Comments on: Disk Fork for my Porteur http://alexwetmore.org/archives/1173 Thu, 09 Oct 2014 15:41:30 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Joe Roggenbuck http://alexwetmore.org/archives/1173/comment-page-1#comment-193834 Joe Roggenbuck Mon, 09 Sep 2013 04:38:05 +0000 http://alexwetmore.org/?p=1173#comment-193834 Hi alex! Beautiful work and inspiring documentation! I was referred by Kris Henry of 44 Bikes to http://www.hayesdiscbrake.com/support/ which has .pdf documents that show all the relationships and specs of different mounts and hubs. It seems like the main issue with this type of front tab is that the front hubs have the rotor too far outboard. The rear standard is to have the rotor mount 15mm inboard of the non-drive side lock nut and the front standard is 10mm. I guess that''s what you were saying to Adie above. I''ve been trying to sort this stuff out all night. I think I''m just going to buy both of Don Ferris'' iso tools and get on with it. At this point it seems like the easiest way for me to do business since they''re not actually that expensive and any tool I make is going to eat time and inevitably still be inferior. Anyway, thanks for the documentation of your fork. Definitely a successful proof of concept, but I think I will find an alternative way to mount an iso disc tab that can reinforce the fork. It seems like having a long tab and tight fit up for brazing will be important. Hi alex!

Beautiful work and inspiring documentation!

I was referred by Kris Henry of 44 Bikes to http://www.hayesdiscbrake.com/support/ which has .pdf documents that show all the relationships and specs of different mounts and hubs. It seems like the main issue with this type of front tab is that the front hubs have the rotor too far outboard. The rear standard is to have the rotor mount 15mm inboard of the non-drive side lock nut and the front standard is 10mm. I guess that’’s what you were saying to Adie above.

I”ve been trying to sort this stuff out all night. I think I”m just going to buy both of Don Ferris” iso tools and get on with it. At this point it seems like the easiest way for me to do business since they”re not actually that expensive and any tool I make is going to eat time and inevitably still be inferior.

Anyway, thanks for the documentation of your fork. Definitely a successful proof of concept, but I think I will find an alternative way to mount an iso disc tab that can reinforce the fork. It seems like having a long tab and tight fit up for brazing will be important.

]]> By: Adie http://alexwetmore.org/archives/1173/comment-page-1#comment-169434 Adie Fri, 14 Jun 2013 16:27:38 +0000 http://alexwetmore.org/?p=1173#comment-169434 Alex, Thanks for the prompt reply. Thats the solution I was looking at. I am going to have to do some careful measurements to figure out exactly how much extra room I need. Unfortunately if i have to take off more than, say, 2mm, i think the strength of the adaptor may be compromised, because the other set of holes (to which the brake body mounts) are drilled all the way through, and I dont want to mill off so much material that those are left open. In that case, I will probably CNC mill a new bracket which mates to my disc tab, maybe out of stainless steel for strength. Adie Alex,
Thanks for the prompt reply.

Thats the solution I was looking at. I am going to have to do some careful measurements to figure out exactly how much extra room I need. Unfortunately if i have to take off more than, say, 2mm, i think the strength of the adaptor may be compromised, because the other set of holes (to which the brake body mounts) are drilled all the way through, and I dont want to mill off so much material that those are left open. In that case, I will probably CNC mill a new bracket which mates to my disc tab, maybe out of stainless steel for strength.

Adie

]]> By: Alex Wetmore http://alexwetmore.org/archives/1173/comment-page-1#comment-169418 Alex Wetmore Fri, 14 Jun 2013 15:29:13 +0000 http://alexwetmore.org/?p=1173#comment-169418 Fred Blasdel also had a copy of my setup made (using the same dropouts) for his new Elephant and ran into the same issue. It caused me to go back and look at drawings again. The standard for rear hubs has the rotor 5mm farther from the locknut than a front hub does. This means that my trick doesn''t really work very well. Since I used an Avid BB7 which has a very adjustable mount I was able to make it work, but I don''t think it will work on some other brakes. I think Fred is using a Shimano brake. I thought that I had made my mount follow the fork blade too closely and that is why things seemed tight. I modified my brake mount (it is one of the original Avid ones) by milling off about 2mm. That was enough, and hopefully that will work for you as well. My brake and Fred''s are both working well. Fred Blasdel also had a copy of my setup made (using the same dropouts) for his new Elephant and ran into the same issue. It caused me to go back and look at drawings again.

