Old bike frame design - name?

[UpWrong]

I recall seeing a couple of upright bikes at the Bespoked show in Bristol a couple of years back which used an old frame design rather than the standard DF. It's bugging me that I can't recall the name for it. There was additional tubing at the front only which was meant to improve strength and support of the headtube. Maybe there was additional tubing from the down tube to the head tube or something. Anyone got any ideas?

[UpWrong]

Pretty sure it was a UK design involving full size wheels, Not Pedersen,Priest, Moulton, Flying gate ....

[Brucey]

bit vague but was it a cross-frame?



cheers

[Gattonero]

IIRC that is called "Pastoor" bike, used by Dutch priest to accomodate their frock? So I was told by the guys at Azor.
As far as strength, those good quality Dutch-bikes have plenty, using heavy-gauge tubing.

[Cyril Haearn]

Could you draw and post a picture of it?

[colin54]

No 2 here ?

https://www.everyonebikes.co.uk/blog/20 ... cycle-show

[Brucey]

IIRC that is called "Pastoor" bike, used by Dutch priest to accomodate their frock? So I was told by the guys at Azor.
As far as strength, those good quality Dutch-bikes have plenty, using heavy-gauge tubing.

Indeed. Invented by Raleigh in 1898



'likely to be imitated' they said....

cheers

[Brucey]

chances are there is a photo of the bike in question somewhere here;

http://www.bespoked.cc/photos2016.html

cheers

[UpWrong]

bit vague but was it a cross-frame?

cheers

No it wasn't cross framed, more like a sub-frame at the front end. I'll take a look through the photos.

[UpWrong]

No 2 here ?

https://www.everyonebikes.co.uk/blog/20 ... cycle-show

No, not that one. I think an additional tube(s) were attached to the downtube or something. Guess I'll need to go to each exhibitors home page. I've been through the bespoked photo galleries quickly and didn't spot it.

[UpWrong]

Ok, I'm pretty sure it's the Paulus Quiros Pike frame I'm thinking of. I can't find a reference to the inspiration for this but have a vague memory that it refers back to an older design. They claim to have done finite element analysis on it at Swansea Uni. What do you think of it?

https://www.paulusquiros.co.uk/pike

[Brucey]

it is a neat idea and it doesn't add much weight to the frame, and it should (unlike the cross-frame) preserve some flexibility in the main frame that will contribute to the ride quality. It is obviously going to take longer to make a frame like this because there are more joints and curved tubes, too. The bending loads that normally appear in both top and down tubes immediately behind the head tube are absent but they are (in effect) replaced by bending loads at the joints onto the front of the top tube and where the brace joins onto the down tube.



Whether this is a worthwhile improvement over what you might achieve by using stiffer/thicker butted tubes in a normal configuration remains to be seen.

cheers

[Cyril Haearn]

Curved or bent tubes use more material than straight ones
What advantages do they have?

[PH]

Regardless of the merits or otherwise of the design, there's some gorgeous looking bikes on that website and I expect the pleasure of owning one goes well beyond the riding. Not seen these before, I've added one to the "When I win the lottery list"

[Brucey]

Curved or bent tubes use more material than straight ones..

only a tiny amount; in the case of the top tube on that frame, I'd be surprised if it is more than about 3/8" longer.

....What advantages do they have?

they flex a little when subjected to tension or compression, where a straight tube wouldn't in the same way. They also look pretty in some cases.

cheers