Seeking advice: Gravel frame 57-60mm clearance + sus fork

[acwj8rwh]

Hi everyone,

I’m currently planning a new gravel build and am looking for some advice on frame selection from the collective knowledge here. I’ve been digging through the recent threads, but I’m struggling to find the perfect match for my specific requirements.

My "Must-Haves":

• Tire clearance: Needs to handle 57-60mm tires.
• Downtube storage: Essential for my setup.
• Seat tube: Must be a standard round shape (no proprietary aero posts).
• Geometry: Looking for something relaxed/endurance-oriented.
• Drivetrain: 1x12 or 1x13.

The Fork Factor:
I plan to run a RockShox Rudy XL (60mm travel). I am fully aware that this will significantly alter the bike's geometry due to the longer axle-to-crown (A-C) measurement. The Rudy XL 60mm has an A-C of approximately 475mm (compared to ~405-410mm for a standard rigid fork). For reference, the rigid fork of the TanTan GR257 weighs about 780g, while the Rudy XL comes in at roughly 1300g+.

Current candidates & geometry analysis (with 20mm sag):

• TanTan GR206: Looks great on Instagram with a Rudy fork, but specs list max clearance of 700x50C. Out.
• TanTan GR257: Explicitly states 57mm clearance and has downtube storage. I ran a analysis for size 51: the head tube angle drops from 71° to 68.4° and the BB height increases by 20.6mm to crazy high 51.4mm. The reach decreases by 25mm. It seems like it might get quite "chopper-like" with this setup. See attached screenshot from bike-stats.
• Mondince FM356: Promises 61mm clearance and also features downtube storage. Interestingly, the initial BB drop is much deeper here. However, the geometry changes when adding the Rudy XL are very similar to the GR257 (Head angle drops from 70.5° to 68.1°, BB height increases by 19.3mm to acceptable 68.7mm). See attached screenshot from bike-stats.

Are there any other frames (like the newer Spcycle models) that offer downtube storage, 57mm+ clearance, and a round seat tube?

Given the significant BB height increase and slackened head angles, I'm concerned about handling stability. Has anyone here experimented with such a drastic A-C increase on these specific frames? Any input, geometry insights, or alternative suggestions would be greatly appreciated!

I am familiar with the Wolf Tooth GeoShift Angle Headset (+/- 2°) and currently use one on another frame to compensate for geometry changes. While this is a great tool to steepen the head angle back up, I am aware that one has to be very careful with the clearance between the fork crown and the downtube when using such a setup.

Thanks in advance.

[gribs]

If you're going to do it you're probably better off looking for something with fairly aggressive geometry to start with, especially a steep seat tube. From my experience over forking mtb frames having too slack a seat angle made them ride dreadfully when sat down which is much more of a problem for a gravel bike.

The Mondince FM316/326 is compatible with a shorter gravel suspension fork so may not be dreadful with a longer one, but only really has clearance for slightly over 50mm tyres.

[Tijoe]

Think in terms of the right bike for the required terrain.   I started going down the path of a gravel bike with a suspension fork, then decided to build up a lightweight rigid 29er hardtail where I could quickly swap out a 100mm gravel SID Ultimate suspension fork to the rigid carbon fork.  Over the years, I have put a lot of miles on these 3 combinations of bikes.  My gravel bike with rigid fork, my 29er rigid fork and the same 29er with the SID.   Overall, I prefer the 29er hardtail with rigid fork.  It gets me over and through the most difficult "gravel bike" types of terrain.  Tire selection, tire size and tire pressure play a big roll in how well the bike performs.   
From my experience and perspective, a suspension fork only shines on descents where there are small drops, roots, washouts, and lots of washboard areas.  (When I ran a 50mm travel on my gravel bike, it was very disappointing overall.)

Above being written:

- If you are expecting to spend much time riding a high percentage of trails and poor condition gravel/rock/washed-out roads, I found this to be best on the 29er with the SID.  By far better handling on the really rough descents.   
-If you plan on riding on a lot of forest service roads, or smoother trails, then a 29er with a rigid fork is fantastic. 
If you plan on riding mixed media asphalt and gravel, where riding speed is important, then a regular gravel bike works best.

PS.  I ordered this frame July 2nd.  I want to try a gravel bike that fits larger tires, to see how it compares with my Spcycle M05 29er that has become my favorite rig these days.   

https://www.aliexpress.us/item/3256812074733285.html

[acwj8rwh]

If you're going to do it you're probably better off looking for something with fairly aggressive geometry to start with, especially a steep seat tube. From my experience over forking mtb frames having too slack a seat angle made them ride dreadfully when sat down which is much more of a problem for a gravel bike.

Best thing would be a frame compensating longer fork length. Haven't seen much of these frames from china.

From my experience and perspective, a suspension fork only shines on descents where there are small drops, roots, washouts, and lots of washboard areas.  (When I ran a 50mm travel on my gravel bike, it was very disappointing overall.)

-If you plan on riding on a lot of forest service roads, or smoother trails, then a 29er with a rigid fork is fantastic. 

I'm currently on a XC MTB titanium frame (1.8kg lol) with a 100mm SID /w FA and dropbars and tt bars. I really like the bike. It's comfortable, fast on forest roads, capable on downhills, but also heavy. I did recently a 65km 90% road ride with ~31kph avg.
Agree on what you say. I really wonder how much I sacrifice when I'd from 100mm SID to a 60mm Rudy XL. Weight-wise it's 'only' 110g.

Overall my motivation for the potentially new bike are:

• bigger frame triangle (2 bottles / additional bike packing luggage space)
• to get a bit lower overall (mainly through BB drop)
• frame storage
• lighter frame (which I would also get from a carbon XC MTB frame)
• road standard wheels (currently on boost)