Carbonda FM936 Sizing

[steveP]

Sizing Question
I am 179 CM (5'10.5") and fall right on the line for a M/L. What would you guys suggest? I am coming off a 1995  26' Proflex 855 size large- so zero experience with the modern GEO.

If it matters I will be running a 120mm fork

[Zdrenka89]

I would say it depends a bit on your type of riding. Can you describe the terrain you intend to use it on?

[carbonazza]

Your height is one part of the equation.
Your inseam, torso length, arm length play a role too.
If you have them standard or short legs, you can go for a L.
If you have long legs vs. torso a M may be better.
I'm 178cm, long legs, and the M is perfect with this 65mm bar: https://www.aliexpress.com/item/1005002037520210.html?spm=a2g0s.9042311.0.0.27424c4dVEteNM

[Julian]

I agree with both of the previous answers. Riding style and body proportions are more important than declared frame size and height.

Generally, the FM 936 has really long reach numbers, but also really low stack heights. So if you compare the geometry to other bikes, it makes more sense to think of the actual distance and angle between BB and grips when the handle bar is set at the desired height (like pinkbike's "RAD"). You can do this using https://www.bike-stats.de/en/

For example: The size medium FM 936 with a 120 fork has approx 466 reach and 599 stack. This is exactly the same as a size large Specialized Epic Evo with 460 reach and 611 stack, only that you could run the bar slightly lower on the FM 936 than on the Epic.

So a size medium FM 936 is pretty much an average size large down country bike. If that's what your're after, go with medium. The size large however isn't huge if compared to an average size large modern trail bike, but those usually have more travel. Doesn't mean that you can't still put a short stem on a large FM 936 and ride it like a trail bike. It just depends on what you want to do with it. Although in any way - even with the long geo of a size large - the suspension design will never feel the same as more downhill focused trail bikes like the Transition Spur for example. Considering that, I'll personally go with a size medium, even though I'm 182cm (6ft) with 87cm inseam. Because I want a down country (race) bike, not a short travel trail bike.

[carbonazza]

Thank you Julian, very interesting view.

[wfl3]

A diff take:   

I'm 5' 9.5" but have a 5' 11" wingspan so sizing always sux for me.  I prefer a longer TT, but need a shorter ST.

I went with the medium FM936 primarily because of dropper concerns with the long ST on the large.  The sizing isn't terrible, but TT is a bit short for my liking.  I'm up to a 70mm stem (and could actually go up another 10-15mm), but the steering gets slower as the stem length increases and the 66 HTA (with 120mm fork) already slows that down considerably.  IMO this bike really needs a 40-50mm stem, especially with a 120mm fork.

That said, it is still fast and fun (both up & down) to ride and I have no buyers remorse - would just prefer it with the longer TT.     

[zilcho]

My experience is similar to Julian.  I'm 6'2" on a size large with a 60mm stem and it feels long at times.  I'm slightly more leg than arm and the already stretched wheelbase feels a little long for me in tight, twisty single track and the front wheel feels too far in front of me when pointing down.  I'd highly consider a medium if I order another but have learned to handle the large.

[steveP]

Wow, everyone, thanks for the detailed responses.

To answer the questions,
Height= 179 CM (5'10.5") without shoes 180 CM (5'11.25") with shoes

My inseam is 33.25" (84.5 cm) with shoes / and 32.5" (82.5CM) without shoes

WingSpan Tip to tip is 73.75 inches/ 6' 1.25"    (187cm)

Reach from armpit to fingertip is 29 1/8"(73.75 cm)

Type of riding

This will be an all-in-one bike (I know there will be compromises) Currently I road ride a 90's road bike- nothing special and a 1995 proflex.

I will want this bike to replace both (I ordered two sets of rims, one with slick street tires and one with MTB tires to swap) and front and rear will have lockouts.

33% trail- I live in the northeast in Rockport, there is no such thing as a fast flowy trail unless it is man-made. Super technical, rocks, roots, ups, downs, drops.

33% gravel/ dirt bike path type stuff with family and friends

33% road riding. I like to ride my bike to work a couple of days a week. It's about 10 miles each way.

[Palmi]

Hi steveP!

I never seen this bike irl, but rode multiple bike with modern geometry. Ok, mostly more trail /enduro oriented ones, but I following geometries and can decide about my frame size from the charts.

I'm 180cm +-1cm depends when they measure
With 200cm arm span .

I would go with the size M with short stem <50mm and wide bar.
But a stem and bar easy to change if it necessary

The bigger one have too long seat tube and you won't be able to use a dropper post longer than ~125mm and it'll be in the way on downhills.

This reach size will also fill LONG in the begining after your old-school frame.

[theirishrider]

I'm 185cm. I ride the L FM926 with a 50mm stem. It feels long for me, but not too long, I don't feel streched. I'm well over the front end on very step climbs and feel 'in' the bike on the descents. I don't know much about geometry so can't guide you more than than that. On the road, I ride a Giant TCR 2019 Large.

[Cerps]

A diff take:   

I'm 5' 9.5" but have a 5' 11" wingspan so sizing always sux for me.  I prefer a longer TT, but need a shorter ST.

I went with the medium FM936 primarily because of dropper concerns with the long ST on the large.  The sizing isn't terrible, but TT is a bit short for my liking.  I'm up to a 70mm stem (and could actually go up another 10-15mm), but the steering gets slower as the stem length increases and the 66 HTA (with 120mm fork) already slows that down considerably.  IMO this bike really needs a 40-50mm stem, especially with a 120mm fork.

That said, it is still fast and fun (both up & down) to ride and I have no buyers remorse - would just prefer it with the longer TT.     

