Sram S7 installation help

al77 said:

Hello, I'm having problems installing a Sram S7 7 Speed hub
(roller brake version unfortunately), please help!!

1- The frame has vertical dropouts so I'm using a chain
tensioner, unfortunately this doesn't keep the chain tension
when back pedalling & the coaster brake activates - the chain
derails at this point. Any fixes for this?

I believe you can get an eccentric bottom bracket, and adjust
the chain tension with that, instead of using a spring-loaded
tensioner. I've seen them mentioned in the context of Rohloff
internal-gear hubs, if that helps your search.

Quoted message said:

Can the roller brake part of the hub be disabled & would that
help to stop the chain coming off?

I'll have to pass on this question, but I think that removing or
otherwise defeating the coaster brake is the only alternative
to some form of horizontal dropouts or an eccentric bottom
bracket.

Quoted message said:

2- How exactly do you set up the Clikbox? The online
documentation from Sram says to have the shifter in 1st gear
while attaching the cable inside the Clikbox whereas I read
elsewhere on the net that it should be in 4th gear - I've
experiemented with various cable lengths & couldn't get either
to work :-( I know the problem is not with the hub itself as
I can get it to change gears by pushing in the shift rod by
hand.

Fitting a new cable involves an adjustment in two places.
Firstly, screw the adjuster on the outside of the clickbox
fully in. This adjuster fits between the end of the outer
cable and the clickbox. Then select first gear and attach the
inner cable without significant slack and tighten its securing
grub screw in the centre of the little pulley inside the
clickbox (top cover removed). This is the initial rough
adjustment.

Then install the clickbox cover use that external adjuster to do
the final adjustment, and any later readjustments. Do this by
changing from 5th gear into 4th. At this point (in 4th gear
after the change from 5th), the points of two arrows visible in
the window of the clickbox cover should align exactly (one is
painted on the clickbox cover, and one rotates with cable
movement). Turn the adjuster until they align.

If you then have problems selecting some gears, check that the
cable moves freely throughout its range. Any further problem
probably means that the cable isn't sitting properly in its
groove at one of the two pulleys, at the opposite extremities
of the cable.

John

John Henderson said:

al77 said:

Hello, I'm having problems installing a Sram S7 7 Speed hub
(roller brake version unfortunately), please help!!

1- The frame has vertical dropouts so I'm using a chain
tensioner, unfortunately this doesn't keep the chain tension
when back pedalling & the coaster brake activates - the chain
derails at this point. Any fixes for this?

I believe you can get an eccentric bottom bracket, and adjust
the chain tension with that, instead of using a spring-loaded
tensioner. I've seen them mentioned in the context of Rohloff
internal-gear hubs, if that helps your search.

An eccentric bottom bracket will require cutting out the existing
bottom bracket shell from the frame and welding in its place. It's not
a job to contemplate casually. (Here's a picture of the shell and the
eccentric:
http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=FS3002
..) It certainly easier and cheaper to get a frame with proper
horizontal dropouts.

Quoted message said:

Quoted message said:

Can the roller brake part of the hub be disabled & would that
help to stop the chain coming off?

I'll have to pass on this question, but I think that removing or
otherwise defeating the coaster brake is the only alternative
to some form of horizontal dropouts or an eccentric bottom
bracket.

I think it was possible on some of the Sturmey-Archer 3-speed hubs with
coaster brake, but perhaps Sheldon can weigh in on this. Internal hubs
have lots of little parts, and defeating *just* the brake might be
possible but certainly difficult.

I think you're better off finding a non-coaster-brake hub
(http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=HU2549)

or a drum-brake hub
(http://harriscyclery.net/page.cfm?PageID=49&action=details&sku=HU2542)
and just deal with a rear hand brake.

Jeff

You should NOT be using a chain tensioner with a coaster brake. When
braking there is a lot of tension on the bottom run of the chain and the
tensioner will be strained causing the top run to go slack. That's why it
derails. I suggest you talk to a hub gear specialist to find out if you can
remove the brake bit. Are you UK based?
BTW if you succeed in getting the brake removed please post here again with
the details as I have a similar problem!!

al77 said:

Hello, I'm having problems installing a Sram S7 7 Speed hub (roller
brake version unfortunately), please help!!

1- The frame has vertical dropouts so I'm using a chain tensioner,
unfortunately this doesn't keep the chain tension when back pedalling &
the coaster brake activates - the chain derails at this point.

Generally speaking you're off to a bad start trying to use a coaster brake together with a chain tensioner.
If you're really keen to get it working there is a bodge you might try - Get two chain tensioners of the sort that looks like a small RD, spring loaded. You might even be able to use two scrapped short cage RD's and improvise some bracketry. Mount one on top of the chain stay for the topside chain run and one below. When pedalling forward the lower one takes care of the chain slack and when braking the top one does it.

Do note that this is a bodge job at your own risk.

Thanks for the suggestions everyone.

