hello guys i am building a custom trailer(actually i built already) and have a problem.. don't know how to attach trailer to my bicycle...well i have searched Internet but could not found trailer attached to a seat-stay....i now some trailers that ae attached in other ways...but i would like to find a hitch that will allow me to attach my trailer to a seat-stay....any ideas? or will this way damage my bike?

Photo would help is this a single wheel trailer or double wheel how long is it and do you need it to pivot and mount point?
ANd are you looking to have the mount point high on the bike frame or low? you say seat stay so are you looking to get it up near the saddle.

sorry don't have a pic.....i just combined aluminum tubes and attached one wheel...one the combined tubes i am going to put medium size suitcase.....the lebgth is about 70-80 com including wheel. so because its single wheel...i need double mount....i am planning to install hitch about 5-10 cm from the end of cassete. here is a link of my bike.......https://www.bikeforums.net/showthread...............so if u sea where is cervelo writen....i want to mount hitch between first letter 'C' and end of last cog.......i am searching for easy mount.....i am planing to travel and stay in hotels...so i want easy hitch to mount and unmount quickly the trailer.....

I have a tag-a-long bike for my daughter that attaches to my mtb on the seatpost. Is that something that would interest you if so I can take a pic of how it is attached and post it it may be of some help let me know.

Only left Chain/seat stay back corner will do.. Bike friday uses a quick disconnect hose fitting
used in Industrial Airtools, the male end usually on the tool being powered,
the F part on a section of hose. [you would attach that to your tow bar.
that usually is a long hose to a big diesel powered compressor in like shipbuilders facilities.

no i prefer to attach my trailer to seat stay rather then seat post or wheel.....

could u plz give me a link...anyway i think i have to attach it to broth sides to have more stability.....so on the right side i wont be able to attach...thats reason i want to attach on seat saty......to reach borth sides

i have two main prob to solve
1.I don't know how to attach my suitcase on trailer, suitcase is medium size and trailer is built plate of aluminum tubes
2. looking for seatstay trailer hitch with quick release.

anyone can answer plz?

There are a batch of different, homemade bike trailer devices at the following link. None of them are exactly what you are describing, but may give you some ideas.
https://www.instructables.com/id/Bicy...-hose-couplin/

could not find the one i want......maybe u could give me a link?

Depending on your bike's dropout spacing you may be able to fashon something using an extra long quick release skewer. Burley used to offer an "alternative hitch" for their d'Lite trailer that used that method.

You've gotten a number of answers and suggestions and rejected all of them.

well i was thinking to attach trailer to frame rather then wheel.....but i will keep in mind...thank u for reply...its so strange have not seen trailers which r mounted to seatstays......

well.....i am looking a little bit different mount that ones were suggested

Perhaps you should go talk to a local who has a welding shop and have them make something for you.
that is , Where you live..

Advantage they can see what the heck you are talking about..
this, thread, seems, picture free, on your offering, text is going no where..

lol.....if i ask here...1 there is no bike shop...2. i defiantly know they wont know 3. i just want trailer hitch that removes very quickly....and is mounted on the frame where seat post and cassette are connected (seat stay)......i don't want to be mounted on seat post because it looks ugly and i don't want it attached to wheel because to take it of is not easy....well i m planning to travel and planning to stay in hotels...so i have to unmount my trailer every day....so i am looking easiest and most comfortable mount..

If you posted pictures of what you have then maybe someone could really give you an answer that meets your standards. You posted pics of your bike, you should be able to take some of your trailer and post them as well.

my trailer is in other city.....to the guy who assembled it...i know sounds weird

I just re-read your posts and noticed you said it was a single wheel trailer. As far as I can tell, you would be best off mounting the hitch to the drop out area by the rear wheel on both sides.

I found this link at the indestructibles website: https://www.instructables.com/id/Sing...ching-to-Bike/ if you look at the page before it as well, it gives more detailed pictures.

You will need something like that. if you have to take it apart quickly, just get a couple of larger wingnuts to replace the standard nuts so you can easily spin them off when you get to your destination.

I noticed that the guy used a nylon locknut to hold the nuts in place by the pivot point. That way he could leave it a tad loose so that the trailer can pivot up and down. You probably won't find a larger wingnut with a nylon insert but what you could do is find a stepped collar of some sort. I found a picture of what I'm talking about: https://rickramsey.net/CRF230Flg/SeatBoltCollars.jpg You would then drill the hole on the trailer frame larger to fit around the smaller step on the collar. Then when you tighten down the wing nut, there should be enough clearance on the smaller step and the frame of your trailer to allow it to pivot even after the wing nut is tightened down firmly.

good decision thank you for your help....

I think something along this design would be best for your design trailer and has a good pivot point.
If you don't want to use the axle mount and still want to use the seat-stay's since you seem to be making it yourself, I'd take some round tubing 6" or so long for stability the size of your seat stay cut it in half line it with some old tire tube to give some protection to the frame paint. I think I'd also add something to the chain stay to make it triangular for strength.
Alter the design on the Bob design to fit the new mounts make some type of clamping system for the half tube to the stays hose clamps would do but I'd prefer something a little more solid.
And good luck on your trip and for something like this I'd want it on good and tight.

Here's some photo's for ideas. Should be pretty easy if you have a hardware store nearby or a welder available. My trek trailerbike is "loose" around the the seat post and does not have an additional pivot point. Others are tight on the seat post and have an additional pivot point. I like the rack connections.

The only problem is that the OP built a single wheel trailer. It needs 2 attachment points on either side of the bike frame. You want the attachment points rather spread apart so the leverage isn't concentrated which could allow the trailer to twist out of line with the rest of the bike. The OP mentioned that he wanted to attach the trailer to the seat stay. The more I think about it, the worse of an idea that would be for a single wheel locked frame trailer to use a seat stay or seat post as a lock point to keep the trailer lined up with the rest of the bike.

You want to have a rather wide attachment point for the trailer frame. That way it spreads the leverage across a wide point and doesn't concentrate it all at one point. The seat stay is only about 34mm wide. The rear drop outs are about 135-150mm. Best to attach the frame to the drop out area.

If the trailer was a 2 wheel trailer, then you would only need one hitch attachment point since there would not be any appreciable side loading. You could then use the seat post as the attachment or even the seat stay.