What is better for hills, 3 speed hub or 7-speed hub?

[modmans2ndcoming]

I like to plan. So, even though my New bike purchase is about a year
out and I will make due with my used bike, I would like to know, what
is better for taking a hill (nothing serious, this is the Detroit area,
and the worst hill is coming up out of an under pass on the road). Is a
3 speed hub better on gear 1 for hills than a 7 speed? I really do not
want to deal with derailleurs since I want simple and low maintenance.
The price difference between the two models is about 225 dollars. all
the other features are the same but for the hub gearing.

If I can take a hill just as well in a 3 speed as I can in a 7 speed,
then I would certainly take the cheaper bike.

thanks,

Jeremy

 

[landotter]

You can change the gear ratios of either by changing the rear cog or
front chainring, so you can achieve the same with both. Now the
question is, once that gear ratio is right in the lowest gear, will it
be bearable with the other two? Probably.

If it's the Nexus 3, the only thing I really don't like about it is the
grip shifter. I'm very partial to the thumb shifter you can get for the
7, but for a coupla hundred bucks, could probably live with the
gripshift.

 

[modmans2ndcoming]

Well.. for me as long as the shifter is accessible with my hands on the
handle bars, I'm good.

How would I know what to make the ratio? If it is too hard then should
I make the rear cog larger first?

also, how will that effect my ability to say tow a trailer with some
work papers in it, or my kids?

 

[landotter]

If it's a good shop they should be able to help ya out. Take it for a
test ride, see how the low gear feels, if it's a bit too hard to pedal,
have them install a rear cog 2 teeth larger. You can also change the
ratio with a smaller front chainring.

You'll be able to do anything a derailleur bike can do as far as towing
as long as you get the ratio right, just won't have the same selection
of gears, which ain't no big deal.

 

[modmans2ndcoming]

the stock cog and chain ring on the bike I'm looking at is 16T and 38T
respectively. how would that handle out of the box do you think?

 

[modmans2ndcoming]

I guess my question then is "how will I know" but the guy at the shop
would be able to help me out there I'm sure.

 

[Leo Lichtman]

Riding uphill out of an underpass should be do-able with a three-speed, and
without especially low gearing. You can get the equivalent of a couple of
steps downshift just by standing up.

Adding a trailer with a couple of kids in it, though, changes things
considerably. If you put on gearing low enough to handle that, you could
easily wind up with gearing that is too low for riding on the level without
the trailer. That may be enough to justify the seven speed hub. Remember,
after you own the bike with a three speed hub, you can't go back and add the
extra money and have the seven speed.

 

[Michael Wileman]

In <[email protected]> "modmans2ndcoming" <[email protected]> writes:

>I like to plan. So, even though my New bike purchase is about a year
>out and I will make due with my used bike, I would like to know, what
>is better for taking a hill (nothing serious, this is the Detroit area,
>and the worst hill is coming up out of an under pass on the road). Is a
>3 speed hub better on gear 1 for hills than a 7 speed? I really do not
>want to deal with derailleurs since I want simple and low maintenance.
>The price difference between the two models is about 225 dollars. all
>the other features are the same but for the hub gearing.

>If I can take a hill just as well in a 3 speed as I can in a 7 speed,
>then I would certainly take the cheaper bike.

You need to say a bit more about why you are riding, and
what sort of bike you are thinking about.

I find a 3-speed is fine for me as transportation. My city
has hills, but not that many, so I swapped out the cog on my
SA AW to get a better high gear. The downside of this is
that you mostly end up coasting downhill. For commuting this
is fine. If you're riding for fitness or fun, it might not
be.

There are a lot of nice old Raleigh 3-speeds that can be
picked up for a song if you keep your eyes open. I'm not
sure what advantage a Nexus 3 would have over them.

Can you pedal out of the saddle safely on a Nexus? That
might be worth it.

Mike

 

[Tim McNamara]

In article <[email protected]>,
"modmans2ndcoming" <[email protected]> wrote:

> I like to plan. So, even though my New bike purchase is about a year
> out and I will make due with my used bike, I would like to know, what
> is better for taking a hill (nothing serious, this is the Detroit
> area, and the worst hill is coming up out of an under pass on the
> road). Is a 3 speed hub better on gear 1 for hills than a 7 speed? I
> really do not want to deal with derailleurs since I want simple and
> low maintenance. The price difference between the two models is about
> 225 dollars. all the other features are the same but for the hub
> gearing.

