Shimano Nexus Inter 7 Hub: Gear train power loss?

My 2003 Van Dessel SuperFly "all 'rounder"/city bike is equipped with the Shimano Nexus Inter 7
planetary gear hub and roller brake.

I don't have the necessary instrumentation to offer any quantified evidence; but in certain gears,
it feels like the hub is eating a lot of pedalling energy. It is quite noticeable.

This doesn't really surprise me. I know there are dozens of gears spinning around in an oil bath
inside the Nexus hub, and that's going to be less efficient than 2 sprockets* and a chain.

I've read that the SRAM/Sachs 7 speed internal hub is a better design. Any comments?

-Barry

* Why do I feel the need to dance to German techno music wearing a black bodysuit when I say the
word "Sprockets"?

 

"B. Sanders" wrote:
>
> My 2003 Van Dessel SuperFly "all 'rounder"/city bike is equipped with the Shimano Nexus Inter 7
> planetary gear hub and roller brake.
>
> I don't have the necessary instrumentation to offer any quantified evidence; but in certain gears,
> it feels like the hub is eating a lot of pedalling energy. It is quite noticeable.
>
> This doesn't really surprise me. I know there are dozens of gears spinning around in an oil bath
> inside the Nexus hub

Nexus hubs are grease lubricated. The rollerbrake is probably pretty stiff to.

--
Marten

 

> * Why do I feel the need to dance to German techno music wearing a black bodysuit when I say the
> word "Sprockets"?
>

Because Mike Meyers is the greatest comic genius to ever walk the face of the earth. (although I
sincerely hope there are no more Austin Powers movies).

Thanks for the reminder though, I do need to use the word "sprockets" more in place of "cogs" (while
in my head doing that one dance what was it, the trout?)

 

"B. Sanders" <[email protected]> wrote:

> My 2003 Van Dessel SuperFly "all 'rounder"/city bike is equipped with the Shimano Nexus Inter 7
> planetary gear hub and roller brake.
>
> I don't have the necessary instrumentation to offer any quantified evidence; but in certain gears,
> it feels like the hub is eating a lot of pedalling energy. It is quite noticeable.

My onboard dynamometer tells me the same thing, that I'm losing one "gear" worth of effort/output
in return for the benefits of the mysterious Nexus Inter-7 hub I have on my latest chopper. No such
sensation when I ride my Sachs Spectro 7 bike, which propels and rolls out as freely as a
derailleur bike.

> I've read that the SRAM/Sachs 7 speed internal hub is a better design. Any comments?

I generally agree. The Sachs hub has the disadvantage of an outside-the-dropout shifting mechanism,
but wins out over the Shimano on efficiency, strength, and longevity. I think it has a better brake
too-- not as much initial "bite" as the Shimano roller brake but way less fade.

It's worth noting that both these hubs loosen up once they've seen some miles, and that they need
proper bearing adjustment just as much as any hub if they are to roll freely. Brand new or
broken-in, though, the Sachs hub is noticeably slicker.

Chalo Colina

 

In article <[email protected]>, [email protected] says...
>My 2003 Van Dessel SuperFly "all 'rounder"/city bike is equipped with the Shimano Nexus Inter 7
>planetary gear hub and roller brake.

I just got one of these.

>I don't have the necessary instrumentation to offer any quantified evidence; but in certain gears,
>it feels like the hub is eating a lot of pedalling energy. It is quite noticeable.

The only difference I notice is that in the 3rd speed it feels like something is grinding. In the
other speeds, it feels quite smooth.
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Alex __O _-\<,_ (_)/ (_)