Best solution to suspension woes front and rear?
Q:
I'm in the process of buying new front and rear springs for my DR650 and was hoping to get some suspension advice first. I have a dirtbike background and ride my DR fairly aggressively. In addition I weigh 220 lbs without gear. Do you suggest the straight rate Eibach springs or the Progressive springs for the front? Also, when I'm replacing my springs, should I also replace the fork oil? If so what type/amount of oil do you guys suggest?
I was also curious about the rear spring. I'm assuming I want the heaviest rate spring (I believe its 8.3 kg/mm) to hold me plus gear. Or, should I go with a lighter spring? Then, can I swap out the rear spring myself or do i need a spring compressor? If I understand correctly, a good 10w oil in the forks with the new springs will make a decent difference. Is there anything I can do with the rear shock while I have it off aside from switching out the spring?
A:
For the front, the Progressive springs will give a little smoother ride on pavement than the straight rate Eibach springs. If you spend the bulk of your riding on good roads the Progressive springs will be a better choice. Straight rate springs will work a bit better off-road or on rough roads. Both choices are significantly stiffer than the stock springs. For the forks, Use 10 weight FORK oil. Set the oil to the stock level - 140mm from the top with no springs and the fork completely collapsed. Then expand the forks and slowly put the springs in the tubes. If you really want to see a major improvement for both on and off-road, I really recommend the Race Tech Fork Cartridge Emulators as well. These make a huge difference in how well the fork functions.
You won't need a spring compressor for the rear spring, the preload collars will back off enough to allow the spring to come off easily. Several people have have good results changing the shock oil with 10w SUSPENSION fluid (NOT Fork Oil!). I think of it as the 'poor man's revalve'. It won't be as good as a Gold Valve installation or a revalve done by a pro suspension shop, but it will make a big improvement over stock. if you want the biggest bang for your buck, install a Race Tech Rear Shock Gold Valve kit yourself and then install the 7.5 kg/mm spring. All of this is doable in a home shop. After you are done you will need to find a shop that can refill the nitrogen, but that is no problem.
Are my fork springs too short?
Q:
I've recently ordered the fork spring kit you sell for the DR650 and have a question for you. Before installing them, I measured them and they are 513 mm in length. The service manual says the service limit of the fork springs is 548 mm. These are not compatible, they are too short. I'm not sure what to do!
A:
The aftermarket fork springs will not be the same length as the originals. There are spacers included to make up the difference in length. To calculate the correct height of the spacer, follow these simple steps to arrive at a spacer that will give you 3/4" of preload when the fork is assembled.
- Insert the new spring into the fork tube with the tube held fully extended and then measure the distance from the top of the spring to the top of the fork tube.
- Then SUBTRACT the distance that the fork cap goes into the tube.
- Now ADD 3/4 of an inch to get the correct length of your spacer.
To follow this logic, lets say the spring is 3 inches below the top of the fork tube, then fork cap goes 1/2 inch down into the tube. So, you are going to need a 3-1/4 inch spacer to get 3/4 inch of preload. Formula: 3" - 1/2" = 2-1/2". 2-1/2" + 3/4" = 3-1/4".