The standard for rear hubs has the rotor 5mm farther from the locknut than a front hub does. This means that my trick doesn”t really work very well. Since I used an Avid BB7 which has a very adjustable mount I was able to make it work, but I don”t think it will work on some other brakes. I think Fred is using a Shimano brake.

I thought that I had made my mount follow the fork blade too closely and that is why things seemed tight. I modified my brake mount (it is one of the original Avid ones) by milling off about 2mm. That was enough, and hopefully that will work for you as well.

My brake and Fred’’s are both working well.

]]> By: Adie http://alexwetmore.org/archives/1173/comment-page-1#comment-169415 Adie Fri, 14 Jun 2013 15:20:36 +0000 http://alexwetmore.org/?p=1173#comment-169415 Hey Alex, I just want to start off by saying your site is a great inspiration for me, just getting into frame building. I have been slowly working on my first frame, a disc brake equipped off road tourer. The fork was directly inspired by the one you show here, namely, raked steel fork blades with a CNC milled disc tab. mine isnt as integrated (or pretty) as yours, but never mind. Today I went to install the brakes for the first time, to check clearances etc before finishing work and paint. Unfortunately I encountered a problem. The rotor ends up too close to the brake tab, so that the brake adapter interferes with the rotor (by a couple of mm, by the looks of it). Copying you, I am using a "rear" adaptor (on 160mm Avid bb7s). I expected this to work, given that the inside face of my disc tab is in the same plane as the dropout (built a jig for it), and I am using a rear adaptor. Any thoughts? My brake adaptor does look considerably thicker than yours, could that explain it? or do wheels vary in how far outboard the disc rotor ends up? its a sram x7 6 bolt hub, 100mm spacing, 9mm axle. Thanks, Adie Hey Alex,
I just want to start off by saying your site is a great inspiration for me, just getting into frame building. I have been slowly working on my first frame, a disc brake equipped off road tourer. The fork was directly inspired by the one you show here, namely, raked steel fork blades with a CNC milled disc tab. mine isnt as integrated (or pretty) as yours, but never mind.

Today I went to install the brakes for the first time, to check clearances etc before finishing work and paint. Unfortunately I encountered a problem. The rotor ends up too close to the brake tab, so that the brake adapter interferes with the rotor (by a couple of mm, by the looks of it). Copying you, I am using a “rear” adaptor (on 160mm Avid bb7s).

I expected this to work, given that the inside face of my disc tab is in the same plane as the dropout (built a jig for it), and I am using a rear adaptor. Any thoughts? My brake adaptor does look considerably thicker than yours, could that explain it? or do wheels vary in how far outboard the disc rotor ends up? its a sram x7 6 bolt hub, 100mm spacing, 9mm axle.

Thanks,
Adie

]]> By: Shiny Stainless and Custom Fork Disc Brake Tab « Gallus Cycles Blog http://alexwetmore.org/archives/1173/comment-page-1#comment-81774 Shiny Stainless and Custom Fork Disc Brake Tab « Gallus Cycles Blog Sun, 25 Mar 2012 21:05:00 +0000 http://alexwetmore.org/?p=1173#comment-81774 [...] to me as an option till I went to NAHBS and saw it on quite a few bikes. I was more influenced by Alex Wetmore’s solution which was to machine a curved [...] [...] to me as an option till I went to NAHBS and saw it on quite a few bikes. I was more influenced by Alex Wetmore’s solution which was to machine a curved [...]

