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  1. #1
    Senior Member NigelHealy's Avatar
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    Brompton BWR 6speed 66miles 7000ft climb - about 2mph slower than roadbike

    I've today done a regular route I do approx weekly, instead of a roadbike but on a Brompton S6L-X. This is a S2L-X from 2006 with the transmission from a 2011 S6L.

    route - http://ridewithgps.com/routes/811734

    Videos and photos here

    At my current level of fitness on my road bike I'd expect to do it in about 6hr30mins.
    Today on a S6L-X Brompton with new transmission (BWR <500 miles, with its new chain and sprockets, new Marathon Plus tires, 44T Brompton crankset and SON hub), I took an hour longer (16% slower).

    Some of that I can account for:
    - wider gear jumps so either too-high or too-low so took too-low, slowing my uphills. If this were a shorter trip, much more within my fitness, I'd more inclined to take too-high.
    - upright position on downhills, no drop-handlebars, slowing my flats and downhills.
    - top gear of 88" , slowing my downhills, my roadbike has top of 108"
    - Marathon Plus tires, slowing me the whole time.
    - small effect is I had an S-bag, from experience it adds so little drag its nearly a fairing.

    On the 1st/2nd gear (hub low) there is a grinding noise, indicates some losses. In all other gears there is some kind of clicking. On downhills, the hub is making the chain hang so I've been putting in middle hub gear when freewheeling hoping it reduces drag?

    The good news is a stock Brompton 6speed can at least *DO* such terrain, 66 miles, 7000ft of climbing, average speed including stopping to eat/drink, talk, and take photos, is 8.8mph vs a roadbike 10mph. If I assume 30mins spent stationary, then average speed 9.5mph vs a roadbike 11mph, which is largely in the my ballpark experience the Brompton is about 2mph slower.

    The BWR according to reports in forums will improve, and I know a new set of Marathon Plus will improve as the terrible tread, Schwalbe feel we need, wears down to get nearer to slicks.

    I've also built a S6R with SRAM and Mountain Drive, it has closer gears and a higher 97" top gear, it should be faster? However, when I was fitting the MD to the frame, when no chain hooked on, I could perceive resistance to rotation, MORE than when having a Brompton crankset on a *** BB (I typed the letters F A G which is the name of the manufacturer but this forum replaced with *!) , so the Schlumpf *IS* producing some losses even in its direct-drive mode, that could well cancel out many of the performance gains it offers (higher top, closer gears with SRAM). I might have a go at applying some grease as per service instructions to the Schlumpf although it should NOT need it as its done very little mileage since new from the factory.
    Last edited by NigelHealy; 12-29-11 at 02:35 PM. Reason: Bikeforum's issue with F.A.G.

  2. #2
    Senior Member rex615's Avatar
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    Quote Originally Posted by NigelHealy View Post
    I've today done a regular route I do approx weekly, >SNIP<
    I took some photos and videos will post later.
    Thanks for the ride report, very interesting. It is good to hear how a challenging ride as this, compares with the Brompton.

    Looking forward to the pics and video.

  3. #3
    Senior Member NigelHealy's Avatar
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    Quote Originally Posted by rex615 View Post
    Thanks for the ride report, very interesting. It is good to hear how a challenging ride as this, compares with the Brompton.

    Looking forward to the pics and video.
    Here http://s334.photobucket.com/albums/m...2028th%202011/

  4. #4
    jur
    jur is offline
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    I have also found that my 20" folders are about 10% slower than my go-fast Swift, and the 16" ones closer to 15% slower.

    My take was the smaller wheels, the tyre types, the weight, the flexiness, the hub gear drag. In your setup I would ditch the Marathon Plus and use Kojaks, with a tyre liner in the back for puncture protection. That's what I have on my Brommie. I just this week installed a Schlumpf Speed Drive on it and I think I can feel the drag, but since I am not looking to save every joule on the Brommie, I am not too fussed.
    My folding bike photo essays www.dekter.net/

  5. #5
    Senior Member NigelHealy's Avatar
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    Quote Originally Posted by jur View Post
    I have also found that my 20" folders are about 10% slower than my go-fast Swift, and the 16" ones closer to 15% slower.

    My take was the smaller wheels, the tyre types, the weight, the flexiness, the hub gear drag. In your setup I would ditch the Marathon Plus and use Kojaks, with a tyre liner in the back for puncture protection. That's what I have on my Brommie. I just this week installed a Schlumpf Speed Drive on it and I think I can feel the drag, but since I am not looking to save every joule on the Brommie, I am not too fussed.
    This model has Ti so it will be springier than steel, but I have the stiffest suspension block. So I was forced up to Marathon Plus reluctantly via punctures from anything less, the wheels came with Brompton's tire, they claim tougher than the Kojaks, lasted only a few weeks then just metal road debris total instant flat, fortunately a block from my home.

  6. #6
    Senior Member rex615's Avatar
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    Quote Originally Posted by NigelHealy View Post
    Here [URL="http://s334.photobucket.com/albums/m...2028th%202011/[/URL]
    Great pics, Love the "Brompted" bike in some of the pics, leaving the tail light on was a nice touch.

    Thanks for sharing.

  7. #7
    Senior Member NigelHealy's Avatar
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    Quote Originally Posted by rex615 View Post
    Great pics, Love the "Brompted" bike in some of the pics, leaving the tail light on was a nice touch.

    Thanks for sharing.
    That is the SON lighting system option, which is the SON front hub and the B+M front light and a Brompton-specific rear light. I bought a S6L in October this year with SON and moved its wheels to a 2006 S2L-X to make the S6L-X/BWR/SON shown. The SON light has a standlight feature which stays on for a few minutes via a capacitor so when stationary at lights it will stay on. I have it set on sensor mode so it comes on automatically when dark enough. It is however not as bright as good battery lights which I use to light up the road so I can see the road when night vision is ruined by oncoming SUV. If no cars existed, the dynohub light is ample. Its hard for me to show how bright lights are when moving, I only have handheld camera.

