FS xc racing bike

[endo.alley]

I am wondering which of the modern-geometry cross country frames people like the best and would recommend. For xc racing and marathon racing mostly. I am looking at the Flybike FM1206, Carbonda  FM909, Carbonda FM936, and Ican S3.

[zilcho]

You're looking at three versions of the same bike more or less. The FM1206 is the FM909, the S3 is the front triangle of the FM936 but with a 4-bar rear triangle using thicker seat stays, and the 909 and 936 have identical geometry other than a shorter seat tube on the 909. Neither the 936 or 909 have shown flaws in the flexstays so I don't think the 4-bar is needed. I'm on the 936 and love it, but for marathon I would lean towards the 909 for an extra bottle on the bike, I hate hydration packs.

[wfl3]

Agree with the poster above.  All will fit the need nicely, but I'd go 909 for the extra bottle mount.

Another plus of the 909 is the shock position allows easy manipulation of the shock lever without the weight, bar clutter and maintenance of a lock out lever (for those that need such).

[endo.alley]

For what is basically a race bike, and a rider of around 135-145 lbs, would the super light version be advantageous? Trying to build a somewhat light bicycle. But not a bike that will break apart under normal cross country racing. Also, are there differences in performance between the vertical shock linkages like the S3, vs the horizontal shock linkages such as the FM909?

[zilcho]

For what is basically a race bike, and a rider of around 135-145 lbs, would the super light version be advantageous? Trying to build a somewhat light bicycle. But not a bike that will break apart under normal cross country racing. Also, are there differences in performance between the vertical shock linkages like the S3, vs the horizontal shock linkages such as the FM909?

The idea that the super light version will some how crumble is silly. If you have the money to spend I say go for it, just don't skimp on parts elsewhere and negate the weight savings. I forget who but someone has been running sims for the linkage of some of the bikes on the forum, if you dig through the 909 or 936 threads you'll find them. There is a slight difference between the two, and it's discussed in one of those posts, but I don't have enough expertise to tell you what the difference would mean on the trail.

[carbonazza]

...but I'd go 909 for the extra bottle mount.

If for some reasons, you prefer the look of the 936, there is a double bottle mount that works well: https://www.aliexpress.com/item/32975689555.html
Put some thread locker on the screws, and no interference with the legs.
At least you can try for the price.

[RongGearRob]

If for some reasons, you prefer the look of the 936, there is a double bottle mount that works well: https://www.aliexpress.com/item/32975689555.html
Put some thread locker on the screws, and no interference with the legs.
At least you can try for the price.

. Has anyone tried this double mount?  The only downside to the Lexon Riot (another XC option the poster may want to consider) the room to fit only 1 bottle.  It's cheap enough to take a flyer on it, but just curious if anyone has and what their impressions are of it.