Greenspeed Magnum Owner's Manual
The Magnum is a new trike design, which builds on 20 years of trike design at Greenspeed. Like the GT Series trikes, the frame folds in the middle, to half the length of the trike for transport, shipping and storage. However the major feature of this trike is its versatility, and ease of use. The Magnum is unique in that the seat is not only adjustable for angle, but also for height, so that riders who have difficulty getting in and out low seats, can have the seat height up to the same height as a kitchen chair, and then as they get fitter, they can lower it and take advantage of better road holding and handling you get with the lower seat. In fact the seat will adjust from 17 inches to 12 inches from the ground, and the cross member is swept back to bring rider closer to the seat, to again assist entry and exit. The large 20” x 2” Big Apple tyres, give remarkably low rolling resistance at higher pressures on smooth roads, and a soft ride on rougher roads and off road at lower pressures. The front wheels are cambered in for stability, to reduce the width of the trike at the axle ends, and to reduce the rolling resistance through the corners. So with 5 inches of ground clearance, and 27 gears, the Magnum is just as at home on the trails as on the roads.
To improve the folding over the GTs, the seat detaches with the Quick Release under the front of the seat, and the two Q/Rs on the adjustable rear seat stays. Then to reduce the size further, the front wheels have a push button Q/R so they can be removed in one second each. A standard bike Q/R is used on the rear wheel, and the handle bars also have Q/Rs to fold forward and for adjustment. To pack into an even smaller space, the crank extension can also be removed, and to pack into the smallest space, the front and rear frames can be separated at the hinge.
As well as having the pop-off wheels, the Magnum is the 1st trike to use the new 90 mm drum brakes, and as they have a 30% improvement in braking power over stock 70 mm drums, the need for disc brakes with their shorter pad life, and tendency to squeal and rub is avoided. The long brake levers are both adjustable for reach, and have parking buttons.
To release the safety catch, slide the pin into the hinge, against the spring loading, and push down on the frame to close the hinge :-
Next fit the Quick Release skewer to the rear wheel axle:-
Then put the rear wheel into the frame. If the axle will not fit into the dropouts, then carefully remove any excess powder coat with a file :-
Adjust the Q/R nut so that the Q/R lever is firm to close :-
Next attach the front wheels. Please note that they labelled R for right, and L for left. This is because the spoke pattern is different in each wheel, to improve the life of the spokes:-
Insert the axles into the hubs, by depressing the button to release the locking balls at the other end of the axle. Then attach the wheels to the trike by again depressing the button, and inserting the axle into the hole in the bottom of the kingpin :-
IMPORTANT! Just like the Quick Release (Q/R) axle on a bike, the Push Button Q/R axle on the trike needs to be correctly adjusted before use. Unlike the bike, there needs to be some play at the wheel, to allow the fast release, and any attempt to remove this could see the wheel come off in use. Thus the inner end of the skewer must not project from the end of the axle - see photos below. On the other hand if there is axial play on the axle, the main nut should be tightened until the play is removed.
Please note that the outer end of the axle with the Q/R button can be damaged if the trike is rolled and end of the axle is ground down on the road, so you may choose to fit axle with the button on the inside as shown below:-
At this point the brakes should be adjusted.
Now that the trike has all its three wheels on, the next thing to do is the fit the crank extension. Make sure the clamp screws are loose, and insert the end of the crank extension into the end for the main tube, being careful not to dislodge the plastic sleeve which is just glued in place :-
Adjust the length according to your X-seam measurement, 41" = 1, and 50" = 10. Then make sure the front derailleur post is vertical in front view, and tighten clamping screws.
Then at the other end of the trike, fit the Rear Derailleur (R/D) to the rear derailleur hanger, and with a 5 mm Allen key.
Then fit the R/D cable. 1st make sure that the right hand R/D shifter lever is as far forward as it will go (top gear). Undo the clamping screw, thread the cable under the washer, pull the cable tight, and tighten the clamping screw:-
Now adjust the low gear throw, by moving the lever as far back as it will go keeping pressure on it, and unscrewing the lower adjusting screw "L" until the R/D guide wheel lines up with the largest cog on the cassette (bottom gear). Alternatively the R/D cage can be pushed to the left by hand pressure, and the screw adjusted until the guide wheel lines up with the large cog.
