[Closed] Demon Frameworks Urban 29er

That's going to be extremely splendid. Make sure and update us!

🙂

I preferred it nekid, looks lovely.

When I see bikes like this for some reason I always think "heavy" . Tell me it's really light..

Lovely apart from the round/square stay junction for me, needs to flow into each other rather than "tacked & welded". Love the lugs though, very art-deco

Why would you design something with such lovely detail and then spoil it with paint .

Edit . IMHO .

Raw. Raw. Raw.
That's just lovely.
Can't help thinking the forks needed some kind of detail at the bottom end.
Like a Landing Gear BMX fork, sort of thing.

Are the brass wheels on the dropouts tensioners?

[url= https://farm4.staticflickr.com/3724/13333818694_c95ff774f5.jp g" target="_blank">https://farm4.staticflickr.com/3724/13333818694_c95ff774f5.jp g"/> [/img][/url][url= https://flic.kr/p/mjgiKL ]urban Demon 4[/url] by [url= https://www.flickr.com/photos/82091817@N08/ ]Dr. Branom[/url], on Flickr

How do they work?
Pics of them would be good.
Oh and I vote for raw too. 😀

I remember the original thread and thinking how stunning this was going to be.

It's still lovely but it looked far nicer without the paint IMO. All of that lovely detail now just looks "painted on" in the pics.

But if you like it that's all that matters.

Raw +1

That raw is gorgeous. Lovely brazing and details.

OP, don't fret about the paintjob. You wanted it, it looks gorgeous.

Just be sure to give us a picture of the full build in front of a badly-creosoted fence or something.

😀

yeah everyone likes the raw look, so do i, but i'm also realistic, i also have a Demon MTB, in a raw/copper finish, it has tarnished a little, not enough to bother me, but after 2 years of owning it it may at some point need refinishing, and by that i mean removing the lacquer, re polishing and then relacquering. with this frame i wanted a far easier and more permanent finish, also in the hand built world a lot of builders are now doing metal finishes which Tom has been doing for a long time so we both felt paint was the way to go.

@rocketdog :-
regarding the square back end junction to the seat tube, my mtb has a similar design, it's not tacked and welded though, it's mitred then brazed, i know what you mean by the "Flow" of the tube having ridden this style frame i know how well it rides and i like the industrial look of the square tubing.

@bikebouy, it's reynolds 853 so should be reasonably light in the frame, the fork will be a little lumpy but i'm not worried about that, it'll balance with the alfine hub!

@singlespeed stu, yes they are tensioners, basically it's just a drop out adjuster in a traditional style from the road bike style world, it's how they used to do it back in the day, you know when designers designed stuff that just works!!

i haven't actually got it yet, these pics are from the painter, Ali at FatCreations near Chichester, when the bike is built i'll get some good photos, it may even have a photo shoot, we'll see.

Excellent, then you will really enjoy that and TBH I'm a teeny bit jealous, cool with it but jealous 😆

Hi Jon (waves) I've been keen to see what you went with paint wise.

I think it looks fantastic painted up 🙂

I actually prefer it to your Copper one.

Full pics needed especially of the internal routing ...... I do love me some internal cable action .....

Beautiful details.

The black & pearl white doesn't do anything for me personally, but I admire the effort, craftsmanship and attention to detail.

I'll probably warm to it when I see the full build.

Tom is in my top 3 favourite UK builders, his attention to detail is amazing. I've heard of him scrapping a whole frame because it was slightly out to his eye and starting over. 3 weeks work in one frame.

I love a raw brazed frame and that is a beautiful example. Looking forward to the finished pics too.

That's a chuffing lovely frame. I was wondering why you'd want to paint that raw finish but that paint job looks even better. Very nice.

A work of art, can't wait to see the finished bike.

so close to being finished

[url= https://farm6.staticflickr.com/5836/21855538891_3f5c1ed361_z.jp g" target="_blank">https://farm6.staticflickr.com/5836/21855538891_3f5c1ed361_z.jp g"/> [/img][/url][url= https://flic.kr/p/ziimh4 ]IMG_4381[/url] by [url= https://www.flickr.com/photos/82091817@N08/ ]Dr. Branom[/url], on Flickr

Stop teasing, get it finished.

