how do you change the bearings on a 20mm front hub??

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how do you change the bearings on a 20mm front hub??
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flag johaines
Posted: Jun 10, 2008 at 12:59 Quote
peedboy wrote:
I have changed the bearings in a hub much like the one you have shown in the picture, twice actually, and it isn't that hard. The bearings are pressed in so there isn't anything to unscrew or unbolt except for the front brake rotor.
Below are the steps to remove and install the new bearings:
1) With the front wheel off the bike, remove the front brake rotor.
2) Remove the dust caps/spacers from both sides of the hub (These are slightly pressed in and you should be able to walk these out by hand or using the end of you axle)
3) You can now see your old bearings and since you are more than likely going to mess them up pretty good getting them out it is a good time to make sure your new bearings match the old ones.
4) This is the fun part, getting the old bearings out, what you want to do is press each bearing out from the opposite side of the hub (when I say press I am assuming you will be using a hammer and some kind of punch, that is what I used) The spacer between the two bearings makes getting a punch on the first bearing kind of hard so what I do is use the front axle again to walk the first bearing out a little, just enough to allow the spacer to move, then you can push the spacer off-center inside the hub and get a punch on one side of the bearing and just work your way around the bearing in a circular pattern with the punch and hammer until the bearing pops out. Please note that you will want the put the hub against something that won't damage it while you are using a hammer and punch to press out the bearing like a piece of wood and you shouldn't have beat on the bearing too hard to get it out. Once you get the first bearing out it is easy sailing as the spacer will came out with the first bearing and you have easy access with a large punch for the second bearing.
5) Time to put the new bearings in. Press in one of the new bearings in one side of the hub making sure not to press against the inner bearing race as this will damage your new bearing (only press against the outer race). Flip the wheel over, install the spacer and repeat the same procedure for installing the second bearing.
6) Reinstall your dust caps/spacers.
7) Bolt on your front brake rotor, mount the wheel back on your bike and go ride!


Sounds great!! but are you sure its possible to take of the spacers by hand? They seamed loose but when i tried to remove them they would not get of. I uset only my hands:P
what do you mean with walk them of?? excuse my english;P
flag ironhorserocks
Posted: Jun 10, 2008 at 13:01 Quote
heres an idea, take it to the shop!! i dont mean to say that you cant do it, but they are trained to do that stuff, it might cost you in labor,but its worth it
flag johaines
Posted: Jun 10, 2008 at 13:06 Quote
ironhorserocks wrote:
heres an idea, take it to the shop!! i dont mean to say that you cant do it, but they are trained to do that stuff, it might cost you in labor,but its worth it
yeah I will but I'm just curious:P
flag peedboy
Posted: Jun 10, 2008 at 15:47 Quote
Regarding "walking" the dust caps off: Just put the front axle in the the cap just far enough so that it is only in the cap and apply some sideways pressure in several different directions while slightly pulling outwards. Those caps are only pressed like 3mm into the hub. With the caps off you can take a good look/feel of the bearings and really see if they are bad and if so you can decide to try and replace the bearings yourself or have your local shop do it. Good luck!
flag FrEeZa
Posted: Feb 25, 2009 at 9:10 Quote
Hi! I have a similar problem, the only thing is the hub doesn't have anything. this is the hub https://www.pinkbike.com/photo/3050383/ It's a Halo. How can I restore it? Do you happen to know how much it's going to cost? CheersBeer
flag tosher777
Posted: Mar 28, 2010 at 9:46 Quote
10 mins to get the bearings out using a universal bearing removal/install tool which i make myself. No damage to the bearings what so ever. If anyone wants one mail me, theyre not expensive.

The ordering code for a typical 20mm front hub sealed bearing (unless you have some weird type) is: 6805 2RS (25MM INTERNAL DIA X 37MM OUTSIDE DIA X 7MM WIDTH).

You need two of these replacement bearings which are readily available at a cost of £2.25 each brand new off Ebay.

http://stores.shop.ebay.co.uk/ebrbearingsupplies__W0QQLHQ5fSellerWithStoreZ1QQ_sasiZ1QQ_sidZ209242304?LH_TitleDesc=1&_nkw=6805

Regards: Tosh
flag TwistedBench
Posted: Mar 28, 2010 at 10:05 Quote
tosher777 wrote:
10 mins to get the bearings out using a universal bearing removal/install tool which i make myself. If anyone wants one mail me, theyre not expensive.

