ZippyDan

EDIT: I am "bumping" and editing this because I still haven't found a solution to my need. My original post follows unedited, but skip down to my most recent post at the bottom of this thread for updates. I am now looking for a "standard" quick-release seat clamp, but with a longer bolt (a.ka. "skewer").

ORIGINAL POST FOLLOWS:

I'm planning to mount a Tern Cargo Rack to a Tern Joe P24.

According to the Cargo Rack page, mounting to a Joe P24 requires "a longer quick-release seat clamp skewer."

I tried reaching out to Tern directly, and they said they no longer have any stock of these "special" adaptors.

I asked for more information and they told me I would need a "quick-release seat-post clamp w/rack mount eyelets" and provided this reference picture:

Tern seat clamp for Cargo Rack and Joe P24

Where can I find an adaptor like this? Will most bike shops recognize this or have this in stock? Are terms like "longer quick-release seat clamp skewer" or "quick-release seat-post clamp w/rack mount eyelets" universally understood and easy to find?

BromptonINrio

Not many shops would have those on stock.
whats the size of the clamp?/

fietsbob

Your situation may mean the Bottom support is the wheel axle QR skewer...
may want a longer one from Shimano's Tandem Hubs, which are 145 rather than 135,, over-locknut dimensions ..

things not sitting in stock on speculation in anticipation of a sale, can be supplied by you asking them to do so..

they seem to suggest you use the skewer of the existing seat post QR,
foregoing the QR height adjustment, you can just seek out a longer bolt & a Nut..

OP needs to measure the seat tube diameter.










...

2_i 

When I google "seatpost rack adapters", I get tons of hits, such as the one here as in your picture. You may need to check the seatpost diameter and figure out whether you need a quick release bolt that can be purchased separately. Maybe a spacer is needed somewhere and a local bike shop may finish the installation off when you bring them the adapter and rack.

tds101 

I can see where this part would come in handy. My rack is a wee bit tilted,...LoL! This part would work out just fine,...I may need to get it myself.

Seatpost Clamp with Rack Mounts

PS: It's also available on Amazon: https://www.amazon.com/s?k=Seatpost+...ref=nb_sb_noss

ZippyDan

Thanks for the help guys.

I don't have the bike with me at the moment, but I reached out to Tern again and they told me I need a 34.9mm or 35mm seat-post clamp.

I'm only concerned with matching the correct dimensions of this clamp, both in terms of the inner diameter of the clamp, but also in terms of the "longer" description.

I'm a bit of a noob when it comes to this topic, and I'm just wondering what qualifies a seat-post clamp as "longer", and I'm therefore worried whether I'll by the right adaptor.

2_i 

The way that I understand that this should work is that you replace the visible bolt there in the clamp with a quick release bolt. The latter is a bolt that you can tighten or loosen, just by flipping a handle. When you loosen the clamp, you can move the seatpost up and down, which you need to do when folding and unfolding the bike. However, maybe someone can chime in who has such an arrangement. I use the particular rack on Bike Friday NWT, but there I can secure the rack to the rear triangle, i.e., I do not need to resort to the seatpost attachment.

ZippyDan

So, I received the quick-release seat-post clamp w/rack-mount eyelets that was recommended to me by Tern customer service.

It "works", however:

As you can see from the original picture, it is not a quick-release seat clamp. Obviously, I knew that when I bought it, but I thought that this problem could be easily remedied by simply buying a quick-release skewer and swapping out the included hex bolt. I WAS WRONG. The way that the eyelets protrude from the clamp, and the additional bulk of the cargo rack support forks which attach to said brackets, prevent the quick-release skewer from operating. The quick-release lever is just too bulky.

Bottom line: the seat-clamp recommended to me by Tern support just doesn't work if I want to retain a quick-release functionality. And I do need that functionality, as several people in my household share the same bike, and the seat height needs to be regularly adjusted.

So, I ran across this page on Tern's site: https://www.ternbicycles.com/en/supp...ease-extension

I'm not sure why I didn't see it before. Maybe I'm bad at google, or maybe they only recently made it available online, or maybe google only recently found it. Anyway, as you can see, the cargo rack is attached to the seat-clamp, not via additional eyelets, but by attacking to an extended quick-release skewer. Looking at the original instructions from my original post, this is exactly what the official Cargo Rack page said I would need...

...yet my interaction with Tern customer support via e-mail left me thinking I needed something else entirely (a seat-clamp with rack-mount eyelets).

So now I need to find this mythical "extended" quick-release skewer. If I can find one, I'm also wondering if it might be possible to use the seat-clamp with rack-mount eyelets, together with the extended skewer, and then use the extension to "pack out" the quick-release lever (with metal or plastic washers/spacers) so that I can have enough clearance to manipulate the lever.

Sardines

Ah this old problem. I have a P24 and P27 tour. All you need is a 60mm or longer (usable length) QR skewer, The problem with using a longer QR skewer is if you use the QR often as I do, you will have to adjust the acorn often.
There is this adaptor from Bicycle Warehouse that works if you don't use your QR often, because the rack mounts will make it harder to slide the seat post down.

If you are more handy, this was my final solution for my P24, the Topeak extra long arms, which you will need to bend to make work. I can't posts links yet sorry! ahha