How long is it taking you? Just hurry up and finish it! (you should have kept it raw btw)

Maybe but at least he can still strip parts off sometime and raw up. 😉

Holy **** that's lovely. The paint came as a total shock, I love it though, the black infills make it

Brilliant job

thanks for the comments, it's been taking sometime for 2 reasons, lack of endless supply of money is one! but also a couple of compatibility issues i was feeling my may around, these are now sorted then in the mean time i managed to lose the cable clamp bolt for the alpine rear hub, so currently it's built but with out the rear gear cable hooked up. only other thing i want which i'm looking for is a Hope eternity seatpost, i know these aren't made anymore but it would perfectly finish it off as other than that it's all Hope, i've spoken to them and they say they think "have one lying around at the back of a storeroom somewhere" so i may be lucky yet!

had a quick ride (in top gear) last night and it does feel lovely. 😀

I love the white personally. It reminds me of something out of Transformers or something Japanese. Great looking bike and lovely details.
I've always fancied a Demon MTB frame.

the photo shoot was a couple of nights ago

[url= https://farm6.staticflickr.com/5760/22671102220_4cdc08f828_b.jp g" target="_blank">https://farm6.staticflickr.com/5760/22671102220_4cdc08f828_b.jp g"/> [/img][/url][url= https://flic.kr/p/AxnjQL ]Demon in the graveyard[/url] by [url= https://www.flickr.com/photos/82091817@N08/ ]Dr. Branom[/url], on Flickr

[url= https://farm1.staticflickr.com/572/22845591642_67c46e0883_b.jp g" target="_blank">https://farm1.staticflickr.com/572/22845591642_67c46e0883_b.jp g"/> [/img][/url][url= https://flic.kr/p/ANMCt5 ]me and the Demon[/url] by [url= https://www.flickr.com/photos/82091817@N08/ ]Dr. Branom[/url], on Flickr

Very nice indeed.

Luvly custom singlespeed and NO Beard - I'm oot .

Do you have a weight for it?

Can you find out what the square tubing actually is (I'm presuming not chair legs 🙂 so guess something like aircraft cro-moly or something from Reynolds non-bike specific ranges)?

it's alfine 11and i don't do beards, always felt people with beards are trying to hide something! 😉

sorry mick, didn't see your post, it's 4130 cromo at the back but i'm not sure who Tom (the builder) gets it from, i haven't weighed it, it's not the lightest thing to be honest but then, it's steel, with a brutal steel fork and and alfine hub, so it's not built for lightweight! i wanted a fast mtb based commuter that looked simple, weight within reason wasn't a consideration especially as i'm a bit of a lump myself.

it's a nice fast rider though, just tanks along

That's lovely, too nice to commute on.

I'd hang that on a wall.

Demon is the best of the new wave of UK builders no doubt about it for me. Neatness and attention to detail are second to none. Love the lugs but strangely I'd like to see what he'd do with a straightforward fillet brazed frame.

Lovely, lovely, lovely - very jealous.

One question, though...

I was surprised to see that the disk mounting slots on rear dropout aren't parallel to each other - doesn't this mean that the orientation of the caliper, relative to the rotor, will change, as you move the wheel/caliper back or forth?

I was surprised to see that the disk mounting slots on rear dropout aren't parallel to each other - doesn't this mean that the orientation of the caliper, relative to the rotor, will change, as you move the wheel/caliper back or forth?

Hard to explain without pictures but I'll try.....

The disc mount ISO spec is 3 arcs of fixed length (2 from the axle centre and one between the bolt holes). The two holes these arcs describe can fall anywhere in a circle around the axle.

Imagine the axle and caliper in the two extremes of forward / rearward travel that his dropouts allow. The arc dimensions are all correct. The slots just join the gaps to give interim positions (all correct-ish to ISO).

You need to draw it or play in CAD to understand properly, but doing it as two slots like that you can get approx double the wheel travel for a given slot length (i.e. I've done a dropout with 25mm of wheel movement and 13mm disc slots).

I've got a jig and dropout in the garage so will try and get some photos.

You're right mick_r, it is hard to explain - because you haven't (not to my tiny brain, anyway 😉 )

I look forward to your photos.

Thinking during washing up..... I'm not certain it is 100% Correct for the Demon dropout due to the horizontal rear disc slot - need to draw it out (or wait for the OP to explain). It is correct for the one in bottom left of this photo:-

[img] [/img]

Unfortunately I can't just find it in the garage to demonstrate properly!

