strada bianca geometry

[sebaudet]

My next bike will be an all-terrain race-bike, due to a likely moving to Bayern in 2015. My specifications are :
- a bike for rainy days (from Provence to Bayern : big change for me ) : 28mm tires with fenders
- a lot of bikeway and unpaved path in the south of Munich : 32mm cyclocross tires (but only dry day)
- and a light bike for Dolomites not very far...

So a strada bianca frame is what I need and it's my future building-project.
I started to buy a set of medium reach brakes (new TRP), a set of 35mm fenders... I think I will try a set of Life OS or Pegorichie OS.

I hesitate between a woundup or a seven fork but the main question is the geometry. I like HT angle 72,8 or 73 deg, and trail close to 58mm (with 23mm tires and close to 60mm with 32mm tires) with a 45 or 46mm fork rake. It seems to be realistic for a strada bianca race-bike and close to the choice of some of the guys here...
But I don't know which chainstay lengths I have to use... On my bikes it's 405 or 408mm, I tried 420mm but I didn't appreciate it ... But with 32mm tires or 28mm plus fenders I don't know if 410mm is sufficient (my seat tube angle will be 73deg), so i need your opinion...

[David Tollefson]

Draw it out -- it should become apparent.

[sebaudet]

it's not easy because I don't know which clearance to have between the tires and the seat-tube to fit well the fenders...

[Wisco]

Honestly, you're overthinking this.

Send an e-mail to Steve with the qualities you are looking for and let him do the rest. It works.

[Eric Estlund]

Are you looking at buying a Hampsten "Strada Bianca" model, or building your own frame for strada bianca riding conditions?

If the later, then follow Davids advise and draw it all out with the fenders. In the layout you'll be able to account for stand off, brake reach, different tires and different fender clearances to see what works for your needs.

[sebaudet]

The aim is to build the frame... honestly my plan was to draw and try as you say... but I was curious to know what is the usual lenght of the chain stay for this type of bike...

[hampco]

415 - 418mm with a BB drop of 75mm

But, as pointed out above, it can be more interesting to figure it out for yourself

[christian]

Steve, congrats on joining the ranks of Google, Xerox, Kleenex!

[acorn]

Be careful too on the fork. I bought the Crack Browns 33mm tire and thought my steel fork would fit it since I was able to fit some 32s in the past. Nope. The Jack Browns measure very close to 33. I re measured my old 32mm tire inflated and it was closer to 29. When I put the Jack Browns in it didn't fit. So, I think axle-to crown measurement is important, as well as, the space you have right below the crown.

I think Wound up makes a tallish road/touring fork that gives good clearance, but if you are like me and don't want the front end of your bike to feel cyclocross-ish or touring-ish because you got a tallish fork, then you gotta stick with a normal road fork in the 370-ish A-C measurement. I know that Wound Up makes such a fork, but not sure if it will fit the Jack Brown tires. It would be tight.

[christian]

you gotta stick with a normal road fork in the 370-ish A-C measurement. I know that Wound Up makes such a fork, but not sure if it will fit the Jack Brown tires. It would be tight.

I think all the forks designed for 47-57mm sidepull brakes are around 376mm axle-to-crown. The Seven 5E long-reach fork will fit a Jack Brown for sure.

[happycampyer]

I think all the forks designed for 47-57mm sidepull brakes are around 376mm axle-to-crown. The Seven 5E long-reach fork will fit a Jack Brown for sure.

Pretty sure the Seven 5E touring fork has an axle-to-crown height of 381mm, but yes, it fits a Crack Brown (I like that!) with ease.

[happycampyer]

Pretty sure the Seven 5E touring fork has an axle-to-crown height of 381mm, but yes, it fits a Crack Brown (I like that!) with ease.

Oops, I meant 383mm.

[afwalker]

sebaudet,
I would think you would enjoy making your fork. Your work is very nice and you could easily make it to the measurements you wanted. I've used the Panceti MTB crown on the bottom of this page:
http://www.ceeway.com/NEWPARTSPAGES/...k%20Crowns.htm
But you might consider the Paris-Brest as well. They're wide enough for fenders.
Pretty cool place here that the maker of the bike you're imitating would share the specs:)
Best form of flattery,
cheers
andy walker

[sebaudet]

For the rear clearance I did somme experiments, it's always better than just theory, on my Life bike (CS 408mm, BB drop 70mm, ST angle 73deg) the Vittoria 32mm is ok (see the pic) !!! And I was surprised because with my test bike (CS 418mm, BB drop 80mm, ST angle the same) the clearance is not far higher. The reason is the BB drop, the formula which give the clearance is here (it can help somebody before drawing and testing so it's my modest contribution) :
distance between drop out axle and ST = CSlenght x sin (STangle-arcsin(BBdrop/CSlenght)) - ST OD/2

2013-10-17 10.45.58.jpg

[sebaudet]

sebaudet,
I would think you would enjoy making your fork. Your work is very nice and you could easily make it to the measurements you wanted. I've used the Panceti MTB crown on the bottom of this page:
http://www.ceeway.com/NEWPARTSPAGES/...k%20Crowns.htm
But you might consider the Paris-Brest as well. They're wide enough for fenders.
Pretty cool place here that the maker of the bike you're imitating would share the specs:)
Best form of flattery,
cheers
andy walker

Thanks but I am stopped now, HF electronics on my tig welder is out of order... Grrrr, and it's a french tig welder....
For the fork I have not enough experience in brasing to make it, I don't want to take risks... and the seven 5E is calling me

[WayneJ]

For the rear clearance I did somme experiments, it's always better than just theory, on my Life bike (CS 408mm, BB drop 70mm, ST angle 73deg) the Vittoria 32mm is ok (see the pic) !!! And I was surprised because with my test bike (CS 418mm, BB drop 80mm, ST angle the same) the clearance is not far higher. The reason is the BB drop, the formula which give the clearance is here (it can help somebody before drawing and testing so it's my modest contribution) :
distance between drop out axle and ST = CSlenght x sin (STangle-arcsin(BBdrop/CSlenght)) - ST OD/2

2013-10-17 10.45.58.jpg

Sebastien,

Are those the same brake pads you used in France when you almost over-cooked that corner?

Just joking ... I hope you and the family are doing well.

[sebaudet]

Hey I hope you are fine as well, I just wait for a new member in the family, a second boy ! Actually I had better pads but you know I thought about this stupid fault when I rode the fontbelle path again one month ago ! It was near the "gamelle" in french

[WayneJ]

Hey I hope you are fine as well, I just wait for a new member in the family, a second boy ! Actually I had better pads but you know I thought about this stupid fault when I rode the fontbelle path again one month ago ! It was near the "gamelle" in french

I still dream about that descent - fantastic day on the bike. Congrats on the soon-to-be new family member. Maybe the next tour champion ?

[sebaudet]

Perhaps, the first lose two calf teeth in falling with his small bike, perhaps not a champion but already a stunt driver !

[c-cycles]

My next bike will be an all-terrain race-bike, due to a likely moving to Bayern in 2015. My specifications are :
- a bike for rainy days (from Provence to Bayern : big change for me ) : 28mm tires with fenders

Maybe you'll end up like Philippe (the post office chief) in "Bienvenue chez les Ch'tis" & learn that Bavaria is not the North Pole ;-) Living not too far from Munich I can tell you that the weather is less bad than most people (especially those from Southern Europe) think. But having a bike with fenders is always a good idea. I'm enjoying my last built with fenders, short brakes & 28mm tires - but this is definitely "a close call".