The ordering code for a 20mm front hub sealed bearing (unless you have some weird type) is: 6805 RS (25MM INTERNAL DIA X 37MM OUTSIDE DIA X 7MM WIDTH).

Regards: Tosh

Please post a picture of your bearing removal tool. I pulled mine by turning a piece of oak down to 20 mm dia (I only have a wood lathe, no metal lathe), cut a slit in the end of it, inserted that end into the hub and used a chisel in the slit to expand the dowel to a good friction fit and drove out the bearing.

BTW - the bearing number you quoted is wrong. 25 mm internal diameter, not for a 20 mm hub, maybe that is a BB bearing.
flag tosher777
Posted: Mar 28, 2010 at 10:11 Quote
TWISTEDBENCH: The internal axle measures 20mm(where your 20mm axle goes through). The outside dia of this axle measures 25mm. This is where the two bearings are seated. Your front fork axle passes throught the internal axle not the bearing, hence the 5mm difference.Smile
flag TwistedBench
Posted: Mar 28, 2010 at 10:22 Quote
Maybe I have one of the wierd hubs. I'm going to go measure & get back to you.
flag TwistedBench
Posted: Mar 28, 2010 at 10:36 Quote
Maybe the Daredevil hub is unusual, I don't know.
Here are pictures of the hub, the end spacer removed (just over 20 mm ID) and the bearing exposed (20 mm ID) I am much more familiar with cup and cone bearings than these new style bikes. But I guess a guy needs to have a good look at his hub before ordering 20 vs 25 mm ID bearings. Smile

photo
photo
4786565
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flag tosher777
Posted: Mar 28, 2010 at 10:38 Quote
Ok. I checked some different hub manufacturer's websites and contrary to what I thought, there is no standard 20mm front hub bearing size. Hope use a 61804 RS.

Appologies for being slightly misleading on bearing sizingWink .
This must be due to:

1) A difference in the internal axle's wall thickness which will give a different outside dia (this being the bearings internal dia)

2) A difference in the internal dia of the hub body (this being the bearings outside dia)

It's easy to get the bearing code though. Once you've removed the offending bearing/s, get a rag and give it a clean and the tiny code will be seen on the nylon/rubber part of the bearing. The code will be made up of between 4 and 6 numbers and usually ends in the letters 'RS' which stand for rubber sealed.


To give those of you an idea of what your hub looks like before attempting to dismantle it, here's an exploded view of a 20mm front hub by Hope.


Unsecure image, only https images allowed: http://www.hopetech.com/database/bulb_f_ass_explo%2Btab.jpg



...and some pics below of my own which ive just dismantled.


photo
..................................................Hub body with axle & bearings removed



photo
..................................................axle & bearings



photo
..................................................bearing 'close up'. Note the ordering code just visible at the top
flag TwistedBench
Posted: Mar 28, 2010 at 10:46 Quote
Thanks. That Hope diagram is very much like the Daredevils with a spacer tube betweent the bearings. The Hope spacers look to be held in place with a circlip, but the Daredevil end spacer is pressed in (a fairly loose press fit).

I sure everybody would like to see the tool you built if you have a picture of it.
flag tosher777
Posted: Mar 28, 2010 at 12:55 Quote
I never got round to patenting the design so anyone that has access to CNC machinery can steal the idea so i wont be posting pics.
You'll just have to buy one ...'then' you can steal it Confused Cry
flag rideonjon
Posted: Mar 29, 2010 at 16:52 Quote
what's so revolutionary about your bearing puller,what does it do that a standard bearing puller won't do.
flag tosher777
Posted: Mar 30, 2010 at 23:49 Quote
rideonjon wrote:
what's so revolutionary about your bearing puller,what does it do that a standard bearing puller won't do.

1) It's not just a puller, it's a full bearing extraction & install tool


2) It's 20mm front wheel hub bearing specific. A standard puller wouldn't fit. (Im also looking to develop it further to be used on rear hubs as well as front hubs.)


3) It has interchangable components to cope with differences in axle/bearing sizes. (If there's a demand I will manufacture interchangable components to suit the most popular makes.)

4) It's probably a fraction of the cost of a puller you may have seen at your LBS.


5) It's BRITISH! Big Grin Wink tup

 


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