I don't actually bother with this type anymore - the dropout in the middle has slots that suit the wheel in the centre range of wheel adjustment. It is then "near enough" to work OK in the extremes of wheel position (but I'm doing stuff for myself not an end customer so happy with certain compromises).

Ok, my geekily curious brain got the better of me and I've got my CAD (ish) program fired up.

What's the angle of the sloping brake mount slot, on the Demon bike?

Have fun! ISO dropout dimensions are:-

Axle-front/top hole 78.11mm
Axle-rear/bottom hole 39.9mm
Caliper mount hole to hole 51mm

ha! you guys are funny! 🙂 the technical stuff doesn't get the better of me as i leave that side of it to Tom!

Tom makes his own drop outs, primarily for aesthetic reasons, but also because he wants to make the entire frame as opposed to buying the parts from for example paragon machine works etc.

i don't claim to be an expert on the design process and dimensions but in very basic terms, the drop outs work. there is enough movement in the slotted disc mount holes to accommodate the movement of the rear axle etc.

This should help explain (if the Demon works like this) - Bianchi with 30mm of wheel movement using 15mm of disc bolt movement.

[img] [/img]

[img] [/img]

I'd imagine you start drawing axle to horizontal slot. The angle / position of the other slot sorts itself out (intersection of 51mm and 78.11mm arcs).

I make my own because bought ones are never the shape I want. My CNC plasma cut option is rather less pretty than Tom's CNC machined - but being cheap and lazy means £20 for 3 pairs suits me fine 🙂

I'd already found those dimension elsewhere, but wanted the angles.

Anyway, I've done the drawing, and I can now see how the sloping holes manage to accommodate a 25mm fore/aft movement of the axle, with just 13mm fore/aft movement of the lower disk mount slot.
I based the drawing on a rough measurement of the upper disk mount slot on the photo provided in the initial post (I made it about 42 degrees.)

Based on this, my drawings make the top slot about 12mm long, which is close enough, considering the inaccuracies of my drawing.

However, this is with the rear of the lower slot directly above the axle - which, obviously, isn't the case in the Demon dropouts. If I try to move the lower slot backwards, to where it looks like it is on the Demon dropout, then the length of the upper slot shortens to 7mm.

The common factor though, regardless of the lower slot position, is that the center of the line between the bolts is at a different distance from the axle, depending on the position of the bolts in the slots. This could possibly cause minor issues if the pads were not fully in contact with the rotor - and have worn unevenly - leaving rough edges in contact with the rotor when the wheel is moved.

I may be overthinking this, and I'm willing to defer to the experience of the frame builder - I just had to get some level of understanding of the geometries involved.

Going to pour myself a large drink now.

</geek>

EDIT: Just saw your new post, and it confirms your assertion that the 25 mm to 13mm movement thing work, but also strengthens my suspicions that the orientation of the caliper changes too.

EXTRA EDIT:
In your picture, is the rear hole, in the circular adapter, one of the caliper mounting holes? If so, where is the other one?

Now my head hurts.... 🙂

The extra hole in my little jig thing isn't anything to do with disc mounting. I can't quite remember why it is there....... You can see the hole where the axle goes, and you can see the two bolts where the caliper bolts on.

With mine, I guess you could say the caliper orientation changes - but only relative to the frame / seatstay. But it DOES NOT change relative to the disc - they both just rotate about the axle. The pads still sweep the same portion of the disc and the disc still passes through the same bit of caliper.

You can spin the horseshoe thing round anywhere you want and bolt the caliper on - pointing out underneath the frame if you must - the caliper is still the same relative to the disc.

Sorry OP! Enjoy riding it. And smile at this whenever you adjust the back wheel 🙂

Ah, I can now see how the horseshoe keeps everything in line, relative to the rotor - but this may not be the case with the Demon dropout, depending on the presence/absence of an equivalent to your horseshoe.

Totally off topic but what are those tyres like?

the tyres are fast, 29x2. think they were the first in the country in that size, i've had them 18 months, they were sourced by Don Walker, the guy that runs the North American Handmade Bicycle Show, they only just came out around the time the bike was on display there before being finished and painted, i like them as they feel comfortable on the road and they are fast rolling, they are now available from Extra Uk as they are the new importer for Maxxis tyres, they previously apparently weren't brought in.