I know a non-brake or disc brake hub would be better but I can't afford
one at the mo. The only reason I have the coaster brake version is
because they are so much cheaper, mine cost about £60 built in to a
wheel with + free front wheel from Germany. Whereas the cheapest I've
seen the non-brake or disc-brake version is well over £100 for the hub
alone.

Yes Steve I am UK Based. I was wondering if the coaster brake could be
removed & replaced with parts for a non-brake or disc brake version.

Steve Watkin said:

You should NOT be using a chain tensioner with a coaster brake. When
braking there is a lot of tension on the bottom run of the chain and the
tensioner will be strained causing the top run to go slack. That's why it
derails. I suggest you talk to a hub gear specialist to find out if you can
remove the brake bit. Are you UK based?
BTW if you succeed in getting the brake removed please post here again with
the details as I have a similar problem!!

PM sent

SW

"al77" <[email hidden]> wrote in message
news:[email hidden]...
Thanks for the suggestions everyone.

I know a non-brake or disc brake hub would be better but I can't afford
one at the mo. The only reason I have the coaster brake version is
because they are so much cheaper, mine cost about £60 built in to a
wheel with + free front wheel from Germany. Whereas the cheapest I've
seen the non-brake or disc-brake version is well over £100 for the hub
alone.

Yes Steve I am UK Based. I was wondering if the coaster brake could be
removed & replaced with parts for a non-brake or disc brake version.

Steve Watkin said:

You should NOT be using a chain tensioner with a coaster brake. When
braking there is a lot of tension on the bottom run of the chain and the
tensioner will be strained causing the top run to go slack. That's why it
derails. I suggest you talk to a hub gear specialist to find out if you
can
remove the brake bit. Are you UK based?
BTW if you succeed in getting the brake removed please post here again
with
the details as I have a similar problem!!

John Henderson said:

al77 said:

Hello, I'm having problems installing a Sram S7 7 Speed hub
(roller brake version unfortunately), please help!!

1- The frame has vertical dropouts so I'm using a chain
tensioner, unfortunately this doesn't keep the chain tension
when back pedalling & the coaster brake activates - the chain
derails at this point. Any fixes for this?

Roller brake or coaster brake? I'm guessing coaster brake... I'm not
sure how to solve the chain tensioner problem. It seems that a phantom
cog chain tensioner might work, but I've never tried it. For a
description of a phantom cog, go to:

<http://www.mtbr.com/faq/ssfaq.shtml#ssConversionsChainTension>

Scroll down to #8.

Quoted message said:

Quoted message said:

2- How exactly do you set up the Clikbox?

Quoted message said:

Fitting a new cable involves an adjustment in two places.
Firstly, screw the adjuster on the outside of the clickbox
fully in. This adjuster fits between the end of the outer
cable and the clickbox. Then select first gear and attach the
inner cable without significant slack and tighten its securing
grub screw in the centre of the little pulley inside the
clickbox (top cover removed). This is the initial rough
adjustment.

Then install the clickbox cover use that external adjuster to do
the final adjustment, and any later readjustments.

With my S7, this process is not possible. The clickbox cover has to be
in place before the clickbox adjuster can be screwed in. In fact, the
clickbox cover has half of the threads for that adjuster. As a result,
it was very difficult to trim the cable length.

Were there different versions of the clickbox? Hopefully the newer ones
have the feature you mention. I've never fixed the cable anchor problem
that we discussed a while back, and if the newer clickboxes have a
better design, I might be interested in buying one.

--
Dave
dvt at psu dot edu

Everyone confesses that exertion which brings out all the powers of body
and mind is the best thing for us; but most people do all they can to
get rid of it, and as a general rule nobody does much more than
circumstances drive them to do. -Harriet Beecher Stowe, abolitionist and
novelist (1811-1896)

Quoted message said:

Quoted message said:

al77 said:

Hello, I'm having problems installing a Sram S7 7 Speed hub
(roller brake version unfortunately), please help!!
1- The frame has vertical dropouts

-snip-

Quoted message said:

Quoted message said:

Quoted message said:

2- How exactly do you set up the Clikbox?

-snip-

John Henderson said:

Fitting a new cable involves an adjustment in two places. Firstly,

Quoted message said:

screw the adjuster on the outside of the clickbox
fully in. This adjuster fits between the end of the outer
cable and the clickbox. Then select first gear and attach the
inner cable without significant slack and tighten its securing
grub screw in the centre of the little pulley inside the
clickbox (top cover removed). This is the initial rough
adjustment.
Then install the clickbox cover use that external adjuster to do
the final adjustment, and any later readjustments.

dvt said:

With my S7, this process is not possible. The clickbox cover has to be
in place before the clickbox adjuster can be screwed in. In fact, the
clickbox cover has half of the threads for that adjuster. As a result,
it was very difficult to trim the cable length.

