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CB1300 wheels for the Bird?


Tom

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I'm looking at some CB1300 wheels from 2003, thinking if they could be fitted to the Bird. It's a simple 5 spoke design, but anything's nicer than the 3-spoke wheel :D looking at some brake disc manufacturer specs and pics, the discs are very different, the PCD, inner diameter, so correct my basic level of knowledge but a CB1300 wheel with the discs and appropriate spacers for the axle would be enough to fit it? I have no intent on de-linking the brakes or changing anything about it, but both bikes have 310mm so I figure the CB rotor would fit on the Bird caliper?

 

Also, from what I've been able to read, the rear should be a direct fit, even the rear discs are the same on those two bikes. Any advice or pro tips welcome :D

 

 

 

 

 

 

 

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  • 3 weeks later...
23 hours ago, FTM said:

Anyone? :D

We didn't get the CB1300 over here, so responses will mostly be limited to members who live in the eastern hemisphere.

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On 10/7/2021 at 1:52 AM, rockmeupto125 said:

Th concern is hub spacing combined with the offset of the disc.  If the discs are the same width apart as an XX, then you can spacer the hub to fit the fork legs.  If not, you're going to have to spacer the calipers to match them.

 

 

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I drew up this comedy of a front view of a wheel...now, if I ever find a CB1300 parked up somewhere, how would I precisely measure the gap from "middle of the caliper" to the hub, in order to figure out if Bird's disc and CB's disc have the same offset?

 

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The only thing you would need to know is how far apart the discs are and how that compares to an XX. From there you will know how much the calipers will need to be moved.

 

Choose ID, OD, or measure from the middle of the disc, just do it the same way for both. I'd measure at a couple different points just on the possibility that one of your data discs is warped.

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Thanks. I'm looking at some bearings catalog, if I'm looking at the right columns, front wheel bearing are as follows;

 

Bird - ID 20 / OD 47 / WID 14

CB  -  ID 20 / OD 45 / WID 12

 

If ID are the same on both...this means axles are the same on both, right?

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  • 2 weeks later...

Did some research today at the garage, measured distance left to right inside of the rotors.

 

'07 CBR600RR - 125.5mm

Bird - 134.3mm

 

Now since disc part numbers (and catalog specs) of 600RR and CB1300 rotors are the same, if we presume CB's rotors are 125.5mm apart as well - it would mean a CB wheel with its discs would need approx. 5mm spacer on each side to fit in Birds calipers, correct? Or am I forgetting something?

 

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So you have a 600RR to compare with, correct?   And you measured the disc separation on the 600 and the 1100 as a comparison?

 

By searching the parts books, you surmised that the 600 and the 1300 rotors will interchange, having the same specifications.

 

The gap in the data is that although the 600 and 1300 discs may be effectively the same, you still don't know if the hub width on the 1300 is the same as the 600, and you can't assume the spacing without that information.

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Internet folklore has the inner to inner spacing of the CB1300 discs at 132mm, so it might work with a metal shim behind the disc.  

 

I'm silly, so I'd try it, but I'd certainly want the CB1300 axle and spacers to go by.  The collar width, step off on the axle, and bearing width are what keeps the forks straight so they don't bind with movement.  You'll need pretty accurate measurement to choose the correct bearing width to keep that width

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Thanks for finding that number, I didn't manage to find it, bad google-fu skills :D how'd you find it?

 

This would mean calipers on the Bird are 1mm "out" to fit the CB1300 discs, which seems like something not to hard to retrofit?

 

Also, just as a thought exercise from an absolute layman (me), what if I'd want to keep the Bird's rotors. This is the only solution that comes to mind. The bolts on the outside of this adapter-spacer could be any "length" I presume, or whatever other factor matters for bolt strength. But the inner bolt pattern, where Bird's rotors would go - my question is would shorter rotor bolts even be allowed? Many OEM bikes seem to have 17mm long bolts here...what would happen if 8mm were used, to keep the spacer as "narrow" as possible?