]]> By: Erik Rodstrom http://alexwetmore.org/archives/1173/comment-page-1#comment-72473 Erik Rodstrom Wed, 25 Jan 2012 19:40:22 +0000 http://alexwetmore.org/?p=1173#comment-72473 Beautiful fork! I have a question about your additional braze ons - For your lowrider rack mount, I''ve been unable to find anything on the usual framebuilder sites listed as such. Are water bottle bosses used for front rack eyelets? Or, are they not strong enough? Sorry for the slight hijack, since I''m not exactly asking about the disc brake portion of the post. Beautiful fork, either way! Beautiful fork!

I have a question about your additional braze ons – For your lowrider rack mount, I”ve been unable to find anything on the usual framebuilder sites listed as such. Are water bottle bosses used for front rack eyelets? Or, are they not strong enough?

Sorry for the slight hijack, since I”m not exactly asking about the disc brake portion of the post. Beautiful fork, either way!

]]> By: Jono http://alexwetmore.org/archives/1173/comment-page-1#comment-66880 Jono Fri, 16 Dec 2011 20:52:55 +0000 http://alexwetmore.org/?p=1173#comment-66880 Alex: This looks really great - nice job! I just sent you an email to get your thoughts on a similar project that I am being forced to undertake since I couldn''t find a curved-blade disc fork that had the correct A-C distance I need. My thought is to have a curved blade fork raked and disc tab added along with a brace, perhaps on the inside of the curve. It certainly won''t be elegant, but should by stout. Would love to get your thoughts on the plan. Cheers, Jon Alex: This looks really great – nice job!

I just sent you an email to get your thoughts on a similar project that I am being forced to undertake since I couldn”t find a curved-blade disc fork that had the correct A-C distance I need.

My thought is to have a curved blade fork raked and disc tab added along with a brace, perhaps on the inside of the curve. It certainly won”t be elegant, but should by stout. Would love to get your thoughts on the plan.

Cheers,

Jon

]]> By: Alex Wetmore http://alexwetmore.org/archives/1173/comment-page-1#comment-65238 Alex Wetmore Thu, 08 Dec 2011 05:20:24 +0000 http://alexwetmore.org/?p=1173#comment-65238 It has about 65mm of rake, just over 40mm of trail on the current frame. I plan on just under with the final frame (which will have a steeper head tube angle). It has about 65mm of rake, just over 40mm of trail on the current frame. I plan on just under with the final frame (which will have a steeper head tube angle).

]]> By: Greg Walton http://alexwetmore.org/archives/1173/comment-page-1#comment-65237 Greg Walton Thu, 08 Dec 2011 05:19:05 +0000 http://alexwetmore.org/?p=1173#comment-65237 Alex, that is a really elegant design solution to a challenging issue. Kudos to you. What rake did you put on the fork and what will your final trail be on the bike? Alex, that is a really elegant design solution to a challenging issue. Kudos to you. What rake did you put on the fork and what will your final trail be on the bike?

]]> By: Rick Isham http://alexwetmore.org/archives/1173/comment-page-1#comment-65219 Rick Isham Thu, 08 Dec 2011 03:17:33 +0000 http://alexwetmore.org/?p=1173#comment-65219 I have been interested in using disk brakes on road forks (and bikes) for a while. A while ago, I came across the work being done by Canyon with two front disks. Have you thought about this approach to even out the forces on the fork? http://www.canyon.com/_en/technology/project68.html It seems that road bikes need to progress from rim brakes. The rim brakes today are not much better than the brakes I used in the early 1970''s. My mountain bike''s brakes are so superior to my road bikes rim brakes. I hope that your new bike is a great sucess. I follow your blog, and enjoy reading about your work. I have been interested in using disk brakes on road forks (and bikes) for a while. A while ago, I came across the work being done by Canyon with two front disks. Have you thought about this approach to even out the forces on the fork?

http://www.canyon.com/_en/technology/project68.html

It seems that road bikes need to progress from rim brakes. The rim brakes today are not much better than the brakes I used in the early 1970′’s. My mountain bike’’s brakes are so superior to my road bikes rim brakes. I hope that your new bike is a great sucess. I follow your blog, and enjoy reading about your work.

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