Dual suspension adjustment question

[wannabee]

I'm used to the old fashion, 10-speed, no shock, wide tired mountain bikes with comfortable seats of the 20th century. I couldn't break them. They were easy to repair or modify.
Well, welcome to the 21st century. Christmas came early this year. I picked up an inexpensive, dual suspension, radical invention that they call a mountain bike. Inexpensive, so if I don't like it, I didn't loose that much.
The front shock has no adjustment, which is fine for me. The middle has an adjustable spring, between the front and the rear. The spring has a label reading 150 pounds affixed to it.
Now comes the hard part. I weigh around 190. Did I get the wrong spring rating on the bike? And, how do I know if it is adjusted properly or not?

[heckler]

Going to need a whole lot more info than that! What you are reading is the spring weight. How that effects the suspension depends on how that is set p. My old coil spring heckler had a550 sping. I don't weigh quite that much.

Make, model of the bike, weight of rider... info man, info!

[wannabee]

Let's see.......it's says Mongoose MGX on the head badge. It has DXR on the side graphics. It also indicates 21 speeds. Steel (magnetic) frame.
Re-reading the info on the spring it says either 750 lbs/in or 150lbs/in, the first digit has been partially removed.
It looks to me that if you compress the spring, you get the harshest ride, decompress the spring, the more mellow the ride. So it looks like a trial and error process, depending on the terrain and how comfortable you want to be.

[Jisch]

For most FS bikes its all about the sag. Generally it should move about 25% of its stroke with your weight on it. Its a bit difficult to measure that on a coil over shock, but I've done it with a twist tie carefully wrapped around the inside of the shock. Push the tie up against the top of the slider, then carefully sit on the bike. The twist tie should move about 25% of the way. If it moves more than that, you need a stiffer spring, less you need a lighter spring.

On coil overs you will also be able to set the pre-load on by spinning the end stop. You can do this to get the best performance, but if you compress it too much the spring may bind up. On my shock I can only turn the end stop in 2 full turns.

On forks, you'll need to get a softer spring from the manufacturer. Changing springs can be a bit more difficult since they are on the inside.

<edit - I just looked up that bike. Don't take this the wrong way, but that's a very low end bike. Be careful. While it looks like a 'real' mountain bike, its not really comparable to more expensive bikes. It would be fine for riding around and doing light mountain biking, but if you start to get more aggressive with it, it will break. The rims are probably the weakest link in the chain - they will go out of round quickly... >

John

[wannabee]

Thanks for the info, Jisch.
Low end......you must have been watching.
The front rim was totally pretzelled. Only thing worth salvaging was the generic tire and tube. The rear has a small flat spot but it's not noticeable. It is true.
I did say that I wouldn't be out much if it doesn't work out. Replacement front rim came from 'stock' in the cellar, from another donor.
I don't do much heavy duty mountain biking, that is, like the stunts and racing that others do. I'd rather walk the toughest parts (wimp, I know) but I've had my fair share of smaller injuries. They all add up. Not getting any younger.
You confirmed my thoughts on how to adjust the spring, for ride, for stiffness. I'll see how it goes.
I like to start with basic rides. Then upgrade, eventually buying more expensive.
Why buy first class and take out a 5 year loan, only to find out that you don't like it.

[heckler]

5 yr loan? Don't know what you payed for the first bike but adding the price of components as they quickly self-destruct adds up really quickly. You can get quite a good deal on a used bike if you look for it. Even brand new, (and this number SEEMS insanely high), $1000 will buy you one heck of a reliable good riding bike. You can do very well for less. Heck, I picked up my Santa Cruz superlight- the whole bike, for $600!

But, as you say, investing a little in investigating a sport makes sense. It will suck you totally in though. There is no escape!

[wannabee]

Took your suggestion Jisch. Replaced the last remaining rim. Now I have a set of fairly good alloy set installed. The old rear is on its way to house bound mtber on a trainer. Never to see the light of day, again.
Heckler, seems as though I study everything to the ninth degree and have no fun playing.
I was all set to pack up and ride last weekend. But, low and behold, the bike doesn't fit my bike rack. Doh! It won't fit inside the car, and the roof is not available.
Luckily I have 2 trunk mount racks the same. I'll have to take out the torch and tig welder and re-make one of the racks, one of these days.
Right now, I'm patching tubes by the wood stove.
Later.....

[Jisch]

My vote is the seatpost clamp breaks next.

John

[radair]

My vote is the seatpost clamp breaks next.
...or the head tube. :o

[TheHare]

I vote, rider hernia!

wannabee, Spend a little more and you will give yourself a much better chance at enjoyment. The clunk, rattle, no brakes, feels like an anchor, no shifting, no 'functional' suspension, makes it tough to give mtb-ing a real try... If you are in the area of Springfield, MA, you are welcome to go for a ride with me, on one of my bikes...

[Slappy]

I was all set to pack up and ride last weekend. But, low and behold, the bike doesn't fit my bike rack. Doh! It won't fit inside the car, and the roof is not available.

How did you get it home in the first place?

[bikapelli]

Dude, We want you to enjoy mountain biking and the mgx isn't gonna make that happen. I've worked in shops and have seen first hand the difference a quality bicycle can make. Take a look at the specialized rockhopper, (I chose this bike for an example only, I'm not getting paid) at $520 it has front suspension and many quality, basic level components that blow the mgx out of the water. This bike is sold in many shops and when you buy it you have a bike shop to build it, all parts are upgradable, and a warranty from Specialized to help you to ensure your satisfaction. Bikes bought at most shops come with 30 day tune ups or some other kind of service to help you through the break in period that all new bikes go through. You don't need dual susp.(but it is nice), a good front susp. bike will beat out a not so good duelly any day. The 10 pound weight difference alone will help you ride to levels you might not have even touched yet. If you feel you need rear susp. you don't want to pay less than $1000 as a rule of thumb. Good luck and if this is to vague I'm sure myself or anyone else on this forum can help you out.

[wannabee]

I had written a short reply to all the things that you'all raised, BUT, the Nemba Forum munchkin wouldn't allow me to post it, even though vBulletin said that I could.
So, thanks for the ideas.
As of now, a newly purchased ride is out of the question. The replacement looked great on the back of the 'local' fire truck, too bad it isn't red in color.
Let's see if this post will make it through.