[Bobby Peru]

Hi everyone! I just bought a Iron Horse SGS DH Pro. I have always wanted a DH bike but couldn't afford it. When Supergo had these babys at 1,400.00 I HAD to get one. Anyways, I have a question on how to adjust the rear shock. It is much too mushy feeling and I know it CAN be adjusted, just HOW? HELP!

 

[Wumpus]

Maybe this will help: http://www.answerproducts.com/helpdesk.asp

 

[Bobby Peru]

That's cool...thanx for the link! I was just kinda hoping for more of an explanation in "laymans terms!"

Show me something once, and I got it...Sometimes it is a little tough to figure it out from the manual. However, the link does help a bunch!

 

[Gonz]

Search in the Suspension and Rear Shock catagories. Use "SPV" as a search word.

 

[Kornphlake]

I'll be nice and tell you everything you need to know... Okay maybe not everything, but I'll tell you what I understand and how I understand it. First, what are the adjustments on the 4 way? Rebound, preload, SPV pressure and SPV volume would be the correct answer. Rebound is pretty straightforward, it's really personal preferance where you set this, if you don't have a preferance just leave it where it is and ride for a month then turn it in or out and ride around a bit to see what you like better. Rebound is how fast the shock will extend after being compressed, faster rebound may feel smoother over repetitive small bumps where as slower rebound may make you feel like you're more connected to the ground. Preload is simply how much tension is in the spring without compressing the shock, this adjustment can be used to dial in the sag which ideally should be about 30% of the total travel. You can measure sag with a ruler by measuring the distance from one eyelet to the other without any weight on the bike, then sit on the bike and have a friend measure the distance again. Subtract the second measurement from the first then divide this by the total travel of the shock and multiply by 100 to get the percent sag (if that made no sense whatsoever I apologize, these kinds of calculations are pretty elementary for me so I assume they would be for others as well.) If you are having to preload your spring more than about a quarter inch to get the right amount of sag you should probablly get a heavier spring. (This may be your biggest problem!!!) SPV pressure is kind of like the amount of stiction you want the shock to have. The pressure holds a valve shut in the compression damping circuit so that you can dial in the amount of force needed to make the shock move. Adding pressure can also help compensate for a spring that is too light, be sure not to exceed the manufacturer's reccomendation for air pressure or drop below the minimum. SPV volume will affect how the shock ramps up, most people like their shock to move easily in the first several inches of its stroke and become stiffer in the ending part of the stroke so you don't bottom out. IH bikes have a progressive linkage which reduces the necessity of this adjustment but you can still tinker around with it to find what you prefer, again if you don't know what you like I reccomend ridding around the way it is for a month or so and then tinker around with it so you can find what you really like. These shocks take a lot of trial and error to figure out, they are so adjustable it can be difficult to figure what change made the differance if you change more than one thing at once. I reccomend making small changes and only one at a time. If you keep turning a knob and think you've found the sweet spot I'd make sure to turn it some more to be sure that additional adjustment bring you back out of the sweet spot. I made the mistake of running the air volume all the way out for almost a year on my bike because I thought it felt better than all the way in or just a couple turns out but I never experimented with anywhere in the middle, finally I figured out that about 4 turns from all the way in is the best for me. Just make sure to test the limits as well as everywhere in between before you think you've got it dialed in, chances are you could dial it a little better.