Topic: Which weighs less? Front wheel hubs

[slikwilli420]

Which one weighs less, the earlier k2-k6 or later k7/k8 hubs? Doing a new front wheel for my race bike and was curious.

[slikwilli420]

Anyone? I would think the later hubs would be lighter, considering the design with them being cut out around the thru bolts for the rotors.

[754]

 I think so too, but Have not confirmed. I prefer the older for looks.
If you have a lathe, just make one flat track style, dont worry about screw in retainers.
Would be way lighter than stock.

[slikwilli420]

 Make a whole new hub or modify and earlier one? What do you mean by "forget about retainers"? Anything I can do to get lighter I will consider.

[DaveBarbier]

Yeah you could put the hub in a lathe and remove the center ribs also (if these hubs are the same as the 550 hubs).


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[ekpent]

 Friend of mine has the ribs removed on his rear hub on a 750 and a high shine polish. Looks nice and different and easier to keep clean.

[slikwilli420]

My current race wheels have been de-finned as well and it does look nice without a doubt. I figured since I was building new wheels anyway, I might as well see if someone had weights of the later and earlier versions. Based on the way the later ones are configured, I would say they are noticeably lighter but didn't want to buy anything until I knew for sure.

[754]

 Flattrack hubs and Morris mags do not use retainers, bearings simply pushed into hubs or into side plates. Still use a center sleeve.
Maybe a late one is a bit lighter, but you are racing  look at the pic.
Make your flanges near stock dia and re use your spokes..

[slikwilli420]

That is killer and exactly what I am looking for. I need to call them to get a price.

[754]

 They are 200 and up just make one .
 Sometimes 100ish on ebay.
If you make flange right diameter. Use your spokes., if you want to run 18 inch make the spoke circle 1 inch smaller.

[bwaller]

What have you decided to use on the rear?

[slikwilli420]

They are 200 and up just make one .
 Sometimes 100ish on ebay.
If you make flange right diameter. Use your spokes., if you want to run 18 inch make the spoke circle 1 inch smaller.

The cost of material and time makes it not worth making on my own. I'm still wondering which hub weighs less but I like the idea of the billet deal.

[slikwilli420]

What have you decided to use on the rear?

I have a billet quick change I will be modifying for that task. Using a Ducati monster rotor and custom carrier and an additional bearing carrier for the sprocket side. Lots of work and figuring but it should save me at least 10 pounds.

[754]

Man you got too much coin, I think..
 25 or less for material, 6-8 hours machining if you are not used to that work.,  I don't sneeze at that kind if work..
 Besides its fun, and pays for your lathe.. and you can say you made it..
Btw only precision is the bearing fits, and be 90 degrees on the ends to mount rotors..
 Itisceasy if you think it through first...

[slikwilli420]

Man you got too much coin, I think..
 25 or less for material, 6-8 hours machining if you are not used to that work.,  I don't sneeze at that kind if work..
 Besides its fun, and pays for your lathe.. and you can say you made it..
Btw only precision is the bearing fits, and be 90 degrees on the ends to mount rotors..
 Itisceasy if you think it through first...

All about cost/benefit ratios Frank. That much time would be better spent on things I cannot buy off the shelf. My lathe won't take a piece that big nor can I buy it that cheap either. Just not worth the headache to me.

[scottly]

If the center of a K7/8 hub was machined past the humps over the bolt holes, short bolts with nuts could be used to fasten the rotor to the hub, like with the flat-track hub? Mount one side in the lathe chuck, and support the other end with a tail-stock center in the inner bearing race. No precision required, and can be done on a small lathe.
 

[754]

 I think that would leave holes open to center of the hub.

[scottly]

There is about .700" of material between the bottom of the bolt holes and the through-bore of the K7 hub. Cutting the inside face to allow clearance for the stock flange nuts would still leave about .500" of meat. If the bore of the early hubs is the same, about 1.450", then the same method could be used.
 

[754]

So if cutting thru will not window the hub, another alternative,may be to insert heli coils in the bolt holes.. Then you need no nuts..

[scottly]

Stock bolt holes may be too big for heli coils?

[RAFster122s]

Would Timesert get around the current bolt hole issue?  Too bad you can't fit a T nut style insert from behind to lock the hub to rotors. If you had a 3 piece design with center hub being a tube with couple ears inside the hub center to  lock it in place.  A recessed screw loose could lock the hub to the carriers. Might be easier to TIG ears on as long as you would not warp the hub center edges doing that welding.  The machine work would be far easier to cut the center tube if you didn't need to maintain the attach points and could tig them into place...

David

[DaveBarbier]

Stock bolt holes may be too big for heli coils?

Helicoils go up pretty big. I see M39 as the max on a few charts. As long as there's enough depth to the hole so the coil isn't sticking out, should work fine. Those holes are probably about an M8 size anyway. Not a problem I think.

[Swoop]

Early hub weighs  3 lbs 5.95 oz.
With bearings and retainer

[slikwilli420]

Early hub weighs  3 lbs 5.95 oz.
With bearings and retainer

Thanks Dowelpin! Now I just need the same for the later hub.

[gschuld]

I weighed both bare hub types back to back and found they were nearly identical in weight.  I have a bare late hub on the shelf and I can grab an early hub from a wheel I was going to dismantle anyway.  I can weight them again if it matters.

George