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Old 2019-05-30, 07:09 PM   #2296
DrD
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Originally Posted by MuniAddict View Post
I'm wondering if this flange mounted disc brake would put too much torsional pressure on the spokes. And since this would be on the left side, I would be very hesitant to use a Dbrake clamped to the knurled bearing.
I don't think the side the disc is mounted on will make any difference to the stress on the spokes. The braking torque should be transferred through the hub shell evenly to the spokes on both sides (and the wheel is not dished). If anything the change in spoke tension due to the braking should be less on the side with the disc adapter since it has a bigger flange.

Sheldon Brown's web site has an interesting article on torque transmission in spoked wheels:

https://www.sheldonbrown.com/torque-spoking.html

Likewise I don't think that the dbrake is a problem with the knurled bearing (caveat: I don't have a Schlumpf hub!) I think the force from the disc brake would actually tend to increase the clamping pressure of the dbrake shell on the bearing (think of the dbrake being pulled up by the caliper gripping on the disc as the wheel rotates thus clamping the bearing tighter). The braking force from the disc brake is transmitted directly to the wheel and doesn't go via the gearbox so it shouldn't put any more torque on the bearing/frame interface. Assuming it does clamp the bearing slightly tighter that probably helps with resisting braking force applied though the pedals.

Fair enough you will probably be going faster with the geared hub so the dbrake will be under a bit more stress during braking, and if you have a 208mm rotor then Pierrox may well be right in what he says about it not lasting long, but that is probably more of a general problem with the dbrake and large rotors.

As I said, I don't have a Schlumpf hub and my own dBrake doesn't get a lot of stress since braking any more than a scuff tends to make me fall off the thing, so this is really just a 'thought experiment' and I may well be wrong.
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Old 2019-05-30, 07:38 PM   #2297
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Thanks for the link DrD, Sheldon is like the messiah when it comes to wheels!

Here are some photos of the final build. No caliper as I mainly wanted to measure the position of the disc with regards to the frame. 4mm. Same distance I measured on my other unis with in-board disc!

Mad4One has caliper tabs on both sides of their frames, I wonder if I can fit a 32" wheel in a 29+ frame...





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Old 2019-05-30, 08:22 PM   #2298
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Quote:
Originally Posted by pierrox View Post
Here are some photos of the final build. No caliper as I mainly wanted to measure the position of the disc with regards to the frame. 4mm. Same distance I measured on my other unis with in-board disc!
Sweet!! I agree that the spokes should be fine. As to the D'Brake, I would just add a "Hugo strut" as it's called named after the inventor on this forum (who sadly passed away in December). I have 2 Hugo struts after braking my D'Brake a while back. On my 36" Oracle with a 203 disc I do lots of heavy XC and I feel fine with it. You can find pictures here on the forum. Mine is less pretty than those here but works just fine (on my Nimbus 26" it's attached to my rim brake mounts, but on my 36 there are none and I just used a run-of-the-mill pipe mount from the hardware store).

I get my 3rd generation Schlumpf hub next week and will be putting it in a KH29. If I have any major problems getting the disc to fit (I expect to do some grinding), good to know there's another option...

Quote:
Originally Posted by pierrox View Post
Mad4One has caliper tabs on both sides of their frames, I wonder if I can fit a 32" wheel in a 29+ frame...
I'm not an expert on the Mad4One frames and don't have one myself, but I think it depends on the tire. I know Marko makes them for really wide plus tires like the 29x3.25" Crux. I measured my 29x3.0" Maxxis on a 47mm KH 29 rim to 30.5" and there's room in the KH frame. I would just write Marko and ask him and he cen tell you right off, as he's really good with technical stuff.

Hmm... I just looked at the photo on the website: https://unaruota.com/ZC/index.php?ma...io22p8hubv6lj7

I don't know: In the photo with the Crux 29x3.25 on a 46mm rim (which should be approx 30.8") it looks to me like only about 1" space to the crown, so my rough guess would be a plain vanilla 32" might fit, but anything wide or knobby is going to be pretty darn close... but there aren't so many 32" tires anyway... the nightrider isn't so high, so just might be possible...
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Last edited by MUCFreerider; 2019-05-30 at 08:23 PM.
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Old 2019-05-30, 08:26 PM   #2299
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Oh, just remembered that I'll see Marko again weekend-after-next at the final stage of the Italian Muni Race in Villanders, South Tirol, Italy, so I will look and ask him.
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36" Nimbus Oracle, VCX 100/125/150, 200mm disc
29+ KH, Maxxis DHR II 29x3, 127/150 Spirits
Schlumpf (KH29) Duro Crux 29x3.25 137/117 Spirits
26" Nimbus, Maxxis DHR IIx2.8, 117/137 Sprt
19" Trials Impact Athmos
20" Qu-Ax Profi Freestyle, 89mm VCX
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Old 2019-05-30, 10:03 PM   #2300
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Laces

I like it.
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Old 2019-05-30, 11:15 PM   #2301
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Another option is a Qu-Ax frame. They don't currently sell the 36" RGB ones separately but the QX series ones are also 100mm spacing with a disk mount on the left hand side.
I'm using one of their QX frames for my 32" freewheel with internal disk hub.

