mrv 

I know, another cone replacement thread - apologies.
here's what I got: https://velobase.com/ViewComponent.a...110&AbsPos=383
- Dura Ace circa '82, hub set. Paid a bit too much to get matching parts for my middling TREK 420.

The front hub has a bit of pitting. Wheels does not have the same OD 16.9mm with a 9mm thread ID.
Loose Screws doesn't have anything in stock. Niagara's shop is not working. Universal has some stuff, but not vintage.

I read an older BF thread about polishing cones. I'm thinking of giving that a go.
Cone into drill press. Slowest speed. 600 grit around a wood dowel, with tap magic. Then 2000 grit. Maybe 800 or 1000 grit in between.

My other thought is to get the Wheels CN-R096, the biggest / longest front hub cone Wheels has, and try that. a $29 experiment. I was going to get new balls anyways.

Suggestions on other websites to search?
Warnings about polishing cones, and altering the radius? (making things worse than having pitted cones)

--- some details of what I got ---
Dura Ace front hub
https://wheelsmfg.com/tech/PDF/hub/hb-7400.pdf
Cone: length 15.7mm. Dia 16.9mm
3/16in ball

squirtdad

Maybe put a a looking for or Want to Buy in the C&V looking or or classified sections respectively

Andrew R Stewart 

Back in the day we considered "polishing" a cone to be producing a mirror finish on a new cone. What is considered here might be better called "regrinding" a cone, much like an engine's valve regrinding.

Regardless of the terms this has been done by quite a few over the years. lathes, drills, die grinders, Dremels have all been used to rotate the cone and/or the abrasive stone. Most stories I have read have had positive results. But than one wouldn't expect a bad response to be crowed to the world Andy

Jeff Neese

I've had good luck resurfacing cones. Despite the conventional wisdom that you are removing the hardened surface layer, and the warnings that they may not last as long afterwards, I've never had a problem. It's easy enough to do, so even if they do develop pitting again, I'll just repeat the process. But so far that hasn't been needed. Several of my bikes are rolling on hubs that I have saved this way.

Hondo6

To be clear: you linked to the Velobase page for the FH-7370. Is that in fact the hubset you got? Because something's not adding up - the page from Wheels Mfg you linked is for the HB-7400. They don't use the same cones.

In your OP, you also say OD of 16.9mm. Did you perhaps mean length?

If so, you might want to remeasure. Shimano's EV for the FH-7370-F gives a different specification for those cones (M9x15.7 for the 100mm OLD version of the hub). Pretty sure the 2nd number is the cone's length. (FWIW: for the
HB-7400-F, Shimano's EV says the cone is M9x16.)

https://si.shimano.com/en/manual/sea...70-F,HB-7400-F

Those diagrams don't give the OD, but the diagrams appear to show cone OD as less than its length for both hubs.

I second the recommendation from @squirtdad above. Regrinding is also an option.

70sSanO

I would probably take a digital caliper and actually measure the existing cone. Race OD/ID, race length, cone length, distance to shoulders, etc.

Once you have a good idea of the original cone dimensions, see if any of the Wheels mfg cones will work. You can print the pics out and extrapolate the missing dimensions. I’m not sure how the seals are configured, but getting the races set properly and being able to get a wrench on them to adjust is the first concern.

If you get a cone that is shorter, you might be able to use different OD washers/spacers and fashion a seal groove with them.

John

Hondo6

Assuming the OP in fact has HB-7370s (-F and -R), seals shouldn't be an issue. Unlike the 7400-series hubs, per Shimano's EVs the 7370-series front hub doesn't appear to have dust seals for the cones. (The rear 7370 appears to have a "dust washer" on the freehub side next to the locknut but nothing of that nature on the NDS side.) Except for the freehub "dust washer" on the rear, the only sealing mechanism for the hubs appears to be their external aero dust covers.

