[kursed56]

Im just kicking around ideas on front brake options and am considering a Sportster front drum. Love the classic simple look.

Anyone know the axle size on the drums? is it 3/4?

My bike is a 77 with stock forks.

If anyone has a drum I can lace to my 40 spoke stock shouldered rim or a complete wheel/drum set up I may be interested.

Or? can I try and find a complete early front end? Forks/trees/wheel/drum?

Thanks again.

 

[wldpilot]

Axle size is 5/8".

 

[kursed56]

I guess I could try and change the drum bearings to 3/4?

Looks like all the mini-drums I see are 5/8 also.

 

[Von Zacho]

You will have to change the bearings to 3/4" and mill your backing plate out to 3/4'' and your spacer will have to be 3/4" as well. Not really a big deal, I had it all made up that way for mine and I dig it.

 

[thefrenchowl]

Old Sporty front drum wheel actually has a metric shaft/ball bearings, 17mm ID...

Patrick

 

[shovithead]

If you use your current 77 front end, you will have to weld a brake anchor tab on the right side, for the drum brake. Really easier to get the drum front end, with a wheel. They can be found pretty easy, and some are not very expensive, if you can stand a little rust or rebuild time. Whole front ends, with the wheel, can be found for under 1000, and with a little patience, closer to 500. If you plan on extending it, do a little research, because the 33.4 sporty tubes flex a lot, if you get them out beyond 6 or 8 inches.

 

[wldpilot]

Old Sporty front drum wheel actually has a metric shaft/ball bearings, 17mm ID...

Patrick

Right you are. Thanks for the correction.

 

[Postal]

If you use your current 77 front end, you will have to weld a brake anchor tab on the right side, for the drum brake

I´ver been plannin on a drum too (´75 with 35mm forks), couldn´t you flip the sliders , that way you would have a mounting tab on the right side and on the rear of the slider. Only problem I see is having the bleeding screws on the inside??

 

[fatass]

You will have to change the bearings to 3/4" and mill your backing plate out to 3/4'' and your spacer will have to be 3/4" as well. Not really a big deal, I had it all made up that way for mine and I dig it.

Can you get Metric OD/standard ID bearings? I tried this with 16mm and came up empty.

BTW, if you don't know, to figure the metrics to inch size, do this:
17mm/25.4 = .669"
16mm/25.4 = .629"

 

[bobscogin]

Can you get Metric OD/standard ID bearings?

I don't think so. At least not "off the shelf".

Bob

 

[SpeedAndNoise]

I know there is a set of bearings with the same OD, that comes in 17mm, and 3/4". Not sure the OD off hand (I think it's 40mm) or the part #'s but it's possible to have a metric OD and standard ID or vice-versa.

 

[fatass]

I know there is a set of bearings with the same OD, that comes in 17mm, and 3/4". Not sure the OD off hand (I think it's 40mm) or the part #'s but it's possible to have a metric OD and standard ID or vice-versa.

Do you know if it's a standard bearing, or is it some special HD thing? All I can find is 40mm OD, 20mm ID. That's almost 1/16" oversize, for you carpenters. Maybe a 19mm ID? That would be nearly fricken perfect.

Edit:

http://www.wbds.com/htm/203SZZ12-MRC.htm

Thanks, Kevin..

 

[SpeedAndNoise]

It's not an HD thing. I called Precision Bearing in Newburgh, NY(845) 561-4330. The guy on the phone knew all the bearing #'s and sizes in his head.

Oh, just saw your link.

 

[fatass]

Yeah, most places list that bearing as a 12mm x 19mm x 40mm. 19 is .748" and my axle measures (in 35° weather) .749". I hope the bearing is a plus-plus tolerance on the ID.

Hmm, now what's the bearing OD on a Sportster drum....? I'll know on Monday, I reckon.

Here's a another link:

http://www.consbrgs.com/page.taf?detail=36_1_13

 

[T_Dubya]

Yeah, most places list that bearing as a 12mm x 19mm x 40mm. 19 is .748" and my axle measures (in 35° weather) .749". I hope the bearing is a plus-plus tolerance on the ID.

Hmm, now what's the bearing OD on a Sportster drum....? I'll know on Monday, I reckon.

Here's a another link:

http://www.consbrgs.com/page.taf?detail=36_1_13

I have an early sporty wheel laced to a 21" I wanted to use with a 3/4 axle also. are the dimensions in the link above the correct size for the bearings i would need?

 

[M.O.Ther]

My bike is a 77.

If anyone has a drum I can lace to my 40 spoke stock shouldered rim or a complete wheel/drum set up I may be interested.

Or? can I try and find a complete early front end? Forks/trees/wheel/drum?

Thanks again.

Forget lacing that '64-'72 Sportster/FX drum to your stock '77 rim. Your rim is drilled and dimpled 2 x 2 like the drum brake rim but the spoke angle is way off. If you want that style of rim (2.50" width, deep square drop center,) you'll need a 43010-70 rim, used on '70-'72 Sporties. If you just want flanged aluminum, you can also use the 43010-64 rim which is a WM3 (2.15" width inside at the bead seat, shallow rounded drop center,) that they used '64-69 with that brake.

If you can find a complete drum brake front end, like you mentioned, it should bolt right up to your '77 Sportster, no machine work, no welding of tabs, no hunting for bearings.