Mountain Biking - is it..

Possible to get a 100mm fork for my Trek 3900?
it came with a 80mm, but im wondering for when i start looking to upgrade stuff when I get my J-O-B lol.

yes a 100 will work, I've used a 100 on my Trek 4300 in the past. The frame will only support 100mm and nothing bigger.

yea im looking to get a 100mm too for my 3900.

The frame will only support 100mm and nothing bigger.

Not true, you need to look at the total length of the fork, crown to leg. On the right track though RICO. I changed to a 130mm from a 100mm and the overall length difference was negligible.

You can do it, but you need to check the A-C height.

You all are speaking above my level lol!
So like what forks will work?
Cause 80mm isnt enough for me. if i hit a big enough root or dip i bottom out.
--- Im only 165 lbs so dont call me fat LOL.


Now another question while I have everyones attention.
Is it normal to have some play in the neck area?
Like when i hit my front brakes and move the bike forward i can feel the fork wiggle inside the neck.

I made sure the bolt was tightened all the way, and it still has some play.

Noooo. That's not good. I'd get that checked. Hints at a headset issue. Should be warrantied.

As for the fork, when you check the specs on a website the measurement you need should be listed as "Axle to Crown height" or something resembling. Find out the A2C on your stock fork, and see that it matches. If you're buying from a LBS, even better. Tell the employee what you have and ask them to check the A2C. You can also ask for a list of forks that will work if he finds you the A2C

http://www.srsuntour-cycling.com/SID=sib6f0425179509505308d3eddf3e6d7/index.php?screen=sh.detail&tnid=1641
i believe thats the fork i currently have.

just mines blue.

ever since i got the bike its had that tad bit of wiggle in it, So, im guessing i should take it in to get looked at?

Yes, defenitely take it in.

A2C is not listed, odd.

EDIT: On second thought, email them here: service@usulcorp.com
Ask for the A2C of that fork, link to it if nessecary. If they have any type of customer service they should tell you no problem.

any one know about the adjustments on that fork?

on the adjustment knob theres a little clear area with a yellow bar in it with red lines.
when i turn the knob, the yellow bar does not move.
I figured that if i turn the knob the yellow bar should go up and down...
IDK..

Ask about that too when you bring the bike in for the clunking, if no one else weighs in.

Your LBS gives you a warranty for a reason. I was there every day for two weeks after I got my last bike.

Its such a pain to go the whole way across town though LOL>

Set a day aside and make it a ride.

You should be checking the bolts' torque every once in a while. Especially when it is a new bike. I check the bb cups, crank bolts, headset, etc. every month-2 months depending on if I have time or feel like it. I did ruin a bb because the cups worked loose. I didn't have the right size crank puller so I just forgot about it until I burned the bb out. I also had the headset looseness problem. Unfortunately I learned from experience that a loose headset can ovalize the headset. Also, it may just be the fork stanchions having play between the lowers. Also, if you had a better fork it probably wont bottom out on you. There isn't much adjustability in a lower-end fork. Upgrades are wonderful!

Also, if you had a better fork it probably wont bottom out on you. There isn't much adjustability in a lower-end fork. Upgrades are wonderful!

Agreed. The fork bottoming out is not an indicator you need more travel, but more adjustability within the travel you already have. That said, I would still make the jump up to 100mm.

Its such a pain to go the whole way across town though LOL>

EGREGIOUS

Anyway, to state what already has, as long as the leg length is similar to your 80mm fork, you should have no problems.

does anyone know what the height is for an 08 trek 3900?

19.5 frame

does anyone know what the height is for an 08 trek 3900?

19.5 frame

The length of the fork? The standover height? For the length of the fork: take a tape-measure and start from the bottom of your headset, where the fork goes through the frame, and measure to the dropouts on your fork, where the axle passes through the fork. This should give you a fairly decent measurement. Might want to take the wheel off so as you can go straight down the center of the fork in your measurement, otherwise you get a little longer measurement due to the angle. Maybe also take the measurement from the top of one side of the crown to the bottom of the leg. I'm not sure what the companies base their measurements on. Anybody?

trying to find the so called A-C height thingy.
the more i think about my fox the more it pisses me off and the more i hate it lol

The AC height is an acronym for Axle to Crown height. It's basically outlined in what I posted in #18. You really only need a tape measure. It's not something where they have to be exactly the same, maybe within 40mm? Usually it's better to go longer than shorter, for me at least. I like a more stable steer, while going shorter would make the steering easier to turn basically. Kind of like raking out the front of a motorcycle really far and slapping apehangers on it. Those guys can't turn for ****.

Does anyone have any ideas as to which fork i should start looking into?
I have a 3900, so I wont be doing any Dirt Jumping or that crazy downhill stuff.
Just some normal mountain bike trails, and maybe some XC type stuff.


preferably 100mm.

i measured from the to of the fork, where it goes into the headtube thing, to the bottom,
its about 17 inches.

