Author Topic: 1975 gitane restoration questions  (Read 593 times)

1975 gitane restoration questions
« on: October 19, 2019, 08:18:16 pm »
I bought a Gitane TdF from 1975 to play with and restore.  I have it completely stripped down and  the frame and forks will be going to Mercian when i have time to take it.

My questions are:

a lot of the parts are slightly rusty with pitted chrome.  Can you rechrome these or do i treat the rust and accept it as "patina".  If I can get all these small parts rechromed where do you reccommend.

The headset had free bearings and i lost some of them!!  Where do i go for new bearings.  Also the bearing suface has some pitting.  Does anybody make replacements (1" french) or is there anyway to help the damage and preserve the surfaces for the future?

similarly for the BB

thank you

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: 1975 gitane restoration questions
« Reply #1 on: October 19, 2019, 09:42:44 pm »
Try City Steels and Bearings in Sheffield/Rotherham next time you're headed north.

Torslanda

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Re: 1975 gitane restoration questions
« Reply #2 on: October 19, 2019, 10:59:15 pm »
Firstly the chrome. Use a brass brush to remove what surface rust you can. Then use cooking foil and water to scour the surface.

If the chrome is flaking off you need to consider re-plating, look for recommendations from your local motorcycle specialist. It depends if you want concourse or serviceable.

As for bearings your LBS will have the sizes you need. Change them all, they're cheap enough. I think that unless you can find a NOS French threaded headset that's the right price you will have to put up with a bit of notchiness. IIRC the thread is 25mm x 24tpi - a standard 1" might be undercut slightly but you would be very lucky. Most BB cups will clean up - esp. those from the 70s.

HTH
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: 1975 gitane restoration questions
« Reply #3 on: October 20, 2019, 12:01:43 am »
French threaded headset parts are usually 25x1mm threaded, i.e.  both the pitch and the diameter are different from BSC.

To get back to a mirror polish on pitted parts means removing the surface back to the depth of the pits.  If the pits are shallow and the part is thick/non structural then this can be done. If however the pits are deep, and the parts are thin-walled and/or highly loaded you can end up with perfectly shiny parts that are no longer fit for service.   On certain parts  the plating process itself may promote hydrogen cracking.

So I'd live with some pitting if it is not too bad, and replace the parts if it is worse than that.  In very many cases even if the parts can be rechromed, it is cheaper to buy replacement parts that are in usable condition.

cheers

Re: 1975 gitane restoration questions
« Reply #4 on: October 20, 2019, 07:51:11 am »
Re-chroming is possible, but pricey. The parts need stripping and polishing before chroming. Most LBCs don’t have a lot of retro knowledge I’m afraid. Dave Marsh at Universal Cycles in Dinnington has a vast supply of knowledge and parts. He also offers re-finishing. He’s easy to track down from google or Facebook- I’d find a link but I’m already late for my Wattbike class/torture.

Re: 1975 gitane restoration questions
« Reply #5 on: October 20, 2019, 10:54:53 am »
For slightly pitted ball bearings races (hubs or bottom bracket), I have had some success with the following method :

1. Disassemble and clean up the balls and races.
2. Pack the races with polishing compound, and put old balls back in place.
3. Assemble everything and tighten a bit more than usual.
4. Turn the hub /bb by hand for 10 minutes.
5. Disassemble and clean up again.
6. Pack with fresh grease and new balls.
7. Tighten normally.

You may need slightly oversized balls, you will find that at your local SKF retailer.

Good luck!
A


Re: 1975 gitane restoration questions
« Reply #6 on: October 20, 2019, 04:43:26 pm »
Thank you all so much for the advice. It is really appreciated.
Chris

Re: 1975 gitane restoration questions
« Reply #7 on: October 21, 2019, 09:15:19 pm »
re replacement bits. If you feel like swopping bits around you may be able to find all the unthreaded components from an english headset will fit together leaving just your upper cup and locknut. If the upper cup is not too bad this might be one way round unavailable french headsets. Be careful if you go into the NOS or used market, there are a number of headsets kicking around for french bicyclettes from the late 50's and early 60's which bear no ressemblance to the ones fitted to quality machines. If it has a knurled locknut beware!!

