Thorn Cycles Forum
Community => Thorn General => Topic started by: macspud on August 20, 2025, 11:40:18 PM
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I saw this Thorn Nomad mk3 on Ebay and noticed what looks to be weld breather holes on the seatstay. Are they usually like this? Seems a good way of filling the seatstays with water.
See pic 3 & 9 top inner of both seatstays.
https://www.ebay.co.uk/itm/326729550054?_skw=rohloff&itmmeta=01K34R21JZ8YZSTFWSX5SE09NA&hash=item4c129948e6:g:ae0AAeSw0TtonJfv&itmprp=enc%3AAQAKAAAA4FkggFvd1GGDu0w3yXCmi1fX8jGexqCR7n6ybXwZbWw6Asoc0jJ6Hd0FOn24382sBToPlxhB%2BgEPm9JTo56u6fJmSaWkBtmqJ55EfK5TXGeArHRUAHyk0jsFFwAspWg7EpzBYXWdTsc56IcJBb66C6qlJbT32MkWwF2CSJMuKvA4723CPFo%2FUu5wnCtpX2W6cqcEkoUs4oCkXFb4c7L4%2F2qkmaQzefvmdIocrBc1cqU3ktTLEGAZe1xZ1LJSbWjDtzf1h6D04AHT3Vfa5B34jPwW9p%2FPjhgzZpvyW2FI038q%7Ctkp%3ABk9SR-aZiJiZZg
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Yes it's usual. At one time I also thought it might be an issue, but it hasn't been, I had one bike for 20 years with breather holes in a similar place. The Mercury also has uncovered holes, down by the dropouts. Frame builders are apparently divided on the subject, the argument being - Keep all moisture out V;s Let the frame breath. Periodically, I spray the inside of my frames with rust inhibitor (I use ACF-50, but there's plenty of choice) I wouldn't get such good coverage without those holes. I'm not saying anyone needs to do that, but it keeps me happy.
Very observant of you too spot those holes from that advert, I was mostly too stunned by the price to notice anything else.
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As a hobbyist framebuilder, I plug my frame and fork breather holes with kneaded beeswax after painting.
It repels water and can be poked-out if future access is needed to respray tube interiors or if you change your mind about plugging the vent holes.
Kneading beeswax transforms it, removes any tendency to flake and makes it moldable, useful also as a natural threadlock compound. I have used it successfully for decades on threaded headsets and old-fasioned adjustable loose-ball bottom bracket cups to prevent loosening. I use Blue (medium) Loctite, anti-seize, or assembly lube as appropriate for other threaded applications.
Best, Dan.
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Yes it's usual. At one time I also thought it might be an issue, but it hasn't been, I had one bike for 20 years with breather holes in a similar place. The Mercury also has uncovered holes, down by the dropouts.
I think if I have to have holes I'd prefer the holes at the bottom where any water ingress will drain rather than at the top where any water ingress will pool. Especially if not using mudguards as is the case with the bike in the listing.
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Very observant of you too spot those holes from that advert, I was mostly too stunned by the price to notice anything else.
The listing is for frame only
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As a hobbyist framebuilder, I plug my frame and fork breather holes with kneaded beeswax after painting.
It repels water and can be poked-out if future access is needed to respray tube interiors or if you change your mind about plugging the vent holes.
Dan,
I will have to get some beeswax, to seal the holes after spraying in some of PH's ACF-50.
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Very observant of you too spot those holes from that advert, I was mostly too stunned by the price to notice anything else.
The listing is for frame only
Yes, at first glance I thought it looked decent value for the bike. Then I noticed it was just the frame, well used (To put it mildly) for more than it originally cost!
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This must be the Thorn Audacious derivative we seldom see, thankfully.
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Very observant of you too spot those holes from that advert, I was mostly too stunned by the price to notice anything else.
The listing is for frame only
Yes, at first glance I thought it looked decent value for the bike. Then I noticed it was just the frame, well used (To put it mildly) for more than it originally cost!
