# Basic full suspension question



## Rusnak_322 (Dec 6, 2009)

Looking to upgrade from my 120mm forked hard tail to a full suspension bike. Just starting the research, I have only demo’d a full suspension bike once 2 years ago.

When moving from a short travel (120mm) to mid travel (140) to long travel (160+) is the suspension similar during their initial travel? Or is the longer stuff more plush?

What I am trying to understand, is a 140 or 160mm fork (or shock) similar over the first part of the travel as a 120mm fork and instead of bottoming it out, it just keeps absorbing? If so, what is the negative of longer (other than weight)? If it is plusher, is the valving more progressive as it gets closer to bottoming out? It looks like they all have similar % of their stroke used for sag, so if you add 20mm of travel to a fork, then 5mm of that gets eaten up with sag leaving only 15mm additional for absorbing harder hits.

I have a good understanding of suspension set up from riding and racing motorcycles and dirt bikes. There, you adjust the valving, spring rates rebound and compression for the situation, but generally don’t alter the travel.

I am looking at a used Commensal Meta V4.2 and probably should get the TR, but the longer travel AM looks better and right now there are more of them for sale for less $.


----------



## TylerVernon (Nov 10, 2019)

What I am trying to understand, is a 140 or 160mm fork (or shock) similar over the first part of the travel as a 120mm fork and instead of bottoming it out, it just keeps absorbing? 

Short answer, yes.

If so, what is the negative of longer (other than weight)?

When you move your body on the bike to make it do things, the suspension has to travel farther before the thing you want to happen happens. This costs you more energy for doing things like...well, pretty much anything except coasting down hill. But suspension and kinematics are so good on modern bikes that this effect is shrinking.


----------



## acedeuce802 (Jun 30, 2017)

You may enjoy a few videos by Vorsprung on YouTube. 



 




A lot of this depends on how you set it up and the rear suspension linkage. There's essentially an "ideal" stiffness near sag and the midstroke. Too stiff and it'll feel harsh, too soft and it won't feel supportive. Ideally you could have an XC bike and a downhill bike that feel the same, the downhill bike just has the travel to take big hits. The reality is that 100mm of travel isn't enough to have the same mid stroke stiffness as the 200mm bike without bottoming out on a single root, unless it ramps up real hard in which case it would be even more harsh than just increasing the stiffness in the midstroke. When comparing something like a 140mm and 160mm bike, you can usually make them both feel very similar around sag and midstroke, but the 140mm bike ramps up at the end and the 160mm bike is more linear. The 160mm will feel more plush on big hits, but they will both feel similar on small stuff, berms, G-outs, etc. One downside to that is BB height, the 160mm bike will be taller and have a higher CG.

This also depends on your terrain. If you setup a 120mm bike how it feels good (same sag/midstroke feel as a 160mm bike, no compromise with short travel) and you only bottom out once or twice per ride, then you'd give up weight, CG height, pedal efficiency, etc if you ran a bigger bike. If you ride in really gnarly stuff and bottom out often and feel that you need to stiffen up the midstroke to keep it from harsh bottoms, then a bigger bike would be worth it.

It's also worth mentioning that travel isn't the end-all-be-all in choosing a bike. When comparing 120/140/160mm bikes from the same brand, usually as they get bigger, the frames get heavier, less anti-squat, beefier/heavier components, longer chainstays, etc. So even though you can tune the 160mm bike to feel the same as the 140mm, it has other attributes that will slow it down on climbs. That gets skewed with other brands, a 150mm VPP bike with trail components may be lighter and pedal better than a 140mm single pivot bike with enduro components, while still offering that plush bottom out resistance.


----------



## Rusnak_322 (Dec 6, 2009)

Thanks for the feedback. I am looking at one particular bike right now, the Commencal Meta that comes in both a trail and enduro version with 27.5 rims and similar geo. Obviously the longer travel will result in longer wheelbase. 

What i want is a used aluminum framed bike. I am getting this bike as a 52 birthday present to myself. I have been riding a 27.5+ bike with a low end 120mm fork that bottoms out hard on drops and jumps. That had been my biggest issue with the bike, that and after an aggressive ride, I can feel it in my knees and ankles for a day or two. I hope that the FS will allow me to ride more often.

I do plan on trying out some bike parks in NY or West Virginia and some downhill jump lines in Columbus, but most of my riding is not that hard core - but lots of roots.


----------



## NorCal_In_AZ (Sep 26, 2019)

Rusnak_322 said:


> I do plan on trying out some bike parks in NY or West Virginia and some downhill jump lines in Columbus, but most of my riding is not that hard core - but lots of roots.


I'm in the camp of buy the bike that matches 90% of your ridding. Not the 10% you might do once or twice a year.


----------



## 33red (Jan 5, 2016)

If you go 150 there is more energy consumed and the climbing suffers.
I went from 120 HT to FS 130/120 and i like it.
Try to test because what you will enjoy is personal.
Part of your bad past experiences was the budget fork so not all 120 are equal.
Do not hesitate to test to fine tune your suspension.
It is not always about more expensive.


----------



## Grinchy8 (Jul 6, 2021)

I’m targeting a 130/140 build, but with options to do 100, 120 or 140 on the rear by the moving the shock in the link. It’s good for almost everything, and I like the rear plush.
I was just out playing on the 130 fork with 100 in back and it’s plenty for dorking a round but not for a big g out. Which I can only dream of doing anyway.

rent a few bikes and see what you like.


----------



## kapusta (Jan 17, 2004)

Rusnak_322 said:


> When moving from a short travel (120mm) to mid travel (140) to long travel (160+) is the suspension similar during their initial travel? Or is the longer stuff more plush?


I think it depends on what you mean by "initial travel". In the very top of the travel, the negative spring design probably has more to do with how the bumps feel than the amount of travel the fork has.

But if you mean how do the forks compare for things like brake dive, lifting in climbs, and responses to rider input....In my experience, a 120mm and 160mm fork are going to feel different, even outside the larger hits. They generally handle differently.

And for stuff like small roots and rocks, I have generally found longer travel to be more plush.


----------



## dundundata (May 15, 2009)

The longer travel is good on the chunkier stuff. You can point it at anything and go. Plush suspension will eat up the trail. Disadvantage is more weight, less efficient pedaling (lower speed on smooth terrain).

My 150/140 build is great at the bigger stuff but I will turn to the 120/110 XC bike for quicker rides. If I had 1 bike it would probably be a 130mm FS like the Stumpjumper (still light with decent travel).


----------



## Rusnak_322 (Dec 6, 2009)

Just an update -
I bought a used 2019 stumpjumper Evo 29 alloy not long after my original post. 140mm rear / 150mm front. 
With that bike, I pretty much stopped riding the XC type trails and now enjoy more of the bigger stuff with more jumps, elevation and drops. I even made it to Snowshoe bike park twice this summer. I love my FS and think that I made a good compromise between the shorter travel bikes and the enduro bikes I was flipping between.


----------

