# Inspecting Suspension Fork on Used Bikes



## tjc4golf (Mar 5, 2010)

I've been riding my road bike for a few years. Please don't hate  

As such I have decent bike maintenance knowledge. But suspension forks are completely new to me. 

I'm looking to get my first mountain bike. Going to buy used to get more bang for buck. I am confident I can inspect everything but the suspension fork (and disc brakes but think I'm going to get something older without discs to save money).

Can anyone tell me how I figure out if a fork is good, serviceable or in need of replacement?


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## moefosho (Apr 30, 2013)

Taken from another thread:

Checking the stanchions is one of the most important things you can do when looking at any 2nd hand fork as far as external checks go, as any damage on those will usually mean a poorly maintained fork. Things to look for would be - chip/scratches on the surface as they will damage seals etc - vertical wear marks that have gone through the anodising (if aluminium stanchions) as this will indicate the fork has dirt etc inside the fork through failed seals. Excess oil on the stanchions is another indicator of bad seals.
Check that the steerer tube is long enough for your frame and inspect the lowers and make sure there are no cracks or other obvious structural defects, especially around the dropouts.
If you are looking at an air fork, making sure it will hold air is also something to check.
Asking the seller about maintenance done on the fork is also handy, but obviously you may have to take their word on whether servicing has been done.


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## tjc4golf (Mar 5, 2010)

Thanks, moefosho! Couple of quick follow up questions:

(1) Re:"check that the steerer tube is long enough for your frame." If it's mounted on frame (I'm aiming to buy a complete bike), is it safe to assume that steerer tube is long enough? If not, how do I tell?

(2) Re: "If you are looking at an air fork, making sure it will hold air is also something to check." How do I tell if it's an air fork (will google make/model but wondering if I can tell from visual inspection)? How do I tell if it holds air?


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## Glide the Clyde (Nov 12, 2009)

See below -- you already did. Stupid double post.


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## matadorCE (Jun 26, 2013)

tjc4golf said:


> Thanks, moefosho! Couple of quick follow up questions:
> 
> (1) Re:"check that the steerer tube is long enough for your frame." If it's mounted on frame (I'm aiming to buy a complete bike), is it safe to assume that steerer tube is long enough? If not, how do I tell?
> 
> (2) Re: "If you are looking at an air fork, making sure it will hold air is also something to check." How do I tell if it's an air fork (will google make/model but wondering if I can tell from visual inspection)? How do I tell if it holds air?


1) if it's on the bike already then it should be already be long enough, but look to see if it has spacers below the headset so that you have some room to play with if you need to adjust your stem/handlebar height

2) Air forks have an air valve covered by a top cap on the non-drive side. you unscrew the cap and you'll see a schrader valve. ask the seller if it leaks air and ask the seller to put some air in when you go test ride the bike.


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## Glide the Clyde (Nov 12, 2009)

If buying a complete bike, then yes the steerer will be long enough for that frame but may still be too short or long for you, depending if it has been cut down and there are no spacers above the headset. If it's too long with spacers, it can be cut down to fit you best. Angled stems and riser or flat bars can be used to compensate and get fit right.

An air fork will have an air fitting like a Schrader, usually at the top of the left fork leg. Dual air forks like the Reba will also have one for the negative chamber at the bottom of the left leg. If it's a fast enough leak, you'll likely hear it and the fork will say into its travel without weight on it. A slower leak needs more time to observe.

Also, check for bushing play in any used fork. The uppers and lower should have no lateral play at all. The fit of upper to lower should be snug throughout the range of travel.

Unless the owner has a receipt for a recent service, I recommend taking it in for servicing or doing it yourself so that internals and stanchions can be inspected as well.


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## tjc4golf (Mar 5, 2010)

Awesome, just watched a few youtubes of air pressure forks. 

Can I check air pressure without high pressure shock pump? Realize this is not a long term solution but wondering if I can use my Joe Blow just to get a little air in there to see if it's leaking when I check a bike out. I'm poor and not sure I want to invest in a shock pump just to test out a few bikes on craigslist.


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## SimpleJon (Mar 28, 2011)

On most air forks the air valve is recessed so tire pump heads won't fit in - also unless you have one of those ultra high pressure track pumps or are super light they generally don't go up to the required pressure. Tire pumps are designed as higher volume lower pressure than a shock pump.
To be honest check the seals for dirt leaking oil and damage to the stanchion around the seal but this can be a lottery - there may be damage to the low friction coating that you can't see but I would buy a seal kit and change them out on any second hand fork before riding it a lot- gives you a chance to make sure that you have clean fluid / oil, good seals and do a decent inspection of the thing. Above all don't overpay for them - make sure you factor all this in when you agree the price. Also make sure that the lowers are not damaged or twisted especially with lightweight XC forks like SIDS or similar


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## AndrwSwitch (Nov 8, 2007)

Unless the bike's been sitting for a really long time, an air fork will have pressure already from whenever it was last filled. So if you sit on the bike and it doesn't sag most of the way into its travel, it's probably alright.