Yep, it is a steep asking price but I'd guess it includes fork (maybe not) though its not got rack mounts, so... A new Nomad mk3 frame from SJSC is £999 not including fork. The listing is for £797 or best offer so some leeway for a more realistic price. Its definitely seems to have had a fair amount of use. What would you think to be a reasonable price? About half that?
On another note. What is the parachute like addition under the handlebars? 🤔
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A new Nomad mk3 frame from SJSC is £999 not including fork. The listing is for £797 or best offer so some leeway for a more realistic price. Its definitely seems to have had a fair amount of use. What would you think to be a reasonable price? About half that?
The listing is for frame only. Things are worth what people will pay, as a best offer we may never know what someone values this at. I'm not going to guess, but when I sold my Surly Ogre frameset on eBay, well used as a delivery bike for two years, I was happy to get £120 less than I'd paid for it, which was by then around half the current price.
On another note. What is the parachute like addition under the handlebars? 🤔
It's a handlebar cradle, popular with bikepackers for light bulky loads like sleeping kit, here's an example:
https://winstanleysbikes.co.uk/aeroe-spider-handlebar-cradle
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Interesting.
I was sure that my Nomad Mk II and Sherpa did not have exposed breather holes and I thought somewhere that I read that Thorn frames do not have them.
I copied this from the brochure I relied on when I ordered my Nomad Mk II frame and fork in 2013, I added underline for emphasis:
... ...
In order to do this, I contacted the finest frame
builder in Taiwan once again.
These people make the top end models of some very
famous American brands!
The first time Robin and I actually met them was at
Eurobike, our builders explained that they had to
send the frames with a little sticker saying “Made in
Taiwan” but it could easily be
removed and that is what the
American companies did. I told
them that they came very highly
recommended and that I
wanted our “hand-built in
Taiwan” decal applied beneath
the lacquer, where it couldn’t be
removed. There was a silence as
what I’d said was translated to
the others. Then they looked at
each other, nodded and then
their faces light up with a smile,
they all stood up and bowed and shook our hands. I
still get a warm feeling when I re-live that meeting
and I can attribute it to their willingness to make
certain that we get all the minor details that we want.
Such as having all the blow holes filled in. (These
small holes are necessary when manufacturing the
frame, to avoid exploding tubes!) yet they can let
water in. I believe that these holes are still present in
all the Americans’ frames!
That is from the Nomad Mk II brochure, Issue 20, Autumn 2012. I did a quick word search for moisture, did not find it, searched for water and found that.
Even though my Nomad Mk II had those holes filled in, I still used a rust inhibitor inside the accessible tubes in my Nomad, but there were not many. I think I only treated the seattube, top tube (both halves, it is an S&S frame), Downtube (both halves) and headtube. To access some of those tubes I had to remove a piece of tape inside the headtube that blocked off the top tube and downtube. I had never thought of using tape like that to prevent water ingress to those tubes, so I made sure I replaced the tape when done. The seattube and downtube both had water bottle cage bolt holes where water could get in from capillary action.
So, apparently either this was missed on that frame, or Thorn has changed their policy. Or, perhaps that feature was unique to only certain Thorn frames.
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On another note. What is the parachute like addition under the handlebars? 🤔
It's a handlebar cradle, popular with bikepackers for light bulky loads like sleeping kit, here's an example:
https://winstanleysbikes.co.uk/aeroe-spider-handlebar-cradle
Ah, I see now.... backpacking kit.
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Interesting.
I was sure that my Nomad Mk II and Sherpa did not have exposed breather holes and I thought somewhere that I read that Thorn frames do not have them.
I copied this from the brochure I relied on when I ordered my Nomad Mk II frame and fork in 2013, I added underline for emphasis:
... ...
In order to do this, I contacted the finest frame
builder in Taiwan once again.
These people make the top end models of some very
famous American brands!
The first time Robin and I actually met them was at
Eurobike, our builders explained that they had to
send the frames with a little sticker saying “Made in
Taiwan” but it could easily be
removed and that is what the
American companies did. I told
them that they came very highly
recommended and that I
wanted our “hand-built in
Taiwan” decal applied beneath
the lacquer, where it couldn’t be
removed. There was a silence as
what I’d said was translated to
the others. Then they looked at
each other, nodded and then
their faces light up with a smile,
they all stood up and bowed and shook our hands. I
still get a warm feeling when I re-live that meeting
and I can attribute it to their willingness to make
certain that we get all the minor details that we want.
