Hub gear for heavy loads?

JennyB said:

The Shimano Nexus 8 is roughly equivalent to a 12-36 cluster. Combined
with a 48/44/28 chainset it would give a range of 21'"-108" which
looks ideal, but would it be able to cope with a total laden weight of
c 300 lbs?

I'd be cautious. My dad's Breezer has a Nexus 8, and it's a wonderful
transmission but it does not feel all that rugged. Admittedly, I've
not ridden it a great deal and having the dealer's mechanic touch up
the shift cable adjustment did seem to help, but about once or twice
every fifteen minutes it will "slip" a notch. I shift a lot, and it
usually happens only once per shift at most, but the sensation does
not instill vast confidence. I'm not a powerful rider and I try to
be considerate of the machinery.

That said, I'm only offering an impression. The "slips" don't seem
destructive and they're not getting worse. If the hub stays the way
it is now it will be a wonderful piece of machinery. Perhaps skillful
adjustment will make the problem go away entirely. I doubt that the
weight carrying capacity of the hub will be a problem, just torque.

hth,

bob prohaska

JennyB said:

I've had a couple of hybrib hub/derailleur gear bikes over the years,
and found it very useful, especially with heavy loads, to be able to
change gear when stationary.

The Shimano Nexus 8 is roughly equivalent to a 12-36 cluster. Combined
with a 48/44/28 chainset it would give a range of 21'"-108" which
looks ideal, but would it be able to cope with a total laden weight of
c 300 lbs?

1. call shimano tech support and ask. if i were them, i'd build for a
"likely" torque application, and 300lbs wouldn't be it. if that's the
case, it'll last ok for a while but it would be prematurely subject to
fatigue.

2. if you're going to have a triple on front, you have to use a chain
tensioner, likely a derailleur. if that's the case, you may as well
just use standard derailleur gears and not carry all that extra hub gear
weight.

In article
<[email hidden]>
,

JennyB said:

I've had a couple of hybrib hub/derailleur gear bikes over the years,
and found it very useful, especially with heavy loads, to be able to
change gear when stationary.

The Shimano Nexus 8 is roughly equivalent to a 12-36 cluster. Combined
with a 48/44/28 chainset it would give a range of 21'"-108" which
looks ideal, but would it be able to cope with a total laden weight of
c 300 lbs?

Hub gears do have a torque limit.
Rohloff explicitly limits their warranty to 42/16 or the equivalent.

--
Michael Press

JennyB said:

I've had a couple of hybrib hub/derailleur gear bikes over the years,
and found it very useful, especially with heavy loads, to be able to
change gear when stationary.

The Shimano Nexus 8 is roughly equivalent to a 12-36 cluster. Combined
with a 48/44/28 chainset it would give a range of 21'"-108" which
looks ideal, but would it be able to cope with a total laden weight of
c 300 lbs?

You might want to look at the SRAM Spectro S7. It has a reputation of
being more robust than the Nexus hub. See this discussion, for instance:

http://tinyurl.com/3aqv8s

I recently put one on a bike for my brother and was pleasantly surprised at
how easy it is to install and adjust.

Gary Young said:

You might want to look at the SRAM Spectro S7. It has a
reputation of being more robust than the Nexus hub. See this
discussion, for instance:

http://tinyurl.com/3aqv8s

I recently put one on a bike for my brother and was pleasantly
surprised at how easy it is to install and adjust.

I'll second that. I'm a heavy rider, and I've put 23,000 km on
my S7 so far.

I maintain a reasonably constant cadence, and change gears a
lot. I've replaced the gear cable a couple of times, but have
had no other problems at all.

John

The nexus is not made for heavy loads. Shimano says this somewhere in their
literature though not quantitatively. It's for city bikes on flat streets.

The Rohloff is bullet proof. The do specify a minimum gear ratio but also
say if you conform to that it's OK to use for off road or racing tandems and
claim they never fail.

It's also about 5x as much money as the Nexus. You also may be fine w/o a
front der. as the Rohloff has a much wider range.

Rocky

"John Henderson" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Gary Young said:

You might want to look at the SRAM Spectro S7. It has a
reputation of being more robust than the Nexus hub. See this
discussion, for instance:

http://tinyurl.com/3aqv8s

I recently put one on a bike for my brother and was pleasantly
surprised at how easy it is to install and adjust.

I'll second that. I'm a heavy rider, and I've put 23,000 km on
my S7 so far.

I maintain a reasonably constant cadence, and change gears a
lot. I've replaced the gear cable a couple of times, but have
had no other problems at all.

John