Air forks don't usually have a lot of volume in the air spring chamber. So a pump's not a great way to find out what the pressure was before you put it on - attaching it will cause some pressure drop.

If the fork doesn't have any air, the seller may have a pump. These come with many retail forks and most owners of air forks or shocks buy one if they didn't, like with many OEMs. So you could air up the fork and listen, though when I had a problem with the valves in my previous fork, I couldn't hear the air escaping and it took a half hour or an hour to lose pressure - long enough to wonder if I might be going crazy, too short to get through a ride.

A major thing to check for is play. Forks shouldn't have any free play. Squeeze the front brake and try to rock the bike. The problem is that there's often play in disc brakes and in poorly adjusted headsets. But it's bad. That's what finally put the nail in the coffin for my old one.


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## tjc4golf (Mar 5, 2010)

Thanks for all the great advice. Used it to score a new bike 

Had to make a few compromises but think I did ok for my budget (spent $450) and got something I can use to get my feet wet and ride til the wheels fall off.

As far as fork goes it's a Marzocchi. Supposedly a model 44 LR Switch-TA Air. Have an email out to Marzocchi looking for confirmation based on serial number. Stanchions look absolutely brand new. Played around with it and everything seems ok. Rock Shox Sid in back seems good too. Also spoke on phone with LBS guy who has worked on bike (though he has never serviced suspension) and he didn't have any concerns.

Thanks again to all for the great advice :thumbsup:


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## moefosho (Apr 30, 2013)

Cool man. Those are pretty cool older bikes. Carbon frame right? I have never ridden a softtail bike that that before. 
What components are on it?


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## tjc4golf (Mar 5, 2010)

Yup, it's carbon. Was hoping it'd come in a little lighter. Right at 28 lbs on my scale. Think it might be the wheelset.

Below is the inventory of parts I did.

Definitely will be switching to a shorter stem to tighten up cockpit a little (thinking 70mm) and going tubeless.

Might do something about the brakes. Couldn't find much info on the Avid 20 brakes (not my pic but you can see them here). If they're crap I might swap with better v brakes (hopefully I can find some top quality used ones cheap now that everyone has gone disc). Or if I can find a cheap front wheel (current hub not disc compatible) and cheap used BB7 on my local craigslist going disc up front (sadly no possibility of disc in rear due to frame).

Frame: 2001 STP 300
Fork: Marzocchi 44 LR Switch-TA Air
Rear Suspension: Rock Shox Sid
Shifters: Shimano Deore XT
Brake Levers: Shimano Deore XT
Front Derailleur: Shimano Deore XT
Rear Derailleur: Shimano XTR
Crankset: Shimano Alivio (22t - 41t)
Casette Shimano ??? (13t-32t)
Front Brake: Avid 20 (v brakes - don't say "single digit" ???)
Rear Brake: Avid 20 (v brakes - don't say "single digit" ???)
Front Hub: ??? (not disc compatible)
Front Rim: Bontrager AT 550
Front Tire: Maxxis Minion DHf Exo 26 x 2.5
Rear Hub: Shimano Parallax FH-MC18
Rear Rim: Weinmann ZAC 19
Rear Tire: Speacialized The Captain Control 26 x 2.0
Stem: Race Face Deus XC 105mm
Handlebars: Easton Monkey Lite SL 
Grips: Azanza Lizard Skins
Headset: Ritchey (model ???)
Seatpost: Easton Havoc
Saddle: Selle Italia Trans Am
Pedals: ???


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## Harold (Dec 23, 2003)

I'll tell you one thing - that big DH tire on the front isn't doing you any favors for bike weight. You can still run a wider one on front for more turning traction and a little more cush, but I'd choose a lighter tire for XC riding (that's what this bike is, anyway).

Also, if the brake pads look like they have some age on them, I'd get fresh ones on. Probably count on new brake/shift cables, too.

Another thing worth noting - that crankset doesn't belong on that bike. It was something cheap someone threw on there, probably because the old one broke or wore out. Alivio level will be flexy and heavy. You could find a used 9spd crankset on the used market that's better quality than that for a reasonable price. I sold an LX Hollowtech II (newer than your bike, but still used) recently for around $25. It's just a step below XT, and cranksets are a very low bang for the buck item, anyway.