Derailleurs are simple and low maintenance. But be that as it may, some
people prefer internal geared hubs. But simple they aren't, as you will
see if you ever look at an exploded diagram of an epicyclic hub. They
only appear simple because the complicated bits are hidden from view.

> If I can take a hill just as well in a 3 speed as I can in a 7 speed,
> then I would certainly take the cheaper bike.

By reputation, 7 speed hubs have much higher friction losses, so
climbing a hill in bottom gear will be harder with the 7 speed hub than
with a derailleur system of the same gear ratio. I have read some
opinions by hub gear users that the bottom two gears are no easier to
pedal than third gear due to the friction losses. However, those are
likely to be lower gears than you would be able to get with a 3 speed.

A 7 speed internal geared hub is basically three 3 speed units combined.
Because each of the 3 speed units has a normal (1:1) gear, you end up
with 7 different gears. With a 7 speed hub, 4th gear is usually normal
(1:1) and the further you get from that, the more friction losses in the
hub- so the bottom gear will have the most losses (all three units will
be in their respective reduction gears). With a 3 speed hub, 2nd is
normal.

From what you describe in terms of the terrain where you will be riding,
I would go with the three speed. It's cheaper, less complicated and
probably will provide you with enough gears 95% of the time.

 

[(PeteCresswell)]

Per Tim McNamara:
>From what you describe in terms of the terrain where you will be riding,
>I would go with the three speed. It's cheaper, less complicated and
>probably will provide you with enough gears 95% of the time.

Heinz Stücke, who spent most of his life riding around the world, says that 3
speeds were enough for him.

"The bicycle has 26" wheels and a three-speed Torpedo hub-gear (incorporating
pedal brake). I never felt that the three speeds were insufficient and I am
happy with the little service the Torpedo has required. As of today I have
pedaled about 385,000 kms."

http://bikechina.com/ct-heinzstucke1z.html
--
PeteCresswell

 

[modmans2ndcoming]

so, do you think that I would be better served by a derailer since I
will want to have a trailer for work or with the kids?

 

[landotter]

modmans2ndcoming wrote:
> the stock cog and chain ring on the bike I'm looking at is 16T and 38T
> respectively. how would that handle out of the box do you think?

As far as I know, the Nexus 3's middle gear is the 1:1, like other 3
speeds, and 39X16 is a really common gear for fixed gears and single
speeds, being at the lower end of what's practical on the street, so if
you had a lower gear than that, which you do, and the step it
large--like 2-3 cog difference on a freewheel--it should be fine for
gently rolling hills.

Why can't you just test ride the damn thing and see for yourself?

 

[catzz66]

modmans2ndcoming wrote:
> so, do you think that I would be better served by a derailer since I
> will want to have a trailer for work or with the kids?
>


Sounds like you can't lose with a 7 speed.

 

[G.T.]

(PeteCresswell) wrote:
> Per Tim McNamara:
>>From what you describe in terms of the terrain where you will be riding,
>
>>I would go with the three speed. It's cheaper, less complicated and
>>probably will provide you with enough gears 95% of the time.
>
>
> Heinz Stücke, who spent most of his life riding around the world, says that 3
> speeds were enough for him.
>

Yes, enough for him but even he admits that he does a lot of walking on
steeper hills.

Greg
--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons

 

[(PeteCresswell)]

Per G.T.:
>Yes, enough for him but even he admits that he does a lot of walking on
>steeper hills.

Check out the weight of his bike and load...
--
PeteCresswell

 

[G.T.]

(PeteCresswell) wrote:
> Per G.T.:
>
>>Yes, enough for him but even he admits that he does a lot of walking on
>>steeper hills.
>
>
> Check out the weight of his bike and load...

Oh, I saw that, that's for sure.

Greg

--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons

 

[modmans2ndcoming]

because I will have to travel out a ways to go for a tester and I
wanted to know it it would be worth my time first.

 

[[email protected]]

On Thu, 20 Apr 2006 08:51:33 -0500, Tim McNamara
<[email protected]> wrote:

[snip]

>By reputation, 7 speed hubs have much higher friction losses, so
>climbing a hill in bottom gear will be harder with the 7 speed hub than
>with a derailleur system of the same gear ratio. I have read some
>opinions by hub gear users that the bottom two gears are no easier to
>pedal than third gear due to the friction losses. However, those are
>likely to be lower gears than you would be able to get with a 3 speed.

[snip]

Dear Tim,

Kyle and Berto tested the efficiency of various internal hub
gears and a derailleur:

http://www.ihpva.org/pubs/HP52.pdf

The two tables at the end compare the various systems at 80,
150, and 200 watts, with a note indicating that the raw
figures would rise 2% to 2.5% if corrected for the extra
loss of the measuring instrument.