 

Second pic is some aftermarket wheel I found - it seems it uses this very specific type of adapter - spacer? 

 

I feel I'm overly complicating this as is, sorry :D

 

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Edited by FTM
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I don't entirely understand what you're trying to say/ask.  The length of a bolt when using a nut doesn't matter other than being long enough to fully engage the nut.  The length of the factory screws going into the wheel are overkill, but I don't know how to calculate a minimum safe length.  I also don't see how the length of them would matter for using an adapter like the one you showed.

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If going for OEM Bird discs on these wheels, the mentioned adapter would be needed, so that the Bird's rotor bolts have to go somewhere - those bolts are 17mm long, so if the adapter isnt 17mm thick, they won't thread all the way in. What if the adapter needs to be, for example, 5mm - I can only see 2 solutions, one would be shorter bolts, another would be making threads in the hub itself, if that's even allowed, to intervene on a alloy wheel like that?

 

I don't know the basics, for example you mentioned that the factory rotor bolts are overkill - but aren't they crucial, they hold the rotor in place and that rotor needs to be rock solid so the brakes can stop your bike down, or am I thinking wrong? :D

 

 

 

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I think the rotor bolts are 8mm, and ISO standards are pretty vague specifying somewhere from 4 to 12 mm of thread depending on how tight the threads are.  I would not feel exceptionally comfortable with a grip at the lower end of that scale.  Neither am I a certified mechanical engineer so while it may be safe, I don't like it.

 

The lands for the rotor mount are machined from the cast surface of the hub to be parallel with the wheel centerline and by definition, the opposing machined surfaces.  The area you are suggesting to thread the hub is a cast, imprecise surface and the rotor will not be true unless lady luck plays a part in the game.

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2 hours ago, FTM said:

If going for OEM Bird discs on these wheels, the mentioned adapter would be needed, so that the Bird's rotor bolts have to go somewhere - those bolts are 17mm long, so if the adapter isnt 17mm thick, they won't thread all the way in. What if the adapter needs to be, for example, 5mm - I can only see 2 solutions, one would be shorter bolts, another would be making threads in the hub itself, if that's even allowed, to intervene on a alloy wheel like that?

 

I don't know the basics, for example you mentioned that the factory rotor bolts are overkill - but aren't they crucial, they hold the rotor in place and that rotor needs to be rock solid so the brakes can stop your bike down, or am I thinking wrong? :D

 

 

 

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Just picture yourself doing 100+ MPH, tight corner coming up quick, grab a handful of brake lever, and the discs are ripped from the wheel.  You know the rest.

My advise?  If possible, I would use the discs that were meant for the wheel you are going to use.

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10 hours ago, FTM said:

If going for OEM Bird discs on these wheels, the mentioned adapter would be needed, so that the Bird's rotor bolts have to go somewhere - those bolts are 17mm long, so if the adapter isnt 17mm thick, they won't thread all the way in. What if the adapter needs to be, for example, 5mm - I can only see 2 solutions, one would be shorter bolts, another would be making threads in the hub itself, if that's even allowed, to intervene on a alloy wheel like that?

 

I don't know the basics, for example you mentioned that the factory rotor bolts are overkill - but aren't they crucial, they hold the rotor in place and that rotor needs to be rock solid so the brakes can stop your bike down, or am I thinking wrong? :D

 

 

 

4ERa86D.jpg

 

 

If the Bird rotor holes are on a smaller circle than the holes in the wheel, like where the green dots are in that photo, I see no way for the adapter to work.  If the wheel had a smaller circle than the rotors then maybe, but unlikely.  I think the rotors center on the wheel and not on the screws, kinda like car wheels that are hub-centric vs. lug-centric.  If the holes in the rotors and the screws are tapered then the rotors are centering by the screws, if they're flat like I think they are they're relying on the machined 'pads' in the wheel for centering.

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