Quote:
I get my 3rd generation Schlumpf hub next week and will be putting it in a KH29. If I have any major problems getting the disc to fit (I expect to do some grinding), good to know there's another option...
I do feel like this adapter is a far superior option as it takes the braking stresses away from the gearing, and if you do have some kind of slippage (partial shift, bearing slip), the brake will still actually be effective at stopping the unicycle.
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Last edited by mowcius; 2019-05-30 at 11:19 PM.
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Old 2019-05-31, 12:05 AM   #2302
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Nimbus Oracle frames are 100mm and have caliper tab mount on left side.
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Old 2019-05-31, 04:42 AM   #2303
lobbybopster
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disc adapter

Quote:
Originally Posted by mowcius View Post

I do feel like this adapter is a far superior option as it takes the braking stresses away from the gearing, and if you do have some kind of slippage (partial shift, bearing slip), the brake will still actually be effective at stopping the unicycle.
I made this for an early schlumpf #102 sqr. tpr. so I could add a inside frame disc to preserve this fine mechanism.
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Old 2019-05-31, 07:44 AM   #2304
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Quote:
Originally Posted by MUCFreerider View Post
... "Hugo strut" as it's called named after the inventor on this forum (who sadly passed away in December).
Wait wait what??? What happened? I remember exchanging with him here.

Quote:
Originally Posted by MUCFreerider View Post
Oh, just remembered that I'll see Marko again weekend-after-next at the final stage of the Italian Muni Race in Villanders, South Tirol, Italy, so I will look and ask him.
I've reached out to him and he's already replied: yes it works, they actually made a G32 using their L frame for a swiss lady.

Quote:
Originally Posted by lobbybopster View Post
I like it.
Thanks, the guy who came up with this idea did a pretty good job!

Quote:
Originally Posted by mowcius View Post
Another option is a Qu-Ax frame. They don't currently sell the 36" RGB ones separately but the QX series ones are also 100mm spacing with a disk mount on the left hand side.
I'm using one of their QX frames for my 32" freewheel with internal disk hub.
Interesting! I spoke to David at QU-AX as he's following this build and he told me they might do a small batch of actual 32" RGB frames in a couple of months - only in green.
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Old 2019-05-31, 08:47 PM   #2305
mowcius
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Quote:
Originally Posted by MuniAddict View Post
Nimbus Oracle frames are 100mm and have caliper tab mount on left side.
Nimbus Oracle frames are only 100mm spacing for 29" and smaller. The 32" and 36" have 125mm width disk hubs.
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Last edited by mowcius; 2019-05-31 at 08:47 PM.
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Old 2019-06-02, 10:01 AM   #2306
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I measured the space between the disc and the spokes and it comes just under half an inch. Which is too little to fit a current caliper as everyone has switched to dual pistons. Lobbybopster dealt with this problem using a Coda caliper - single piston. I'm trying to find one, but no luck yet. Anyone can point me to a single piston model still in production, that would be great. I'm also looking at the second hand market.

Another option would be a cable operated disc caliper, they seem thinner but I have yet to find dimensions on the web. Looks like the Shimano CX77 could be a good candidate -single side- or the TRP Spyre but the dual side operation could make it too thick.

I read somewhere that calipers for trial bikes are narrower, but then again can't quite find dimensions out there.

I can also gain a couple of mm by bringing the disc closer to the frame, won't be enough for a regular hydraulic caliper though.
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Old 2019-06-02, 03:15 PM   #2307
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Quote:
Originally Posted by pierrox View Post
I measured the space between the disc and the spokes and it comes just under half an inch. Which is too little to fit a current caliper as everyone has switched to dual pistons. Lobbybopster dealt with this problem using a Coda caliper - single piston. I'm trying to find one, but no luck yet. Anyone can point me to a single piston model still in production, that would be great. I'm also looking at the second hand market.

Another option would be a cable operated disc caliper, they seem thinner but I have yet to find dimensions on the web. Looks like the Shimano CX77 could be a good candidate -single side- or the TRP Spyre but the dual side operation could make it too thick.

I read somewhere that calipers for trial bikes are narrower, but then again can't quite find dimensions out there.

I can also gain a couple of mm by bringing the disc closer to the frame, won't be enough for a regular hydraulic caliper though.
I measure a minimum space needed between the disk and spokes on my TRP Spyre mechanical caliper as 11/16". Looks like it would be too thick.
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Old 2019-06-02, 05:33 PM   #2308
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Thanks Jim!
I might order a Shimano then, just to be able to measure it! And I can always send it back.

Anyone here has a spare Coda or other single piston caliper, I'm taking it! Even better if you're located in Europe.
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Old 2019-06-12, 02:10 AM   #2309
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Does Schlumpf innovations ever respond to emails?

I have been trying to get parts for a broken schlumpf hub for 3 months.

Sent him a list of what was needed March 1st, said they would ship it a week later, never heard from them again and wont reply to any emails.
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Old 2019-06-12, 02:28 AM   #2310
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Does Schlumpf innovations ever respond to emails?
I was pretty successful communicating with Schlumpf through the office manager. Not sure it's appropriate to copy her email into this thread, but PM me if you need it.
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