cruiserandmax

I'd like to replace the bearings in the headset on the Trek 1400 I am re-building. The fork feels smooth enough when twisting- but there is enough noise combined with the fact I have no idea how long since last overhaul that I think it's just prudent to do now. Not having opened them up yet- will I be looking at caged or loose bearings? And since it's an aluminum frame should I be putting aluminum bearings in when replacing? Should I just take them out to figure out their dimensions for replacing? I think this is a 1990 frame..

FBinNY 

I assume you're speaking of replacing the BALLS.

If so, it's pretty simple. You need to match the diameter, typically 3/16" though may be different.

They are always steel, regardless of the frame, which they don't touch anyway.

If you prefer a retainer, it's brand and model specific. However most experienced mechanics prefer loose balls, and many believe that headset life is better that way.

Determine the size, then shop for grade 25 balls. That's much better than needed, but a super cheap luxury, so why skimp.

cruiserandmax

Thanks for the loose balls & grade 25 tip- if they are in some kind of cage when I open it I will aim to replace with the same count of loose balls

veganbikes

Not really sure what you will be looking at since I haven't looked inside and if you haven't either nobody knows. If you want to stick with the headset and just use loose balls do as FBinNY suggested get some nice Grade 25 balls in the size needed and use some good grease (Phil Wood is my go to). If you want to swap things out and potentially upgrade to sealed cartridge bearings (some people like loose balls more) Velo Orange has a nice polished or black sealed bearing 1" headset that would likely be a good fit for under $60 or you can get spendy and get yourself a Chris King Gripnut (which is generally what I run on my threaded headset bikes) Of course with the new headset route you would need tools in which to remove the old one or just pay a shop to install.

From what I recall the 1400 is 105 equipped and was for a while MUSA so potentially a decent bike nothing super fancy but certainly a good solid workhorse. So not a terrible bike to put a little money in especially if you like it.

FBinNY 

It never hurts to upgrade a bike you really like.

That said, I consider headsets the worst place to spend good money on. There are plenty of possible upgrades that offer more bang for the buck.

veganbikes

Yeah probably in some cases or at least up a to point but I do like sealed bearings. Obviously Chris King headsets are just bling to be bling but they do last a long time and look good. But yeah if it was between a CK headset and a better derailleur or brakes or something like that the CK headset would lose.

dedhed

With older threaded headsets, stack height unknown makes it hard to recommend a particular item

GamblerGORD53

Where are these magic LBS places that offer diff grade bearings?? LOL
I had a CK Grip nut. Total gaRbaGe POS. Not even the LBS could figure it out.
I wouldn't toss the caged bearing set either.
I tried the 2 best brands of sealed sets on my 1 1/8" threaded tour bike. Didn't like the feel and neither could I feel how to adjust them.
Been NOS 1 cage and loose ball ever since.

And besides that, after a 1000 miles on my NEW Simcoe roadster, I took it apart to find it had half the grease it should of had. Buggers.
The 5/32" balls lost the shine and so are shot. Lucky I have a headset in my stash, with cages the same size.

maddog34

Chances are that the grease has hardened and that hard grease is the "noise"... a drip or three of penetrating oil will loosen the old grease.

You will need more bearing balls than a "caged bearing" has in it... the Ball size is most likely 5/32" not 3/16" as someone else said... remove and inspect each ball for pitting... also inspect the Races for pitting. i use a magnifying glass or my fingernails to check for pits in the bearing balls. Any roughness will make the steering notchy when set to the correct "No drag, no slop" tension. use "as many balls as i can fit MINUS ONE or Even Two" as a rule of how many to use.

Caged bearings are the industry standard.. getting 20 tiny bearings to stay put as you slide the fork in place is an exercise in frustration and a great way to lose a few. The runaways have a talent for finding the perfect hiding spot.. uncanny. Spooky! Slip the cage bearing assy. in and easily slip the fork in.. Done.

Setting Proper Headset tension requires at least one "thin Wrench" of a 32mm size, some may measure 36, but MOST are 32mm.. MEASURE to know for sure... an adjustable wrench of large enough opening can be used on the top nut. It WILL take more than one attempt to get the setting correct... no slop, no roughness... the bars should fall to the side without input from you, if the bike is level and lifted slightly off the floor, with no control cables on the handlebars.... The bearing tension tightens when you tighten the top nut, too.....
Grabbing the topnut or cone nut with pliers will remind you of your mistake every time you look at your Bike.

Trek !400s are cool bikes... enjoy!

RB1-luvr

someone tell me if I'm wrong here, but if he replaces caged bearings with loose, he will be putting in more balls than the cages had, no?

bikemig 

It's a pain to install loose ball bearings but not super hard. Another possibility is to run loose bearings on the bottom and a cage on the top. The top races seldom fail but the bottom can and does get damaged from hitting bumps and the like over time. Old Peugeots came like that from the factory (cage on top, loose bearings on the bottom). Maybe they knew what they were doing.

SurferRosa

Yes, that's usually true. If he doesn't know the correct count for loose balls, he can fill it and then remove one or two in each race/cup.

Hondo6

Particularly true when it comes to VO headsets, which tend to run higher in stack height (VO 1" threaded are generally >40mm stack height, as I recall) than many.

dedhed

My go to is $30 Tange Levin at <35mm and lots of options.

dedhed

Fill the race with grease, stick balls in the grease, they stay put. Still have issues, do lower race first with bike upside down.

