Low Cost Front Fork Adjustment

The front forks on the Tiger are basic non adjustable items. While they offer a reasonable amount of feedback and damping, it doesn't take much to overwhelm them. The forks also suffer from a large amount of stiction. This can cause the front wheel to shake at around forty mph when under a neutral throttle. Touching the brakes, or throttle stops the shake immediately.

There are a few ways of dealing with these suspension issues. One is to part exchange the bike for a new Tiger XCX which comes with adjustable WP suspension. But, this is a costly option. It's almost as if Triumph knew they were cutting corners on the Tiger XC!

The second option would be to revalve the fork internals. There are a few options on the market now ranging from different springs, to combination cartridge kits. This again can be a costly exercise with prices starting around £500.

But, I decided to try the third, cheaper option. The damping of the forks during both compression and rebound feels quite harsh. This harsh feeling gets a little better after an enthusiastic ride, or a longer ride loaded up with luggage. This indicated to me that the fork oil may be a little too heavy. I decided to try changing the fork oil to a lighter weight oil, and experiment with altering the air gap. I already had various bottles of new fork oil. So, it was only going to cost me a bit of time.

I removed the forks from the bike, and started to strip them down so that I could drain the oil. The first job was to remove the top caps. The fork caps are made of aluminium with the same structural integrity as room temperature French brie. They can get damaged very easily. But, the good news is that they are cheap ( less than £5 each ) to replace with nice shiny new ones. Guess how I found out!

An old trick to protect the fork caps while you remove them is to use a spare workshop glove between the cap and the socket. This prevents the socket from slipping and damaging the cap.

Always protect your nuts!

 

With the caps unscrewed they then needed to be removed so that I could get to the rest of the internal components. With the caps removed I threaded on a damper rod puller so that I could pull up the damper rod and remove the spring retaining nut and seat. You normally need a special tool for this. But, the springs are quite weak on the Tiger so this could be done by hand. There is a lock nut just under the dished spring seat. Holding the spacer tube ( tube with the hole in it in the picture below ) with one hand, and pulling up the damper rod with the other allowed me to get a spanner on the lock nut.

 

 

I could of just turned the forks upside down, drained the oil out and added the same amount of new oil. But, this is not best practice, as you cannot accurately measure the oil level/ air gap correctly this way.

 

With the spring retainer removed I could slide the spring out and drain the oil. Before draining the oil, I measured the oil level to use as a guide later. I left the fork to drain upside down for a while. One the oil had drained, I pumped the damper rod to drain the damping cartridge as much as possible.

 

 

Spring and spacer removed. Keep all the parts in the order you removed them so they go back the same way.

 

 

Draining the oil. I measured the amount of oil drained from the forks as a guide to refilling.

 

Now I could reassemble the forks. Triumph specify a fork oil level / air gap of 107mm using a 10wt oil. When I measured the oil level in my forks, I had a reading of 112mm. As, the oil is measured

by quantity rather than the more accurate level during production, this slight discrepancy was to be expected.

I decided to change the oil to a lighter 5wt, with an air gap of 125mm to begin with. I added the 5wt oil and pumped the damper rod a few times to remove any air in the cartridge. I set the air gap to 115mm first with my air gap tool. This is where I expect to find the best compromise once I had test ridden the bike a few times. I then set the air gap to 125mm, and measured the amount of oil I removed between the two air gap settings. This would allow me to add the correct amount of oil to set the air gap to 115mm if needed.

  

Setting the air gap/ oil level. This is done with the fork compressed and the spring removed.

 

I reassembled the forks, which was a simple case of refitting the parts in the reverse order of removal. Once the forks where reassembled I polished the stations with some P.T.F.E. dry lube spray to try and help prevent the stiction problem. I then fitted the forks back in to the bike. With the forks refitted, it was time for a few test rides.

 

Straight away the forks felt much more supple. Fork travel had increased slightly, using more of the damping available. I placed a cable tie around the station prior to riding to give an indication of the amount of travel used. However, when hitting a bump during braking, or when carrying out an emergency stop the forks felt like they were close to their stops.

 

I added the extra oil to bring the air gap down to 115mm. It is only a small amount of oil, but it has made a massive difference. I now feel like the forks are as good as they can be without throwing money at them.  Combined with the new Michelin Anakee 3 tyres I fitted a while ago, the bike is much more confidence inspiring to ride.