Retrobike Forum Index

It is currently Fri Jul 20, 2018 7:15 am

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 38 posts ]  Go to page Previous  1, 2, 3, 4  Next
Author Message
 Post subject: Re:
PostPosted: Mon Jul 09, 2018 7:41 pm 
Retro Guru

Joined: Sun Aug 22, 2010 7:07 pm
Posts: 1501
Location: Cotswolds
It was traditional among french racers to fit a hardwood "bung" held in place by the brake bolt. The one place on a frame where a breakage is catastrophic is above the fork crown. Your face would go straight down onto the road. The wood allowed an element of safety, holding up till you stopped.
We never considered this with our Reynolds fork columns, but a few bumps on the front with perhaps overheating in the brazing could cause fracture in inferior parts.
Racing in France in 1969 we were only reluctantly allowed to start without the wooden life saver.

Keith


Top
 Profile  
 
 Post subject: Re: Re:
PostPosted: Mon Jul 09, 2018 9:05 pm 
Devout Dirtbag
User avatar

Joined: Fri Jul 29, 2016 11:31 am
Posts: 128
Location: North Kent Coast UK
keithglos wrote:
It was traditional among french racers to fit a hardwood "bung" held in place by the brake bolt. The one place on a frame where a breakage is catastrophic is above the fork crown. Your face would go straight down onto the road. The wood allowed an element of safety, holding up till you stopped.
We never considered this with our Reynolds fork columns, but a few bumps on the front with perhaps overheating in the brazing could cause fracture in inferior parts.
Racing in France in 1969 we were only reluctantly allowed to start without the wooden life saver.

Keith


I did a fair amount of reading about that with my French frame and it seems some saw it as a great idea for seamed steerers and some a possible corrosion risk as it could hold moisture and rot the forks from the inside out.

Ironically the only time I've had a steerer failure and just above the crown race was on a pair of Raleigh Reynolds 531 forks last year, luckily I was just hopping up a dropped kerb but it still gave me a nasty bump on the head and frightened the crap out of me, especially when I realised I'd done a good couple of hundred miles on that bike after it had been rebuilt with absolutely no warning of impending failure and just before the failure had been doing quite a lick. When I had a good look inside the forks it had a little sleeve put inside it that I hadn't seen before, they must have been repaired at some point but there was no obvious sign of it on the outside when I painted them and you couldn't see the sleeve otherwise. I do have a photo of the break somewhere so I'll have to see if I can find it.


Top
 Profile  
 
 Post subject: Re: Re:
PostPosted: Mon Jul 09, 2018 9:13 pm 
Devout Dirtbag
User avatar

Joined: Fri Jul 29, 2016 11:31 am
Posts: 128
Location: North Kent Coast UK
torqueless wrote:
Well, I've not done any research to speak of, but I would have thought that if a steerer had a seam, and any tendency to disintegrate along it, and you wished to maintain it's integrity, the last thing you'd want to do is to plug the steerer with an expander-bolt stem at one end and an hygroscopic material like wood at the other. Especially plugging it tightly- As I understand it, those hardwood plugs of yore on the continent were supposed to be put in very tight.

http://www.retrobike.co.uk/forum/viewto ... p;start=10


Yes that's exactly the conclusion it seems some came to, in that after time they could rot the forks from the inside out.

Not having any experience from the time I only had what I read on the internet to go on which can be a very good and very bad thing in equal measure but there are quite a few pictures of seamed steerers in the articles I read. All that said I'm much more inclined to go with Keith's recollections as he has experience of the time.


Top
 Profile  
 
 Post subject: Re:
PostPosted: Mon Jul 09, 2018 9:56 pm 
Dirt Disciple

Joined: Mon Jul 02, 2018 10:00 pm
Posts: 15
Hello. I confess that I have some troubles to understand all that have been said. If you want I can check in my fork some details but please try to simple lol
The frame and the fork gone last Friday to paint but tomorrow it s ready.