HillRider

You do have your problems with headsets, don't you. As to various grade bearing balls, no, the LBS is most likely to only stock Grade 25 but you can get the entire spectrum of grades from any industrial supply house like McMaster-Carr and Grainger.

The problem with replacing threaded headsets is matching OEM stack height or finding a lower stack height model. Those bonded Treks came with fairly short stack height headsets and the steerer was factory cut to just match so there aren't a lot options. I had a '92 1420 so I had to deal with the same problem.

Replacing individual loose balls can be tedious but running a good bead of grease in the cup first to glue them in place and using big tweezers to place them works well. Not a fun job but you don't have to do it often.

SurferRosa

I've seen folks do this on YouTube, but I don't understand the reasoning, even with tiny freewheel bearings. Maybe their fingers are extra, extra large or it's a dexterity issue. It's not surgery.

smd4

I know, right? Tweezers??

maddog34

for the record.. the last bike i tore down that had loose balls in the headset was an old Chimo straight out of the 70's... about one year ago. The balls dropped out all over the floor.

I RARELY run across a bike with a loose ball Headset.. most are older ones from the 60's 70's and they don't have any parts that are salvageable. "sort and scrap" only.

How many tiny balls do you add when converting to "Loose Balls"? 3? 4? to a system known to last longer than the rest of the bike by DECADES if it isn't exposed to constant Rain and Pressure Washing...

i'm not attacking anyone, just adding my Real World, Daily, experience.

funniest odd habit i've run into? NO Grease and Larger balls in BMX wheel hubs.. Seriously! NO Grease... and Balls that RUIN the cones within minutes.... loose jam nuts were a first clue to this destructive idea... thankfully, that goofy trend ended a few years back... sigh.

What baffles me is the fascination with "sealed Cartridge" bearings in headsets...the balls are even smaller and the things fail about once a year in hard use applications Like CX and MTB. The Force becomes a SIDE LOAD on bearings that Are NOT designed to handle much of a side load.... my CX racer needed at least one new Cartridge every 6 months or less.

John Valuk

I think that you might be thinking of the Levin CDS - and I agree, they can be a great solution for replacing a low-stack-height headset.

That's what I used on my 1995 Trek 730 Multitrack, when replacing the original Tange Seiki Passage headset.

cyccommute 

Unless someone replaced the bearings, they are likely caged. Most all OEM headsets from that era are. You can replace them with caged or with loose. If you replace with loose, you will have to add bearings. As stated above, put grease in the cup and put in bearings one at a time. The number of bearings needed will be enough to fill the cup but it will look like you have room for one more but you won’t be able to fit it in correctly. Make sure the bearings are pushed into the cup firmly.

cyccommute 

Gotta disagree. Headsets take more a beating than any of the other bearings on the bike. Wheel bearings spread the load and, more importantly, the impacts over 2 bearing surfaces. Crank bearings don’t experience that much load. For the headset, the load and impact are concentrated in the lower headset bearing, specifically at the back of the cup. It’s no wonder that headsets dimple and that threaded headsets loosen.

A headset like the Chris King is practically indestructible. The bearing takes the load better without deforming and they need little to no maintenance. I have a King headset that was installed in 2000 (yes, I keep records) and it is still going strong. I have another King headset that was used when it was installed in 2006, has been transferred to a second bike, has in excess of 26,000 miles on it, and has been problem free for that entire time. More importantly, it has be unmaintained that whole time. I consider it one of the best upgrades I’ve ever done on all my bikes.

cyccommute 

What baffles me is what you are doing to ruin a cartridge bearing in that short of a time. I’m a big guy and I ride hard. I’ve never had a cartridge bearing fail in a headset in 20+ years of use of them in my mountain bikes. All 10 of my bikes have cartridge bearing headsets and most of them are well over 10 years old including in my 3 mountain bikes. I’ve never even serviced any one of them…including the one that is actually over 20 years old…much less replaced the bearing. I compare that to what I used to have to do with loose bearing headsets in the previous 20 years of riding. Headsets in the early mountain biking were almost replaced after each ride. One of my first specialized tool purchases was the headset press, headset cup removal tool, and crown setter tool that I still have today. It got a whole lot of use from the early 90s to around 2000 because of the indexed steering that comes from using loose bearing headsets.

FBinNY 

No problem regarding disagreement. I offered an opinion with the understanding that there's plenty of room for various opinions here. However, considering the costs and life expectancies of various options, I submit that one could replace many headsets, ending up with equal total life and change in their pocket.

But that's not the point here, which is to clarify how headsets fail.

Your statements re impact and dimples imply a causal relationship. That would be true IF the dimples were caused by impacts (brinelling). However, the dimples we see in worn headsets are not impact related at all, They're caused by vibration and lubrication failure. The correct term for this is fretting, aka false brinelling, and there's plenty of literature on this subject. (search fretting bearing failure) Headsets fail because there's inadequate movement, so lubrication at the contact points doesn't get replaced and vibration causes abrasion at the dry ball/race interface.

If one is truly focused on headset life, one might bet far and away the most bang for the buck by using any decent quality headset and lubrication with a grease known for it's anti-fretting properties.

Kontact

I think recommending that OP go with looseball is a mistake. He has clearly never done this before and now he is being asked to guess the number of balls to insert, or use judgement he doesn't have any experience to inform.

cruiserandmax , re-use the bearing retainers. The balls pop in and out. Pop the old out, clean the retainer, buy new ones and pop those back in. Pay attention to the way the retainer sits in the cups - people get them upside down sometimes.