FM1001 / FM1156 - 135mm frame

[FlaMtnBkr]

Thanks for the reply. I thought you had posted a couple bikes in the 1002 thread but must have gotten the 2 mixed up.

Glad you are liking it! If I don't get the 831 sorted out I'll be looking really hard at these 2 if I decide to try again with a "chiner" frame. Otherwise I'll go with a name brand bike as there wasn't much savings after getting it completely built and sorted out.

[FullCarbonAlchemist]

Well with 27.5” wheel and 2.6” rocket ron on 30mm id rim this is what it looks like. Plenty of clearance! Seems with 29” wheel side clearance would be similar.

What’s your BB height like? I’ve been thinking about a mixed wheel setup and am trying to decide whether that will work in my area (Maine) because I ride a lot of very rocky trails where pedal strikes are a big issue.

[Freda]

BB height is on the low side, at least for riding in rocky terrain. It is ok, but not perfect. I will probably switch to full 29” at some point. I use 170mm cranks.

[endo.alley]

What’s your BB height like? I’ve been thinking about a mixed wheel setup and am trying to decide whether that will work in my area (Maine) because I ride a lot of very rocky trails where pedal strikes are a big issue.

You might be able to raise it up in the rear by 5-10 mm with an offset shock bushing.

[Freda]

I actually thought about this too, but do they actually work for making it longer? Doesn’t it just spin around and settle in the lower position eventually?

And also since it is trunnion mounted fork you only make it around 5mm higher at the rear axle.

You might be able to raise it up in the rear by 5-10 mm with an offset shock bushing.

[FullCarbonAlchemist]

My assumption was that offset bushings wouldn’t be great for these flipped trunnion shocks because the only end you can add one to is under heavy rotational forces. I’d assume with enough punishment it would start to settle into the angle of least resistance, and probably lose some of the offset.

I’ve heard contradictory things about offset bushings: that you should never put them on a high rotation mount point, and also that they’re held so tightly by the bolt that they shouldn’t be able to move. I’d assume both are true to some degree but I’ve had enough headaches with bike stuff over the past few years that I’d rather not take the risk.

[Julian]

A friend of mine is running the offset bushing to bring up the BB, I think so long as the spacing is perfect and all the tightening force goes to secure the bushing, it should be fine.

But putting it on a rotating part has the side effect of changing the leverage ratio.

[Julian]

So the effects of a 2mm offset bushing are:

- BB higher by 3mm
- head angle steeper by 0,3 degrees
- leverage ratio slightly less progressive
- 1mm more travel

[Stig]

Maybe a dumb question, but how do I run the cables using the white tubes that come in the frame?  Am I supposed to tape the cable to the tube and pull or push the inner cable into the tube and then replace the tube with outer cable?

[carbonazza]

Maybe a dumb question, but how do I run the cables using the white tubes that come in the frame?  Am I supposed to tape the cable to the tube and pull or push the inner cable into the tube and then replace the tube with outer cable?

If you can pass the hose in that tube, then once out, pull the tube out.
If not, taping them is an option. Don't pull too much as you may detach it.
Just push the hose, and lightly pull the tube as a guide and not as a force.

[bossman302]

Maybe a dumb question, but how do I run the cables using the white tubes that come in the frame?  Am I supposed to tape the cable to the tube and pull or push the inner cable into the tube and then replace the tube with outer cable?

Running the cable housing for the dropper is super easy. Just tape the white tube to the cable housing. The rear brake hose and derailleur housing I found to be super difficult. The lower part of the rear triangle has some super tight bends. I found it easy to un-do the lower pivot of the rear triangle and pull the cables through.

[ShepCO]

What is the purpose of the bolts at back of the chain stays on the FM1001?  It doesn’t appear that many bikes have these. Is it a bad thing?  Seems like it could lead to unwanted creaking etc. Thanks!

[endo.alley]

That is the rear pivot of a Horst link suspension. If that pivot was not there, you would stress or even crack the rear triangle as you engaged the suspension. The particular arrangement of pivots on a Horst link design also defines the axel path of the suspension as well as other important parameters.

[jonnybearback]

You're seeing a few frames now using "flex stays" rather than these physical pivots.
The flex stays are designed to provide the small angular change between seat stays and chainstays that pivots also provide.
Bearing based pivots tend to still be used on longer travel bikes where weight is less of an issue than a light xc bike which are trending into the flex stays design.
People used to moan about bushings.being used in that application rather than bearings, but as there's often so little rotation there anyways bearings could be considered overkill

[endo.alley]

Flex pivots are by design a flexy rear end on the bike. The performance is similar to a single pivot. With all the braking issues associated. Works with 80mm to maybe 110 mm travel I think. So it works on a lightweight racing or cross country frame. I remeber this on the old Merlin race bikes. Yeti, Trek, and Scott used to use this rear end. Specialized too maybe still does. And lots of dated geometry Chinese frames.