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SRAM S7 - how to block it in direct drive

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SRAM S7 - how to block it in direct drive

Old 03-06-08, 05:45 AM
  #1  
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SRAM S7 - how to block it in direct drive

I have a SRAM S7 hub gear. I don't need the gears, and I want to get rid of the clickbox that protrudes laterally. I am interested in using it as a coaster brake hub.

So I am hoping there is a way to block the hub in direct drive (1st speed) and then not use the clickbox anymore. Any idea how this could be done?
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Old 03-06-08, 09:03 AM
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I do not have an answer for you, but isn't 4th gear the direct gear on it? I know it is on a Nexus, and I think I remember that it is on the Sachs/SRAM Spectro.

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Old 03-06-08, 09:32 AM
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Here's my solution: Send me your hub, and I'll send you a SS coaster hub!
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Old 03-06-08, 11:43 PM
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Ah, I get it...it was a trick question!


Very clever...
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Old 03-16-08, 11:38 AM
  #5  
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I'm still looking for a solution. One where I don't need the clickbox would be preferred.
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Old 03-16-08, 12:02 PM
  #6  
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Originally Posted by jgedwa View Post
I do not have an answer for you, but isn't 4th gear the direct gear on it? I know it is on a Nexus, and I think I remember that it is on the Sachs/SRAM Spectro.

jim
No, direct drive on the SRAM S7 is #1. The Nexus 7 does not have a direct drive. These are the gear ratios for the Nexus 7:

3.1
2.7
2.3
2.0
1.7
1.5
1.3

For your information, neither does the Nexus 8 have a direct drive gear. here are the gear ratios for the Nexus 8:

3.3
2.9
2.5
2.0
1.7
1.5
1.3
1.1
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Old 03-16-08, 07:08 PM
  #7  
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Originally Posted by wroomwroomoops View Post
No, direct drive on the SRAM S7 is #1. The Nexus 7 does not have a direct drive. These are the gear ratios for the Nexus 7:

3.1
2.7
2.3
2.0
1.7
1.5
1.3

For your information, neither does the Nexus 8 have a direct drive gear. here are the gear ratios for the Nexus 8:

3.3
2.9
2.5
2.0
1.7
1.5
1.3
1.1


Not sure where you got those numbers, but they are incorrect. Nexus 8 does have a 1 to 1 direct in 5th gear. Ratios are as follows.
8 -1.615:1
7 -1.419:1
6 -1.223:1
5 -1:1
4 -0.851:1
3 -0.748:1
2 -0.644:1
1 -0.527:1
Sram S7 is direct in 4th, not first.
7 -1:1.74
6 -1:1.48
5 -1:1.24
4 -1:1.000
3 -1:0.81
2 -1:0.68
1 -1:0.57
You are correct with regard to the Nexus 7, however, no direct. The only gearhub I am aware of with direct in 1st is the SA 8speed.
EDIT: Numbers for Nexus are output -input, Sram list is input to output. That's what can happen when you cut and paste.

Last edited by Dan Burkhart; 03-16-08 at 07:13 PM.
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Old 03-16-08, 08:31 PM
  #8  
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Originally Posted by Dan Burkhart View Post
Not sure where you got those numbers, but they are incorrect. Nexus 8 does have a 1 to 1 direct in 5th gear. Ratios are as follows.
8 -1.615:1
7 -1.419:1
6 -1.223:1
5 -1:1
4 -0.851:1
3 -0.748:1
2 -0.644:1
1 -0.527:1
Sram S7 is direct in 4th, not first.
7 -1:1.74
6 -1:1.48
5 -1:1.24
4 -1:1.000
3 -1:0.81
2 -1:0.68
1 -1:0.57
You are correct with regard to the Nexus 7, however, no direct. The only gearhub I am aware of with direct in 1st is the SA 8speed.
EDIT: Numbers for Nexus are output -input, Sram list is input to output. That's what can happen when you cut and paste.
You are correct with the gear ratios - my mistake was to copy the GAIN ratios column. (Are you sure the 1:1 gear ratio in #5 for the Nexus 8 is actual direct drive?)
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Old 03-16-08, 08:48 PM
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How is this hub shifted? Is it a cable pull to engage a clutch?
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Old 03-16-08, 09:52 PM
  #10  
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Originally Posted by I_bRAD View Post
How is this hub shifted? Is it a cable pull to engage a clutch?
At this address you can find two .PDF files that explain, somewhat, the operation of the hub:
http://www.sram24.com/newtechdoc/eng...s/srams7e.html

You can get a bit of info, for example, on page 10 of the second .PDF document. I am not sure what "clutch" means in the context of your sentence. The first of the two .PDF files seems to be somewhat informative, too.
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Old 03-16-08, 09:57 PM
  #11  
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I have to say that I'm still at a loss for why you want to use a gear hub as a single speed setup. Why not just get a track bike wheel or a regular road/mountain wheel and use a single cog on the freehub? It'll be a lot lighter overall.

