dubbann

So i picked this bike up last year and pretty much all i know about it is that its a Bertin because there is so little information about these bikes on the net. It had durifort tubing and is made in france and the serial number is 740138. I found a picture of a C34 on the web that looks almost Identical, but the fork on my bertin has a much more distinguished curve to it. This spreads the wheel base out a lot. Here is a link to the one I found on Bertin Classic Cycles:

https://bertinclassiccycles.files.wor...ertin-1975.jpg

so my question is if anyone knows enough to help me define what model of Bertin I have or if anyone could give an appraisal. Also if someone could explain the purpose of having such a wide wheel base on a bike, that would be wonderful.

Here is a picture of my bike



Thanks,
Nic

JPZ66

Might I suggest this site ? It has a great deal of info and quite a few photos.....

https://bertinclassiccycles.wordpress...icycle-models/

Cheers,

Joe

Poguemahone

That is a very extreme fork rake, and it does not look to me like the front wheel sits proper relative to the fork crown-- possibly an aftermarket bend. Certainly need more and better photos, in particular of the area around the fork crown (towards the top of fork). Shots of the rear drops would be helpfull, as well as seat post diameter, in assessing the frame. The current photo just isn't enough to make any sort of assessment from, sorry.

repechage

I think the fork was modified. Possibly to fit smaller diameter wheels, 26" or 650's. From the foil seat tube graphic the frame is probably from the earlier 70's. Looks like possibly Durifort fork tubing, a middle range bike.
The fork although without head set at the moment if fit up the top tube would probably be declining toward the front, another tip off that the fork was raked more. I would carefully check the chrome on the fork blades for stress, chrome in general does not like to be stretched and compressed that much.
I would be reluctant to bend the fork back to level the top tube, three cold settings is not the best practice.

bertinjim 

Hi, Dubbann-

The example bike from your embedded link is probably a C 70 despite the paint and decal similarity to your own bike. Yours definitely seems to be from the early 1970s but I believe it is a Bertin C 31 with Durifort frame and forks. The fork rake seen in your personal bike's photo is not original. At some point, the fork has been bent, probably by an extreme jump or by wheelies. The top tube should be absolutely level and yours is not. It is absolutely essential for safety that you have a bike shop or framebuilder check the fork - I believe you will find it damaged at the crown/steerer tube joint.

Typically, a C 31 would have more fork rake than a C 34 or C 70 because it was a sport touring type bike but this example is well beyond any catalogue or real world photos I have ever seen. Currently, in damaged condition, it would be premature to consider its value.

bertinjim