Yes, a 52mm chainline and 2.6" tires is everywhere because that is the max of what is possible with that combo. You wondered why not a 49mm chainline though- That is getting too tight for the chain stay yoke. 49mm CL with 2.4" tire clearance would be achievable though. Tire size drives chainline and you can see examples all over: Fat bikes, road bikes, gravel bikes, etc. One of the tightest points on a frame is the driveside chainstay yoke. This has been the case for decades (centuries?) with old steel frames being indented to squeeze the chainstay in between the tire and the chainstay.
As for super long chainstays. Sure you could build an FS bike around a 455+ rear center that could probably accommodate a 49mm chainline, but is there really a (large) market for that?
Jan. 13, 2022, 9:35 a.m. - WheelNut
Yes, a 52mm chainline and 2.6" tires is everywhere because that is the max of what is possible with that combo. You wondered why not a 49mm chainline though- That is getting too tight for the chain stay yoke. 49mm CL with 2.4" tire clearance would be achievable though. Tire size drives chainline and you can see examples all over: Fat bikes, road bikes, gravel bikes, etc. One of the tightest points on a frame is the driveside chainstay yoke. This has been the case for decades (centuries?) with old steel frames being indented to squeeze the chainstay in between the tire and the chainstay. As for super long chainstays. Sure you could build an FS bike around a 455+ rear center that could probably accommodate a 49mm chainline, but is there really a (large) market for that?