If you don't plan on going back to the gear hub sell off the wheel and shifter to finance the single speed conversion. In fact you'll have more money left over by far.

Or if you just want to try the single speed deal to see if this is for you then just pick a gear and ride it in that one gear until you decide if you like it or not.
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Old 03-16-08, 10:34 PM
  #12  
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I wonder what would happen if I had the clickbox connected to the hub, shifted into #4 gear (direct drive) and removed the clickbox at that point. It doesn't seem like something SRAM would recommend, based on their documentation. Would I wreck the hub in some way? To be honest, I don't mind wrecking it if I would still maintain the direct drive, as the non-direct gears are of no use to me.

I was even considering to remove all the planetary gears from the hub and just leave the coaster brake - which, I am speculating, should be encased separately aniway. But what I miss for such an attempt, is an exploded view of the internals (I think that's how this kind of diagram, where every part is visible, is called).

EDIT: I found the exploded view doc. It's located at
http://www.sram.com/en/service/sram/...nuals_2004.php

Last edited by wroomwroomoops; 03-16-08 at 10:47 PM.
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Old 03-16-08, 10:42 PM
  #13  
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Originally Posted by BCRider View Post
I have to say that I'm still at a loss for why you want to use a gear hub as a single speed setup. Why not just get a track bike wheel or a regular road/mountain wheel and use a single cog on the freehub? It'll be a lot lighter overall.

If you don't plan on going back to the gear hub sell off the wheel and shifter to finance the single speed conversion. In fact you'll have more money left over by far.

Or if you just want to try the single speed deal to see if this is for you then just pick a gear and ride it in that one gear until you decide if you like it or not.
I can't sell the hub for the price of a coaster brake hub. I have reposted this auction already the third time in a row: http://huuto.net/fi/showitem.php3?itemid=74022782 No takers. So what you say may be true hypothetically but practice disagrees with you.
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Old 03-17-08, 03:08 AM
  #14  
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Originally Posted by wroomwroomoops View Post
I wonder what would happen if I had the clickbox connected to the hub, shifted into #4 gear (direct drive) and removed the clickbox at that point. It doesn't seem like something SRAM would recommend, based on their documentation. Would I wreck the hub in some way? To be honest, I don't mind wrecking it if I would still maintain the direct drive, as the non-direct gears are of no use to me.

I was even considering to remove all the planetary gears from the hub and just leave the coaster brake - which, I am speculating, should be encased separately aniway. But what I miss for such an attempt, is an exploded view of the internals (I think that's how this kind of diagram, where every part is visible, is called).

EDIT: I found the exploded view doc. It's located at
http://www.sram.com/en/service/sram/...nuals_2004.php


If you remove the clickbox, the return spring in the hub will push out the shifter pins and you will be in seventh gear. If you want to block it in fourth, you would have to find a way to fix the inner and outher shifter pins in their corresponding position. Not easy.
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Old 03-17-08, 04:55 AM
  #15  
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Originally Posted by Batavus View Post
If you remove the clickbox, the return spring in the hub will push out the shifter pins and you will be in seventh gear. If you want to block it in fourth, you would have to find a way to fix the inner and outher shifter pins in their corresponding position. Not easy.
Seventh, or first gear? SRAM mentions shifting into 1st gear before removing the clickbox, so I thought maybe you meant 1st gear.

Now, the return spring you mention: is it the one numbered (25) in the maintenance manual? (see attachment)
Attached Images
File Type: png
s7-spring.png (13.2 KB, 39 views)
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Old 03-17-08, 07:41 AM
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Originally Posted by wroomwroomoops View Post
I wonder what would happen if I had the clickbox connected to the hub, shifted into #4 gear (direct drive) and removed the clickbox at that point. It doesn't seem like something SRAM would recommend, based on their documentation. Would I wreck the hub in some way? To be honest, I don't mind wrecking it if I would still maintain the direct drive, as the non-direct gears are of no use to me.

I was even considering to remove all the planetary gears from the hub and just leave the coaster brake - which, I am speculating, should be encased separately aniway. But what I miss for such an attempt, is an exploded view of the internals (I think that's how this kind of diagram, where every part is visible, is called).

