[Notthatbryan]

Do you notice it on steep downs also? Or just on technical rolling terrain?

I don't notice it on steep downs. I don't feel like bigger compressions are the problem, but more of the repeated smaller hits that bother my hands. The brake dive I mainly notice on braking into switchbacks and tight turns.

 

[Notthatbryan]

And this is also the same terrain you're having brake dive issues on?

Yes, the same terrain. I mainly notice the brake dive when braking into switchbacks or other sharp turns.

 

[Notthatbryan]

Do you notice it on steep downs also? Or just on technical rolling terrain? What bike is it on? Have you had this issue before on other bikes? What bike were you riding before and did you have the issue.

I am wondering if some of it comes down to bike fit. i.e. Steeper seat tube angle puts more weight on your hands when sitting on rolling terrain. Steep SA work really well for straight up and down, but can be less ideal in rolling terrain depending on your body proportions.

I had similar issues with my hands before due to breaking both wrists, but I haven't ridden in 20 years. The last bike I was riding before was a Cannondale xc hardtail. I got back into it hard in July and have been doing 30-40 miles a week.
I'm currently on a 2021 Giant trance x 29.

 

[Notthatbryan]

I weight 175 and run mine at 85 psi with no tokens. Like someone said earlier it seems counterintuitive to add more psi but it actually made a big difference for me. Small bump is good, no brake dive and plenty of mid stroke support.

Can't hurt to try higher pressure out.

 

[547319]

Brake dive can be fixed with more pressure or with low speed compression. My fox 34 grip2s seem to run better with more pressure. With my Mezzer I was able to dial in low speed to help with brake dive.

I don't think it's only the fork, I think it's also your riding position. I would try messing with spacers under the stem and saddle setback (i.e. slide the seat away from the handlebars on the rails). Those changes have been key to keeping my hands happy on rolling technical terrain.

 

[Notthatbryan]

Brake dive can be fixed with more pressure or with low speed compression. My fox 34 grip2s seem to run better with more pressure. With my Mezzer I was able to dial in low speed to help with brake dive.

I don't think it's only the fork, I think it's also your riding position. I would try messing with spacers under the stem and saddle setback (i.e. slide the seat away from the handlebars on the rails). Those changes have been key to keeping my hands happy on rolling technical terrain.

I dropped the stem down one spacer (5mm iirc) and have the seat back a bit already to get more comfortable on the bike.

 

[233946]

I dropped the stem down one spacer (5mm iirc) and have the seat back a bit already to get more comfortable on the bike.

Just to flesh it out, can we get all the info? Weight, height, bike, bike size, rear suspension setup? It sounds like you have already methodically gone through everything, but fresh eyes might uncover some ideas. I am wondering if you are running too much sag or not enough rear rebound which is leading to more weight shift forward.

 

[294037]

I'm a little hesitant to increase the compression damping since it may compromise the small bump performance and also the grip damper doesn't have detents so fine adjustments are less repeatable than I'd like.

How do you know it will compromise small bump performance? Did you try it? Yes they don't have detents but you can at least test in 1/8 turns to get a proper feel for where the damping is at.

Depending on year, the shims are often free to flap around if the adjuster is too far open, so closing the adjuster enough to secure them again can make a world of difference

I'm considering a DSD runt or a grip 2 damper to address the dive.

Vorsprung Secus is a much better spring upgrade, and would be my top suggestion. Grip 2 will be a little better but I would do that second

You mentioned tyres, pressure looks ok, but have you tried lower? What width are they and what type of terrain do you ride? If it is especially rough, rocky or fast you may need a beefier casing with lower pressures

 

[Dougal]

The problem is the damper. At fully open you've got no LSC and only some HSC from the base-valve and the mid-valve is trying to do everything.

I've had good results tuning these but they're very fiddly as they're very sensitive to stack preload. Like 0.05mm makes a big difference sensitive.

 

[Notthatbryan]

Just to flesh it out, can we get all the info? Weight, height, bike, bike size, rear suspension setup? It sounds like you have already methodically gone through everything, but fresh eyes might uncover some ideas. I am wondering if you are running too much sag or not enough rear rebound which is leading to more weight shift forward.

I'm currently right about 170lbs, 175 geared up.
I'm 5'9" with a 31 inch inseam
Bike is a 2021 giant trance x29 size medium.

Rear suspension setup is the fox dps performance (tune D6H3). I'm running 165 psi in the shock with rebound 7 clicks from open. This ends up at 13 mm of sag (just under 25% in the rear, 55 mm shock stroke).
I tried the rebound at 6 clicks and it feels two slow to return when compressing the rear in the garage. It's noticably slow to extend. It's a big difference from 7 clicks open. The rear feels like it's performing well.I believe the rear shock has a small volume reducer in it, but since I'm satisfied with it's performance I haven't cracked it open yet.