Top
 Profile  
 
PostPosted: Mon Jul 09, 2018 10:07 pm 
Dirt Disciple

Joined: Mon Jul 02, 2018 10:00 pm
Posts: 15
allenh wrote:
Yes from the little bit of research I've done Nervor was pretty widely used on French frames but the steerers were quite often seemed which is where the wooden bung in the bottom comes from, I can't see whether @nunojoao's is seemed or not but mine definitely isn't

@nunojoao is there a wooden bung in the bottom of your forks? Usually there is a hole drilled through and the brake bolt goes through it. It does seem that these do get taken out though as they can hold moisture and cause the bottom of the forks to rust. And if you shine a torch down the steerer does it look like there is a seam down the side? you should also be able to see it at the bottom underneath the brake bridge because as you've stripped the paint you should see the join.


I can’t see any wooden bung. About the seam I am gone check the steerer inside the fork and than I say something


Top
 Profile  
 
 Post subject: Re:
PostPosted: Tue Jul 10, 2018 8:49 am 
Retro Guru
User avatar

Joined: Mon Sep 24, 2012 9:10 pm
Posts: 981
nunojoao- Do you know whether the bottom bracket threads on this frame are French (35mm x 1mm) thread?
Or Italian thread (36mm x 24tpi)? Or Swiss thread?

From Sheldon Brown:
"Some French bicycles, notably many Motobécane models, used Swiss thread bottom brackets.
These have the same thread and diameter as French, but use a left thread for the fixed cup."



The thread might be inscribed on the BB cups, if you still have them.


Top
 Profile  
 
 Post subject: Re: Re:
PostPosted: Tue Jul 10, 2018 9:24 am 
Devout Dirtbag
User avatar

Joined: Fri Jul 29, 2016 11:31 am
Posts: 128
Location: North Kent Coast UK
nunojoao wrote:
Hello. I confess that I have some troubles to understand all that have been said. If you want I can check in my fork some details but please try to simple lol
The frame and the fork gone last Friday to paint but tomorrow it s ready.


Hi nunoJoao with my frame which is very similar to yours I was asked about the steerer being Nervor which yours is and whether the head tube was seamed. Looking at your photo's I don't think your head tube is seamed but if you look down inside the headtube with a torch and see a vertical line then it probably is


Top
 Profile  
 
 Post subject: Re: Re:
PostPosted: Wed Jul 11, 2018 6:45 pm 
Dirt Disciple

Joined: Mon Jul 02, 2018 10:00 pm
Posts: 15
torqueless wrote:
nunojoao- Do you know whether the bottom bracket threads on this frame are French (35mm x 1mm) thread?
Or Italian thread (36mm x 24tpi)? Or Swiss thread?

From Sheldon Brown:
"Some French bicycles, notably many Motobécane models, used Swiss thread bottom brackets.
These have the same thread and diameter as French, but use a left thread for the fixed cup."



The thread might be inscribed on the BB cups, if you still have them.


I think the BB is a Sakae 36mmx24tpi but later I am gone check that.


Top
 Profile  
 
 Post subject: Re: Re:
PostPosted: Wed Jul 11, 2018 6:48 pm 
Dirt Disciple

Joined: Mon Jul 02, 2018 10:00 pm
Posts: 15
allenh wrote:
nunojoao wrote:
Hello. I confess that I have some troubles to understand all that have been said. If you want I can check in my fork some details but please try to simple lol
The frame and the fork gone last Friday to paint but tomorrow it s ready.


Hi nunoJoao with my frame which is very similar to yours I was asked about the steerer being Nervor which yours is and whether the head tube was seamed. Looking at your photo's I don't think your head tube is seamed but if you look down inside the headtube with a torch and see a vertical line then it probably is


Thanks. I looked inside and I don t see any vertical line, so I assume that is not seamed.


Top
 Profile  
 
PostPosted: Thu Jul 12, 2018 9:06 am 
Devout Dirtbag
User avatar

Joined: Fri Jul 29, 2016 11:31 am
Posts: 128
Location: North Kent Coast UK
@nunojoao I started to paint my frame yesterday and found another similarity between our frames in that mine also has a RGF bottom bracket shell so it seems the only difference is that I can't find any markings on my steerer where yours does clearly state Nervor.

Also it looks like the original colour for yours was orange or red looking at the paint left on the steerer.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 38 posts ]  Go to page Previous  1, 2, 3, 4  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 39 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

About Us

Follow Retrobike

Other cool stuff

All content © 2005-2015 Retrobike unless otherwise stated.
Cookies Policy.
bikedeals - the best bike deals in one place
FatCOGS - Fat Chance Owner's Group

Powered by phpBB® Forum Software © phpBB Group