swing arm in the oven?

[gbw]

Got my shipment from Z1 yesterday so tonight's project is putting all the bearings back in the rear wheel and the swing arm. I'm not worried about the 3 wheel bearings but those swing arm bearings make me a little nervous.

People say freeze the bearings and heat the place they are going. The bearings are in the freezer and I'm thinking about putting the swing arm in the oven. I'm thinking 250 F for 2 hours. What do you think? Am I asking for trouble? Any suggestions?

Thanks,
gbw

[BentRod]

so long as you don;t go much hotter than that and you allow it to cool down slowly, you should be ok.

[andrewclaycomb]

I can understand the idea that freezing the bearings will shrink the metal, but why would you heat the swingarm? wouldn't that make the metal swell which would just be negating the whole point of freezing the bearings. If anything freeze the swingarm with the bearings so all the metal shrinks.

I'm going to be changing the rear bearings this weekend using the frozen bearing technique.

[gbw]

I can understand the idea that freezing the bearings will shrink the metal, but why would you heat the swingarm? wouldn't that make the metal swell which would just be negating the whole point of freezing the bearings. If anything freeze the swingarm with the bearings so all the metal shrinks.

I'm going to be changing the rear bearings this weekend using the frozen bearing technique.

Thank you for replying. If my thinking is correct, the goal here is to make the bearing as small as possible and the hole in the swing arm as big as possible so the installation goes easily. Freezing the bearing causes that metal to contract making the bearing smaller. Heating the swing arm (theoretically) should make the metal expand causing the hole to become bigger. It seems to me this combination causes the best possible condition for installing the bearings.

I'll take some pics and tell you how it goes. Fingers crossed.

Thanks again,
gbw

[spyug]

The bearing (or bushing) to swingarm is an interference fit meaning the bearing will not go into the swingarm tube without persuasion i.e it is an extremely tight fit). The idea of freezing the bearing and heating the tube causes the fit between both to be loose allowing easy assembly. If you freeze them both down you gain nothing other than a slight difference that may be gained by the amount that different metals may contract. The freeze one, heat the other is the standard practice bearing assembly ( you would do the same with your steering head stem and bearings.)

If you have access to a propane torch, a few minutes of flame to the mouth of the tube will do the job. Just be careful not to burn off the paint.

The fit might still be quite tight so get a length of threaded a couple of inches longer than the width of the tube. Also get a couple of nuts and washers large enough to fit the circumference of the bearing face. Do them one at a time. Heat one side, push in the bearing as far as you can. Make sure it goes in square. With nut and washer on one side insert the rod. Add the washer and nut on the other side and tighten up ( wrench on both nuts). This will draw the bearing in until seated. Repeat with the other side.

This is the easiest way to do this job I've found after doing 3 bikes in the last 4 years.

Hope this helps.

Let us know how you make out.

Cheers,
Spyug.

[gbw]

The bearing (or bushing) to swingarm is an interference fit meaning the bearing will not go into the swingarm tube without persuasion i.e it is an extremely tight fit). The idea of freezing the bearing and heating the tube causes the fit between both to be loose allowing easy assembly. If you freeze them both down you gain nothing other than a slight difference that may be gained by the amount that different metals may contract. The freeze one, heat the other is the standard practice bearing assembly ( you would do the same with your steering head stem and bearings.)

If you have access to a propane torch, a few minutes of flame to the mouth of the tube will do the job. Just be careful not to burn off the paint.

The fit might still be quite tight so get a length of threaded a couple of inches longer than the width of the tube. Also get a couple of nuts and washers large enough to fit the circumference of the bearing face. Do them one at a time. Heat one side, push in the bearing as far as you can. Make sure it goes in square. With nut and washer on one side insert the rod. Add the washer and nut on the other side and tighten up ( wrench on both nuts). This will draw the bearing in until seated. Repeat with the other side.

This is the easiest way to do this job I've found after doing 3 bikes in the last 4 years.

Hope this helps.

Let us know how you make out.

Cheers,
Spyug.

WOW. This is great advice. This is exactly what I'm going to do. Question: The bearings/bushings I removed were flush to the outside edge of the swing arm. However, it looks like the seat is a little further down the shaft maybe a 1/4 inch or so. Do I draw the bearing all the way to the seat or just until it is flush with the outside of the swing arm?

[Mark M]

I can understand the idea that freezing the bearings will shrink the metal, but why would you heat the swingarm? wouldn't that make the metal swell

Nope, heating makes every dimension grow, including bores. As Spyug says, it is standard practice when fitting bearings with an interference fit.

Mark

[Nessism]

Used the heating method with great success to get roller bearings out of castings before. Freezing works also, used for installation.

[SqDancerLynn1]

It depends on how wide the bearing is ?? I would probably have it go in the extra 1/8"

[spots25]

well, as long as you stay below 727 degrees Celsius, you should be okay

[Zooks]

well, as long as you stay below 727 degrees Celsius, you should be okay

Don't ya love a smarty pants??? LOL

[gbw]

well, as long as you stay below 727 degrees Celsius, you should be okay

No risk there. I only measure temperature in Fahrenheit.

[Junkie]

well, as long as you stay below 727 degrees Celsius, you should be okay

staying below the melting temperature is not enough to not change the properties of steel... I don't know about Al.

[z1b900]

burnt hands

freeze is good,, dont understand the oven,,surely it would be too hot to handle!!, need oven gloves, akward to manipulate with,,if you let it cool down, it would have shrunk back to original,,also, i have done blacksmithing and know where to apply heat to straighten or bend,, metal heated all over will not contract back to exact, you got the think of the swingarm forks, not just pivot, which is thick,,suggest threaded rod, about 1/2", large washers and nuts, press fit both bearings at same time with ratchet,, would not even have to freeze, also, soon as you take out of freezer, you got to work fast, because it is de-freezing all the time, unless you do it in the freezer,,,,,,,
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[1978GS1000custom]

before i invested in a hydraulic press i would just take stuff like this to any NAPA store and it would cost no more than a few bucks if anything. NAPA stores all have a hydraulic press in store due to they sell alot of these types of bearings and races as well as ball joints and other stuff and they offer this service to customers (even when you dont buy a part from them) to help aid with the repair. they also have a set of correct guides so the bearing gos in straight. also putting the swingarm in the oven is really not that effective. if your not near a NAPA store just call a few local autoparts stores in your area one of them surley if not all of them will have one. if all else is not available go with the threaded rod mentioned below (which you can get at any home depo or lowes or hardware store). thats the safest way and make sure to have some big wrenchs and perhaps a bench vise to hold it all while you work and wear goggles and gloves, safety first. hope this helps.