Front fork is a Fox 36 rhythm (tune D369) at 78 psi, rebound 6 clicks open, 0 volume reducers. This has me at 30mm of sag (20% for the 150mm fork)

With this setup both front and rear are using about 80% of travel on most rides. I don't feel like I'm hitting anything big enough that either should be bottoming out regularly. The rear feels a little more poppy than the front, but overall balanced. Neither end feels like it wants to kick on jumps when I do my part (I don't jump a lot).


Tires are DHF 2.5 /Dissector2.4, both EXO casing. 20/22psi F/R.

 

[Notthatbryan]

How do you know it will compromise small bump performance? Did you try it? Yes they don't have detents but you can at least test in 1/8 turns to get a proper feel for where the damping is at.

Depending on year, the shims are often free to flap around if the adjuster is too far open, so closing the adjuster enough to secure them again can make a world of difference


Vorsprung Secus is a much better spring upgrade, and would be my top suggestion. Grip 2 will be a little better but I would do that second

You mentioned tyres, pressure looks ok, but have you tried lower? What width are they and what type of terrain do you ride? If it is especially rough, rocky or fast you may need a beefier casing with lower pressures

I don't know that adding compression will compromise the sensitivity, but that's my concern. I dislike the imprecise nature of not having detents, but that's just me being a little ocd. If I give the compression adjuster a quarter turn it makes a big difference just in the garage.
Really I should try this out and see if I can dial it in.

Tires are 2.5 front 2.4 rear. I have not tried lower than 20/23 psi. Primary terrain is rooty and rocky.

Why do you say the Secus is a better spring upgrade?

 

[Notthatbryan]

dang it, wrong button

 

[Notthatbryan]

The problem is the damper. At fully open you've got no LSC and only some HSC from the base-valve and the mid-valve is trying to do everything.

I've had good results tuning these but they're very fiddly as they're very sensitive to stack preload. Like 0.05mm makes a big difference sensitive.

This was the thought process I had for upgrading to a grip2 damper. To gain separate high and low speed compression adjustability. That way I could add a touch of low speed compression damping more precisely.
Talking 0.05 mm is right in my world, that size variation will kill any part I deal with in my day job.

 

[Notthatbryan]

Here are my thoughts so far based on everything.
1. Try more compression damping with my current settings, this is the easiest to try and easiest to change on the trail.
2. Try more pressure. Bump up pressure to 80psi, I've run 80 before and thought 78 felt better.

Those are the things to try out before throwing parts at it or replacing the shock.

 

[jeremy3220]

You can always mark the LSC dial position on the fork upper using a marker, or marker on a piece of helicopter tape if you don't want to mark the fork itself.

Also, the main parameter affecting brake dive is the air spring. Compression slows the rate of the dive but often we're on the brakes long enough that the fork still compresses to around the same point. Adding compression is definitely worth a shot but view it as a fine tuning tool. Your main focus should probably be spring rate though.

 

[Notthatbryan]

You can always mark the LSC dial position on the fork upper using a marker, or marker on a piece of helicopter tape if you don't want to mark the fork itself.

Also, the main parameter affecting brake dive is the air spring. Compression slows the rate of the dive but often we're on the brakes long enough that the fork still compresses to around the same point. Adding compression is definitely worth a shot but view it as a fine tuning tool. Your main focus should probably be spring rate though.

Silver sharpie is the plan

 

[commplex]

Fwiw I have noticed the rhythm fork performs better at 15% sag and lsc dial 1/8-1/4 closed. I personally think you are starting too far into the travel at 30%. Again, I am 175 and I run 85 psi in mine with no tokens. Lower psi gave me the same kinda harsh feeling over consecutive small bumps.

 

[233946]

Fwiw I have noticed the rhythm fork performs better at 15% sag and lsc dial 1/8-1/4 closed. I personally think you are starting too far into the travel at 30%. Again, I am 175 and I run 85 psi in mine with no tokens. Lower psi gave me the same kinda harsh feeling over consecutive small bumps.

This. On the Rhythm on my son’s bike I had it at 85 psi when I first rode it and it was harsh and dove a bit. 95psi and it was a different fork, much better.

@nothtatbrian I would try 85psi in the front, as everything else in your setup looks dialed in. Play with the higher pressure before for the compression.

 

[Notthatbryan]

Fwiw I have noticed the rhythm fork performs better at 15% sag and lsc dial 1/8-1/4 closed. I personally think you are starting too far into the travel at 30%. Again, I am 175 and I run 85 psi in mine with no tokens. Lower psi gave me the same kinda harsh feeling over consecutive small bumps.

I'm at 30mm sag NOT 30%
30mm is right at 20%
I'll try 85 psi and see where that gets me.

 

[Notthatbryan]

This. On the Rhythm on my son’s bike I had it at 85 psi when I first rode it and it was harsh and dove a bit. 95psi and it was a different fork, much better.

@nothtatbrian I would try 85psi in the front, as everything else in your setup looks dialed in. Play with the higher pressure before for the compression.

Sounds like a plan of attack. Spring pressure sounds like the best starting option, then try adding a bit of compression if needed.