Critique my new gravel frame

Here is the geo of my new gravel frame. It will be a 1x. I ride in the east coast.
I am 6’5" tall, 242LBS with a 36" inseam. I am not sure what rear drop outs I will use. I want to use flat mount but I have not found anything I like. Don’t really want plate drop outs since I am not sure I can make the slots. I am still deciding. Will use a Strato yoke.

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What is your overall design intent (one sentence that describes the bike)?

Fit Questions:

  • fit preference (racy, athletic, relaxed, casual)?
  • Saddle height (bb to top of saddle)
  • Handlebar choice (model and width)

Use case Questions:

  • Terrain
  • typical elevation gain and descend

Technical Questions

  • tire clearance?
  • Drivetrain standard?
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Hi there! New member to the forum here. I’m a pretty inexperienced framebuilder having only built several frames for myself, but I wanted to jump in and say that I am confident you’d be able to slot the stays for a plate-style dropout. I’ve used plate style PMW dropouts on a couple bikes and I really like how they build. I just slot the stays with a hacksaw. I like the design of the bike! One note: keep an eye on chainstay clearance to the spokes as they go from the rim to the hub flanges. Your design is tight to the wheel (which I think is rad!) but the spokes aren’t shown in the top down images of the stays.

Unrelated: I saw I missed the Kingdom ride - psyched about another New England get together in the future (I’m in Vermont)!

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Do anything adventure bike.
Fit I would like it relaxed and casual. It will be used for bike packing and touring. Want to do the Green Mountain Growler this summer so it will be packed.
Saddle height is 830mm
I have a salsa cowchip I would like to use since I have it
Terrain would be paved to class 4 VT roads with some single track thrown in.
Elevation I really dont know. In CT there is some but nothing like VT
Tire clearance will be a 50mm for the class 4 roads and single track.

Drivetrain: Will I do want to use Paul’s Klamper but not sure what shifters to use. I want to use a MTB cassette with a 10-52 for the climbs.
I have Ignite cranks already that I want to use. So trying to figure out the drivetrain.

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Fit:

Stack

With that saddle height, I think you should consider a much higher stack. In the 660mm range. That will require a >220mm headtube.

Generally humans your size end up running out of steerer tube length. Most carbon forks have 350mm of steerer:

  • stem = 40mm
  • spacers = 30mm
  • headset cover = 10mm
  • lower cup = 15mm

That means your max headtube length is around 250mm.

STA

I find taller people do better with slacker seat tube angles. I would consider 73.5 or even 73STA

Handling

I would consider 440 or even 450mm chainstays

  • IMO Chainstays length is about weight distribution, not about the length
  • big bikes already have a strong rear weight bias, so the typical "short chainstays long front center’ happens
  • Longer chainstay also needs to be paired with the slacker STA

Tubing

Seat tube Diameter

You might need to consider a 31.8 straight guage seat tube with a topper for 27.2 seatposts. This will allow you to run a bigger 31.8 top tube

Downtube

I would look into using a 38mm downtube. The Velospec Pro has a very nice butted profile and is made of some really good quality steel: VELOSPEC PRO 38.1MM Ø X 1/7/9 X 800 DOWN TUBE AC3810709-800 — BICYCLE FABRICATION SUPPLY

What I would do:

I find that tall riders condition themselves to bad fit. They often run low saddle heights to make the bar drop more manageable and prevent themselves from tipping back on climbs.

If I were in your situation, I would use the shorted chainstays that will fit a 700x50mm tire and 1x 42t GRX chainline. Playing around in CAD, you get there with 450mm pretty easily with minimal/no dimpling:


If you go down to 40t chainring and want to play around with dimpling or digging around for a pre-bent stay, you can probably get down to 440mm length. For you I wouldn’t go any shorter. The longer CS will allow you to have a slacker STA

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Your drawing is missing the BB drop as well as the fork offset, So I can’t make any critiques there, but having ridden a few bikes, I really like the 69 degree head angle with a 50 mm fork offset for “gravel” bikes.

Without the BB drop, it’s hard to tell for sure, but your rear tire will contact the seat tube if it is any lower than 60mm. You might want to increase the chainstay length just so you have a little mud clearance.

Since this bike is going to be made for a large person carrying gear while cruising and bikepacking, I’d advocate for a more drop bar MTB vibe:

  • Boost spacing front and rear
  • Rigid MTB carbon fork
  • Long and strong stays (min 460mm)
  • 29er XC tires
  • Long front center with shorter (50mm) stem

Make this sucker ride like a Cadillac. You’ll enjoy the ride so much more if you’re comfortable after of full day of rough road riding.

