4G T drive bearing conversion

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Velodrome

Well-Known Member
May 27, 2011
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Phoenix-ish
Just ordered my berings. Thanks for coming up with this CF! Gonna give it a go with the used 4G I just picked up ( pre welded too )
 

cobrafreak

New Member
Feb 16, 2011
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sacramento ca
Cool. Here is a tip I don't think I have mentioned before on taking down the output shaft. I use a Harbor Freight electric angle grinder and I put flap disks in it to take down the shaft. Flap disks are metal finishing disks that one prepares metal surfaces usually after rough grinding and before paint prep. It removes metal at a slower rate than a regular grinding stone and the finished surface is much smoother. Better results can be reached with a flap disk.
 

Velodrome

Well-Known Member
May 27, 2011
2,387
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Phoenix-ish
I think I'd run away from that. The whole idea of the conversion is to increase reliability and reduce maintence needs. Those will attract dirt like crazy! Go for the sealed ones.
 

Keeponkeepnon

New Member
Mar 11, 2013
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California
It seems these bearings are used by the RC car guys. I found them for $0.99 here for rubber shielded in the USA:
http://www.avidrc.com/product/1/bearings/334/13x20x4-Rubber-MR2013-2RS-bearings.html

Or here for $1.50 each or $1.00 if you buy 10 at a time, in Australia:
http://rckinghobbies.com/index.php/pro-spec/13x20x4-revo-pro-spec-race-bearing.html

Edit: I ordered and received bearings from Avid. Very quick turn around. I ordered at midnight, they were sent out the next day, in transit day 2 and I received them day 3 from half a continent away. You can't tell anything about the quality of bearings without using them but they feel smooth and I find no fault in them. I will edit again with test results in a month.
 
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DaveH

New Member
Mar 11, 2013
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Gig Harbor WA
Wouldnt it be more feasible to use 15x21x4 bearings and just bore out the clutch bell 1mm? I'm REAL leery of turning down my shaft.

I've found several site offering the 12x21 bearings though, how thick is the clutch bell hub metal?

For that matter if the clutch bell metal is soft enough we might be able to just press them into place with a press.

I've been looking for the 15x20x4 and cant find any, however I find a lot of Chinese industry offering 15x20x4.5 bearings - but I havent found anything I can order online with.
 
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Keeponkeepnon

New Member
Mar 11, 2013
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California
I'm REAL leery of turning down my shaft.

I've been looking for the 15x20x4 and cant find any, however I find a lot of Chinese industry offering 12x30x4.5 bearings - but I havent found anything I can order online with.
I see 15x20x3.5 bearings are readily available. If you can't stand the thought of taking material off your shaft then try those. 6 bearings at 4 mm wide would be 24mm. 7 bearings at 3.5 mm would be 24.5mm.
 

moonerdizzle

New Member
Jun 28, 2009
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Cheese head capitol
I see 15x20x3.5 bearings are readily available. If you can't stand the thought of taking material off your shaft then try those. 6 bearings at 4 mm wide would be 24mm. 7 bearings at 3.5 mm would be 24.5mm.
Every 15x20 bearing I have found is a roller bearing which will not work. Roller bearings need harden races. Plus our cranks have a key way in them. If you tried to use them bearings they would blow apart in under a minute.
 

DaveH

New Member
Mar 11, 2013
9
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Gig Harbor WA
Those would work, they've got stainless versions of them for $22 each (!!).
2 or 3 of them with 15mm ID spacers (steel tube?) on the shaft.

The big problem there is that they're not sealed/shielded.

Really all you need is 2 bearings - an inner and outer. There isnt much of a load on them from what I understand.

I wish one of the vendors would bite the bullet and buy a couple hundred of the ones from China. Damn minimum order size....

Edit: Looking at it, 5/8th shaft is actually 15.875mm. I'm going to look around for 15.875x20x# bearings and 16x bearings
 
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Keeponkeepnon

New Member
Mar 11, 2013
27
0
0
California
Is the shaft truly 5/8" or is it some metric number close to 5/8" and us guys in the USA therefore call it 5/8"? Coming from that part of the world I expect things to be metric.