Here are the raw 150-watt 1st gear efficiencies:

94.2 Sachs 3-speed
93.0 Shimano 3-speed 93.50% average
93.3 Sturmey 3-speed

95.6 Shimano 4-speed

89.9 Sachs 7-speed
91.8 Shimano 7-speed 90.27% average
89.1 Sturmey 7-speed

90.6 Rohloff 14-speed

94.6 Shimano 3x9 derailleur (from table 2)

The 3-speed hubs are indeed slightly more efficient than the
7 and 14 speed hubs, but the most actual amount of power
lost is less than 4 watts.

Here are the raw 150-watt efficiencies for the lowest 3
gears:

91.8 92.9 89.9 Shimano 07 varies 3.0%
89.1 89.0 91.1 Sturmey 07 varies 2.1%
90.6 92.5 89.9 Rohloff 14 varies 2.6%

(The Sachs 7 broke and couldn't do second or third gear.)

For the working 7 and 14 speed hubs, the first gear
efficiency is always in between the other two gears. Again,
the most actual power lost is less than 5 watts.

To give some idea of the difference, here's what a speed
calculator that can easily change transmission efficiency
predicts for its default rider grinding up a 7% slope.

http://w3.iac.net/~curta/bp/velocity/velocity.html

Shimano 07
1st 91.8 5.2504 mph
2nd 92.9 5.3106 mph
3rd 89.9 5.1461 mph

Sturmey 07
1st 89.1 5.1022 mph
2nd 89.0 5.0967 mph
3rd 91.1 5.2120 mph

Rohloff 14
1st 90.6 5.1846 mph
2nd 92.5 5.2887 mph
3rd 89.9 5.1461 mph

After an hour of steady climbing, the first-gear riders
would be in the middle of the pack, which would have spread
out over about 1,130 feet.

The gearing efficiency differences do exist, but they're
probably too small for any rider to measure reliably even
with a speedometer that reads in 0.1 mph increments.

In any case, the comfort and cadence provided by a
particular gear probably matters more than any slight
improvement in theoretical efficiency. Fiddling with the
numbers is fun, but riders tend to choose a gear whose
cadence feels better.

Cheers,

Carl Fogel

 

[Dave Reckoning]

"Tim McNamara" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>,
> "modmans2ndcoming" <[email protected]> wrote:
>
>> I like to plan. So, even though my New bike purchase is about a year
>> out and I will make due with my used bike, I would like to know, what
>> is better for taking a hill (nothing serious, this is the Detroit
>> area, and the worst hill is coming up out of an under pass on the
>> road). Is a 3 speed hub better on gear 1 for hills than a 7 speed? I
>> really do not want to deal with derailleurs since I want simple and
>> low maintenance. The price difference between the two models is about
>> 225 dollars. all the other features are the same but for the hub
>> gearing.
>
> Derailleurs are simple and low maintenance. But be that as it may, some
> people prefer internal geared hubs. But simple they aren't, as you will
> see if you ever look at an exploded diagram of an epicyclic hub. They
> only appear simple because the complicated bits are hidden from view.
>
>> If I can take a hill just as well in a 3 speed as I can in a 7 speed,
>> then I would certainly take the cheaper bike.
>
> By reputation, 7 speed hubs have much higher friction losses, so
> climbing a hill in bottom gear will be harder with the 7 speed hub than
> with a derailleur system of the same gear ratio. I have read some
> opinions by hub gear users that the bottom two gears are no easier to
> pedal than third gear due to the friction losses. However, those are
> likely to be lower gears than you would be able to get with a 3 speed.
>
> A 7 speed internal geared hub is basically three 3 speed units combined.
> Because each of the 3 speed units has a normal (1:1) gear, you end up
> with 7 different gears. With a 7 speed hub, 4th gear is usually normal
> (1:1) and the further you get from that, the more friction losses in the
> hub- so the bottom gear will have the most losses (all three units will
> be in their respective reduction gears). With a 3 speed hub, 2nd is
> normal.
>
> From what you describe in terms of the terrain where you will be riding,
> I would go with the three speed. It's cheaper, less complicated and
> probably will provide you with enough gears 95% of the time.

If you need a lower gear try a larger sprocket. I ttried a 7 speed and went
back to my SA S3C 3 speed. I could swear that 7 speed Nexus ate half of my
power up steep hills.

Dave
Noblesville IN