Bikes

The Tomac DH legacy continues with the Primer 220, a full blown DH bike designed to make mincemeat of the competition. The Primer 220 is the work of Mountain Bike Hall of Famer and Manitou-suspension fork founder Doug Bradbury, who's experience during Johnny T's pro racing days led him to design another bike of World Cup heritage. Featuring 220mm of luscious travel, the Primer has enough CNC-machined aircraft-grade 7075 T-6 aluminum to launch a space program.

• 220mm rear travel, designed for a 203mm travel fork
• 11.5 pound (5215g) frame weight for medium size
• 7050 aluminum front triangle and rear end with CNC aluminum links and dropouts
• Single pivot linkage design with oversized 83mm bottom bracket shell
• Custom hex axle (included with frame)
• Low leverage 9.5 x 3 inch stroke rear shock
• Oversized bearings
• Low stand over height
• Available in small, medium and large

Geometry

Technology

Even though the Primer 220 is a brand-new model, it is the result of many years of thought and experience. The brainchild of Doug Bradbury, brought to life by engineer Mark Landsaat, the Primer is the next evolution of the original downhill bike Johnny raced in 1999 and 2000 seasons.

Like the original Tomac DH bike, the Primer is a single pivot bike with a linkage driven shock. But there are a bevy of improvements to the overall suspension design, linkage set up and swingarm. Let?s start with the leverage ratio and suspension rate. When we originally designed the bike, we felt an optimized design would allow us to use a standard 350 pound spring on a medium size bike and a leverage ratio that was under 3 to 1. With this set up and with a stock range of springs, it would be simple for any weight rider to set the bike up for any type of track, be it smooth, rough or anywhere in between. We wanted a fairly standard wheel path that would provide a consistent feel throughout the travel.

We settled on a leverage ratio of 2.9 to 1, with a suspension rate that is progressive up to 140mm travel and then becomes virtually linear. We did this because as you go into the travel, the rear shock itself becomes more progressive. If the bike?s ending suspension rate is progressive, and the shock is progressive, deeper in the travel the suspension will both become overly firm and the bike will not achieve full travel. The current set up allows the bike to feel consistent and smooth through the travel.

The suspension linkage is all CNC machined out of billet aluminum with oversize pivots bolts and full compliment bearings. You will notice that the linkage, like the rest of the bike, is low slung, a key in maintaining a low center of gravity. Motorcycle riders have long known that keeping the CG as low as possible is what gives the bike a light feel and allows a bike to corner well without sacrificing stability.

Speaking of stability, one of the main focuses of the Primer was nailing the geometry. We wanted it to be relaxed enough so that the bike would feel stable on fast straights, but not so slack that you would not be able to corner aggressively. We designed the bike around a 66 degree head angle and a 62 degree seat angle, with a bottom bracket height of 14.84 inches (unsagged). The geometry, combined with the low CG of the bike overall, makes the bike very easy to ride. I will quote World Cup rider Claudio Caluori directly, who did a bulk of the testing on the Primer. ?Robin (Hagen) and I were really stoked on the primers,? says Caluori. ?We were testing the two bikes on a really rough, rooty and rocky trail in Germany. The bike felt really stable on rough stuff. You could take it wherever you wanted.?

But all of the stability in the world wouldn?t amount to much if it didn?t have equal stiffness and strength, which is why we put an equal amount of thought (and FEA) into the shaping of the tubes. As an example, you can see a high degree of top tube and down tube shaping. You will also notice the top tube has a flat section near the head tube. The head tube impact test showed that this added strength and weld area, which in turn allowed us to eliminate gusseting between the head tube and down tube. Besides the fact that the elimination of the gusseting improves the looks a bit (please note the comparable lack of welding in this area), it was also a bit of a technical accomplishment and lessened overall frame weight. In addition, the top and down tube shapes really enhance the front end stiffness of the bike.

The Primer is designed to be used with a 200mm suspension fork. This might seem odd to have 200mm in the front and 220mm in back, but the goal is to provide an overall balanced ride once sag has been set. We recommend 35 to 45% of sag in the rear, where DH forks typically require only 20 to 25% of sag. When you are done setting front and rear suspension sag, you would have the same positive travel, and thus achieve a balanced ride.

Another goal of the new Primer was to standardize all the component interfaces. Gone is the oversize bottom bracket shell and custom wheel spacing in favor of the common 83mm/150mm combination respectively. In addition, there has been a major refocus on enhancing rear end stiffness. There?s a single-sided hex axle (provided) and the swingarm has been fully triangulated.

The finished Primer is the result of over 2 years of work and 7 different prototypes. It will be ridden by the Tomac Factory Downhill Team on the World Cup circuit next year.

Setup Guide - Suspension Setup
One of the best ways you can maximize the performance of your bicycle is by ensuring correct rear shock sag. To set sag, sit on the bike in a normal riding position near a wall to steady yourself. Without bouncing on the saddle or pedals, distribute your weight on the saddle and pedals in a normal riding position while holding the handlebars. Have a friend measure the distance between the front and back shock mounts.

Primer 200: this measurement should be between 225 and 235mm. This measurement means that 35% to 45% of the total shock travel is used as sag. This is appropriate for downhill riding.