EDIT: I found the exploded view doc. It's located at
http://www.sram.com/en/service/sram/...nuals_2004.php
If you remove the clickbox in 4th, or any gear other than first for that matter, the rod and outer sleeve, which shift the sun gears and select driver engagement between ring gear or planetary carrier respectively will simply spring out to their default position, meaning the hub will be in 1st gear.
I'm sorry, I just don't have an answer for you with respect to locking it in 4th.
Ya know, single speed coaster brake hubs retail around 35 bucks.
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Old 03-17-08, 07:51 AM
  #17  
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Originally Posted by wroomwroomoops View Post
You are correct with the gear ratios - my mistake was to copy the GAIN ratios column. (Are you sure the 1:1 gear ratio in #5 for the Nexus 8 is actual direct drive?)
Do you mean direct coupling as opposed to compound gearing that adds up to 1-1? If so, the answer is yes.
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Old 03-17-08, 08:32 AM
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Originally Posted by Dan Burkhart View Post
If you remove the clickbox in 4th, or any gear other than first for that matter, the rod and outer sleeve, which shift the sun gears and select driver engagement between ring gear or planetary carrier respectively will simply spring out to their default position, meaning the hub will be in 1st gear.
I'm sorry, I just don't have an answer for you with respect to locking it in 4th.
Ya know, single speed coaster brake hubs retail around 35 bucks.
I'll probably take the hub apart and figure out something.
I live in Finland. There's no way I can buy a singlespeed coaster brake hub for less than $120 with postage. EDIT: Sammyboy found a really cheap singlespeed hub in the UK.

Originally Posted by Dan Burkhart View Post
Do you mean direct coupling as opposed to compound gearing that adds up to 1-1? If so, the answer is yes.
OK, thanks. Good to know.

Last edited by wroomwroomoops; 03-17-08 at 09:50 AM.
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Old 03-17-08, 08:48 AM
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There is one other hub that has direct drive on first, the Nexus 4. I don't think this is at all helpful in this situation, I mention it merely as a point of order......

Here, however, is an SS Coaster hub, 10 (15 Euros, $20). I'm sure you can order it from them for sensible shipping, but if not, I will happily order one and ship it to you, in exchange for your S7. To be honest, I'll do it just to be helpful, but I do have a use for a 7 speed hub:

http://www.sjscycles.co.uk/product-0...hole-12643.htm
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Old 03-17-08, 09:47 AM
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Originally Posted by Sammyboy View Post
There is one other hub that has direct drive on first, the Nexus 4. I don't think this is at all helpful in this situation, I mention it merely as a point of order......

Here, however, is an SS Coaster hub, 10 (15 Euros, $20). I'm sure you can order it from them for sensible shipping, but if not, I will happily order one and ship it to you, in exchange for your S7. To be honest, I'll do it just to be helpful, but I do have a use for a 7 speed hub:

http://www.sjscycles.co.uk/product-0...hole-12643.htm
That changes everything - I'm ordering it!

And Sturmey-Archer sprockets are compatible with SRAM sprockets! Great, I don't need to order a sprocket!

Last edited by wroomwroomoops; 03-17-08 at 09:58 AM.
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Old 03-17-08, 11:54 AM
  #21  
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DARN! Sammyboy beat me to making you and offer to trade...
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Old 04-01-08, 10:09 AM
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Now that I have an S7, I might have figured out a way to do this, but you'll need to keep the clickbox.

Use the shifter to shift into 4th gear, with the clickbox properly adjusted. Mark the position of the clickbox when in 4th gear.

Now, you'll need to anchor a shift cable to your frame and manually lock the clickbox in 4th gear using the marks you made previously.
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Old 04-24-08, 01:49 PM
  #23  
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I've figured out how to do this without the clickbox.

You'll have to use only the outer shift pin. By locking it in the "middle" position, you should be able to get 4th gear. You can experiment with this configuration by removing the middle shift pin, where you'll only get gears 1, 4, and 7 with the default clickbox and shifter.
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Old 05-23-19, 12:34 AM
  #24  
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K6-III, so actually pull out the middle pin? Is it easy to lock the outer pin. My clickbox, cable and handle is broken, so I want to lock in one of the middle gears (3 or 4). Tired of 1st.
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Old 05-23-19, 10:01 AM
  #25  
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I'm still looking for a solution. One where I don't need the clickbox , would be preferred.
That would be a Sturmey Archer .. Or a Sachs hub from before the Sram buyout/Takeover..






//...

Last edited by fietsbob; 05-23-19 at 10:05 AM.
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