Finally check that as the lever is moved from top to bottom, the guide wheel still lines up with the cogs. When the lever is moved from top gear, back one notch to 8th gear, the guide pulley should now line up with the 2nd smallest cog, and if this does not happen, adjust the cable adjuster until this happens.
Next fit the chain. 1 st thread the cable through the return chain guide tube from the rear :-
Then take it around the small chain ring from below, over the top, through the front derailleur cage, and into the top, drive side, chain tube :-
Feed it down the tube, and then guide it under the pulley, and above the keeper:-
Then over the rear wheel cassette and through the R/D cage, making sure that chain runs inside the upper and lower guide tags as shown :-
Now it is best to just hook the two ends of the chain together with a wire hook, or other temporary means while the seat is fitted. Then once the seat is fitted, the leg length can be checked as the crank position will vary, depending on the recline of the seat adopted. And once the seating position is established, then crank position can be adjusted to suit, and finally the chain length adjust to suit:-
To fit the seat, 1st fit the lower ends of the telescopic seat struts to the bosses in the chain stays. Note the the larger recess on the strut fits to the boss, and the smaller recess accepts the head of the Allen head cap screw. If the cap screws are too tight to screw in, then there is likely to be powder coat in the hole, and you will need to run a M8 tap through the hole before fitting the strut.
Next fit the upper or inner parts of the struts to the seat. Note that the flats sit against the seat tags. Also note that on latter models longer screws and locknuts are provided to prevent the cap screws from unscrewing as the seat is adjusted or removed.
Fit the top parts of the struts into the lower parts, and then fit the front of the seat onto the front seat Quick Release mounting in the desired height slot.
Tighten the Q/R nut until the lever is very firm to close:-
IMPORTANT! Put a drop of oil on the Q/R lever pivots on both the front and rear seat Q/Rs and work it into the pivot bearing surfaces. This will enable you get the Q/R to hold more securely with less pressure. You can also do this the handlebar Q/Rs.
Now that the seat has been fitted, you can check you leg length adjustment. Adjust the seat angle to suit your taste. Remembering that the further you recline the seat, the easier it will be to push the trike, especially into the wind, as the major resistance to forward motion is simply the invisible air around us. Extend one of the pedals out us far as it will go, and then sit back in the seat, and see if your heel will just touch the pedal with your leg straight out. If this is not the case, undo the clamp screws and more the crank extension in or out until this is the case. Then make sure the front derailleur post is vertical, and tighten the clamping screws.
Now that the leg length has been adjusted, the chain length can be adjusted. The easiest method of doing this is to leave the chain on the smallest front chain ring, and smallest rear cog, and join the chain with the rear derailleur in the slack position, as shown below :-
To do this, determine where chain needs to be broken, drive out the appropriate pin with a chain breaker, and join the two ends together with the quick link.
Now fit the front derailleur cable. To keep the cable out of the way of the cranks, the latest Magnum have the crank extension drilled so that the cable can be routed up through the middle of it. Some owners have found that using a V brake noodle makes a neater job, and may require the holes on the crank extension to be opened up a little. It may also be useful if you are tall, as the original cable is a bit on the short side.
Now check that that you have enough chain to run large to large, by lifting the rear wheel off the ground, turning the cranks, moving the chain to the large front chain ring with the left hand shifting lever, and to the large rear cog by moving the right hand lever all the way back. If the chain rubs underneath the cross piece in front the rear wheel, the chain is too short. So it is best to err on the side of having the chain too long, until you have gone for a couple of rides, just in case you need to move the crank extension further out to get comfortable pedalling. If the chain is too long, then the worst that will happen is it will drag on the ground in small to small, and small to small do not need to used, as there is much overlap in the gears. In fact the small chain ring should only be used when the the combination of the middle ring and the largest cog on the back are not low enough. More information about Magnum gear ratios on this spread sheet.
Updated 10/11/2012.. to be continued...