Such as having all the blow holes filled in. (These
small holes are necessary when manufacturing the
frame, to avoid exploding tubes!) yet they can let
water in. I believe that these holes are still present in
all the Americans’ frames!
That is from the Nomad Mk II brochure, Issue 20, Autumn 2012. I did a quick word search for moisture, did not find it, searched for water and found that.
Even though my Nomad Mk II had those holes filled in, I still used a rust inhibitor inside the accessible tubes in my Nomad, but there were not many. I think I only treated the seattube, top tube (both halves, it is an S&S frame), Downtube (both halves) and headtube. To access some of those tubes I had to remove a piece of tape inside the headtube that blocked off the top tube and downtube. I had never thought of using tape like that to prevent water ingress to those tubes, so I made sure I replaced the tape when done. The seattube and downtube both had water bottle cage bolt holes where water could get in from capillary action.
So, apparently either this was missed on that frame, or Thorn has changed their policy. Or, perhaps that feature was unique to only certain Thorn frames.
Yes, I thought I remembered that. Its the reason I brought up the subject. Its interesting that the holes are no longer hidden and covered.
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Yes, I thought I remembered that. Its the reason I brought up the subject. Its interesting that the holes are no longer hidden and covered.
Or, it is a one off mistake at the factory.
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Yes, I thought I remembered that. Its the reason I brought up the subject. Its interesting that the holes are no longer hidden and covered.
Or, it is a one off mistake at the factory.
No, you can see them in the Thorn brochure for the Mk3 Nomad.
At one time Thorn used to seal each individual tube and make quite a big thing about it. I'm sure they were genuine in thinking there was an advantage, but no other framebuilder I've spoken too considered it more than marketing, and of course ideas change. It's always been pretty rare for frames to rot from the inside, I suspect even more so since ED coating became the norm. The couple of examples I've seen, had suffered such abuse a couple of breather holes wouldn't have made any difference one way or the other. There may be some connection between ED coating and breather holes, it may be that the process requires the holes to be left, I'm just guessing here, it isn't something I know anything about.
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Breather holes have the advantage that you can treat the insides of more tubes with an anti-corrosion product. This probably isn't necessary on most Thorn frames, which are usually treated before delivery.
And, if you wish, you can "seal" them afterwards to slow/stop water entry. I generally use window sealant, as I have this around for other jobs.
I currently treat frames I acquire (usually second-hand) with AC50 spray, then block the holes in small tubes with window sealant after leaving the frame/forks to dry for several days.
Seat tubes and head tubes/steerers need occasional checking, as water can get in around the seatpost or stem (in my experience, more often with Aheadset type steerers), but these two areas are relatively easy to access and treat.
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If a frame has holes at the top of the stays it would seem logical to occasionally park it upside down to ensure no moisture inside……and at the same time remove the seatpost.
My NOS Raven forks have holes at the bottom and before fitting I squirted a little ACF50 in and left them upside down overnight before fitting. Can’t do any harm
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My errand bike is a 1994 Bridgestone MB-6. It has a lot of breather holes. It was stored outside for over a decade before I bought it. I took everything off the frame to try to make it a functional bike again. There was a lot of rust inside the frame, but the frame was still sound. I sprayed a lot of Frame Saver into the frame to try to stop any further rusting. Put it back together again with some new parts and expendables.
And proceeded to store it outside for another half decade. But now it is stored inside.
It has not seen any lasting damage.
That said, I have seen on this forum photos of rust perforations in some of the older UK made frames. And I recall one person had a rusted out downtube on an S&S coupled Thorn where water got into the downtube but only flowed down to the coupler where it accumulated until a rust perforation allowed it to drain. When I saw that on this forum, I was quite happy that I had put the frame saver into that particular tube on my Nomad Mk II.
I do question the logic of a breather hole up high, not down low on a seatstay.