Precision Race Hanger for Seismic Spring Truck

(1 customer review)


Price is for ONE (1) hanger – w/option for custom assembly to Baseplate geometry and Spring strength of your choice.



Precision Race Hanger for Seismic Spring Truck.
Available in 90mm, 100mm, and 130mm – w/option for custom assembly to Baseplate geometry and Spring strength of your choice.
Ideal for elite LDP and slalom racers!

Hand-fitted with precision 8mm axles by legendary skate machinist Geezer-X. Fully finished with Pivot Bearing, Spring Nut/Screw assemblies, and Wheel Nuts. Faced at ends. Does not include Baseplate, Pivot Bolt, or Springs unless option is selected.

Axles are manufactured in the U.S. from 8640 CrMo steel, with 22mm bearing seats centerless-ground to 7.98mm.  Hardened to Grade 8 standard and black-oxide coated. Threads are rolled not cut.

Precision 8mm axles mean less torsional play between the bearing and the axle. This translates to faster and more precise roll; more consistent wheel contact and grip while cornering; more predictable slide release and hookup; and longer wheel and bearing life.

Price is for ONE (1) hanger – w/option for custom assembly to Baseplate geometry and Spring strength of your choice.

1 review for Precision Race Hanger for Seismic Spring Truck

  1. Paul Howard

    I’m not the fastest slalom racer out there, but I’ve been on the podium in my “B”class days and I’ve qualified into the middle of the”A” group for years (just never made it onto the podium, ha,ha). I have 2 setups, my “smaller” course board for tight and tight-general/hybrid and my “bigger” course board for bigger-general/hybrid and Giant slalom. My favorite REAR trucks for 10+ years on my “Bigger-course board” has been 2 – 30 deg Seismics with modified hangers (by Eric Wallgren- I’m guessing these current ones listed were modified on a lathe by Eric Wallgren also?) a 100mm(used with most slalom wheels) and a 130mm (used with centerset wheels) on a 20″ wheelbase. I have NEVER ever had rear “fishtail” speed wobbles, that includes a few G/S races with tailwinds and getting around 40mph. Once I took my “big-course” board downhilling with friends and we passed 50+mph car traffic on a road parallel to us, again, very stable ride. The traction is really good since the action of pivot is near the axle(lower) than conventional or reverse kingpin trucks that have the pivoting closer to the board(higher and closer to the foot) which is why I use them for rear trucks on bigger slalom courses with big offsets and I want to keep traction. Even when I’ve broken traction, I felt like I had good control . The Green and Purple springs have worked really well for me giving me good solid stability and resistance in back for slalom, I weigh 160-168lbs in all my gear if that helps give you ideas for springs to put in. I also neg wedge my rear Seismic about 5 deg and use very modified Tracker RT-X’s in front for almost all slalom, I did use a 45deg Seismic 130 front in a Super G race that was 40+mph since I wanted the traction and stability at that speed, it worked really well. Also, Seismic axles are actually STRAIGHT the way axles should be, and since these specialty racing hangers have been turned on a lathe, the bearing interface surface is a nice actual 90 deg like it’s supposed to be(stock Seismics seem to be pretty good this way anyway). Thanks Dan (and Eric)! – Paul Howard

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Truck Axle Tolerance

Seismic axles (both G5 and Aeon) are manufactured to be 7.95mm in diameter, with a small negative-only tolerance. Racing truck makers who advertise “true 8.0mm axles” generally follow a similar specification. Average brands use 5/16-inch (7.9375mm) axles.

The inner race of standard wheel bearings has a diameter of 8.0mm, with a small manufacturing tolerance. Truck axles need to have a diameter slightly smaller than that, or else some bearings may not fit or even get stuck.

Truck Hole Pattern

Seismic trucks (both G5 and Aeon) support both “Old School” and “New School” mounting hole patterns. In the case of the G5, this was a significant engineering challenge given the truck’s unique structure.

The Old School mounting hole pattern has holes that are 2.50″ (63.5mm) center-to-center longways. In the New School hole pattern, that distance is only 53.5mm (2.11″). Both patterns have holes that are 1.625″ center-to-center sideways.

G5 Truck Mounting Advisory

Seismic G5 Baseplates have a unique structure and require full bottom surface support. Mount them directly onto the bottom of your deck, or else with stiff riser blocks between the trucks and the deck. Do not use rubber or urethane shock pads. These amplify stresses on the Baseplates – especially if the mounting bolts are over-tightened or tightened unevenly. Then relatively minor impacts can push the Baseplates past their breaking point.

G5 trucks will not fit through standard drop-through mounting holes, and they should not be drop-mounted to LDP bracket extensions. Unless extremely stiff riser blocks (preferably wood or even metal) are placed underneath the trucks, they should not be top-mounted on LDP brackets or on decks with drop-through mounting holes.

