Diaz Suspension Design

04/15/2026

What's really driving the butter wagon? ... New seals / bushing?

We got a 2027 Lyric in the shop to ride and test. I test ride all forks stock before doing any kind of tuning / air volume adjustments. I want to experience how the manufacturer intended the fork to ride. This also helps a lot with communicating with customers about what they are experiencing with their suspension.

I do disabled them before riding to double check that everything is functioning correctly.

When I pulled the seals from the lyric I noticed that they did not have an inner energizing spring in the wiper seal. I also saw that the cavity on the inner side was much more shallow than the older seals.

I would say there is a significant amount of difference in stiction when comparing the old seals to the new seals just sliding them back and forth on the tubes after being lubed with slick Honey.

We know that removing the energizing spring lessons the amount of squeeze / friction / sealing force on the tube. However we don't know exactly how much squeeze is engineered into each seal before the energizing spring is added to the old seal.

The biggest change I see that I believe would have an even greater influence on the friction of the seal is the much shorter inner lip of the new seal.

These seals are both pressure sensitive. As pressure builds inside the fork when compressed that pressure then pushes on the inner lip of the seal creating a tighter seal. This is why forks feel sticky when they have excess pressure build up in the lowers. Because the seal becomes tighter with the extra pressure buildup. Also the reason manufacturers have started to user pressure release buttons on forks.

The fact that the new seal has a much smaller lip than the old seal means it's going to be much less pressure sensitive. Just a quick measurement the old seal has about a 1.7mm lip compared to the old seal that has about a 5mm lip.

Why is this important if you can bleed excess pressure from your fork. Because at sag and or deeper into the stroke pressure builds and this should decrease friction.

The last picture is the new Bushings that have slots in them to let oil pass through.

04/03/2026

This post explains why spacers were included in the Runt patent but never manufactured or used. They added no benefit to a two stage positive air spring. Any adjustment made with spacers can be done by simply changing air pressures.

1. I ran test on our LABA7 spring rate tester to confirm the above statement. Test were run with a 150mm 36 with a base line of a stock 150 Runt with 70 psi in the Low and 140 psi in the high chamber.

2. A drawing from the Runt patent with spacers circled.

3. A 20 mm piston was used as a spacer inside the high chamber of the Runt body. To test the effects of a spacer inside the high chamber of a runt.

4. Graph of test results the spacer did ad some progression at the end of the spring rate. However the same exact progression was achieved with a stock 150 runt with no spacer inside by simply adding 10 more psi to the High chamber. Therefore I decided that spacers were not needed.
Blue - stock 150 runt with 70 L 140 H
Red - 20 mm spacer inside runt with 70 L 140H
Green- stock 150 runt with 70 L 150H

5. Zoom on graph the green and red line are pretty much overlayed. You could probably run another 5 psi in the stock Runt high chamber and get them perfectly the same. Bottom line is you don't need spacers you can do all the adjustments by changing air pressures without having to disassemble Runt.

6. A shorter piston was used to simulate spacing a piston higher up inside the bore. (Not taking up enough volume)

7. The short piston did reduce the progression at the end of the the spring rate. However the same exact reduction in progression was achieved with a stock 150 runt full length piston by simply running 20 psi less in the High chamber. Therefore I decided that spacers were not needed.
Blue. - Stock 150 runt with 70 L 140 H
Green- short piston with 70 L 140H
Red. - stock 150 Runt with 70 L 120 H

8. Zoom on graph. The green and red line are pretty much overlayed. You could probably run 5 psi less in the high chamber of the red to get them perfectly the same. Again no point in spacers because you can do all the adjustment needed just by changing pressures.

Next post travel adjustment compensation

03/31/2026

I literally put spacers in the drawings but In testing they had no benefit at all. When you start to take up volume inside the runt the spring gets very progressive and you have to run lower air pressure in your low chamber. The lower pressure removes mid stroke support but still stays very progressive so you might as well run tokens. If you space the piston higher it doesn't take up enough volume to generate mid stroke support. So you have to run higher low pressures and again your getting back to the spring rates of tokens. This is why we have pistons and change the volume for every 10mm of travel differences.
The adjustability that's possible with just changing air pressures negates any need for volume or travel spacers.

03/31/2026

02/25/2026

The cleanest Titanium top cap? ..... Here's a fun project I've been working on. Ever since we started machining parts in house I've wanted to make a Titanium top cap but I didn't want a hex broached into the top or just a through bolt like most on the market. I wanted the top to be completely clean .
My solution was to cross drill holes and use a small piece of bar stock as a tool to tighten and loosen it.
It gets up to 35 in/lbs of torque which is more than enough to tighten a head set.
In a pinch you can use a 2mm Allen wrench to tighten / loosen it however the tool is recommended.
A stainless steel threaded stud is locked into place with red loctite. This insures that it will not seize with the star nut.
Logo is laser etched.
Two versions one rounded one flatter.

Ready to ship on the website for $80.

02/19/2026

Working on adding Podium Runt to the website. Should be up tomorrow.

02/03/2026

Finishing up a short run of runts to get all the variants back in stock. Next stop is Anodizing then Laser.
NEW IN THIS BATCH IS PODIUM AND 2026 FOX 36.

10/21/2025

We bring you the next DSD Patent Pending air spring.
The most advanced / adjustable spring on the market. It is the only air spring capable of duplicating a coil fork spring rate from beginning to end with the infinite adjustablity of air.
It is the first and only air spring with adjustable preload.
It has adjustable negative air volume.
It reduces progression in the lowers so that you can decide how much progression you want.

I have been working on this project for a long time now and it turned out even better than I could believe. It transformed one of the worst forks on the market (in my opinion) into one of the best ! I started with the Zeb because it was probably the most complained about fork for not getting full travel and harshness. It was the best proving ground for my ideas.

There is way too much to unpack in one post.

Link in bio takes you to the Lower Runt info page.

10/17/2025

The HBO needle/ assembly unseated and shock was bottoming out on the needle lodged sideways in the damper tube.