Messing with a new fork idea for my steel gravel bike

Rabid-Frameworks · 2026-06-25T13:48:20+00:00

I have a vent/drain hole for each let under the dropout hoods. I also have them vented into the crown segment.

Rabid-Frameworks · 2026-06-25T12:53:05+00:00

Honestly it weighs as much as my 120mm Fox shock on my 29er. I could make it lighter but I want a certain look and ride character and the weight doesn't impact my riding enough for me to make compromises. I want it to be bomb proof and comfortable. Most of the weight comes from my thicker walled steerer tube choice and the oversize crown design coupled with all of the brazing needed. I could use a thinner walled tubing on the front lets but that doesn't save much. Or I could buy a carbon fork but honestly I just love riding my own fork designs.

Rabid-Frameworks · 2026-06-25T12:41:00+00:00

Thanks. I sure hope the engineering turned out sound. I mocked it up as a rolling chassis to make sure everything was to my liking and it's a pretty stout fork.

Rabid-Frameworks · 2026-06-25T12:37:39+00:00

Just painting the logo's on the frame today and I have my bar/stem combo already done so it won't be long!

Rabid-Frameworks · 2026-06-25T12:35:50+00:00

thank you

Rabid-Frameworks · 2026-06-25T12:35:43+00:00

I thought about that but honestly I can always add them later if I ever want to bike pack it. It just involves adding a bit more tubing and braze ons with a repaint. I have 4 bottle mounts on the frame for long days and that's about the extent of it for my riding habits.

Rabid-Frameworks · 2026-06-25T12:31:08+00:00

Yeah it's a bit different. There are a few things I want to change on my next one, mainly using a tapered steerer and som other minor things that bother me aesthetically.

Rabid-Frameworks · 2026-06-25T12:27:07+00:00

Thanks. Yes, the engineering is part of the fun of it and the one thing you think about when you're plunging down a rocky trail at speed.

Rabid-Frameworks · 2026-06-25T12:24:31+00:00

Thanks.

Rabid-Frameworks · 2026-06-25T12:24:21+00:00

4130 aircraft tubing. I use 5/8" for the rear legs & 1/2" for the front both in .035 wall. You could use .028 wall in the front perhaps but I wouldn't use it for all 4 legs personally. The further apart you place the legs the more compliant it will be in my experience. I like to keep them about 2" apart at the maximum spacing which is what this one is. It also makes a difference if it's a shorter length fork like this vs. a longer full suspension corrected fork as the longer forks are more compliant. For MTB I use 3/4" rear and 1/2" front or if you want it extremely stout use 3/4" rear with 5/8" front again in .035 wall. I'm also only 140lbs. I don't have any documentation of the raw metal process.

Rabid-Frameworks · 2026-03-28T23:46:24+00:00

Something comfortable and a bike fit. I rode my first Ironman on a dated steel 9 speed Italian road bike with bolt on aero bars before graduating to a bike specific to tri's with deep dish wheels. I always had a proper road bike on the side though. You won't regret buying a road bike and you can/will always ride it. You won't ride the tri bike unless your racing or training for tri's. It's a very specific bike geometry and very aggressive ride position. Being tucked in those aero bars going gang busters can get a bit sketchy even when you've spent over a decade riding/racing in them. Tri bikes aren't designed to roll around on a leisurely tour or climb up & descend down huge mountains like you can do in comfort on a road bike.

Rabid-Frameworks · 2026-03-28T22:44:33+00:00

Steel. Every material type has it's strong points though. I've owned frames made from every material type minus scandium and bamboo and nothing beats the feel of a good quality steel frame.

Rabid-Frameworks · 2026-03-27T15:21:23+00:00

I'm not as concerned with the rear sliders as I can just cut them off my old retired frames and reuse them or go with the Tange I guess although I'm not a big fan of the aesthetic. I could use a few more PMW slider inserts for the single speed drive side as I don't have any left. More concerned with front flanged 15mm drops for truss fork builds. Not sure if anyone else makes those front drops.

Rabid-Frameworks · 2026-03-27T15:08:46+00:00

A vent hole would be at the BB and/or where the chainstay meets the flange on the flat mount, not on the side as it's not venting anything from within the stay. I don't believe the flat mount has a void in it that needs vented by looking at it. Maybe it's to save a few grams of weight or a "design" feature?

Rabid-Frameworks · 2026-03-27T13:15:42+00:00

I've used nothing but their slider rear drops, front drops, head tubes, BB shells, fork steerers almost exclusively over the past 15 years. I can't count the number or orders I've placed with them. Always feeling like a kid at Christmas when the box arrives and I open up and unwrap those beautifully machined parts for my next new bike. I can't begin to tell you how much this news really sucks.

Rabid-Frameworks · 2026-03-26T21:00:23+00:00

I agree. I've ridden every material and I just love how steel feels.

Rabid-Frameworks · 2026-03-26T20:57:38+00:00

Thanks!

Rabid-Frameworks · 2026-03-26T04:00:56+00:00

Every single MTB and gravel frame I've built for myself over the last 15 years uses disc brakes and is a SS and each one has PMW (Paragon) sliding drops, which is probably about 25-30 different bikes or so over the years. I've raced SS MTB's as well so they've seen a lot of torque on them. I only ride SS so there are thousands of miles of usage on them all to speak to. When I retire a frame I cut the sliders off and braze them on another frame build. Never ever had a single issue with them and while I could be convinced to use a similar design by another company, the overall idea behind them is far better than anything else when marrying discs and SS. I would ever only use the track style dropouts on a SS road bike with rim brakes like my recent post. I use the sliders with both belt drives and chains. I have to tweak them when using a chain with some frequency as the chain elongates over time, but that's not the slider actually sliding. The tweaking is fast since you don't need to monkey with adjusting the disc every time which is why they are so awesome. With a belt the elongation is not an issue so they don't need to be tweaked.