What you’ve designed so far looks more like a gravel race bike, which is fine for day rides when you’re putting down the hammer.

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Great, Thank you so much. I was thinking more of a monster cross bike also.

This is the fork I will be running since I have it on the first gravel bike I made.
State Bicycle Co. - Carbon Fiber "Monster" Gravel Fork | State Bicycle Co..

Here is the new design,

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Here is the latest. Not sure what CS to use. I was going to use a Strato yoke to make my life easier.

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This. Defo longer stays! Especially if you’re considering touring and want to run panniers. And everthing that @manzanitacycles said too!

Also for more of a comfort position with drop bars I try to set the tops at least level with my saddle. The Tanglefoot Hardtack in XL might be a good comparison for that setup. Stack heigh is 690! There’s a full review here. Hell it’s even got Ignite cranks on it.

I think Paul Klampers are a great brake. I also find the short pull version has a smoother cable transition and the brake. If you’re going that route and want flat mount then maybe it’s worth spending a bit extra for the Paragon’s Dedicated Sliding dropouts. That bike would be a lot of fun to try SS!

Also @Daniel_Y, I wonder much do you think this relates to not being able to get the bars high enough? I have long legs and used to prefer slack STA’s. Then I started using riser bars to get a more comfortable postionn and now I want to sit further forwards and would prefer a steeper STA most of my bikes.

The pink numbers drive your fit on the bike. I can’t tell you what works there. But you can take those measurements from another bike and move them over and make adjustments based on the bike’s intentions.

The yellow numbers drive how the bike will ride.

The green numbers are driven by the yellow and pink numbers. They’re helpful to get a wholistic idea of the design.

Things like seat tube angle, BB drop, reach, stack, effective TT length, are driven dimensions for custom frames.

  • I’d ditch flat mount brakes and run post mount Paul Klampers (excellent choice) with a 203/180 rotor combo.

  • You can use a pair of Cobra yokes for Boost chainlines.

  • The PMW DR2065 dropouts are nice. Lots of real estate to work with. Plus, Paragon makes an IS brake mount that’s pre mitered to fit. Easy peasy.

  • I’d be tempted to design for a straight pin seatpost in case you ever want to run a dropper.

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@manzanitacycles thank you so much for the drawing and insight. I am new to this and it is great to have builders like yourself and the the others that responded to this.
I do like that drawing. I do want an option to run a dropper.
Have to loose a few more pounds before I can run the Whiskey fork.

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What are people using for shifters with mechanical brakes like the Paul klamper?
I want to use road shifters with mountain cassettes and RD.
If I remember that sram AXS road will shift a mountain RD.

Is this the best option?

I know the Microshift sword would work also but not sure when it will be out. The cassette is less teeth but will work especially for the price.

Any other cheaper options the will shift a mountain RD?

Found the Ratio upgrade kit. I need to find some used 11sp Sram shifter and it looks like a good option.

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That won’t work, AXS = wireless. Sram and Shimano do not make cable pull shifts and brake shifters anymore. Campy makes one: Chorus

This might be blasphemous, but I am not a fan of mechanical disc brakes. The new GRX 12s hydraulic is cheap, works really well, and is easy to set up. They added more pad clearance which reduces brake rub.

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I’ve used similar options to the three you have there (well, Advent X and not Sword). Advent X with their road shifters worked great. The Ratio kit worked well too. Right now I am happiest with AXS XPLR because I really like the gearing gaps on the 11-44 cassette. On my mountain bikes I run 9spd Microshift Advent (no X) and I love that it’s cheap and performs great with minimal maintenance, but on my road-ish bikes (if they’re 1x) I like the gearing jumps much better on a 12 speed cassette. So I’d recommend either Ratio or AXS happily!

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I thought AXS will work with road and mtb derailleurs? These are for rim brakes. I maybe wrong.

I agree with the hydro but want to support Paul and US products. Maybe it will be easier just getting GRX

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AXS will work with road and mountain 1x systems. I think Daniel was mentioning that at this point Sram isn’t producing any new cable actuated braking AXS groups. You can still find older AXS rim brake shifters (I have a set of Force AXS that I use with Growtac calipers on my road bike).

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These are AXS for mechanical brakes.

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Totally, that’s what I currently have (the D1 Force AXS shifters for rim brake)! I had a heck of a time finding any to buy, and I still don’t really see any out there, so I wasn’t sure if they were phasing those out of production or not. But I see a couple vendors with restocking dates now, so maybe they are just much more limited in production.

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World wide has in stock.

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