadence for the same speed, it is just as easy / hard to pedal on either combo

    March 15, 2018 at 7:57 pm #914527
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    Jimthebikeguy.com

    I am not quite sure what you
    I am not quite sure what you are getting at but just bear in mind that it takes a very very fit rider to sustain power through either a 50-11 or 52-11 combo for long periods. If you look at the wear on the average riders cassette, its all in the middle. You maybe spend 3% of your ride in that absolute top gear (50-11 with a compact, for example). So its barely worth having. More usable gearing in terms of front chainrings is 46/32, as you can easily envisage spending a good amount of time turning the 46-11 combo on a nice A road run, and the smaller ring means you can run a tighter block at back (11-28 maybe) which eliminates some of the indelicate shift action getting up to/coming off of a 32 tooth sprocket.

    March 15, 2018 at 5:21 pm #914525
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    Miller

    Can you get some test rides

    Can you get some test rides on road bikes so your thinking isn’t all theoretical? You might just love the road bike experience. 

    March 15, 2018 at 3:39 pm #914523
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    kvert

    Excellent comments. To answer

    Excellent comments. To answer the road/gravel tire question… yes, I currently ride on a Maxxis Rambler/Re-fuse 40mm combo. The Re-fuse is probably the closest I want to get to road slicks on the bike, without being a road slick at all, even though the rims could certainly take thinner ones.

    Again, very interesting and it at least it basically confirms what I felt in my gut–that there is not really going to be some magical advantage that I can hope for in gearing alone. I feel like I’m the epitome of a rec rider where if I do a couple hours on Zwift I can hover around the 3.5kw/g mark but I also consider that a very hard effort and I’ll be spent afterwards.

    Yea, my downhills will probably go by quicker and my long and steady ascents might improve just a bit–but the majority of the ride will be the same. So I’m back to not being able to use some “need to have it” mechanical advantage to convince myself of making the purchse… pure luxury purchase now. Hah. 🙂

    March 15, 2018 at 3:27 pm #914521
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    Boatsie

    Mechanical advantage isn’t
    Mechanical advantage isn’t always an advantage.
    Take a car. Like a human the car has a torque band. At a climb, we the pilot has choice. Drop it back or hold top cog . If we hold top cog we slow and then stall yet if we had dropped it back we could have easily climbed the hill. Hence the mechanical advantage became an impossible task.
    We all get head winds, tail winds, gradients. The flatter your routes the tighter your groups or your prepared to walk up a swift descent.
    The cogs on that will get you up and down, reads really sweet broad range but unless you’re an Olympian peddling 150km pre work daily or similar, I guess 52-11 would be used as rather swift descents. 🙂

    March 15, 2018 at 3:05 pm #914519
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    Miller

    Don’t worry about gearing

    Don’t worry about gearing efficiency, drivetrain losses are not significant with derailleur gears assuming they’re not faulty or gunged up. Stop thinking about direct, indirect, whatever.

    What does count is having the range of gears you need.  Your proposed 52/36 11/30 setup would work fine although 52-11 is a very tall gear more suited to racing than normal riding around. I’d prefer a 50-34 up front but it’s not a big deal.

    Di2, or EPS as I prefer to call it, might be a luxury but you’ll absolutely love it.

     

    March 15, 2018 at 3:00 pm #914517
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    VeloUSA

    I am going to assume you’ve

    I am going to assume you’ve ridden your gravel on the road with gravel tires. With this in mind and knowing good road tires would improve rolling resistance how much gear changes are you looking for, and how often do you spin on the smallest cog?

    For example on gear rations:

    1. Running 52/12 is 8.7%. Running 42/10 is 8.5% – .2% difference

                           52/11 is 9.5% – 1% difference

    2. Running 50/11 is 9.2%. Running 42/10 is 8.5% – .7% difference

    The least expensive option to try is getting good road tires. eg; Conti 4000s II in 25/28mm. Mount them an go ride (if your current rims can take smaller tires). You’ll know then if a bigger chain ring is what you want, or not. You’ll also know that you can mount the Conti’s on your new ride.

    March 15, 2018 at 2:49 pm #914515
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    zero_trooper

    It may be a ‘completely
    It may be a ‘completely unscientific question’, but it’s certainly an interesting one.
    Enjoying the responses.

    March 15, 2018 at 2:49 pm #914513
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    Boatsie

    Daveyraveygravey wrote:

    Daveyraveygravey wrote:

    My road bike has 52/36 and 11-32, I use all the gears.  If I lived in the Alps I would be tempted to go proper compact at the front but other wise I think you want a big chainset.

    I am old school though, until 3 years ago I rode a 53/39 with 12-28.  I could get up the Sussex hills with that, but I would be painfully slow and out of the saddle to do it.  My friends on compacts would sit and spin and ease away from me.

     

    That reads perfect. I ended with 53/39 with 13-23. Mainly because price. Less than 10 quid each on 2 cassettes and £15 a combination on 4 cassettes.
    Being a tight group might have made chain easy too.
    I don’t mind walking up steeps though; sort of used to it. If I had used my brain better I would have liked to try 50/39 13-14-15-16-17-18-19-21-23 and will be at such later.

    Gear ratios are important if you want to remain in comfortable effort zone. A real example is into a head wind . If hurting at 53 -13, by dropping back 2 to 53-15 and increasing peddling rpm by 50% the road speed increases 71%!
    Muscles love heat, ligaments enjoy the beat. Less energy is wasted although diet is where food ware brings enjoyment of wear.
    But like Daveyraveygravey wrote. I believe you’d like a 52 😉 you get used to what you have.

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