Were there different versions of the clickbox? Hopefully the newer ones
have the feature you mention. I've never fixed the cable anchor problem
that we discussed a while back, and if the newer clickboxes have a
better design, I might be interested in buying one.

Yes, several small changes over many years.

There's a Sachs/SRAM gauge called a "fish" which measures the wire
length beyond the casing. Snap fish on casing, pull wire tight, snip at
end of gauge. (IIRC, there are more than one length spec for these,
Sachs vs. SRAM eras). Perhaps an inline adjuster?

Agreed 'trial and error' wire length would be frustrating.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

There is a spares parts list with exploded diagrams of the hubs at
http://www.sram.com/_media/pdf/sram/dealers/SRAM_Sparepartscatalog_ghs_MY07.pdf
the S7 versions are on the pages numbered 52-61 (although to select to
print these pages it was more like pages 20-30 in the print dialog box
for some reason). Maybe this will help to see if removing the coaster
brake is possible..

Also re: setting up the clikbox. I've found that there are tools to
help you measure the cable length correctly. 2 different tools for old
(up to 2002) & new (2003 onwards) versions of the clikbox. In the UK
Bonthrone bikes stock both - http://www.bonthronebikes.co.uk/428-18723
or http://www.bonthronebikes.co.uk/428-18732 as well as a lot of other
Sram spares.

Yes I did mean coaster brake not roller brake, oops!

I've been given a few contacts in the UK who may be able to help with
this by Steve. Any further developments & I will post here again..

thanks again for all the help with this. Alan

A Muzi said:

Quoted message said:

Quoted message said:

al77 wrote:
> Hello, I'm having problems installing a Sram S7 7 Speed hub
> (roller brake version unfortunately), please help!!
> 1- The frame has vertical dropouts

-snip-

Quoted message said:

Quoted message said:

> 2- How exactly do you set up the Clikbox?

-snip-

John Henderson said:

Fitting a new cable involves an adjustment in two places. Firstly,

Quoted message said:

screw the adjuster on the outside of the clickbox
fully in. This adjuster fits between the end of the outer
cable and the clickbox. Then select first gear and attach the
inner cable without significant slack and tighten its securing
grub screw in the centre of the little pulley inside the
clickbox (top cover removed). This is the initial rough
adjustment.
Then install the clickbox cover use that external adjuster to do
the final adjustment, and any later readjustments.

dvt said:

With my S7, this process is not possible. The clickbox cover has to be
in place before the clickbox adjuster can be screwed in. In fact, the
clickbox cover has half of the threads for that adjuster. As a result,
it was very difficult to trim the cable length.

Were there different versions of the clickbox? Hopefully the newer ones
have the feature you mention. I've never fixed the cable anchor problem
that we discussed a while back, and if the newer clickboxes have a
better design, I might be interested in buying one.

Yes, several small changes over many years.

There's a Sachs/SRAM gauge called a "fish" which measures the wire
length beyond the casing. Snap fish on casing, pull wire tight, snip at
end of gauge. (IIRC, there are more than one length spec for these,
Sachs vs. SRAM eras). Perhaps an inline adjuster?

Agreed 'trial and error' wire length would be frustrating.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Has anyone come across one of the 'Crud Mr Control' things?
http://www.bonthronebikes.co.uk/508-17182 I'm not sure if it's a
tensioner that uses a spring or if the tension is fixed by adjusting
the distance the jockey wheels from the centre of the device. Not sure
where it mounts, on the axle maybe? or if it would keep tension when
forward or backpedalling. I can't find any more info on it. Does
anyone know them? thanks, alan

dabac said:

al77 said:

Hello, I'm having problems installing a Sram S7 7 Speed hub (roller
brake version unfortunately), please help!!

1- The frame has vertical dropouts so I'm using a chain tensioner,
unfortunately this doesn't keep the chain tension when back pedalling
&
the coaster brake activates - the chain derails at this point.

Generally speaking you're off to a bad start trying to use a coaster
brake together with a chain tensioner.
If you're really keen to get it working there is a bodge you might try
- Get two chain tensioners of the sort that looks like a small RD,
spring loaded. You might even be able to use two scrapped short cage
RD's and improvise some bracketry. Mount one on top of the chain stay
for the topside chain run and one below. When pedalling forward the
lower one takes care of the chain slack and when braking the top one
does it.

Do note that this is a bodge job at your own risk.

--
dabac

al77 said:

Has anyone come across one of the 'Crud Mr Control' things?
http://www.bonthronebikes.co.uk/508-17182

It looks like it would mount to the bottom bracket, adjustable, but not spring-loaded. I wouldn't trust it to stand up to the loads of back-pedal activated brake.
You need to be aware that if you really intend to USE the brake the chain tension at back pedal becomes quite significant, so either you need to use something spring loaded that allows for a straight lower chainline at back pedal. Or, you have to find a really strong way of tensioning the chain. (the ghost sprocket comes to mind, can't see chain tension becoming high enough to taco a sprocket...)