Wheels and Fork Improvement T120

Our subscriber has recently asked us about his Triumph Bonneville T120, which he uses for long-distance rides. In general, as an owner of the motorcycle, he is very satisfied with the bike, despite the fact that this model is not really a touring bike but rather for country riding. The only significant flaws that the bike has are wheels with tubes and inefficient suspension.

It is very difficult to fix a flat tyre on such a bike as Bonneville T120. One needs to have a set of tools to take off mufflers and the wheel, and some special tools to remove a stiff tyre. Plus, the maintenance will take some time and energy.

Original Bonneville/Thruxton/Scrambler suspension doesn't work well when there are compression impacts on poor roads at high speed. On the T120 model the manufacturer made the fork a little more complex: there is a damper in one fork leg and damper rod in the other. This makes the rebound and compression characteristics independent, but it doesn't solve the problem. Also, the chance to bend the rim increases with each hard impact.

Wheels

Tubeless wheels for the Triumph classic models are produced by Italian manufacturers Alpina and Kineo. Both are fine, but Alpina wheels are used by professional riders in racing and rallying. The wheels have strong rims, which is very important if reliability is a priority. Plus, Alpina's set is cheaper. Therefore we decided to install these wheels on the bike.

Suspension

There are many options and solutions for suspension — any of them will be better than the standard configuration. We have already installed Bitubo JBH cartridges with all adjustments (compression, rebound, preload), they work well and have a fair price.

These cartridges are a separate adjustable shock: a spring and sealed damper filled with oil, which also has a chamber with compressed nitrogen, separated from the oil by a piston. The pressure prevents the oil cavitation, which makes the shock soft. Also, there is a complex variable flow valve inside the damper, which provides low- and high-speed damping (unlike the holes in a standard fork). The only drawback of this solution is the complexity of the maintenance. To rebuild the Bitubo cartridge, you need a special tool for pumping nitrogen into the damper, since there is no valve.

The same situation is with the rear shocks. It is good if the oil is under pressure and there are all adjustments. Of course, the shock materials, the resistance of the rod, the spring characteristics are important, but all premium brands have this, so you will not feel the difference.

Bonneville T120 has a number of certain maintenance features:

• To remove the rear wheel, it is necessary to remove the mufflers, and in our case also the rear footpegs due to the mountings of the side bags.
• When tightening the front sprocket nut, it is convenient to block the rear wheel with the brake, but on the T120, you have to unscrew the brake master cylinder to get to the sprocket. It is good that the nut tightening torque is relatively small, and you can manually block the rear wheel.
• The front fender is mounted on a very rigid plate that pulls and secures the fork legs. For front wheel installation, the fender should be installed after fixing the right fork leg on the axle. But the fender cannot be installed after the wheel is installed. There is no correct sequence in the manual, so the question remains open.

As a result, with the new wheels a flat tyre is no big deal — it can be easily repaired without removing the wheels by installing a repair plug. The new fork will noticeably improve ride comfort and stability, and preserve the rims on impact.

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