Baby Puke

People, I need some serious gearhead help.
Backstory- I've always had some issues with my Zipp 900 disc. Right out of the box, the spacer between the bearings seemed too small, so that putting the correct torque (6ftlbs?) on the axle locknuts caused the bearings to over-preload. So right away, I had some notchy bearings, and had to get around the preload issue by using blue lock tight and tightening the locknuts so that the play was *just* taken out.
Anyhow, that didn't keep my drive side bearing from self destructing during a kilo this year. Thankfully in the first half-lap, so I got a restart (and still finished 2nd). After returning home, I had the bearings replaced, but since then there is radial play between the axle and the bearing inner race, noticeable play that should NOT be there. I tried talking to Zipp warranty, but no dice. I've been talking to the machine shop attached to my university here, but it's looking more and more that the only way to remedy this is a full re-fabrication of the entire axle assembly, which I'd like to avoid.
So I need a favor: Is there anyone out there who owns a Zipp 900 AND a micrometer/caliper? The inner dimension of the 81602 bearing is 15mm, and my axle is measuring 14.90mm, at the bearing seat and along the whole axle surface. Is there someone who could measure their axle at the bearing seat areas and give me a number?
It's a long shot, but thank you in advance if anyone can do this!

topflightpro

BP, can you post some pics of exactly what you want measured?

I've got that wheel and axle. I don't have the Micrometer, but I might know someone who does and could borrow it to take the measurements. I'm just not 100 percent clear on what you need.

rustymongrel

I have both a 900 and a micrometer!

It might matter what generation hub you have, so I'd suggest posting pictures.

Baby Puke

You guys rule. The wheel is at my office, so can't take photos until Monday, but it's the previous generation 900 with the 182 hub. You know, the one with the NLA axle! I just need the axle measured where it sits under the bearings.

Baby Puke

Below are a couple of images of the 182 track axle. The technical drawing has the areas of the axle I need measured highlighted. Major hi-fives to anyone who can accomplish this for me.

rustymongrel

I measured mine with my mic. NDS bearing surface was 0.5894" and DS was 0.5891"... so 14.95~14.97mm

When the axle is slipped through the bearings there is noticeable play. Once the DS locknut is tightened the play is eliminated. On my wheel the DS locknut tightens against a spacer which slips over the axle and pushes against the bearings inner race.

I posted a detailed account here once on how to use Miche Primato hub hardware on a 900. The Primato uses a 10mm threaded solid axle with "cones" and lock nuts for 15mm ID sealed bearings. It allows you to set the preload and lock the nuts against the cone; doing away with the centre sleeve. It's probably less rigid than the stock track axle.

I have a lathe and may be able to make a replacement if you don't mind a long lead time.

Baby Puke

Thank you so much Rusty! Yeah, it looks like I lost some clearance there. Just as a comparison, I disassembled my Mavic iO and Corima four spoke to compare the amount of play in each. The Mavic is a slight interference fit, so zero play, and while the Corima was not, there was little to no radial play even with the locknuts removed.

That's very interesting about the Miche Primato axle. This is plug and play, no spacers need to be made to center the rim? I've been looking at hub/axle designs and the Mavic Comete also lacks a center sleeve, so it can't be that bad! Alternatively I may look into shims to get the center sleeve usable, or have a local replacement made out of steel.

Thanks so much for the help, that is massively useful to me!

rustymongrel

The Miche bits do require extra spacers and it's not all that perfect as the NDS cone is difficult to adjust being so far inboard.

One could make a new axle that has a similar preload adjustment to the newer Zipp discs. That's probably what I would do if it were me, I like being able to fine tune the bearings on my Super-9.

Baby Puke

Rusty, can I ask you about the dimensions of the super9 axle? I wonder if it could be retrofit to the 900 with a bearing change. What is the diameter of the axle at the bearing seats?

rustymongrel

It's larger, 17mm I'm pretty sure.

rustymongrel

I looked into this, the 900 has 24mm OD bearing seats and unfortunately 17x24 bearings don't seem to exist (the Super 9 uses 17x26 and 17x30 bearings).

My offer to machine a new axle for you still stands... I like projects

Baby Puke

Hey Rusty, thanks for the offer. I may take you up on that, but first I'm going to have the inner spacer remanufactured locally to the proper length and out of studier stuff than the original aluminum, and see if that tightens things up enough. Second option, I'll give the Miche axle a go, and if that fails I may talk to you about a new axle. It does look like a pretty complicated piece though. It has my local machine shop stumped at the moment.

Baby Puke

*facepalm* Fixed it. Seems the shop did not seat the bearings all the way, so it appeared the spacer was too short. On a hunch I rigged up a low-rent "bearing press" (front road QR skewer and random spacers) and was able to take the slop out. Tightened up the axle as it should have been from new and things are tight. Dinged the bearings in the process, once they are replaced should be good to go.

Disturbing thing is that the bearings were not completely seated initially from the factory. Three years of head scratching put to rest in a few moments of blind desperation. Duh. At least it's a happy ending.

Thanks for the advice and assistance all!

edpwh

Hi, I'm looking for 182 track axle but out of luck. You mention you had a Miche Primato hub hardware on a 900 could I have more information on that?

Thanks