Anyone have any ideas on a half decent fork that actually works? lol

Check out Marz. Find something close to a 17" A2C. Maybe a RS Dart?

What is your budget? Sorry if you posted it already.

Ehh, I don't have a set budget.
Cheaper the better.

I mean, Im not paying 250 for a fork, as its more than half the price of the bike.
Ill go maybe no higher than 120-150ish.


(anyone have any good used ones? LOL)

what would i be classified as?
Cross country or all mountain.

Id imagine XC, as thats what type of fork the bike came with even though its cheap as crap.


BTW took my bike into the shop today, well, my dad did, and they fixed my wiggle problem. =)

It's somewhat XC. XC when used on a low-end fork means "light trail or road", basically. Too heavy to race with, not set up to jump or drop with.

Well, Ive been offered a chance to start training with racers and members of SORBA, One of my teachers is a member and asked if I would like to start doing some racing.
So, I'll be upgrading quite a bit this summer..

--- geeze, I need a job.....
Just need some help on the forks because BMX bikes didn't have suspension, I'm new to all this, and I'm openly admitting, I don't know much about suspension forks, except that mine sucks.

Pretty much anything over $100 is going to be better than the one you have now. However, this is not saying much. My fork cost about 100-200 more than my bike originally did, but it's worth the money. If there is one place to spend money on a bike it's the suspension. Then the brakes. In my opinion, that is.

Ride the hell out of the Trek, work hard, get a decent job. Build up a real XC bike. By "real" I mean a weight-weenie, quasi-roadie special. Good luck.

I'm not a moron crankshaft, i know what you mean by real.
You can quit treating me like a little kid any day now.
Thanks for the input pyro.
Starting to like some of the Marz. forks, but they don't list prices.. that scares me.

Marz's website is international, that's why.

isn't to hard to list US prices, Euro Prices, and what ever else there is.

It can be. As far as I know their site is updated only when the models change.

Which forks are you interested in?

I don't know its hard to decide lol

http://www.marzocchi.com/Template/listSPAForksMTB.asp?IDFolder=113&LN=UK&Sito=mtb&IDIntendedUse=2460&IDAnno=55897

I need prices to determine LOL.

Actually on jensonusa the rock shox darts are nicely priced =)

If you contact their support, they may be able to help you. http://www.marzocchi.com/template/detailSPACompany.asp?IDFolder=109&IDOggetto=1849&LN=UK

Darts work alright. Make sure they have V-brake mounts, though.

http://www.jensonusa.com/store/product/FK405A01-Rock+Shox+Dart+3+Fork+07.aspx

dart 3 seems to be fairly good. the reviews show a person upgrading from my current fork, and they say its loads better. Yea, they have V-brake mounts, but Disk brakes is in my future.
I think, this fork will be one of the contenders, problem is, I don't know if it's the right lengths.
any other fork ideas out there?
My fork now is like a freaking pogo stick. I could probably take it off and jump around on it.

You know you need new hubs for disc brakes, right?

Well, the dart isn't much better than what you have on there, but it is an improvement.

Yea, I got that all somewhat figured out.

Well, the dart isn't much better than what you have on there, but it is an improvement.

Thats not good enough then.
Offer some ideas man, still trying to learn all this suspension crap lol.

I'd search ebay or craigslist for a used fork that is in decent shape or save up some for a Marzocchi MX Pro.

Thats not good enough then.
Offer some ideas man, still trying to learn all this suspension crap lol.

Adjust your budget upwards if you want improvement. What is wrong with the performance of your current fork? Why not ride it til it breaks? There are other upgrades to consider on your 3900...

My current fork bottoms out to easily, and its like riding with a pogo stick as your fork. The adjustments suck bad on it also.

currently the two i have on my list is the dart-3 or the Marz. MZ Supercomp
Since they are 08's there hardly any good reviews on them.

any input

Rock Shox Totem. It will work, trust me. Seriously though, if you're not willing to spend the cash don't expect anything above and beyond. If you really want an upgrade, just put up with the fork you have now and wait until you have enough capital amassed. It's really not that bad riding a pogo stick. It will make you a better rider because you will have to fight harder to stay on track. You will find your flow better, young grasshopper. If you think you're going to be serious about staying with mountain biking then the investment will be worth it. It is like night and day when you upgrade enough. I went from an rst gila to a rockshox revelation air-sprung and I almost crapped myself the first time I rode it.

yea... 1k for a fork.
Ill by a 6 series trek or something before i get that lol

Marzocchi Super Monster.

ok, please don't get stupid on me, I know for a fact, that wouldn't work on my bike,
Im just trying to get some ideas, as my birthday is comming up.
Since I really don't know much about forks, besides that mines sucks and I hate it, im looking for help.

I can probably stretch my budget a bit.
I can always go half-ers with my parents.