need a fresh pair of eyes on this problem. im a competant bike fettler, i have the proper tools & know how to use them and im using the proper hope bearings, but…

ive been through 2 sets of rear bearings in 2 months, and i cannot figure out why. is it a worn axle causing the problem or worn seals? i really cant figure this one – anyone have any suggestions as to how i can fix this?

ta

Ben

how are you fitting the new bearings? drifting in with hammer / sockets or pressing in with threaded bar / press etc?

new bearings = new seals. Worn axle shouldn't wear bearing.

Misalignment/jet-wash or muc-off?

ive got the proper hope tools, i do use muc off but thats never done any damage before so im at a loss.

front or rear? If rear could be a dodgy seal on the freehub

real hope bearings or "bearing shop/ebay specials"

Are the bearings getting seated properly? if not you could be putting side loadings on them which will ruin them in short order.

You certain you didn't damage them putting them in?

did hope not have a dodgy batch of bearings?

Its a puzzler for sure

cynic-al – Member

Worn axle shouldn't wear bearing.

Worn axle will easily knock the bearings out, ball roller bearings are designed for radial loads only, as soon as the load goes off centre then it puts higher than design load stresses on the bearings. A worn axle will do exactly this.I'm sure hope do a replacement axle? Or you could use loctite stud and bearing fit..

Are your outer seals in good condition and lubed ?

ball roller bearings are designed for radial loads only

thats funny, a prof. in engineering once told us that they were suitable for non-radial forces, hence commonly being used for shaft location. SKF disagree too 🙂

a bent/distorted axle should be fairly apparent, no?

yep genuine bearings – the axle is in generally good nick but it has a slight notch from my first attempt at removing a bearing (in a dark garage!) – you can only just feel the notch and it doesnt appear to be in contact with the actual bearings.

think i'll try another set from another supplier with some super web grease!

must have had the hosepipe on a bit too high or something, just strange becasue the previous bearings lasted 18 month under the same conditions….

thats funny, a prof. in engineering once told us that they were suitable for non-radial forces, hence commonly being used for shaft location. SKF disagree too

Ahh well it's semantics isnt it, the type used in wheel bearings are called deep groove ball bearings, primarily designed for radial load but can take some axial load, They can take about 10% of the load axially that they take radially. It doesnt take much misalignment to make the axial load massive. Angular contact ball bearings are fine for axial load, like your headset bearings.

anyone have any suggestions as to how i can fix this?

given all the great stories told of Hope's service backup (and I have sent stuff to them a few times and always been really impressed with their service), my suggestion would be to pack up the wheel and send to Hope – you'll most likely have it back within a few days and be charged very little, if anything.

toys19 – good knowledge, that'll teach me for being a smartarse! 🙂

Cherck the axle for being bent – roll it along a flat surface. Is it one set you have had fail in a short time or two?

two sets in about 7 weeks,first set were cheap and cheerful this second set are the proper hope bearings, its odd because all the bearings have gone rough, not just one or two like over the past couple of years.

and they do seem to be very wet, and all the grease i put in has been well and truly washed out. but like i say – just a gentle hosing down is all they've seen.

i shall check the axle in the morning and see if its bent at all – but i dont think it is, there just a little notch that i mentioned in the other post.

Did you open up the bearings to put extra grease in? You may have ruined the seals and shortened their life. Controversial but possible. Personally I would never open up sealed bearings unless I had new seals to put in – bot others disagree.

nope, just added the grease in around the hub body. i think its a bad idea opening up bearings too.

thanks for your input mate – i'll have a better look at the axle in the morning.

if the axle is good then i'll stop using the hosepipe and use some extra thick super web grease and see what happens.

TJ shut it!

toys19 – Member
cynic-al – Member
Worn axle shouldn't wear bearing.

Worn axle will easily knock the bearings out, ball roller bearings are designed for radial loads only, as soon as the load goes off centre then it puts higher than design load stresses on the bearings. A worn axle will do exactly this.I'm sure hope do a replacement axle? Or you could use loctite stud and bearing fit..

Presuming it's worn equally along its length, where the bearing fits to it, how can it do this?

EDIT I can see how now. Tenner says it's not worn though.

Yeah but bearing seals are crummy and were never designed to kep ot the crap MTBing sends at them. To make it bomb proof you need a proper seal like on a motorcycle engine. Luckily hope know this and have fitted seals to the outside of the pro 2, is your seal ok? The shaft might not be bent, it could be worn, so how easy do the bearings sit on the shaft? If its sloppy then that's a likely source.

cynic-al – Member

TJ shut it!

toys19 – Member
cynic-al – Member
Worn axle shouldn't wear bearing.

Worn axle will easily knock the bearings out, ball roller bearings are designed for radial loads only, as soon as the load goes off centre then it puts higher than design load stresses on the bearings. A worn axle will do exactly this.I'm sure hope do a replacement axle? Or you could use loctite stud and bearing fit..

Presuming it's worn equally along its length, where the bearing fits to it, how can it do this?