I feel your pain.  I'm just under 5'9" and my wingspan is just under 6".  I end up with the same dropper concerns and compromises when buying bikes.  I tend to go with the smaller bike and longer, negative rise stem to try and get the reach as far as I can.

[richardsonj96]

Hi all,

New member here.

Looking to build a new mountain bike and the FM936 caught my eye, but the geometry is confusing. I'm 5'10" tall, 69" wingspan (haha), with a 32in inseam. So I'm average dimensions except slightly shorter arms. Normal ride medium/large frames, but that reach number is absurd.

My planned use is to race XC, marathon, and general riding near Denver and mountains of Colorado. I race road and XC, which is why I like bikes that pedal really well, but we have gnarly descents in CO too. I plan to put on a 120mm fork for this reason just to add a bit more support for longer days.

I had a 2018 Santa Cruz Blur that I bought when I in size large with a 60mm stem and it felt a bit long and sluggish turning sometimes in switchbacks, but I also didn't really feel like I was getting pitched over the front wheel unless it was hella steep because of the longer reach. I plan to replace my Blur with this bike, which I bought when I was a shop employee. My other bike was a 2018 Specialized Enduro, which had a 440mm reach. I loved how flickable the bike was, but sold it because I just didn't ride it enough, plus I like to pedal.

What size should I pick? Deciding between the small and longish stem or medium with short trail stem.

I could just strip everything off my Blur... but that's a lot of work selling parts and I still end up with an overpriced 2018 frame without the slacker geo.

Any help is greatly appreciated. Included a screenshot of my bikes for geo comparisons if it's of any help. Happy trails!

[Zomb1e]

Looking to build a new mountain bike and the FM936 caught my eye, but the geometry is confusing. I'm 5'10" tall, 69" wingspan (haha), with a 32in inseam. So I'm average dimensions except slightly shorter arms. Normal ride medium/large frames, but that reach number is absurd.

Don't look at reach when comparing frames with different geo. You'd better compare ETT (or even better saddle to center of handlebar distance) and RAD (distance from BB to grips center). This tool may help you to calculate these dimensions: https://madscientistmtb.com/bike-geometry-compare/

[Lovewookie]

I'm 5' 9.5" but have a 5' 11" wingspan so sizing always sux for me.  I prefer a longer TT, but need a shorter ST.

I went with the medium FM936 primarily because of dropper concerns with the long ST on the large.  The sizing isn't terrible, but TT is a bit short for my liking.  I'm up to a 70mm stem (and could actually go up another 10-15mm), but the steering gets slower as the stem length increases and the 66 HTA (with 120mm fork) already slows that down considerably.  IMO this bike really needs a 40-50mm stem, especially with a 120mm fork.

I was exactly the same, being 6'2, long torso, short legs. wanted to go with a XL, but the 540mm seat tube really put me off, as my normal saddle height is around 785mm. I figured the 500mm reach would be OK for a large so bought one of them.

In hindsight it was a bad move. the top tube length seemed OK, but the 66deg HA (with 120mm fork) means that anything over a 70mm stem feels floppy on the ups and not brilliant on the flatter stuff. unfortunately, with a 76deg SA, the position felt really short, also, while the SA positioned it so there was more weight over the front to stop it being wandery, I'm the sort of person who likes to have my bum X cm behind the BB. makes it difficult to do that, and when I did use a laybak post to get close, I'd need to put in so much pressure in the shock that it would either be wallowy seated, or pretty stiff when out of the saddle. in short, very difficult to get right. Not quite URT feeling, more akin to a non brain specialized from the mid 2000's.

would it have been any different on a XL? maybe. I could have fitted a short dropper, for XC, and a <70mm stem would have worked for seated reach to bars OK. I would have probably adapted to being a bit more over the BB, when I had the right stem length.

I did find however, that the very active suspension didn't suit my riding style at all. So even on a larger size I wouldn't have enjoyed the ride.

[casual_build]

Hi all,

New member here.

Looking to build a new mountain bike and the FM936 caught my eye, but the geometry is confusing. I'm 5'10" tall, 69" wingspan (haha), with a 32in inseam. So I'm average dimensions except slightly shorter arms. Normal ride medium/large frames, but that reach number is absurd.

My planned use is to race XC, marathon, and general riding near Denver and mountains of Colorado. I race road and XC, which is why I like bikes that pedal really well, but we have gnarly descents in CO too. I plan to put on a 120mm fork for this reason just to add a bit more support for longer days.

I had a 2018 Santa Cruz Blur that I bought when I in size large with a 60mm stem and it felt a bit long and sluggish turning sometimes in switchbacks, but I also didn't really feel like I was getting pitched over the front wheel unless it was hella steep because of the longer reach. I plan to replace my Blur with this bike, which I bought when I was a shop employee. My other bike was a 2018 Specialized Enduro, which had a 440mm reach. I loved how flickable the bike was, but sold it because I just didn't ride it enough, plus I like to pedal.

What size should I pick? Deciding between the small and longish stem or medium with short trail stem.

I could just strip everything off my Blur... but that's a lot of work selling parts and I still end up with an overpriced 2018 frame without the slacker geo.

Any help is greatly appreciated. Included a screenshot of my bikes for geo comparisons if it's of any help. Happy trails!

I am riding in the front range too. I've had my FM936 for two years now its been a blast. I'm 5'10 and ride a medium, but now I am building a Large FM1002 as the FM936 is a bit too XC focused for an advanced front range trail bike.  I only do trail riding.
My FM936 is perfect for the majority of blue/green trails here. It weighs 26lbs, pedals well, and handles downhill just fine. I want a FM1002 for the slack headtube angle, higher BB, and increased rear travel, so I can eat up steep downhills.

For XC riding, I would look at the FM909 as it might be slightly lighter and for a front range MTB quiver of one, I would pick the FM1001.