Tandem Cycling - Zipp 808 tandem wheelset

Precision Tandems has a Zipp 808 tandem wheelset on their webpage. Anybody happen to have experience with these wheels?

I talked to Zipp awhile back about building up a set of 808 Clydesdale rims on tandem hubs. The rep told me that the 145 mm spacing would make for a problem with the acute angle between the spoke and the hub, and therefore Zipp would not warranty such a wheel.

I've got a call in to Precision tandems to get their take.

Any thoughts?

I have a friend in our racing club who has a Zona tandem that he uses in District and National Championships. It has the 133mm ??? (single bike) spacing. He uses stock Zipp Clydes as one of his wheelset choices. However, his male/male teams do not go over 300 pounds.

I would assume that the 808s on Precision's website are built using clincher Clyde rims. However, I assume there is a weight limitation put on by Precision. I suspect they would be fine for TTs on certain courses but would require more thought and analysis for road races / criteriums.

Which hub were you planning to use?

While attending SAMPE in MAy, I spoke with a couple of guys from ZIPP. I too had interest in building some aero wheels and consulted their advice.

They indicated the possibility of just buying the rims, with spoke count of my choice. They did indicate there would be some lead time but felt it could be done.

My plan was to go 36 hole rear, 32 hole front and lace them to Hugis. Those rims alone are big $$$$$$$$.

PK

Precision Tandems has them with White Industry hubs. The problem as I understand it, is not the spoke count, but the 145 mm spacing.

Why would a 145 rear be different? The spoke angle from rim to hub trying to break out the carbon fibre around the spoke hole? Guys I spoke with indicated they could do virtually any drilling, one would assume this is spoke bed angle also.

This leads into my second plan, and that was building faux 808's. I'm waiting for someone local to ruin one of these rims, but not so bad I can't pull a mold from it.

PK

Why would a 145 rear be different? The spoke angle from rim to hub trying to break out the carbon fibre around the spoke hole?



That was the reason the Zipp rep gave when he said they would not reccomend it, or warranty it.

I'm betting they didn't put a ton of thought into that answer. If the nipples were up near the rim strip (I don't think they are) it is a possibility that their spoke hole clearances in the rims are really tight, and they don't want the middle of the spoke rubbing the inner edge of the deep rim. Given that this is not the case, I can't imagine the side loads are that much different at 45* than 35*, especially if you can put a high flange fixed gear hub (shallower spoke angle) hub on them. I think your route of calling Precision sounds like a good plan.
Alternatively (and yes I'm biased), call Hed about a similar depth rim as I know they've done 145 hubs for things in the past.

Note: Post edited when I remembered how the 808 is constructed.

Why would a 145 rear be different? The spoke angle from rim to hub trying to break out the carbon fibre around the spoke hole? Guys I spoke with indicated they could do virtually any drilling, one would assume this is spoke bed angle also.

This leads into my second plan, and that was building faux 808's. I'm waiting for someone local to ruin one of these rims, but not so bad I can't pull a mold from it.

PK

As in making a fairing of the same shape and bonding it to an aluminum rim? Not bad Idea (That's basically a Hed Jet), but as a heads up, you're going to have a good time placing the spoke holes where the middle of the spoke exits the fairing.

Guys I spoke with indicated they could do virtually any drilling, one would assume this is spoke bed angle also.






Went ahead and bought them. Talking with Mark at Precision Tandem. The wheels were built by Dave Walker (the Paketa tandem designer) They're laced to White Industry hubs and have 32 spokes.

Given that the regular 808's have 16/20 spokes, and the 808 Clydesdales have 24 spokes, I'm thinking that they must be custom drilled, and that they took care of the spoke angle drilling them.

Went ahead and bought them. Talking with Mark at Precision Tandem. The wheels were built by Dave Walker (the Paketa tandem designer) They're laced to White Industry hubs and have 32 spokes.

Given that the regular 808's have 16/20 spokes, and the 808 Clydesdales have 24 spokes, I'm thinking that they must be custom drilled, and that they took care of the spoke angle drilling them.


This was the impression I got. Just not a rim you can get off the shelf.

PK

As in making a fairing of the same shape and bonding it to an aluminum rim? Not bad Idea (That's basically a Hed Jet), but as a heads up, you're going to have a good time placing the spoke holes where the middle of the spoke exits the fairing.

I wasn't going to bond it to the rim. Plan was to make 5 internal ribs, bonded in place on fairing, to rest against the rim ID. The fairing would be a two piece setup, with a small flange along the inner circumference. A series of small low profile screws and tape would secure the two halves.

As for the spokes, I was considering slots as opposed to holes.

It might just be easier to build a light but strong disc wheel from Carbon / Nomex honeycomb. Then I can use any hub with proper axle width, tandem rated drive coupling. Bond the hub and rim to the core, and sculpt the core to shape. Add the face sheets and cure them. It will take two alignment tools for the hub/core/rim setup, and a set of cheap bearings with no grease for the 250 degree cures.

I need more free time to do this important stuff, I wish work was more understanding about priorities.

PK

I've done discs (worked @ Hed for a summer). Getting a nomex cored disk true can be a bit touchy, and you really only get one shot. Honestly, I recommend making thin carbon or fiberglass/thinfoam disc covers for your wheel. You won't have to worry about it breaking, it'll be lots cheaper, lots easier, and to reiterate, lots safer too. You'll also be able to take them off, and won't have to get another cassette/tire. Given that you made them yourself, it may also be lighter. Disc wheels are cool, but when I make stuff for faired recumbent projects it's always disc covers.

I have a Calfee tandem and have thought about a set of Zipp wheels. Mike, the sales manager at Calfee, says they have a wheel builder that will build you a set of Zipps with 32 spokes on White Industries hubs. I bought my bike at Hubbub up by Cleveland, OH and they said they could build me a set of Zipps for my tandem. So, I believe there would be many wheel builders that could get Zipp to drill the rims with as many spoke holes as you need and you choose the hubs and spokes and you've got yourself a pair of Zipps for a tandem.

From an article on Velonews (http://www.velonews.com/article/92589/part-2-of-zack-vestal-s-profile-of-wheel-maker-zipp) about Zipp.

"Zipp rims are not drilled for spoke holes until an order comes in, permitting custom spoke counts and hub selection."