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World record biggest shift
I was clicking around other people's links and came across this:
Originally Posted by osteoclast
(Post 16337022)
Have a look at Sheldon Brown's multi-range gearing: 51/28 with 12-24 FW. Anyone do this?
Gear Theory for Bicyclists My O.T.B. - Only The Best This is a really big shift! 23 teeth. Obviously it's possible to install such a shift but how well could the upshift work? The biggest shift on most common modern bikes is the 16 teeth between 50-34 on a compact. The MTB doubles have a bigger ratio shift at 36/22 but the number of teeth is smaller, 14. SRAM has a new group out for E-bikes, it's the same range as an 11-speed MTB but has 8 speeds and bigger shifts. The shifts are uneven and I guessed the reason was to control the number of teeth between the gears. The upper shifts are all 8 teeth. https://www.sram.com/sram/mountain/p...block-cassette The Eagle 12-speed cassette also has a final shift of 8 teeth from 42 to 50. What's the biggest shift you've seen? In ratio or teeth, at either end. Teeth are more impressive, I think. |
2 Attachment(s)
Originally Posted by Darth Lefty
(Post 19150094)
I was clicking around other people's links and came across this:
More here and here Gear Theory for Bicyclists My O.T.B. - Only The Best This is a really big shift! 23 teeth. Obviously it's possible to install such a shift but how well could the upshift work? The biggest shift on most common modern bikes is the 16 teeth between 50-34 on a compact. The MTB doubles have a bigger ratio shift at 36/22 but the number of teeth is smaller, 14. SRAM has a new group out for E-bikes, it's the same range as an 11-speed MTB but has 8 speeds and bigger shifts. The shifts are uneven and I guessed the reason was to control the number of teeth between the gears. The upper shifts are all 8 teeth. https://www.sram.com/sram/mountain/p...block-cassette The Eagle 12-speed cassette also has a final shift of 8 teeth from 42 to 50. What's the biggest shift you've seen? In ratio or teeth, at either end. Teeth are more impressive, I think. Attachment 541283 Attachment 541284 |
Biggest tooth gap and/or biggest ratio of a single shift.
Total range of derailleur gears has gone bonkers with the current Shimano MTB 33-speeds which have 6.6:1 overall. I think the only things that beat that have a third shifter. |
Originally Posted by Darth Lefty
(Post 19150140)
Biggest tooth gap and/or biggest ratio of a single shift.
Total range of derailleur gears has gone bonkers with the current Shimano MTB 33-speeds which have 6.6:1 overall. I think the only things that beat that have a third shifter. |
Back in the 1960s there was a gearing fanatic by the name of Chuck Harris who made his own derailleurs, chain rings and cogs. His favourite personal set-up was a 13-17-26-34-42T freewheel combined with 26-44-68T chain rings.
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Originally Posted by T-Mar
(Post 19150200)
Back in the 1960s there was a gearing fanatic by the name of Chuck Harris who made his own derailleurs, chain rings and cogs. His favourite personal set-up was a 13-17-26-34-42T freewheel combined with 26-44-68T chain rings.
https://www.facebook.com/Chuck-Harri...4695303248672/ Chuck Harris at the Ohio City Bicycle CoOp http://home.earthlink.net/~mike.web/img/CH/CHbike.jpg |
68-13! Jinkies! If you had some sort of Superman legs, that would have to be near 50mph @ 90rpm... on a steep hill, or behind a semi, that is.
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Well, my recumbents have 24-42-52 triples. The Shimano FD-R443 front derailleur handles the upshift pretty well, but it's a heck of a jump. It's kind of like spin-spin-spin-shift-grind-grind. Best done when the hill's flattened out.
It's hard to see, but both bikes are pictured on the http://www.bikeforums.net/classic-vi...r-gugie-2.html thread. We usually use the 42 tooth rings for cruising and the 52 tooth rings for zooming. If we need to drop to the 24 tooth, well, we really need it. The missus and I have climbed 17 percent grades carrying touring loads. Pedaling at 3mph is no fun, but it beats getting off and pushing. |
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Biggest single jump on any of my bikes is the 42 - 60t (18 teeth) on my Bike Friday. Works ok but I tend to stay on the big ring most of the time.
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Originally Posted by jamesdak
(Post 19150833)
And here I thought my 34/53 was a big jump. :o
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Originally Posted by DrIsotope
(Post 19150527)
68-13! Jinkies! If you had some sort of Superman legs, that would have to be near 50mph @ 90rpm... on a steep hill, or behind a semi, that is.
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The crank on my Holdworth has 27t and 50t rings. Upshifts are not a problem, but I had some trouble with downshifts for a while; the chain would miss the little ring on the way down. A chain catcher solved that. My Squarebuilt has a similar setup, but 27t-47t.
https://im1.shutterfly.com/media/47a...D550/ry%3D400/ |
Originally Posted by Lascauxcaveman
(Post 19150879)
That's pretty impressive, using unmodified equipment. What FD is that? How well does it handle the jump?
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Many French touring bikes came with 13 or 14-26T freewheels and 50 or 52-26T chainrings. Long arm Huret derailleurs were designed to handle that kind of spread.
They didn't work that well on the "Alpine" gearing that was popular during the Bike Boom: 14-28, 30 or 32T FWs and 52-42T chainrings. verktyg :50: Chas. |
Originally Posted by verktyg
(Post 19151045)
Many French touring bikes came with 13 or 14-26T freewheels and 50 or 52-26T chainrings. Long arm Huret derailleurs were designed to handle that kind of spread.
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