Tandem full suspension oddity!

I recently acquired a Thorn tandem to compliment the Thorn kiddieback tandem we already have 🙂

Tis a nice thing – Reynolds 531, mix of XT and LX, S&S frame couplers…and weird front and rear leading link suspension!

It needs a bit of work, nothing’s broken, but it’s showing its age. Will be replacing front BB, saddles, bars/stem.

The suspension works, but is a bit clunky, I’m assuming it’s just a spring either side with a rudimentary damper on one side too.

Before I strip the springs and damper, has anyone ever seen or worked on one of these before?

There’s no online info about it as far as I can find. Joining the Thorn Bikes forum seems impossible (I tried before as well when I bought the kiddieback tandem, but it seems to be a closed shop. Maybe invites only?!)

Anyway, here’s some pics of it in all it’s weird glory!

Wow! Is that a leading arm design on the front and then like a telescopic fork on the back?

Omg it’s amazing. And even better it has my husband stumped. I will see if I can find out anything from my bike nerd network!

Have you tried phoning thorn?

I get the impression there might be so the person who designed it or welded it still working there.

I don’t know where I get this impression. Possibly because I associate it with sjs cycles who seem to have a depth of stock going back years.

The bike is super cool!

How does it pivot around the suspension? Is it a single pivot?

I make the occasional weird steel bike frame but that is just amazing. Only Thorn would make the bike equivalent of Morgan sliding pillar suspension (which is also awful according to the couple of Morgan 3 wheeler owners / restorers I work with).

First question about the fork has to be –  why? There are hundreds of commercially available forks you could try. Saying that, we briefly ran out Cannondale MTB tandem with a Girvin Vector fork and the steering was the best it had ever been so there might be something about linkage forks and tandem steering geometry. But I was just too worried about snapping them.

Holy bat-bike of much weirdness.
I want a go!

I knew you bunch of weirdos would like it! 😉

Here’s a couple of pics of the non-drive side with the damper units.

@tall_martin – the rear dropouts are connected to the bottom of the suspension/spring unit, so it has a vertical axle path.

@mick_r – I know, it’s so weird! Seems very sturdy though, barely any lateral flex.

is there no end to your perversion? 🙂 🙂 🙂

you’ll be trebucheting the missus over the top of that bastard!

Fancy a go Del? :kiss:

That was seriously expensive when new. I recall the rear from distant memory. S&S couplers add to the expense. And fabulous condition. I think it’s a one off. Obviously it predates disc brakes. I’d say early 90’s.

You could try contacting SJS Cycles, they used to deal with Thorn and were pretty knowledgeable about tandems.

@TiRed – bit later than that I think…

I’ve just been down a Google rabbit-hole using the Wayback Machine 😉

The Duoglide is in the Thorn Tandem catalogues from 1999 to 2003.

The suspension setup is the snappily named ‘Brownland Leading Link Fork’ and the ‘ Brownlands Live Axle Rear Suspension’.

Based on the spec on this one (8spd LX) I’d say it’s a 1999 or 2000 model.

I can’t imagine they sold many of them!

The retired couple I bought it off said they bought it from the original owners about 10 years ago, and I don’t think they rode it very often. Apparently they had it serviced at Halfords every couple of years(!), which probably explains the nasty screwdriver marks on the EBB, the lack of grease on the seatposts, and the non-functioning rear v-brake.

It’s AI generated, im not stupid.

It’s AI generated, im not stupid

Ah, busted, I’m playing the long game on next year’s April Fools.

That’s fantastic! And reassuring to see from that screenshot you posted that ‘all parts can be individually replaced when damaged or worn and are in stock at all times’…

That’s – interesting. If you’re on Facebook, post it up onthe Tandem Club group, it will spark a bit of discussion

If you are in the “collecting tandems” game, there’s a Ventana El Conquistador de Montañas Full Suspension Tandem on there for only £500 – size Large / medium, Maverick DUC32 forks. Mrs NBT has banned me from getting it, we’ve only just sold a tandem and she won’t go on an MTB tandem with me again 🙁

That is awesome. What a lovely, great bike!

But those forks give me the shivers!

But those forks give me the shivers!

I see what you did there. But that would be the single crown

No idea, but I just wanted to say I absolutely love it.

Very tempted by that Ventana but don’t have anyone to ride it with me!

That Ventana is very cool!

Nowhere near me (un)fortunately, and I suspect I’d not be able to sneak a third tandem into the garage 😆

munrobikerFree Member
No idea, but I just wanted to say I absolutely love it.

Very tempted by that Ventana but don’t have anyone to ride it with me!

I think you should purchase it. Then post here: Wanted stoker. It will be interesting to see how the process goes.

NBT and I used to have a mtb tandem. It was great fun, but, quite scary not being able to steer, brake or change gear on the back. Also tricky not being able to move you body around as you would on a solo mtb. Everyone should have a go.

Everyone should have a go.

Mrs_oab and I hired one in about 1996.
She’s refused to get on one since!

Yeah we got rid of the Cannondale. The main problem was we had different lead legs when descending which caused all kinds of fun off road….

Mrs_oab and I hired one in about 1996.
She’s refused to get on one since!

A tandem is a relationship accelerator. Wherever your relationship is going, a tandem will get you there faster

Gah, old, odd standards 🙁

I want to put an aheadset stem on it (more bar choice in 31.8), so I (naively) assumed it was a 1″ headset as it has a quill stem.

Ordered a 1″ threaded to 1 1/8″ aheadset adaptor, but it’s too small. Turns out it’s a 1 1/8″ threaded steerer. I don’t even remember that being a thing!?

.

The front EBB had been attacked with a sharp object at some point and was pretty mangled. Luckily I had a nice Phil Woods 68mm EBB in the spares bin (as you do), and that fits nicely + an apparently unused 68 x 122 UN55 BB – again from the spares hoard 🙂

.

Next up: shimming a stem to fit the seatpost for the stoker bars (the old stoker stem is a rusty POS); fitting some nicer stoker bars; giving the seatposts a good clean and grease, and fitting more suitable saddles.

.

I might also try disassembling the springs and dampers, just to see how rudimentary they actually are!

Front suspension – needed 5 & 6mm Allen keys and a 12mm spanner.

2 springs and an oil damper (with no oil in it!) Topped up with 5w fork oil, though thicker might be better?

It’s all very nicely made, but definitely has the air of something a skilled engineer/machinist has put their spare time into.

First proper ride out on the beast today – apart from a couple of quick shakedown pootles.

Did 50km around East Devon with my 10yr old daughter….20kmh average, which considering the roads around here and the amount of water currently on them, isn’t far off what I’d manage on my own!

Tandem works great, the suspension is a little clunky, but definitely takes the edge off potholes, etc.

Given it a bit of a spruce up, and fitted a few nicer bits from the spares box – it’s now running old 8/9 spd XTR mechs and XT v-brakes. Replaced bars and seatposts too – black looks nicer 🙂

^ ^ ^ Fantastic ^ ^ ^

Agreed. Absolutely brilliant

That’s a definite ‘gis a go on your bike mister’ thing of wonder…

When does daughter turn tables and you become stoker?

When does daughter turn tables and you become stoker?

We discussed it on the ride yesterday – she wants to have a go, but I think another year or two of growth is needed.

I can definitely feel her power on the hills. she’s got a very slim build, but 5 years of ballet and tap dancing has given her powerful legs!

Looks awesome !

I’ve put a suspension fork and 2.3 tires on our kiddie back tandem and the difference in comfort is incredible. The furthest it’s been is 4 Miles so the rolling resistance is negligible

That’s brilliant, and especially well done to her!