At 5/24/2006 01:51 PM +0000, joebz@optonline.net wrote:
>This is getting off topic, but having ridden both these units a lot
>over the years, the Sachs 7-speed is a very serious and effective unit
Joe, I'm not suggesting the Sachs/SRAM isn't a very nice piece of kit. In fact I'll be installing one on a friends modern bike next week (and an S5 on his wife's '58 Rudge). And, I'm anxiously awaiting for the new SRAM iDrive 9 speed.
But IMHO a two cable Sturmey 5 speed would be better suited to Nikki's '70s Raleigh Sprite. Much easier conversion too. Just screw out the AW guts from the hub shell and screw in the S5 innards. Add an old friction shifter and a second cable and you are done. No spreading of the rear triangle and building a rear wheel. Will a Sachs/SRAM axle even fit into the narrow slots on an old Raleigh?
A SRAM 7 speed would cost over $200 with shifter and clickbox. Then
add cost of a rim and spokes. The last NOS S5 I bought was
$45. Last year I bought 3 for $35 ea. and 2 Alloy shelled S5/2s for
$65 ea., all NOS.
>while the Sturmey 5-speed not a very desirable option in the epicyclic world.
Can we be talking about the same hub? Around here they are highly
sought after.
> Both the lowest and highest gears on the Sturmey run through two
> sets of gears
Could we be seeing the power of suggestion at work here? "You think the power in the wide ratio mode goes through both sets of gears so your legs feel significant extra resistance? I know better, so my legs don't."
There are two sets of gears, but only one set is under load at a
time. The left cable determines whether the wide or medium ratio set
is used, by locking one or the other sun gear to the axle.
> and are notably inefficient.
Once the wide ratio set gets broken in, which takes quite a while as
they aren't used as much, I can't sense any difference in
efficiency. We've replaced the derailleur systems on several of our
bikes, those that get ridden the most, with S5s and don't feel we've
given up anything but range and fuss.
> First gear is so inefficient that it provides little reduction in
> pedalling resistance when actually under load.
I beg to differ. I just finished a hilly 81 mile ride on an S5 with
less than 100 miles on it at the start. While the wide/low wasn't as
smooth as my well used hubs, it made a big difference and got me up
hills I couldn't have ridden in medium/low.
> So you tend to use it as an AW, which is never that great anyway.
AW never that great? That it has it been in production since 1938,
suggests that many would disagree.
> The Sachs feels much more effecient,
Not to my feet.
> the ratios make sense
In what way do the SA ratios not make sense and the Sach's do?
The middle 5 gears on a Sachs are 68%-81%-100%-124%-148%
The 5 gears on a Sturmey Archer are 66.7%-78.9%-100%-126.6%-150%
Even if a person could actually feel the differences, it would still
make sense to have slightly wider steps when you have fewer gears.
> and I suspect it is better made than Sturmey products post 1965 or so.
That may be true. But I've overhauled so many SA hubs, taken from worn out bikes, which needed no parts replaced, that I figure they are built as well as they need to be.
Mark Stonich;
Minneapolis Minnesota
http://mnhpva.org
http://bikesmithdesign.com