Wheels and Fork Improvement T120

Our subscriber has recently asked us about Triumph Bonneville T120 motorcycle which is used 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 for tourist but for suburban riding. The only significant flaws that the bike has are wheels with tubes and inefficient suspensions.

It is very difficult to fix a flat tyre on such a bike as Bonneville Т120. One needs to have a set of tools to take off mufflers and the wheel, and some special tools to take off a rigid tyre. Plus, the maintenance will take some time and energy. 

Original Bonnevile/Thruxton/Scrambler suspensions don't function 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 another one. That helps to reach the independence of rebound and compression festures, 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.

Suspensions

There are many options and solutions for suspensions - any of them will be better than the standard configuration. We have already installed cartridges Bitubo JBH 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 absorber soft. Also, there is a complex variable flow valve inside the damper, which has a slow and fast resistance (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 absorber material, 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 wheels.
• The front fender is mounted on a very rigid plate that pulls and secures the fork legs. In terms of front wheel installing, 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, to get a flat tyre with the new wheels is not that bad - 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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