Nexus 8 Speed Hub for Commuting

[Michael Lanches]

I recently read an article in Australian Cyclist about the Trek 7400. It includes a 7 speed Shimano
Nexus Hub and roller brake. I believe that this will be shortly upgraded to 8 speed.

I have a 24 speed GT mountain bike with Rock Shox Judys and slicks. Mostly Deore Lx components
and xt derailer. I have been commuting to work on and off for around 7 years. Recently I have
gotten totally sick of it due to the distance (16km each way) and the maintenance of the gears
and chain required.

My derailer shift cable has never been right (professionally adjusted) and shimano chainrings and
spockets wear out far too fast etc. Not to mention a slight buckled rear wheel rubbing on the
V-Brakes. And maintenance required for the Rock Shox to keep them flowing nicely.

I figured that if maintenance could be reduced I would be happier.

I am considering selling the GT and buying a Trek 6045 (the 26" wheel version of the 7400). It
includes the nexus 7or 8 speed hub.

I need some advice from the experts formalise my decision :-

Will the hub it significant reduce maintenance ? Is chain and sprocket wear reduced ? Do nexus hubs
shift as well as an XT/LX derailer (when perfectly adjusted) ? Does the hub incur significant
resistance ? What does the roller brake compare to ? (canti's with shimano pads, V-brakes with
koolstop pads, Magura disks etc) Does the hub give you enough gear range ?

Any advice or net links woud be appreciated.

-
_______________________________________________________
Michael Lanchester

PS I have alreadly looked at www.sheldonbrown.com

 

[John Henderson]

"Michael Lanchester" wrote:

> I recently read an article in Australian Cyclist about the Trek 7400. It includes a 7 speed
> Shimano Nexus Hub and roller brake. I believe that this will be shortly upgraded to 8 speed.
>
> I have a 24 speed GT mountain bike with Rock Shox Judys and slicks. Mostly Deore Lx components and
> xt derailer. I have been commuting to work on and off for around 7 years. Recently I have gotten
> totally sick of it due to the distance (16km each way) and the maintenance of the gears and chain
> required.

I switched from a derailleur system to an internal hub for the same sorts of reasons. I bought a
bike with a Shimano Nexus 4-speed automatic hub (because it was half-price) with a view to quickly
changing hat to a conventional 7-speed internal. I soon imported and fitted a Sram/Sachs Spectro S7.
So I can comment on some of your questions.

> My derailer shift cable has never been right (professionally adjusted) and shimano chainrings and
> spockets wear out far too fast etc. Not to mention a slight buckled rear wheel rubbing on the
> V-Brakes. And maintenance required for the Rock Shox to keep them flowing nicely.
>
> I figured that if maintenance could be reduced I would be happier.
>
> I am considering selling the GT and buying a Trek 6045 (the 26" wheel version of the 7400). It
> includes the nexus 7or 8 speed hub.
>
> I need some advice from the experts formalise my decision :-
>
> Will the hub it significant reduce maintenance ?

These hubs are maintenance-free to quite high mileages. I've now got about 6,000 km up on mine, and
I hope to get at least 10 times that before I need to service it.

I recently disassembled and re-greased an old Shimano internal 3-speed hub that had done 3 of my
kids on a BMX. It had no signs of wear. It's ready for any grand-kids now.

> Is chain and sprocket wear reduced ?

The sprockets aren't showing signs of wear, but I've replaced the chain (and will need to do so
again soon). I'm sure the chain would last much longer if I cleaned it - but I've been simply
re-oiling it, ignoring the dirt.

Occasional chain adjustment is required, to accommodate wear.

In any case, most bike shops sell the generic 3-splined rear sprockets that fit these internal hubs
(Shimano and Sachs included) for something like $10.

> Do nexus hubs shift as well as an XT/LX derailer (when perfectly adjusted) ?

The Sachs hub changes very reliably if you stop peddling for a fraction of a second. When
stationary, a touch of back-peddling does the same job. The Shimano 4-speed would change even under
peddling pressure (but made the occasional protesting noise).

Does the hub incur significant resistance ?

Not that I can detect, but Sachs is reputed to have slightly less drag than Shimano. I think a pair
of gunked-up rear derailleur jockey wheels would induce more drag than one of these hubs.

> What does the roller brake compare to ? (canti's with shimano pads, V-brakes with koolstop pads,
> Magura disks etc)

The Shimano Nexus roller brake would lock up the back wheel very easily. That's much more difficult
to do with the Sachs internal drum brake (unless the front brake's applied as well, throwing the
weight forwards). However, the Shimano brake quickly suffered brake-fade on any prolonged steep
descent - soon fading out to nearly nothing if no front brake was used, presumably due to heat
build-up. I haven't been able to induce brake fade on the Sachs unit - it's absolutely consistent.

> Does the hub give you enough gear range ?

Almost enough for me. The Sachs 7-speed has about the same total range as the new Shimano 8-speed.
The Shimano 7-speed has less.

In terms of gear-inches, I've got the Sachs set up with a range from 30.6 to 93.3. Within my
acceptable cadence range, this gives me road speeds from about 8 km/h to 45 km/h.

One advantage of the Shimano units is that they (and their replacement parts) are available
in Australia. For that reason, I think I'd have chosen the Shimano 8-speed if it was
available at the time.

John