# Zipp 404 & 11 speed - tight RD clearance ?



## tom_h (May 6, 2008)

Did a "trial" fit of a new 2010 Zipp 404 wheelset and 2009 Campy Chorus 11 today. 

The very tight clearance of the rear derailleur to spokes is very unnerving. 

Normally I prefer to have a popsicle stick thickness of minimum clearance = 1.9 - 2.0 mm (very high tech !), which is achieved on my Campy Shamal wheelset.

But, I'm estimating clearance between the RD and Zipp spokes is about 1.25 mm :-O
Likely this is "normal", nothing is bent or broken.

My question is, any tips for optimal setup? 
-- Live with the 1.25 mm clearance? 
-- Eliminate any "overshift" to the largest cog, which may slow down the shift to that cog ?
-- Insert a 0.5mm spacer behind cassette for more clearance? I think I have enough outboard clearance to the chainstay.

Note the Zipp wheelset is mainly intended for racing, not everyday use.

TIA.


----------



## setonz (Mar 7, 2009)

To run 11 speed on zipp hubs you need to add a spacer to the free hub body, get in touch with your local zipp dealer and they will be able to help you out.


----------



## tom_h (May 6, 2008)

The only relevant article I saw at Zipp website,
http://www.zipp.com/support/maintenance/campy11.php , 
was adapting Model Year 2005 – 2008 year Zipp Wheels with 82/182 or 108/208 hubs, to Campy 11 : adding a second 0.25mm spacer behind the _freehub_ (not cassette). No mention of spacer behind the cassette.

I was under the impression the 2009 & up wheels (88/188 hubs), were good to go "as is" for Campy 11, but obviously I'm not real happy with the tight RD clearance. I'll call Zipp tech support and dig deeper into this.


----------



## tom_h (May 6, 2008)

tom_h said:


> The only relevant article I saw at Zipp website,
> http://www.zipp.com/support/maintenance/campy11.php ,
> was adapting Model Year 2005 – 2008 year Zipp Wheels with 82/182 or 108/208 hubs, to Campy 11 : adding a second 0.25mm spacer behind the _freehub_ (not cassette). No mention of spacer behind the cassette.
> 
> I was under the impression the 2009 & up wheels (88/188 hubs), were good to go "as is" for Campy 11, but obviously I'm not real happy with the tight RD clearance. I'll call Zipp tech support and dig deeper into this.


ADDED:
I suppose there's a remote chance that one of the two 0.25mm spacers that are supposed to be behind the _freehub_ is missing, due to incorrect assembly. I'll listen to what Zipp says, then if necessary I'll remove the freehub & double-check for 2 spacers.


----------



## tom_h (May 6, 2008)

*Zipp's reply ...*

Talked to Scott (?) @ Zipp tech support.

He said while 2 x 0.25mm spacers behind the campy freehub is normal setup, Zipp approves up to 3 spacers. He will mail out extra spacers to me :thumbsup: 

That should provide the extra safety margin. It appears I have enough outboard clearance between the lockring & chain, to the frame stays.

Remains to be seen, if I'll always have to re-adj RD everytime I install the 404s  , or whether the extra spacer will simply push out the freehub to match my other wheels.


----------



## tom_h (May 6, 2008)

*more measurements*



tom_h said:


> Talked to Scott (?) @ Zipp tech support.
> 
> He said while 2 x 0.25mm spacers behind the campy freehub is normal setup, Zipp approves up to 3 spacers. He will mail out extra spacers to me
> 
> ...


While waiting for that third 0.25mm spacer to arrive, did some more measuring of clearances

*Zipp 404 *(2010 tubular, model 88/188 hubs)
RD – Spokes: 0.94 mm.
Lock ring – chain stay: 1.03 mm.

*Powertap Elite Plus hub w/ Velocity Deep-V rim* (2010 clincher)
RD – Spokes: 2.2 mm.
Lock ring – chain stay: 1.62 mm

*Campy Shamal Ultra* (2009 clincher)
Didn't measure, didn't want to swap cassettes ;-)

The Zipp freehub is already pushed outboard more than the PT freehub. Optimal rear derailleur adjustment mandates re-adjust every time I change wheelset :-( 

I would also have to change pads (alum vs carbon rim) , and widen rear caliper separation at every wheelset change (the Zipp rim is ~5mm wider than the Campy Shamal and Velocity alloy rims).

Undoubtedly I will get very fast at this :-/

Inserting a 3rd Zipp 0.25mm spacer behind the freehub will reduce the lockring-chainstay clearance to 0.75mm, but that seems safer than tight RD-spoke clearance. It will also "worsen" the RD alignment difference between the PT and Zipp hubs.

All this is a consequence of the different hub designs. The Zipp 188 rear hub is well-designed for maximum flange separation (laterally stiffer wheel), but not likely I'd notice it.

If I was starting over from scratch, I'd give more thought to standardizing on one hub make & model for all my wheelsets, as this would make the rear derailleur alignment issues disappear. 

But since I can't afford a crank-based powermeter, and pedal powermeters are still vaporware, hub standardizing isn't yet practical for me.


----------



## Eric_H (Feb 5, 2004)

Thanks for the measurements. The differences that exist between hub manufacturers seems to be worse for 11spd than 10spd, which makes sense as the cog spacing is tighter and therefore the margin for shifting issues is narrower. I am stil on 10spd and I use Campy Eurus or Fulcrum R3 for training, and Edge/DT240S for racing. I know there must be a subtle difference in the DT geometry compared to Campy for the freehub/dropout as I find I need to make a quick adjustment with the barrel adjuster when I change wheels to eliminate a bit of noise. But I do not have to resort to adjusting the high limit screw on the derailleur.

IME, the easiest way around the brake pad swapping is just to have another set of pad holders complete with your CF brake pads of choice. It is much quicker to simply swap the entire pad assembly than have to yank the pads in and out of the holders. Swap pad holders, line up/toe in, and then let out a bit of cable at the anchor bolt for the wider Zipp rim. Less than 10 minutes, done anywhere.

You could avoid all of this hassle (but the brake pads) by buying a set of Campy Bora Ultras for race wheels, same freehub and rim width as your Shamals. Then swap over to a SRM to eliminate the PT/Velocity setup. Surely you have an extra $8K kicking around??


----------