There could be extra weight in the cassette, too. If the previous owner threw something cheap on it at some point, just to get a functional cassette installed. I wouldn't bother replacing that until it's worn out.

Otherwise, it's a pretty good bike. The wheelset might be heavier than necessary, true. Because it's for a non-disc bike, you might have luck finding something on the used market for a good price. Just depends on the budget you have to work with. That's not critical, though. My FS is about 11yrs old, is aluminum, and weighs a hair over that, depending on the rubber I have installed at the time.


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## tjc4golf (Mar 5, 2010)

Good call on tire. Didn't realize it was so heavy. One added Panaracer Fire XC Pro to shopping list (based on # of reviews and review score looks like I can't go wrong with that). Saves 2/3 lb rotational weight. Add Stan's tubless and hopefully I can drop a full lb of rotational weight.

Shoping list now looks like this:


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## Berkley (May 21, 2007)

That's a decent fork, but it doesn't belong on that bike. Not in the 140mm travel setting at least. The stock fork only had 80mm of travel.

2001 Trek STP 300 - BikePedia


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## Harold (Dec 23, 2003)

Going from a 105mm stem to 75mm is a huge change. Are you sure you need to do that for fit? The geometry of that bike is a little older, and will be better suited to longer stems, FWIW.

Also, the FireXC Pro is kindof a 'meh' tire. I frequently will ask a shop for their tire recommendations when I'm visiting a new place. If they tell me the FireXC is a good tire for local conditions, I know that either they don't ride mtb's and don't know otherwise, or they're only telling me the tire they sell the most of because it's cheap (possibly both).

Just so you're aware, if you've never done Stan's before, you'd be better off starting with a kit. There are a ton of different ways you can 'ghetto' or 'semi-ghetto' a tubeless setup, but sometimes those take a lot of work and may never work well. Particularly with cheap tires. The kit eliminates some of that hassle. I set up tubeless for the first time using some tires I got cheap from a local Performance store on sale. It was more of a hassle than it was worth considering how poorly they held air, and I had UST rims so I didn't need to seal the rims, too.

Tubeless-ready tires work WORLDS better. IMO, if you want to save money with cheap tires, just use tubes. If you want the performance benefits of tubeless, don't skimp on rubber.


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## tjc4golf (Mar 5, 2010)

Berkley said:


> That's a decent fork, but it doesn't belong on that bike. Not in the 140mm travel setting at least. The stock fork only had 80mm of travel.
> 
> 2001 Trek STP 300 - BikePedia


Travel is adjustable on the fork so I can turn it down a bit. What do I sacrifice with the longer travel fork? Is it heavier? Anyone want to trade for a like new Marzocchi?



NateHawk said:


> Going from a 105mm stem to 75mm is a huge change. Are you sure you need to do that for fit? The geometry of that bike is a little older, and will be better suited to longer stems, FWIW.


No idea if 75mm is right. 105 feels a little long and stems in the 70ish range seem to be hot on the forums. Maybe I'll try something in the middle...



NateHawk said:


> Just so you're aware, if you've never done Stan's before, you'd be better off starting with a kit. There are a ton of different ways you can 'ghetto' or 'semi-ghetto' a tubeless setup, but sometimes those take a lot of work and may never work well. Particularly with cheap tires. The kit eliminates some of that hassle. I set up tubeless for the first time using some tires I got cheap from a local Performance store on sale. It was more of a hassle than it was worth considering how poorly they held air, and I had UST rims so I didn't need to seal the rims, too.


Yeah, after watching some youtubes was going to do a ghetto version with just stan's tape, gorilla tape or the old tubes. Most seem to have been sucessful with this but may rethink based on your comments.



NateHawk said:


> Tubeless-ready tires work WORLDS better. IMO, if you want to save money with cheap tires, just use tubes. If you want the performance benefits of tubeless, don't skimp on rubber.


See you aren't a huge fan of the panaracer but I'm not looking to spend big bucks and there's a UST version on my local CL I could probably pick up for $25-30 (asking $35)


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## AndrwSwitch (Nov 8, 2007)

Cool bike.

With regard to the brakes - V-brakes are pretty simple. Now and then, someone screws them up, but I'd be surprised if you can find anything that's really better than the Avids you have on there. At least, unless something's worn out.

The brake pads are a good point. So if you don't feel like you're getting good braking, start there. I like Kool Stop Salmon, and I like the cartridge pad/holder approach.

New cables and housings are something else to look at. That applies to shifting too.