EDIT I can see how now. Tenner says it's not worn though.

Glad you can see but I'll explain anyway as I'm a knowall pedant:
If the bearing seizes the inner race could spin on the axle, which could either rub an even wear ring all the way round or just rub a groove on the top of the axle. (remember the axle is static). Worse if the bearing was slightly off and seized then the groove it wears could be canted. Conversely it could do either of these things to the housing in the hub too, but it's normally less likely as the larger diameter of the outer housing tends to give a tighter grip on the bearing race. Shaft wear like this due to inner race rotation is captain common. I'm not betting on anything as for all I know the OP is a mechanical oaf who keeps twa**ing his bearings in with a lump hammer and a cold chisel. (PS OP I'm sure your not honest…)

EDIT its more likely to wear groove in the bottom of the axle. brain fade. Not that you will know which is top or bottom once you've removed the axle, and if you ever remove the wheel and put it back in whilst the bearing is siezed then the top/bottom will have moved anyway..

Do you have the seal tool jobbie (i realise you said proper hope tools though)? Hope Seal Tool @ CRC

Just that I've rebuilt my pro2's over the last few days and only remembered it at the last minute, but it does properly press the seal on the freehub into the hub shell.

Obvious I know, but it's always the little things….

MrCrushrider – Member
nope, just added the grease in around the hub body. i think its a bad idea opening up bearings too.

Can't understand what adding grease around the hub body is going to do, pop the seals off and regrease inside if you want to get a bit more life from a sealed bearing. Low bearing life sounds like too much washing and use of Muc-off, try keeping m-off away from your hubs.

Pro 2 bearings are cack. Fact. That's all you need to know.

(Go on, campare one to an XC bearing, then you'll know why XC bearings last so much longer)

when you've pressed the replacements into the hub shell do they move smoothly if you cop hold of the inner race and rotate it?
if the bearing OD is on the large end of tolerance and the hub is on the small side you might be loading the bearings just by fitting them?

Oh dear – my Pro IIs lasted 3 and 5 years respectively on the rear and are still going strong on the front. IMHO jet washing is the culpret after a muddy wet ride – Thats my five pence 🙂

Foxy the phrase is "that's my two penneth"

Origin

Yes you have said that before I think or someone has picked me up on that – but "That's my five pence" is what I say and as I have as many grey hairs as brown I dont think I am gonna change 😉 Just like me not being able to type teh on a keyboard 🙂

Its "The" i have problems with "teh" is easy

sam r – Member

toys19 – good knowledge, that'll teach me for being a smartarse!

sam r not that good, I had a look in my SKF book this morning and apparently some SKF deep groove roller bearings can take up to 25% of the radial load, and larger ones can take 50% of radial load, not 10% as I said previously. But that being said axial load bearings such as thrust bearings and angular contact bearings will take a much much higher axial load than a deep groove roller will take in radial load. So I think it need clarification. If you have predominantly axial loads (like headsets or clutch thrust bearings) then a thrust type or angular contact bearing is what you need. For rolling applications like wheels the mode is predominantly radial with some axial.

That being said if you have misalignment or poor fitting then the axial loads could easily become 2, 3 or 10 times the radial load – Failure.

morning all – thanks for your responses! some of you are up very early today!

checked axle and all is ok. and yep i use the proper seal tools, i've got the full set from hope.

i reckon that muc off / naff grease and too much hosepipe over the last week or so must have done the damage. its just odd that before this my bearings lasted 2+ years. maybe the area i've mooved to is has hard water or something! 😛

I hardly have bearing problems, and I've never used muc off, doesn't it have caustic soda in it?

I'd fill the bearings with grease despite the guarantee of instant corrosion by TJ et al.

how do you get the seals on and off the bearings? stanley knife?

or similar, yes – prize off from inner side (and watch your world fall apart).

so take both seals off then what flush with degreaser and add some proper sticky stuff in?

sorry for all the Qs, never done this before…

Take both off, fill one side with grease (no point in taking old stuff out IMO), push seal back on, other side should now be full also, push that seal back on.

If you are careful you should not bend the seals, if you do, flatten/straighten them. Some will say even a microscopic distortion makes them useless, I don't see that as the lip of the seal should stil be in contact with the bearing inner/outer.

cool – cheers cynic-al, i'll have a go with some old bearings before i experiment with the new ones!

I've just changed my first pro2 bearing out after about three years. Acceptable wear IMO, although not quite as good as bulbs. I only needed to change the hub shell bearings.

I think prising seals off for re-greasing is ok and SKF seems to think so too, since they make reference to it on their website – specifically increasing the re-lubrication interval in dirty conditions (ring and bells?)

Prise the seal from the larger outer side though, since that seal edge doesn't see any work, so if any incidental damage occurs, it shouldn't matter too much.

I've used RnR Superweb grease for years, but having run out earlier this year I've been using Prep-M and it seems to be more water resistant, despite having a similar consistency. Based on that, any grease with an emphasis on waterproofedness would seem to be better than 'stringy grease'.