Interesting! I read this about the Shimano Nexus SG-C3000-7R 7-Speed Internally Geared 36h Rear Hub: “
Not intended for off-road use as standing on the pedals, riding up steep hills or using an too low of a gear ratio may damage the pawls inside the hub" Uh, that sounds like it would not hold up if I rode it fast/hard.
Fun fact: neither the Shimano Nexus 7 nor the Alfine 11 IGHs have a true 1:1, direct drive gear ratio. They both simulate 1:1 by two-stage compounding down and back up! Fun fact: the efficiencies vary among derailleur gear ratios, but nobody ever worries about it. There have been posters who had the ratios and compounding explained to them about a particular IGH, then went and rode the bike and by golly! they could feel the various inefficiencies in the gears just the way it had been explained to them! Except...the ratios and compounding were explained wrong and what they were 'feeling' was all in their mind. The Sturmey-Archer 8 is designed for the rider to be in the most efficient ratios when riding uphill/with a load/against the wind. A design compromise, yes, but certainly not a horrible one. Say, willing to respace the rear OLD on that '74 Falcon?
I figure I should be able to handle some minor variations in efficiency between gears -- just don't want to complete the bike only to find most of the gears intolerable to ride. Well, I am asking questions; might get enough answer to make a choice I can live with.
Yes, this will be my first time cold-setting a frame, almost certainly. That said, I found
THIS HUB and I see it's made in 120mm, that would be a bonus. Alas, on that site out of stock -- then again, on that site almost all hubs are out of stock!
Originally Posted by
Salubrious
My 'No' is that there is not a fundamental flaw in your plan
The only exception IME/IMO is 'unless you get an Alfine 11-speed' which IMO is a poorly designed hub. I also found that Shimano would not support its being fixed when it developed problems, which seems very likely. The efficiency thing IME isn't a worry. If you go with a vintage Sturmey Archer you'll find them as free in any gear as the best Campagnolo hub made. The efficiency drops with more and more gears, but I can tell you that in the case of the Rohloff, which arguably is the ultimate IGH and is also the least efficient, that two variables exist that don't get the attention they should and apply to any IGH. The first is the IGHs take a bit of break-in. The Rohloff needs about 700 miles to really free up IME. They are never measured after break-in; apparently only right out of the box. The second is that if there is any dirt or the like to mess with your derailleur system its efficiency drops to below that of the Rohloff's measured numbers. So to really have the numbers you quoted be a thing, you have to really be on top of your maintenance. One gummy jockey wheel or slightly gummed up chain can mess with it enough that even a Rohloff is more efficient. My only other advice is research your IGH prior to purchase. If getting an 8-speed my choice would be the Shimano Alfine (its as good as the 11-speed is bad if that make any sense). Any IGH can be shifted without loosing cadence. You have to practice a bit but the trick is to shift when one of your feet is at 12 o'clock in its stroke- IOW when its torque is least. The amount of time you spend servicing things is reduced and its nice to shift quickly at any speed including a dead stop. IME the British SA hubs are designed to shift while peddling. This is particularly true of the 4 and 5 speed hubs.
Thanks for the clarification!
Sounds like I should cross the Alfine 11 speed off the list. I think the sweet spot for me is 5 to 8 speeds anyway, this should allow a wide range of terrain except mountains.
Originally Posted by
Doug Fattic
One thing that might help guide your decision are the shifters. Most IGHs are used with upright instead of drop bars so most shifters are designed accordingly. In other words most don't work well with drop bars. Sturmey Archer has a variety of shifters for their 3 speed hubs including one that can go one a down tube shifter boss. They have a bar end model too..
I can be flexible, was actually thinking about a twist grip at the end of drop bars. Hmm, does a thumb shifter designed for upright bars fit the same boss as downtube friction shifters?
Originally Posted by
ascherer
Sturmey 8-speed needs a small chainring up front. I have one on my 1971 Raleigh International, which is my take on a lighter and livelier Sports for city commuting and errands. Pana-Sanyo dynamo front hub, Origin8 crankset, Mafac Racers, 35c Páselas. The Sturmey’s a fine hub, and sorry but all the measures of efficiency are lost on me. Especially when I have it loaded with groceries or my work gear
Presuming I can find the correct chainrings, it might look odd but perhaps that is OK. Again, I plan 50.4BCD
Originally Posted by
GamblerGORD53
A lot of hogwash in this thread. LOL. I have a SA RD3, XL-RD5w, Nexus 7i with deplorable roller brake, and Rohloff14 with disc brake. I just rode my 50 lb CCM 3 speed 92 miles the first full day ride this year. It hums along around 14 mph just fine. GIs are 47/ 63/ 84. Any other gear range is a stupid idea. The fastest and easiest by far is the older SA 5w with finicky shifting. Efficiency is 96/ 97% at least, there are gaps between some gears of course. It has done 46 mph and my longest ride at 133.6 miles. R14 would only do 43 on the same hill. The R14 does take thousands of miles to loosen up all the seals. The bike is 78 lbs most of the time. I go 16 mph a lot of the time with medium effort. IMO, the efficiency is 94 to 96% like often stated. The $$$ is 100% JUSTIFIED. I did 2 tours at 120 lbs, 8,100 miles. I didn't see any deraileur tour bikes passing me. Funny how it's slagged by guys with $10,000 CF racers that can't carry a box of kleenex. LOL
The Nexus 7i is less efficient but the best for shifting in traffic, with a 2 trigger shifter. The 7 gears are perfectly spaced, with 3 GI less on the top than the SA 5w. With a disc brake it should be closer to the SA hubs. The flaw with the SA 8 is the biggest gap at the bottom and top. So gears 1 to 2 would have about 33 GI then 45 GI. The 5w is the opposite with 17% from 1 to 2nd. I absolutely love my SA XL-FDD dyno drum brake front hubs. Best bike part ever made.
>>> Shifting any IGH with any load is STUPID. That's why cars have a CLUTCH. But anyway, your 1974 bike has 120 mm dropouts.
Sounds like you have some experience here. But, yeah, exactly what here qualifies as hogwash? Inquiring minds want to know.
Pretty sure I just won't drop the $1500 for a Rohloff. That enough for me to build/restore several bikes, difficult to justify. If it was to be my only bike-- yeah.