A slightly shorter cone might be useable if otherwise compatible as you suggest, or possibly with very thin spacers/shims. However, Shimano EVs show the axles for those hubs as having a keyway. (Not sure that the keyed washers are really necessary except possibly to keep contaminants out, simply mentioning it as a possible additional complicating factor.)

maddog34

most bearing cones are Surface hardened... that hardened layer is only a couple thousandths of an inch thick...

if you try to remove the pits, you will remove the hardened surface... this will also allow rust to develop quickly, speeding future pitting.

i bought a pair of 7400 DA hubs on Ebay a few years ago.. the front hub had pitted cones... i then found another DA 7400 front hub at a Swap meet... it had Surface Corrosion on the aluminum but the Cones were in great condition... i bought it as a donor... $10.

grumpus

As well as the drill press I'd use a rotary tool with an abrasive burr to re-profile the cone before any polishing, otherwise you're just polishing a distorted surface. But don't expect it to work well or for long - the hard face layer on a cone isn't thick, once it's noticeably pitted it's probably gone too far. You could try case hardening it after polishing, then polish again. My experience of trying to rescue worn hubs is that the cups are probably worn too, so the bearings won't work well even with new cones of the correct type. Often the wear has been caused by overtightening, sometimes when new, rather than total neglect.

3alarmer 

...If I understand you correctly, you just have the hubs, and have not built them into wheels yet ?
My thoughts are that unless you come across some donor hub cones cheaply, you just go with different hubs to build your wheels.

When I build a wheel, it takes me time and energy. I expect to use it for a long time. That front hub sounds like it won't outlast the rim, which would be my goal.

mrv 

Thanks everyone for your input! Folks like y'all keep me paying for a BF subscription year after year.

To Hondo's comments - Thanks for the Shimano catalog. I never think of it - not sure why - but it's very helpful.
The front is the FH 7370 100mm. So the cone is the M9 x 15.7mm length. See pics below, I'm measure ~15.9mm on my dad's old calipers. And ~16.9mm for the OD. In velo base, there are no M9 cones with that large an OD.

-- To other comments: I purchased the hubset from BF to build them up. Sort of in for a penny in for a pound, now. (or for the US, in for a dime, in for a dollar)

-- These hub have these large plastic caps. There's not o-ring or other dust seal. Which is why I was thinking I could use a slightly smaller OD cone. I would lose about 1mm on the radius. There is a key way, so I add spacers and keep the keyed washer to attempt to keep dirt out.
Probably I'll attempt to polish, ride them for a while, then replace the cones after I forget how much I've already spent....


--

Hondo6

Yeah, the Shimano docs are definitely misleading on length vs OD for that cone. In the EV, they certainly look longer than their OD.

Speculation: I'd guess - and this is only a guess, so I could be wrong - that you'd be OK with a slightly shorter cone if the following two are true:

1. It's designed for use on a Shimano front wheel using 3/16" bearing balls; and
2. It's not so short, length-wise, that you can't get a cone wrench on it for adjustment when assembled.

I'm presuming above that Shimano used the same radius of curvature for all of their 9mm axle front cones for hubs using 3/16" bearing balls. That may or may not be true.

I also don't think a smaller OD would be a problem, provided it's not grossly smaller. But I'll defer to our more experienced mechanic commenters on that point.

Best of luck. I'd probably try new cones first or see if I could find another good used set (but good used Dura Ace AX cones are likely going to be hard to find). I'd save regrinding for my last resort option due to the surface hardening concerns already addressed above.

But it's your bike/time/money, so that's your call.

SJX426 

Yeah, this need a little polishing
P1000288 on Flickr

Unobtanium Helicomatic rear hub cone.

The Shimano DA 7400 isn't much different for the rear. You have to watch out for the front because a lot of "7403" hubs aren't. they just look the same. The plastic rings are different too because one cone uses an O ring and 7403 uses a wiping seal that has a larger ID on the plastic ring. I haven't figured out what value there is in rotating the ring between open and close.
FH-7403 cone RS1 1 on Flickr

grumpus

That looks like it got sloppy through wear and neglect, then someone cranked the cone up trying to tighten away the movement - one spin and then crunch.