Check out parktool.com for great articles on maintenance. Actually, good maintenance is about the best thing going for getting the best performance out of your bike.


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## Harold (Dec 23, 2003)

Deals can be had on the good stuff if you look hard. 26er tires are not popular so some shops may be looking to unload excess stock. I found some 2.4 tubeless ready continental x-king protections for $35/ea ($65 tires) recently just because they had old packaging.

When it comes to stems, you generally don't want to move more than 5-10mm at a time. You may try a 95-100mm stem but with a little more rise than you have. There are several parts swap threads throughout the forums and different size stems are common. May not cost you a dime.

As for the fork, it isn't so much the amount of travel that messes things up but the axle to fork crown (just beneath the bottom cup of the headset) length. The fork on that bike is significantly longer than stock. This changes the geometry of the bike, and not always for the better. Depending on the bike, it can void the warranty. On this one, it's not like the warranty is a concern, but the reason why it may void a warranty should be. That longer axle to crown length puts more strain on the head tube of the frame. Frames need to be designed to handle a certain fork length. At the time this bike was new, 140mm forks were rare and for downhill bikes, so it certainly would not have been designed around that fork length. You would probably do well to keep your eyes peeled for a 80-100mm fork on the used market. Selling the one you have should make up all or most of that cost.


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## Berkley (May 21, 2007)

tjc4golf said:


> Travel is adjustable on the fork so I can turn it down a bit. What do I sacrifice with the longer travel fork? Is it heavier? Anyone want to trade for a like new Marzocchi?


It raises the bottom bracket and slacks out the front end a little bit. In extreme cases, the added stress *could* cause failure.

It will probably ride alright around 100-110mm, but much more than that and handling gets wonky.


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## tjc4golf (Mar 5, 2010)

*The saga continues...*

Scored a Castellano Fango yesterday. Has a proper 100mm fork. Really like this bike and think it will serve me well. Photo and details below.

Hopefully I can now get my money back out of the Trek.

Thanks again to all that helped educate me!



Frame	Fango 18"
Fork	2002 Manitou Black Elite
Rear Suspension	Fango ???
Shifters	Shimano Deore LX
Brake Levers	Avid SL
Front Derailleur	Shimano Deore XT
Rear Derailleur	Shimano Deore XT
Crankset	Shimano XTR
Casette	???
Front Brake	Avid Single Digit SL
Rear Brake	Avid Single Digit SL
Front Hub	Bontrager ???
Front Rim	Bontrager Race Tubeless
Front Tire	Bontrager Revolt Super X 2.0
Rear Hub	Bontrager ???
Rear Rim	Bontrager Race Tubeless
Rear Tire	Bontrager Revolt Super X 2.0
Stem	Thompson
Handlebars	Race Face NEXT Carbon
Grips	Yeti
Headset	Bontrager
Seatpost	Thompson
Saddle	Sepecialized
Pedals	Unknown Clip Ins (ordered wellgo mg1)


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## Harold (Dec 23, 2003)

Considering what you now have, it may be worth it to take the best parts between the two bikes and put them into one bike. Then sell all the other parts separately.


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## Glide the Clyde (Nov 12, 2009)

Hmmm, soft tails in abundance where you live?


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## tjc4golf (Mar 5, 2010)

NateHawk said:


> Considering what you now have, it may be worth it to take the best parts between the two bikes and put them into one bike. Then sell all the other parts separately.


I thought about this but it seems any swaps would only move me up one groupset level (i.e. Shifters LX => XT and rear derailler XT => XTR) on the Fango frame (that's the frame I'm going to keep). Also, while the Trek components seem to be in pretty good shape, the Fango components seem to be almost new.

Along those lines, one idea I have been entertaining is getting a Manitou SX-e 100mm fork for $40 (or less... $40 is asking price on CL) and putting that on Trek before I sell it. That way Trek buyer is getting a fork that better fits the frame and would allow me to sell the Marzocchi fork separately. One thing stopping me from doing this is uncertainty regarding what the Marzocchi would be worth on its own. Tried looking on eBay for completed listings but couldn't find any comprables. So I'm not sure if this would be worth the extra effort. Any thoughts?



Glide the Clyde said:


> Hmmm, soft tails in abundance where you live?


Haha. Yeah, maybe. I wasn't actively seeking a softail. It just so happened that the only bikes I could find in right size with decent components that fit my budget happened to be softails.


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## AndrwSwitch (Nov 8, 2007)

In your shoes, I wouldn't buy a fork for a bike I was trying to sell. If you don't think you can sell it as a package, part it.


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