Donohue 559 low-trail conversion

That should be pretty close to what I'm hopefully finishing within a few months: a 700c to 559mm conversion of an audax style Paul Donohue frame, with custom forks, ca. 50mm tyres, shimano 105 (10sp 5700) group and hubs reused from previous build and cantilever brakes (couldn't be bothered to draw those).

The donor frameset looks like this:

I had it briefly built like this:

I did initially consider other options, like the Surly LHT, but this frame turned out to be suitable for 559 wheel size conversion giving the extra tyre volume I wanted. There's just enough room for the rear tyre, and the original seat and head tube angles were steep enough to cope with slackening from a longer fork that is needed to maintain BB height.

I wanted to try out the front load low trail thing, so I chose reasonably low 40mm trail.

I've already built the wheels and have most of the parts ready. The two major things left are getting cantilever bosses soldered to the frame, and waiting for the fork to be finished.

Right now I'm trying to decide the colour of the fork. I'm getting it painted from the builder so it won't match the frame exactly, but I think I could live with "vaguely similar". The other option is choosing some distinctly different colour/shade, like a darker blue.

Played with possible colours a bit.

Seriously considering something like that. I was briefly concerned about evoking a faux-geekhouse vibe, but, well, probably shouldn't be a problem in this case.

Nice project! Looking forward to it.

ild say paint diff colour. itll look like an "aaaaalllllmost" instead of awesome like the pink. or maybe purple would work?

youre not respraying the frame where the cantis will mounted?

would like very faux geekhouse but awesomenif yould paint the rear triangle another kray colour..?

I've pretty much settled on a deep turquoise, like this:

Rear triagle respray could actually be nice, also because as you can see the chainstays have pretty large patches without paint. But I think I'll just do some touching up initially. I'll definitely keep the idea in mind, though.

Maybe a nice pastel paintjob/color combos?

Not something that would typically appeal to me, but admittably that might work with the frame colour. Still, RAL 5021 is looking pretty strong right now.

Ooooh, this is interesting. If the tyre volume makes up for the reduced rim radius, why do you need a new fork? Because the tyre volume does not make up for the reduced radius? What would the effect of lowering the BB be if you used the original fork?

What did you use to do those drawings? Looks great.

As a fully paid-up member of the big downtube Donohue club I definitely approve.

I think deep turquoise frame and rear triangle would look great.

The wider tyres don't quite make up for the reduced rim size, the difference is about 1cm compared to 30mm 700c tyres. The original forks are also not wide enough for the kojaks.

The line drawings are made with librecad, and colours added in inkscape (both open source). I traced the more detailed bits through from photos, scaled accordingly.

I'd really love a matching 853 track donohue, cool stuff.

Some progress, I got the frame back from a "local" builder (Konga bicycles, quotes because of a 600km round trip) with the cantilever bosses now in place:

I also asked for bosses for a third bottle cage under the down tube:

The forks are still being built, but that gives me time to patch up the bare metal spots.

Looks good.

Really interesting project.

how much did the extra pair of bottle cage mounts cost?

I don't know how much the extra bottle cage mounts alone would have cost, but they were about 20 euros on top of the total sum.

The bottle cage placement was a bit of a guesswork as I had already sent the frame when I came up with the idea. This position should bring the cage just in front of the inner chainring, which might leave enough room for a 0.75 litre bottle even with a front mudguard.

How will you touch up the paint?

I've been thinking of putting on just some primer first for protection, and if I can be bothered, get some better matching touch up paint on top of that.

So it probably won't be pretty, but I'm hoping multiple layers with light sanding & polishing with a rubbing compound in between will help a bit.

The frame could do with a completely new paint, but for this summer the priority is just to get the build together.

Nice - did you settle on a colour for the forks?

Yeah, I did. I decided to go with boring, i.e. a dark blue. Pink was a real option, but in the end I though something a bit less conspicuous would be more fitting.

I did a bit of countryside gravel road riding on a fixed the last weekend, and at one point ended up plodding through some loose sand basically on someones farmyard, and then jumping over a reasonably sized ditch. Having been hauling a brightly coloured bike might have made me even more self-conscious. /csb

How's this progressing?

Nothing very exiting to report, but thanks for asking. I'm still waiting for the forks & a front rack to be finished. Patching up the paint feels a bit pointless exercise, I'm fairly sure I'll get the frame powder coated during the winter. I've still tried to do a reasonably thorough job, cleaning up rust with wire wool and citric acid before paint and sanding between the layers.

I got a Tubus Tara low rider and Ortlieb panniers for the front, so together with the platform rack there'll be plenty carrying capacity. I guess I should start planning a longer ride to make some use of that :-) .

My plan for the bike are one to a few days, 100km+ per day rides at my own pace. No long distance touring, scheduled rides or commuting at this point, so essentially I can choose to ride when the weather is nice. That's why I think the Kojaks will do fine even on unpaved roads (I'd imagine they are useless in mud). As a knobbly alternative I went for a pair of 2 inch Continental Race Kings. Rolling resistance for the 2.2" version is among the lowest measured in the tests referenced here, should be good for my use.

If you're here just for the pics:

:) Lovely stem. Am doing an experimental 584 mm conversion of my road bike these days. with approximately the same intended usage as your 559. Looking forward to future updates!

Pretty much similar to my 584mm bike with clearance for 54mm tyres (I like saying wheel size like that, sound very much as if we're talking fighter plane).

40mm trails is sensible, but will take a while to get the hang of if you intend not to ride without a front load regularly.

But if you're getting custom fork, why are you sticking to threadless?

No reason other than looks, I suppose. The way this turned out, old MTBs and their drop bar conversions were a big inspiration. Though I'm not sure how the modern shimano group fits with that explanation.

I'll admit that the famous (formerly) raw Elephant may have given me some ideas, so the similarity might be more than incidental. Though, my first unrealized draft was carboncycles 26" MTB disc fork with a mielec frame*, so the form hasn't been fixed from the start.

• In addition to decreasing trail compared to larger diameter wheels, 559mm would allow relatively short front-center distance, i.e. a steeper head tube angle. So reasonably short trail could be feasible even without a specific long rake fork.