  8. #8
    Senior Member NigelHealy's Avatar
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    Quote Originally Posted by jur View Post
    I just this week installed a Schlumpf Speed Drive on it and I think I can feel the drag, but since I am not looking to save every joule on the Brommie, I am not too fussed.
    A Speed Drive with the BWR makes a good idea, as does either the High Speed Drive or Mountain Drive with the older SRAM. The BWR shown here is on the flat in upshift but if you had a Speed Drive with say 33T you'd get 22"-109" with 70" being Shlumpf on overdrive and hub on smaller sprocket and rear hub direct-drive.

    I've toyed with a custom 30T/54T front manual-move so I'm in direct-drive more often and just manually move for the long ascents but then I'm giving hassle for gentler climbs which a 44T avoids. Its hard to find "just right" customizations...

    I've managed to upload some videos
    http://s334.photobucket.com/albums/m421/NigelHealy/Brompton/To%20the%20coast%20December%2028th%202011/?action=viewĄt=MVI_0513-1.mp4
    http://s334.photobucket.com/albums/m421/NigelHealy/Brompton/To%20the%20coast%20December%2028th%202011/?action=viewĄt=MVI_0512-1.mp4
    http://s334.photobucket.com/albums/m421/NigelHealy/Brompton/To%20the%20coast%20December%2028th%202011/?action=viewĄt=MVI_0503-1.mp4
    http://s334.photobucket.com/albums/m...MVI_0523-1.mp4
    Last edited by NigelHealy; 12-29-11 at 11:11 PM.

  9. #9
    coprolite fietsbob's Avatar
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    Maybe a TA Cyclotourist crank will resolve the issues with the swaged arm fitting
    less than solidly with the OEM Stronglight stuff. ..
    since the TA arm bolts (5) to the outer.. inner bolts (6) to the outer.
    they do make chainrings, in France, from 26t upward.
    the arm have not been made in a few years, copies are around.

    I'm using a Mountain drive and the 54-15 on the AW3, ratios can be replicated
    with a 13 & a 47, as an inner , and the 54 as an outer
    not sure how 2 chainrings
    will stack on the MD spider , the spacer is = to a chainring thickness ,
    trouser guard shifting out side the spider does not double the space, as it
    is half the thickness of the chainring .. so not enough total length
    of distance between the inner chainring and the inside face of the crankarm..
    Last edited by fietsbob; 01-01-12 at 11:24 AM.

  10. #10
    Senior Member NigelHealy's Avatar
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    I did the same route today, but instead of a S6L-X/BWR-44T/SON, I did it on a S6R/SRAM/SchlumpfMD-56T. The elapsed time was higher. So even so closer gears to be nearer to ideal cadence, and a higher gear to help on downhills, the fact of adding a hub (Schlumpf Mountain Drive) was taking more away overall? Still it felt easier on the steepest climb nearer the end, as I had lower gears when I wanted, and if I were lugging camping gear, I'd need those gears. For all but a few short steep sections, I never went below my 3rd gear.

    Photos and videos

    So my conclusions overall:
    1. Don't use a folder like a Brompton unless folding is a required/possible part of the route (I knew that already, just good to know the relative effect)
    2. fewer and simpler hubs to get just enough gearing is better
    3. add more gearing if the terrain or weight of kit will require


    The only surprising bit is I thought I'd be same/better with SRAM+MD than BWR, I'd heard that BWR was less efficient and that Schlumpf efficient but seems just adding more hubs is more drag, so only have them fitted if you NEED them.

    I'm wondering if I should build a hub-less Brompton, I can actually make a 2-speed rear with a front-derailleur 30T/54T (I have the parts..... .)

    Seriously, I was simply using the Christmas holidays to try out combinations, I'm going to use a roadbike for when folding is not a part of the day and at least I know the relative speed impact if I want some folding flexibility, its also good to know the bikes I built the last week can actually handle the gradients and distances. Slower, but no less capable. The Touring Brompton I built is going to be used probably less than 10 days this year. The day-bike is going to be go-to bike if folding is needing, which it tends to be on commuting and shopping trips, and my M2L-X is probably going to be the children's folder as they are less muscly for lugging the 1Kg more of a 6-speed.
    Last edited by NigelHealy; 01-02-12 at 12:01 AM.

  11. #11
    Loves to suffer freighttraininguphill's Avatar
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    Love the pictures and videos! Those are some beautiful climbs, so you know what that means. I'll have to climb them someday if I get down there.

    I have heard that IGH hubs are not as efficient as derailleur drivetrains. As an owner of two IGH-equipped bikes, I believe it. I also hate how finicky the Sturmey-Archer 3-speed hub is on my folding Worksman Port-O-Trike. It's a PITA to get it adjusted right so it doesn't skip in second and third gears.

  12. #12
    Senior Member Sangetsu's Avatar
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    I have noticed a rather large difference in the efficiency of my Birdy when compared to my road bike. The Birdy rolls down (slows down) more quickly when coasting on flat terrain, which indicates more rolling resistance. I use Kojaks inflated to 120 psi (no flats at all after nearly a year of heavy riding), with the standard 18" wheels and Shimano parallax hubs. The 10 speed XT drive line is about as efficient as the Record kit on my road bike.

    Obviously, it is easier to maintain speed on my road bike, and for the really long rides it remains my top choice. But for getting around town, or when I want to ride in far-off places that I must get to by train or bus, the Birdy is my first choice.

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