In short. No, 100mm won’t have the same plushness as 120mm if set up identically. Have you tried playing with sag? What are you currently running front and rear?

 

Sag is 20% front and 25% rear. I think the Scott 106mm linkage took away some off-the-top plushness in open mode due to altering the leverage thus the overall handling.
Guess I'll attempt to answer my own question(s): go back to stock 100/100 with old fork and work forwards. See if the 2022 SC34 vs SC32 difference is a smack in the face difference. It's not like for a race bike I need trail bike plush, but for 8 hour races and long training rides it all adds up to comfort AND speed.
Time to tear stuff apart.

 

I’m a little unsure if your issue is handling or plushness. Going from a 51mm offset to a 44mm offset would change handling. An older 100mm fork will never be as plush as a new 120mm fork

 

I have been jumping between a 100mm and 120mm sc34.

Small and medium bumps is very similar/the same. The difference is on the big hits. On the 100mm fork I am constantly smashing wheel to crown when compared to the 100mm

 

I'm still not clear on why the 120mm is unsat.

 

I think that after so many years and miles on the 100mm setup with 51mm rake SC32, the new SC34 and the aforementioned 106mm linkage may have taken away the Spark RC's sharpness as a race bike. Maybe it's the higher bb which I do like for pedal clearance. Maybe the front travel and rake don't play nice with the new linkage which I believe altered the Spark's kinematics. It's my first 44mm rake, all my bikes throughout the years from 100mm to 140mm had 51mm.
Guess I was asking if a 100mm SC34 would remain a big improvement in terms of performance and stiffness for my relatively tame XC trails or if it was just another Band-Aid in trying to make my Spark RC something it's not.

 

Maybe you just like the handling of a quicker bike. You not only slowed down the steering by slackening the HT by a degree but you also slowed down the steering at the same time by the decrease in offset. Double whammy. People on the forums tend to have group think, slacker is better. However that isn’t true when you like a quicker handling bike. I initially set up my sniper as 100mm and liked it. Thought I would try 120 so made a few changes and while I liked it a little more on the downs I didn’t like it nearly as much on the fun twisty stuff I really tend to like. Then I jumped back on my rigid Ti bike after my son had stolen it for the year. The precision and steering response immediately put a smile back on my face. I had given the Sniper a solid year to get used to it and honestly thought I had really started to like it, especially at 100mm. One ride back on a bike that carves up singletrack as fast as you can through it around And I haven’t touched my sniper now in 6 months. I simply don’t like slack bikes. Honestly, every single ride I am amazed at how well my 2011 bike handles. I am getting another bike built by the same builder and I was going to ask to go a little slacker on the front end, more of a “Downcountry” hard tail. F that, for me, I want a race bike. Funny thing is that almost all of my downhill Strava times are PRd on my Rigid HT, not my “downcountry” slack bike.

 

In some areas of bike setup, I don't much care, but fork travel can be finicky. On my HT I ended up with a SC34 @110 because neither the SC32 @100 -- I'm 30 pounds heavier than you -- or the SC34 @120 seemed quite right.

Go with your intuition.

 

It’s no big deal running a 2022 Fox 34 Stepcast as a 100 mm travel fork. Along with the airspring shaft if you want it to match the default factory setup there is 4.5cc blue volume spacer in the negative chamber of the 2022 Fox 34 Stepcast 100mm fork. I have it removed in my fork but it’s there by default.

Post #137

Race fork. Light weight or slightly heavier and stiffer.

I managed to get my hands on one of the 2022 Fox SC34 in 100mm travel. To simplify things, I like it, a lot. I didn't think it would feel that much better than a SC 32 but it does. However, is it actually faster? I debate this with bikes, there are lots of stuff I like, wide rims, big...

www.mtbr.com

If you’re not getting along with the modified handling I’d suggest putting the bike back to 100mm travel front and rear, with the Fox 32 Stepcast fork and original link for a week or so to compare and have a good think about what you do or don’t like.

You changed the front tyre at the same time so it might turn out that you’re not liking the characteristics of the new tyre.

 

It’s no big deal running a 2022 Fox 34 Stepcast as a 100 mm travel fork. Along with the airspring shaft if you want it to match the default factory setup there is 4.5cc blue volume spacer in the negative chamber of the 2022 Fox 34 Stepcast 100mm fork. I have it removed in my fork but it’s there by default.

Post #137

Race fork. Light weight or slightly heavier and stiffer.

I managed to get my hands on one of the 2022 Fox SC34 in 100mm travel. To simplify things, I like it, a lot. I didn't think it would feel that much better than a SC 32 but it does. However, is it actually faster? I debate this with bikes, there are lots of stuff I like, wide rims, big...

www.mtbr.com

If you’re not getting along with the modified handling I’d suggest putting the bike back to 100mm travel front and rear, with the Fox 32 Stepcast fork and original link for a week or so to compare and have a good think about what you do or don’t like.

You changed the front tyre at the same time so it might turn out that you’re not liking the characteristics of the new tyre.

I’m going to do just that. I also Went back to my old tire model but a brand new one.

 

Easy answer, just buy another bike setup the way you are thinking and do hot laps and compare times...... it's just money after all, can't take it with you.

 

What you’re feeling is the difference in fork offset. Going from 51 to 44 will be noticeable.

 

I'd suggest the standard shock linkage and 120mm fork first. Then 100mm air shaft if you don't get the feel you like by putting the stock linkage back on.

Change one variable at a time.

 

As others have mentioned, you really muddied the waters with using a fork with less rake - this effectively increased your trail and wheel flop much more than the slacker HTA caused with the longer travel. I know it's a bit late now, but a 120mm fork with a 51mm rake would have been much closer to your old setup from a front end steering perspective and give you that extra 20mm of travel.

This trail calculator can illustrate things quite well for you:

Bicycle Trail Calculator | yojimg.net

 

Thanks. I have a buyer locally for the 44mm SC34, but one day I'll end up with a newer frame that takes this fork. I could put a 100mm air shaft in for the time being. It'd give me stiffer and better quality travel compared to the 2017 SC32. Going to calculate trail and head angle with the 100mm 44mm fork via geometryCalc which doesn't take into account rake.

As it stands right now my beloved XC training bike is so jacked up, and while I return things to the known setup, my gravel bike has seen double duty training as of late. Which is fine.

 

I run mine at 110 on my Blur and really like it. Seems like a nice middle ground.

 

I am leaning more toward the 110mm air shaft.

After returning my 2019 Spark RC to 100/100 it felt so much better. Having said that, my training laps felt more fatiguing. I think the newer fork rigidity really pays dividends on off cambers full of square edge even in early timed laps. It wasn't the travel quantity, it was the overall fork quality. And I had more pedal strikes removing the 106mm travel linkage, not surprising.

I think this comes down to mostly cockpit setup. Just need to make SC34 in whatever travel config match my 100/100 51mm rake bike, and then get used to it. My new frame options take 44mm rake SC120 (Exie or Blur TR) have trail #s closer to 110. I'll try the 44 rake SC34 one more week before selling and getting 51mm rake SC34 for this bike and the next frame.