Recommended Sag Applications
Downhill (Primer 220) 35-45% Sag

Preload Adjustment Coil Shocks
Coil spring preload adjustments are done with the spring preload adjustment ring. Adjust the spring preload adjuster up or down to achieve the desired amount of sag. Never exceed 8 mm/.325" of preload on the coil spring. Always make sure that you have a minimum of 1 mm of preload on the spring. If you reach the maximum spring preload (8 mm) and the sag is too much, you?ll need to go to the next higher spring rate. If you reach the minimum amount of spring preload (1 mm) and there is not enough sag, you?ll need to go to the next lightest spring rate.

Rebound Damping Adjustment
The rebound damping controls the return rate of the shock after it has been compressed to absorb a bump. Rebound damping can be adjusted for different spring rates, terrain, and rider preferences. Rebound on shocks can be adjusted by the red knob on Fox shock and the blue knob on Manitou shocks, which is located on the shaft eyelet mount on coil shocks and the air canister eyelet mount on air shocks. As a general rule, rebound that is adjusted too fast will exhibit a springy ride that has excessive pedaling movement and kick up the rear end on multiple bumps and big hits. Rebound that is adjusted too slow will exhibit a packing of the rear wheel that is identified by a low ride height, stiff feeling on multiple bumps and the rear wheel drifting to one side on stutter (braking) bumps. A good rebound starting point is to set the shock to achieve a return movement that is just short of ?snapping back?.

FAQ

Which Bike is Right for Me?
We love bikes and would love to hear from you, so if there?s even a question about which bike is right for you, please contact us via e- mail or phone so we can talk bikes.

Why is the Primer 220mm of travel in the rear and 200mm in the front?
Since you run more sag in the rear shock than the fork, when the sag is set, you should have equal positive travel front and rear.

Why Use a Linkage Driven Suspension System?
It?s the best way to separate the travel of the swingarm from the force into the shock. With standard single pivot bikes (non-linkage), you are just compressing the shock at the same force as the wheel is travelling. With a linkage system, you can control the shock rate and separate the forces onto the suspension.

What is the Primer Made of?
It?s made of 7005 series aluminum, which provide maximum strength for applications like World Cup DH racing. The top and down tubes are hydroformed triple butted 7005 aluminum, and the dropouts and yokes are CNC aluminum.

Why Use an 1.5 Headset for the Primer?
The 1.5 head tube increases the weld surface, and strengthens the front triangle?s impact strength. It also allows you to run an internal bearing system for the headset to reduce overall bar height.

Why a Hex Axle Rear Axle?
It provides a 15% increase in rear end stiffness without any weight increase.

What is the Rear Shock Eye To Eye?
The Primer uses a 9.5X3 inch rear shock (240X76), 8mmX30mm front hardware and 8mmX22mm hardware in the rear.

Can I Get a Spare Parts?
Yes, just contact use for any spare parts you should need.

What is the seat post size?
30.9 on all Tomac bikes.

How Involved in Johnny with Tomac?
Johnny is still heavily involved with the company. Not only does participate in the R&D and ride testing of all the bikes, but Johnny the businessman also helps determine the strategic direction of the company.

What if My Bike Creaks?
Sometimes after repetitive washings or extensive riding in the elements, the main pivot and link bolts will become dry and can cause creaking. Simple removing, cleaning, relubricating and reinstalling the bolts will eliminate any creaking. If creaking continues, you may need to replace the bearings. Remember to inspect the frame for any damage before each ride.

Where Do You Test the Bikes?
We tested the Primer almost exclusively on the World Cup race circuit.

What'?s the Service Life on the Bearings?
The service life of the bearings is determined by the amount and conditions that you ride in. That said, we focused extensively on maximizing bearing life. Not only did we use full compliment bearings throughout, but we made sure that all the bearing surfaces are tucked away from contaminants like dirt and grit. Lastly, the design of the frame inherently puts little stress on the bearings themselves. Keeping them clean and under minimal load means longer service intervals on the bearings.

How Can I Tell If I Need New Bearings?
Remove the rear wheel and the rear shock from the frame. Cycle the bike through its travel by pulling up and down on the rear end. Do you notice any grittiness or binding? Put your hand over all of the pivots and move the rear end again. Does it seem notchy? If so, you will need to contact the authorized Tomac retailer in your country. Go to www.tomac.com for more information.

Who is the Greatest Mountain Biker of All Time?
John Tomac, of course! No single rider has been more competitive in all disciplines of our sport, including XC, Dual Slalom and DH. A former World Champion, National Champion in both XC and DH, and one of the icons of our sports, there?s no denying John Tomac?s impact on mountain biking.

How Involved in Johnny with Tomac?
Johnny is still heavily involved with the company. Not only does participate in the R&D and ride testing of all the bikes, but Johnny the businessman also helps determine the strategic direction of the company.

I Can?t Find the Answer to My Question
Please let us know we can improve our FAQS section by e-mailing or calling us.

Owners Manual

Click here for the owners manual PDF file.

Warranty

For warranty questions please
e-mail

Reviews

Ask a Tech

Is there something you always wanted to know about your Tomac, but never knew where to ask? Well, you have arrived. Send us over your questions and we will get you a quick response.

Click here to e-mail questions.