SJX426 

Don't know. Upon disassembly after purchase, this is the finding. Got rid of the hub.

Hondo6

@mrv : before lacing those hubs, make sure you review this document. The DA 73XX hubs were somewhat unique in that they were designed to be laced differently than most hubs - e.g., all spokes were inserted from the inside of the flange.

https://si.shimano.com/en/manual/sea...271&doctype=SI

Shimano has "renewed" their document repository yet again, and now it can be a hard document to find. The link above works today. It might not after their next "renewal".

If the link doesn't work for you, PM me. I've saved a copy for future reference.

Edited to add: The document linked above is for the 72XX-series hubs. Those were the other Dura Ace level hubs that shared the design. I haven't been able to find a similar document for the 73XX series hubs, but the info should be applicable to both since both share the recessed-spoke design.

grumpus

I quite liked the Helicomatic system. I still have the lock-ring spanner but it's seen much more use as a bottle opener.

grumpus

I think it's fairly evident from the shape of the recessed spoke holes which way they're supposed to go together. I wonder why this "vast improvement over conventional hubs" didn't have more impact.

(No, not really.)

Hondo6

Probably, and the OP seems to be pretty smart. But I've always thought it best to flag a potential issue and have someone tell me, "Yeah, I already knew that" than wish later I had.

As I understand it, it actually did result in a better wheel (stronger). But it's a classic case of an incremental improvement that was too small to make practical difference IMO.

Plus, there's the "tradition" factor ("Spokes are supposed to alternate inside/outside!").

Shimano's done things like this several times. Sometimes they're simply not ready for prime time (Positron). Sometimes they're genuinely good ideas that simply didn't catch on (the 8-pointed "star" nut on some 1980s Dura Ace and Ultegra/600 headsets - gave a better grip on the nut, reducing chance of damage, but looked "odd" and required a special tool). Sometimes they're simply ahead of their time (aero). Sometimes people just don't like them (low normal derailleurs). And sometimes they connect and hit it out of the park (SIS, STI, and numerous others).

grumpus

They've done some great stuff and some weird stuff; I liked the idea of the 600AX pedals but only had a brief opportunity to try them, but Rapid Rise doesn't and what exactly was Front Freewheel System about?

Hondo6

The late Sheldon Brown called the FFS a solution in search of a problem. It allowed shifting while coasting, so I'd put it in the same category as the recessed spoke setup for the 73XX hubs - no real practical benefit in the real world.

Rapid Rise may be in the same category. Supposedly it improved downshifting (can't say for sure based on personal experience, since I've never owned one and have no basis for comparison). But isince conventional high-normal RDs worked well enough, well, seems to fall into the "no reason to reinvent the wheel" category. That's my assessment, anyway.

70sSanO

Unfortunately Rapid Rise doesn’t improve downshifting, especially into the large cogs where the return spring has the least amount of tension.

Rapid Rise will allow someone to dump the cassette faster when not under stress. Think old school single finger paintball.

John

Hondo6

Thanks for the info. As I said above, I've never owned one so have zero basis for comparison myself. Just reporting what I'd read in a generally reliable source.

Reinforces my assessment, actually. Still sounds like "not enough real-world practical utility to be successful" to me.

70sSanO

While this is going OT, the real-world (practical/non-practical) utility is consistent shifting operation of trigger/STI shifters. Although my wife mastered downtube shifters, she was always frustrated riding on (easy!) trails with triggers and incorrect shifting direction. By installing RR it was always push thumb forward to go faster/harder peddling, pull back index finger to go slower/easier peddling. Works the same with STI large lever/small lever.

John

Hondo6

Agreed. Unfortunately, tradition and "normal practice" are very difficult hurdles to clear.

As I recall Shimano wasn't the first to try to normalize shifting lever direction with Rapid Rise, either. If I recall correctly, Suntour tried to do the same with some of their early FDs and downtube/stem shifters by making the FD work "backwards" with respect to everyone else's FDs.

That wasn't successful, either.