Rhil Wood used to do a bb that had a number of modulable cups for the different thread standards. They were on Harris Cyclery (Sheldon Brown's commercial outlet). Otherwise there are also bbs that are designed for knackered threads and tighten on themselves. Stronglight used to do one that required the entry to the threads chamfered at 45° so that it lined up when tightened on itself (from memory that is what it did). Otherwise rethreading to italian is the easy option to getting a choice of modern bbs (same thread pitch, same width shell just 36mm in place of 35mm diameter cups). In my experience it is the axles that pit before the cups so find a replacement axle and replace bearings will recover things. Note though that french standard axles are not the same as english ones. I cannot answer for italian ones in this respect, they might be and might be a lot easier to find. French standard Campag cup and cone bbs seem to be virtually indestructible (like their pedals also).

Pedal threads can be retapped very easily to english but given that french thread pedals may be among the easier items to find it seems a pity to do this unless you want to use non-original pedals (automatic for  example).

Afterthought I have an italian bb axle somewhere that I could measure and compare with a french one. Won't take me more than a couple of months to find it in all the junk :)

Afterthought 2. Some french LBS that ought to know better replace french headsets with english ones with aluminium cups. The ally recuts its own thread and gets the bike out of the shop. Doing this requires the headset to be frequently retightened (like everytime you go out?). Loctite is not a total answer!

Gattopardo

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Re: 1975 gitane restoration questions
« Reply #8 on: October 21, 2019, 09:57:10 pm »
I'm about to go through this with my old handbuilt french frame.

I'm just going to go with the clean the frame and parts and try and keep the patina.  Not sure about the tubs, do I keep or replace?  The chrome I am using torslandia trick as it works well, even 1500-2000 grit wet and dry sanding paper to really make it shine.

While the bearing surfaces I'm going to try french tandems trick and see if it improves the surfaces.

Re: 1975 gitane restoration questions
« Reply #9 on: October 22, 2019, 06:47:22 am »
Another trick if you have an indexed headset, i.e., the handlebar always lock itself at a precise position due to the balls having digged a dent in the races. These headsets usually have caged balls, which means all the balls always end up at the exact same position, hence the digging process. After a thorough cleanup, replace the caged balls by loose balls, and try to fit one more ball than before. This way, you will be sure that the balls won't be able to line up with the holes.

A

Re: 1975 gitane restoration questions
« Reply #10 on: October 22, 2019, 10:42:57 am »
it is also prudent to turn one of the lower races by 1/2 an increment; this ensures that the headset is free-est moving when in the straight ahead position, when you are liable to feel it worst of all. 

BTW how many extra balls you are able to fit (once the clip is removed) will vary with the type of headset. It can be as few as just one (with a campag headset, say) but it can be many more balls with other headsets.

cheers

Re: 1975 gitane restoration questions
« Reply #11 on: October 24, 2019, 06:44:07 am »
Try French eBay for parts.  Shouldn't be too hard.  Do it before Brexshit, or you'll be paying duty, VAT and Parcelforce's repacking charge as if it were coming from the USA.  Oh, the joy.
Never tell me the odds.

guidon

  • formerly known as cyclone
Re: 1975 gitane restoration questions
« Reply #12 on: October 24, 2019, 11:47:03 am »
what stack height do you need? I volunteer for a bike recycling association and being in France have a good selection of used bits...condition varies though... Cheers Yan

Re: 1975 gitane restoration questions
« Reply #13 on: October 24, 2019, 12:03:34 pm »
Try French eBay for parts.  Shouldn't be too hard.  Do it before Brexshit, or you'll be paying duty, VAT and Parcelforce's repacking charge as if it were coming from the USA.  Oh, the joy.

I was (possibly wrongly) assuming that even in the worst case of a no-deal on 31 October, there would be a so-called transition period until end of 2020 or 2021 with no duty, VAT, etc. Can you confirm this?

P.S. : sorry if my post rather belongs to the POBI board!