Chinertown

Chinese Carbon MTB => 29er => Topic started by: FullCarbonAlchemist on September 14, 2022, 03:46:17 AM

Title: FM1002 - 160 or 170mm fork?
Post by: FullCarbonAlchemist on September 14, 2022, 03:46:17 AM
I’ve been running my FM1002 with a 170mm fork since I built it up in the spring, and I know several others here are too. Who’s running it at 160? Has anyone tried both?

I’m about to swap forks on mine and the Fox 38 I want to put on is currently set to 160 (I also have a 170 air shaft for it) so I’ve been thinking about this a lot. I’m also thinking about building a FM1003 next so once I have that bike with a 180 fork, maybe keeping my AM bike at 170 is a little redundant.

This debate has come up a few times so I thought I’d make a thread specifically to discuss it: let’s hear your thoughts!
Title: Re: FM1002 - 160 or 170mm fork?
Post by: Swolie74 on September 14, 2022, 08:08:36 AM
I’ve been running my FM1002 with a 170mm fork since I built it up in the spring, and I know several others here are too. Who’s running it at 160? Has anyone tried both?

I’m about to swap forks on mine and the Fox 38 I want to put on is currently set to 160 (I also have a 170 air shaft for it) so I’ve been thinking about this a lot. I’m also thinking about building a FM1003 next so once I have that bike with a 180 fork, maybe keeping my AM bike at 170 is a little redundant.

This debate has come up a few times so I thought I’d make a thread specifically to discuss it: let’s hear your thoughts!

While I don't currently have this frame set, I would say that the geometry doesn't lend itself as well to over forking that the 1001 does...
Title: Re: FM1002 - 160 or 170mm fork?
Post by: casual_build on September 14, 2022, 11:06:41 AM
I haven't tried a 160mm fork, but the 170mm fork seems to perform well while climbing. The geo give a ~64.5 Degree head angle with a 160mm fork. I wanted something slacker and more confidence inspiring so I over forked 10mm. I think its right for me.

I am also curious if anyone has tried both.

While I don't currently have this frame set, I would say that the geometry doesn't lend itself as well to over forking that the 1001 does...

What do you mean? Are you talking about the bend in the frame?
Title: Re: FM1002 - 160 or 170mm fork?
Post by: Swolie74 on September 14, 2022, 12:16:50 PM
I haven't tried a 160mm fork, but the 170mm fork seems to perform well while climbing. The geo give a ~64.5 Degree head angle with a 160mm fork. I wanted something slacker and more confidence inspiring so I over forked 10mm. I think its right for me.

I am also curious if anyone has tried both.

What do you mean? Are you talking about the bend in the frame?

the 1002 is currently listed with a head tube angle of 64.5 with a 150mm fork, if you put a 170 on there it will be even slacker/longer.... I would guess under 63*. Also for me (tall AF), the slacker seat tube angle creates issues climbing.
Title: Re: FM1002 - 160 or 170mm fork?
Post by: casual_build on September 14, 2022, 01:45:55 PM
the 1002 is currently listed with a head tube angle of 64.5 with a 150mm fork, if you put a 170 on there it will be even slacker/longer.... I would guess under 63*. Also for me (tall AF), the slacker seat tube angle creates issues climbing.

If you look at the geometry, the 64.5 degree angle is for a 572mm axle to crown fork. I am not sure what fork they were using that has 150mm of travel and is 572mm axle to crown. Most 160mm forks are 571mm so actually under length. Using a measuring app my head angle looks to be ~64.1 with a 170mm fork
Title: Re: FM1002 - 160 or 170mm fork?
Post by: casual_build on September 14, 2022, 02:39:57 PM
Check out what this guy thinks about taking a 160mm frame and putting a 170mm fork on it.

https://youtu.be/aZ40ikmWLXM?t=583
Title: Re: FM1002 - 160 or 170mm fork?
Post by: endo.alley on October 16, 2022, 03:41:54 PM
I have only used a 170 Rock Shox Lyric. Works fine. I don't see how a smaller fork will improve by much. I don't think this bike will ever be a screaming climber no matter the fork length. But it's a solid ok climber.