G5 Spring Truck Dis-Assembly and Re-Assembly

To dis-assemble a G5 truck: Place the board or truck upside-down, on the floor or a low workbench. Always pull off the Pivot Bolt Retaining Clip and untighten the Spring Tension Adjusters. Then press down on the hanger and hold while unscrewing the Pivot Bolt. (Note: If you don’t untighten the Spring Adjusters and hold the hanger down, Spring pressure adds resistance to unscrewing the Pivot Bolt and creates stresses that can damage the threads of the Baseplate Nut as the Bolt is removed.)

To re-assemble a G5 truck: Place the board or truck upside-down, on the floor or a low workbench. Always make sure to fully loosen the Spring Tension Adjusters. Otherwise much more pressure is needed to align the Hanger and Baseplate for insertion of the Pivot Bolt.

Set the Springs in the Baseplate with the sliding “piston” caps facing up. Place the Hanger on top, with the Spring Adjuster tips inside the piston cap sockets.

Press the Hanger down and hold it in place (using your bodyweight if necessary), to align the parts and keep Spring pressure off the Pivot Bolt. Then use a 7/32″ Allen wrench to press the Bolt through the truck and screw it into the Baseplate Nut. Fasten firmly, but don’t over-tighten. Sometimes a small downward push with the wrench helps the Bolt tip catch the threads of the Nut.

Always re-attach Pivot Bolt Retaining Clip after re-assembling truck. Replace Clip if it becomes bent.
Product modifications, including machining and use of non-Seismic components, are at your own risk.

If the Pivot Bolt unscrews only partway during disassembly and then gets stuck, the Baseplate Nut is probably stripped. To get the Pivot Bolt out of a stripped Nut, first place the truck in a vice (if possible). Pound the head of the Bolt back into the truck. This will force the stripped Nut out of its pocket in the Baseplate. Then slide a small flathead screwdriver (preferably #3) between the Nut and its pocket, or grasp the Nut with a strong pliers. This increases tension between the Pivot Bolt and the Nut, and it usually helps the Bolt cut through the Nut’s stripped threads. After unscrewing the Bolt, reassemble using a fresh Bolt and Nut.

G5 Spring Truck Noise

Seismic G5 Spring Trucks were engineered as a high-precision product, with virtually no slop in their steering articulation. So like a race car, they don’t dampen road vibrations much and may seem noisy compared to lower-precision trucks that use bushings. Some skaters are more sensitive to that than others.

Actual rattling noises can occur for a variety of reasons, regardless of the trucks you’re using. The most common cause is riding on rough surfaces with loose hardware and/or wheels that are too hard for the surface. In addition, bearing spacers can rattle between the bearings or against the axles if they’re the wrong size, or if the wheel core tolerances are off.

Try using softer wheels with properly-spaced bearings. Also check the fastening tension of your mounting hardware, wheel nuts, and truck pivot bolts. (Loose pivot bolts can also invite dirt and grime to gunk up the works, which in turn can lead to excess friction among the moving parts.)

The Seismic G5 technology itself was carefully engineered to eliminate squeaking, clicking and rattling, but a few seldom-seen issues can lead to these or other noises.

Most squeaking and clicking stems from friction between the small inner springs, the main outer springs, and the long-necked “sliding” spring caps. To reduce or eliminate the noise, try rotating the spring assemblies a quarter or half turn inside the spring chambers. (Loosen the tension screws first, then just turn the springs with your fingers.) After that, tighten the tension screws at least 1.5 turns. For added measure, drop a bit of silicone or graphite lubricant inside the long spring caps.

Finally, spring tension screws that are fully loosened may occasionally rattle inside the Seismic truck hangers, though ordinarily spring pressure keeps them quite still. Try tightening them 1.5 turns. This puts them in a “neutral” position where they function as intended. The trucks won’t feel stiffer when riding, but pressure from the springs will keep the screws from rattling.

Truck Wedging

The steering geometry of the Seismic G5 Spring Truck is absolutely fixed and perfectly consistent – either 30-degrees (Stable-Turn) or 45-degrees (Quick-Turn). The steering geometry of the Seismic Aeon Truck is also very consistent, especially for an RKP design. So wedged (angled) risers have a totally direct and predictable effect on their performance.

To quicken steering response, orient the wedge with the thin end facing the end of the deck. Usually called “wedging,” this is most commonly done with the front truck. Just remember this reduces your leverage on the G5 springs or Aeon bushings, so you might want to loosen them or even switch to softer ones.

To slow steering response, orient the wedge with the thick end facing the end of the deck. Usually called “de-wedging,” this is most commonly done with the rear truck, especially on racing boards. Just remember this increases your leverage on the G5 springs or Aeon bushings, so you might want to tighten them or even switch to stiffer ones.

Optimal truck mounting depends on many different variables – wheelbase, riding speed, skating style, personal preference and even body height. You’ll need to experiment to see what works best for you.