Changing Wheel Bearings

[Ascalon]

I am contemplating doing the wheel bearings on the front wheel of my ST4s.

Would I be better off using a drift from the rear of the bearing or investing in some internal pullers to tackle them from the front?

Where to get a suitable drift to work in the space? And what material should it be?

I know about knocking them in with the old bearing or a suitable socket on the outer rim, but I would be very cautious about using a drift incorrectly on my lovely Marchesini wheels.

A

[VanWinkle]

I use a round aluminium bar as a bearing drift, alu will bend and buckle before it does any damage. Before puttin your new bearings in, stick them in the freezer overnight. this will shrink them and make the bearings easier to fit.

[Cibbersicks]

I use a round aluminium bar as a bearing drift, alu will bend and buckle before it does any damage. Before puttin your new bearings in, stick them in the freezer overnight. this will shrink them and make the bearings easier to fit.

I really wouldn't do this, myself and other workmates have had nothing but a pain in the arse when giving this method a go. Once you've heated the aperture you are fitting the bearing into, we've found that the bearing seems to pinch up really quickly as the cold temperature of the bearing transfers to the other material and causes it to rapidly cool down and pinch the bearing up, normally when the bearing is in completely the wrong place.

Driving the bearings out shouldn't be a problem with plenty of heat on the area, using a drift from the other side. Just be careful and methodical, don't go at it with a gung-ho approach and you'll be fine. Same goes for driving the bearings in. Again plenty of heat, and apply a film of grease to the outer race before fitting.

When I say use plenty of heat, have a friend on standby with the blowtorch because if you feel it getting harder to drive in, you need another pair of hands to apply the heat.

[Ascalon]

Hmm,

right.

Don't have either a heat gun or an alu drift.

Would a bloody big hair dryer be of any use for applying heat?

Where would one get a large bit of alu bar suitable for the purpose?

Also, are bearing spacers between the two bearings normally used on these type of wheels? Are they a pain to relocate when puttni back in the bearings?

Cheers,

A

[alexp5]

^Wot e said.

I've never frozen a bearing, just build up the heat gently on the bearing housing but get plenty of heat into it. I use a brass bar as a drift, snaffled from work years ago.

[Cibbersicks]

A hair dryer won't pump out enough heat for this job, you need it really hot so you can't touch it.

[VanWinkle]

I really wouldn't do this, myself and other workmates have had nothing but a pain in the arse when giving this method a go. Once you've heated the aperture you are fitting the bearing into, we've found that the bearing seems to pinch up really quickly as the cold temperature of the bearing transfers to the other material and causes it to rapidly cool down and pinch the bearing up, normally when the bearing is in completely the wrong place.

Really?.. I find that hard to believe, Ive changed hundreds of wheel bearings in my time and always stuck them in the freezer, they go in with ease or minimal force and i cant understand what you and your mates do to find it difficult...horses for courses and all that tho.

ah, its ok, Ive re-read your reply, your heating the bearing holder before putting the cold one in, there is no need to use heat when the bearing has been in the freezer. Just line it up true and press it home..jobs a good'un.

[Cibbersicks]

But you get to play with fire my way so you look so, so much cooler.... plus you can quote Pulp Fiction -

"I'm gonna send some hard hittin n****z with a pair a pliers an' a blowtorch - I'ma get medieval on yo' ass!"

[VanWinkle]

:lol:

[Ascalon]

OK,

I caved and am getting a pro to do it, ride in ride out.

I am not chickening out, I reckon I'll get myself a proper drift for the job and do it next time on my track bike, which will probably need a complete set before the season opens.

Cheers all,

A

[gurninman]

I don't use a drift at all - I use a rawl bolt

Tighten it up in the bearing, and you get a better twatting force on it and no risk of damaging the wheel

[Ascalon]

I don't use a drift at all - I use a rawl bolt

Tighten it up in the bearing, and you get a better twatting force on it and no risk of damaging the wheel

But do you need a slide hammer for use with oyur Rawl bolt?

A

[gurninman]

No, just tighten it up in the bearing and beat the fucker out.

Actually, I suppose I do use a drift on the head of the rawl bolt, but only so I don't hit the wheel with me twatting stick

[gsxr renegade]

I just used a fucking great screwdriver to smack the old bearings out. You’re not going to use them again, so who cares if they get damaged? (Taking care not to damage the wheel in the process though)

The new bearings were just hammerd home using a socket that was the same size as the outer race, and a copper mallet, then should you slip while hammering the bearing in, you won’t damage anything. You’ll rip your hand to shreds mind – but the wheel will be fine.

Once one of the bearings is seated properly, just pop the long spacer in the middle, and seat the other bearing. Jobs a good un!

[wesifume]

I can bring a heat Gun to Dublin tomorrow if you haven't given in..even though you said you did.

We did the heat the wheel, freeze the bearing method on the WesiSuki..worked grand so it did.

Big drift ( alu bar with a lip on the end and a bit of hammer..job jobbed, putting back in, heat plus frozen bearing plus old bearing or spacer)

[Ascalon]

Thanks guys, but it is more a case of ordering bearings, waiting for bearings.

From what I can gather, it is a simple enough job, but as this is my day to day bike, I've opted for the ride in ride out service with a local guy who has the bearings on the shelf.

Thanks for the offer Wesi, but I'm out of the country tomorrow and the next day, so getting it sorted Friday morning.

A

[wesifume]

Iggys place?

[theo]

Its all about temperature differential.

A home freezer really isnt usefully cold (maybe 30 degrees Celsius max under ambient temperature). An oven is much easier to control and get a larger differential.

Also you have to bear in mind that steel (the bearing) will have a much lower expansion coefficent than aluminium (the wheel), so a 30 degree change in temperature will mean a larger dimensional change for the wheel than a 30 degree drop for the bearing.

I know this is no use to you now as your getting it done by a firm.

Having seen how some people do this kinda thing (think mechanic smashing bearings in or out cos theyre paid by the hour), this is something Id always wanna do myself.

[Ascalon]

Got this sorted yesterday and I am glad I did.

Robbie in MotoTechnic sorted it and he showed me what is done.

There is a spacer between the two bearings and on one end it has a very small recess to facilitate knocking out the first bearing.

If you didn't know it was there, it would have been very easy to make a bollix of it.

Robbie has a specially adapted tool just for the job and had the job done in minutes.

Thanks for all the advice.

A

[abos]

A bit of general info in my experience one wheel bearing is butted up to a seat machined in the wheel and the other one floats and is spaced out by the tube in between the bearings. This is so that when the wheel spindle is tightened the internal spacer takes the stress and not the alloy of the wheel. So you should always knock out the bearing seated against the wheel ( there is usually a notch that allows a drift in I always use a brass drift i made one years ago and i have done dozens off bearings with it) when you have this bearing out you can remove the spacer and knock out the other bearing by tapping around the outer race at 3,6.9 and 12 o'clock until it is out. Wheel bearings i always press in cold and have never heated the wheel i have also used 16 mm studding and plates with nuts to align the bearings and with a combination of tapping the stud and tightening the nuts pulled the bearings in to line don't just tighten the nuts as you will stress the wheel hope this helps.

Rgds

JA.

[abos]

One other thing always remove the discs or support the wheel boss from below as discs can easily be damaged doing these bearings and i do find a smear of good copaslip grease makes things easier I've had a tin for 30 years and it still is only half empty so not to much!