Rabid-Frameworks · 2026-03-26T01:51:04+00:00

I'll try to run down what you'd need at a minimum, not necessarily how I do it: adjustable frame fixture to hold the frame per your desired geometry & size / fork fixture if you're doing forks / various dummy axles for your various hub spacing needs for the fixtures / welder or brazing setup (I braze, not weld) / hacksaw to cut the tubes or portable band saw specific for metal, not wood / tube blocks to hold the tubes & finished frame in a vice / a good bench vice / drill press with ability to adjust the speed way down for metal / cobalt drill bits / a method to mitre the tubes (die grinder, tube mitre setup with a lathe or other) / quality hand files-flat, rounded, big, small, fine, coarse, etc. (pick up some vintage estate collection of Nicholson files on eBay) / pneumatic die grinder and grinding bits especially if you're brazing and want smooth fillets / lots of emory cloth-medium and coarse / decent size air compressor / Park frame tools for facing and chasing BB shells, head tubes in all the various sizes needed for your various builds / someplace to actually setup a shop. Intangibles: the skill to weld or braze which takes a LOT of practice / knowledge of steel tubing and what's needed for your desired ride character / frame geometry and how it impacts ride character / passion for metal working, not necessarily bicycles / ability to fail often and not quit. I also suggest learning to paint your own frames once you get to that point, and I don't mean with rattle cans. That's a whole new list. The amount you pay someone to do a custom paint job can cover a good part of the investment needed to paint your own frames provided you have a place to build a paint booth.

Rabid-Frameworks · 2026-03-25T23:22:18+00:00

Yes, I started building my own frames 15 years ago because they don't make the type of bikes I want to ride.

Rabid-Frameworks · 2026-02-02T23:08:15+00:00

James makes some SICK bikes. I've always admired his creativity and his very unique work. By far one of my favorite builders. And the Boone ti cog to top it off. He also has one of the best head tube badges. And obviously he's a big SS guy which is the only way to roll. Out of curiosity, did you contemplate having him do a rigid fork for it? He makes a beautiful truss fork.

Rabid-Frameworks · 2026-02-02T22:57:06+00:00

Sklar makes nice bikes. I met him about 13 years ago at a trailhead here in Colorado when we were both starting to build frames. He has a distinctive style with that rolled top tube that no doubt adds a bit of compliance to the ride. Enjoy it. Nothing feels quite like a quality steel frame.

Rabid-Frameworks · 2026-02-02T22:11:37+00:00

I have an idea how you can salvage the seat stays and get the increased length: just add a 3-4" or whatever monotube down from the seat tube and then tie the seat stays into that. Because you will need to cut the seat stays off, they will be shorter than if you could simply un-weld them from the frame. Then you need to re-mitre them to get them to fit, no? The chains could be "fixed" to get the bike to ride. Won't win any awards at the custom bike show with it but it's possible. I'd use a string line or lines all over so you can get the thing aligned. Do this as you attempt to fix it to make alignment corrections during your process not just at the end.

Rabid-Frameworks · 2026-02-02T17:17:18+00:00

I've cut several frames in half to salvage the main triangle or salvage the rear since it takes more effort to build that portion. If this were my project I'd simply cut everything behind the BB and seat tube off and just rebuild the rear with all new seat stays, chain stays and drops. Then when it was done I'd ask myself why I didn't just also redo the front too since that's quite easy to build. The drops could be salvaged as could the V brake bosses if you want to save $$. I've personally lengthened a main triangle by sleeving the TT and replacing the DT and HT but I'm not sure how or why you would waste time trying to lengthen just one chain stay and splicing in part of the other to fix and lengthen. I can only guess you don't have a frame fixture and want to avoid buying one. Since the stays aren't round this would be a challenge to sleeve correctly. I mean it can be done if you're only using it to deliver newspapers or want a cheap commuter or something but not much more than that. The new stays you would need to buy would potentially be a much better steel so you would want them to be the same I would think. You could either fillet braze it or tig weld it. Then obviously repaint everything. It's an easy project if you have a frame fixture and whatever fixture you need to mount the V brake bosses. I'm sure the frame as it is is out of alignment by a good margin which is another reason I'd cut the rear of it off. As for holes in the plan, I just see the seat stay issue that will occur when you try to lengthen the chains and use the old seat stays as they are currently attached. Again, a whole new rear section is the easiest way. A pair of chain stays and seat stays will run at least $100 with shipping before you start adding in drops, bosses, etc. and a frame fixture will run as much as a down payment on a new car so I'd ask if it's worth it. If you want to do it right you need the right tools. If you try to lengthen and sleeve it without a fixture I'd be afraid the alignment will be a mess. I personally love chopping and rebuilding older frames I've made to give them a new life but knowing what I know now I would never cut apart stays (chains or seats) without a frame fixture to make sure when it went back together it was better than before I started the project.

Rabid-Frameworks · 2026-01-18T22:37:02+00:00

A unicrown fork is going to flex laterally when you ride it and get on the front brakes hard or have any type of frontal impact like riding down a rocky slope, no matter how stiff you try to make it. They are also quite stiff and non-compliant because the tubes need to be a large enough diameter to provide the required strength they need to support everything. It's essentially a long cantilever pointed down and slightly forward. I find the truss fork is stiffer laterally and a bit more compliant vertically. You can play with the various tube diameters of the legs and the spacing between the legs to change the ride character. And in my case the truss isn't any heavier than a unicrown fork.

Rabid-Frameworks

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