Rebuilding a 70s road bike

[DavidH]

Last October I gave my girlfriend a beautiful old road bike that I believe is from the 70s. I had replaced the essentials (brakes, cables, tyres, seat, handlebar tape etc) but left most of the original parts (including wheels) and some are causing problems, especially in the winter weather. The brakes can't grip onto the wheels in the wet and the friction gearing is liable to slip when adjusted despite attempts to maintain it. As a result I have leant her my spare mountain bike (to stop the lack of brakes killing her!) and I intend to make some changes which I need some advice with.

My previous bike was an 80s Carlton frame with all new components including a set of great 700c wheels (Mavic Open Pro, single gear). Unfortunately it was vandalised 8 months ago leaving the frame bent and the back wheel completely mangled. I'm hoping to use it as a donor for some parts for the 70s bike. My current plan is this:

- Replace her original 26" 1 1/4 wheels with 700cs, both my undamaged front and a new rear

Her front forks are the old ~96mm spacing but my front wheel is a 100mm. I assume cold setting the forks slightly to accommodate this extra width is fine. The rear has 120mm spacing which I think would be normal for a new rear wheel? There are only gears on the rear wheel and I'd like to keep it that way. Would I be right in assuming the old cassette (not sure of details without checking) are unlikely to fit a replacement back wheel? I'm currently looking at options like this but unsure what cassette to get, and whether her derailleur will need updating? I'll have a closer look at these parts tonight to be more specific.

- Replace her old brake levers (suicide type) with the levers from my Carlton (newer components)

The brake components themselves should be fine but I could always swap them over too if necessary. She has centre-pulls which I think I'm right in saying are fine?

- Possibly replace friction gearing - unsure of best option

This is where I'm most unsure, and where I'd like to avoid spending too much if possible. She's happy with the gears available on the bike but the friction gearing isn't up to the job. Can I just replace that with a newer version, and if so which? If I have to replace the cassette for the new back wheel do I need a new derailleur and new gearing system? I'd love to just buy combined brake shifters for her but they seem very expensive!

Sorry for the vague points and lack of knowledge, I've tried reading around as much as possible (Shelbon Brown's stuff mostly) and I'm an Engineering PhD student so I'd like to think I can handle this, just need advice to fill in my knowledge gaps! Any input is greatly appreciated.

[WOOLIFERKINS]

Presuming you have the clearance to fit 700Cs you are going to have to change the brake calipers anyway as there will not be enough clearance to adjust the pads to fit from the 26" wheels. I would get some Tektro levers and calipers

Presuming it is 7 speed or less, moving to 8 speed and onwards will need cold setting the rear drops. Is it cassette or is it freehub?

The gears will only self shift if the pull from the spring in the rear mech overcomes the friction on the lever. Yours is band on as opposed to having lugs on the frame these are still available from SJS

[DavidH]

Presuming you have the clearance to fit 700Cs you are going to have to change the brake calipers anyway as there will not be enough clearance to adjust the pads to fit from the 26" wheels. I would get some Tektro levers and calipers

I have brake levers and calipers just like that on my Carlton, I'll find out exact details but I can swap that all over hopefully. Good to know I need the new calipers. Also, I'm pretty confident there is sufficient clearance for 700c wheels.

Presuming it is 7 speed or less, moving to 8 speed and onwards will need cold setting the rear drops. Is it cassette or is it freehub?

I'm not sure what the difference is, does this describe the difference? I can check tonight.

The gears will only self shift if the pull from the spring in the rear mech overcomes the friction on the lever. Yours is band on as opposed to having lugs on the frame these are still available from SJS

I assumed that was the case, will replacing the shifter solve this?

Thank you for a detailed answer.

[fastpedaller]

Potential issues and their resolution for a 70's bike

120mm OLN spacing on rear - frame has to either be cold set to 130mm ( to be able to use a modern hub) , or use a zenith or similar threaded hub with 120 OLN, but this will restrict the use to 5 speed (or ultra 6) and index gearing will not work so it's friction only!
700c rims are 4mm on radius less than 27" rims, so unless the callipers will reach, alternatives are needed.
Those tektro ones only have 49mm drop, so probably not enough, and unless you can get 'nutted -on ' callipers you will need to machine the rear of the fork to take the recessed nut .... and then if you want to fit guards, not easy!
I'd suggest callipers with nuts may be available from SJS or Spa.

[DavidH]

120mm OLN spacing on rear - frame has to either be cold set to 130mm ( to be able to use a modern hub) , or use a zenith or similar threaded hub with 120 OLN, but this will restrict the use to 5 speed (or ultra 6) and index gearing will not work so it's friction only!

I'm happy to keep the current gears if possible, or just change for newer versions of the same part. How can I find out if the gears already on it can be used with a new wheel?

700c rims are 4mm on radius less than 27" rims, so unless the callipers will reach, alternatives are needed.
Those tektro ones only have 49mm drop, so probably not enough, and unless you can get 'nutted -on ' callipers you will need to machine the rear of the fork to take the recessed nut .... and then if you want to fit guards, not easy!
I'd suggest callipers with nuts may be available from SJS or Spa.

Thanks for this information, I'll check what my Carlton's brakes are and report back later.

[merseymouth]

Hi All, Unless I'm having another Senior Moment I believe that the stirrups will be fine as the bike currently wears 26" x 1.125" rims? So 700c rims will be slightly bigger. Also with the right sort of freewheel, 6 speed, Indexing is certainly possible using a 120mm rear hub. As for "Suicide Levers"? BIN THEM! TTFN MM

[mjr]

Last October I gave my girlfriend a beautiful old road bike that I believe is from the 70s. I had replaced the essentials (brakes, cables, tyres, seat, handlebar tape etc) but left most of the original parts (including wheels) and some are causing problems, especially in the winter weather. The brakes can't grip onto the wheels in the wet and the friction gearing is liable to slip when adjusted despite attempts to maintain it.

(highlighting/emphasis mine) Are they steel wheels and did you replace the pads with steel-compatible ones? Something like Fibrax Raincheaters? With the rise of aluminium rims, this seems to be a surprisingly common mistake with old bikes.

- Possibly replace friction gearing - unsure of best option

This is where I'm most unsure, and where I'd like to avoid spending too much if possible. She's happy with the gears available on the bike but the friction gearing isn't up to the job. Can I just replace that with a newer version, and if so which?

Probably and I think it could be replaced with any gear levers that have the same cable pull. If you change the derailleur, then that'll determine the cable pull needed. I'm using a Shimano 7-speed switchable shifter in friction mode on one bike and it works fine, even though there's only 6 gears. By "isn't up to the job" do you mean only the slipping (I think some levers get so old and can't be tightened any more) or is there some other problem?

I slightly dislike indexed gearing: firstly, it's an extra small nuisance getting it exactly slick; and secondly, most combined brake/shifters can't be checked by position so I'm forever forgetting what gear I'm in!

[mjr]

Hi All, Unless I'm having another Senior Moment I believe that the stirrups will be fine as the bike currently wears 26" x 1.125" rims? So 700c rims will be slightly bigger.

26 x 1¼" is 597mm diameter and 700c is 622mm so you're right. (26 x 1.125" rims would be 559mm but no-one mentioned them before your Senior Moment ). 27 x 1¼" would be 630mm and more common on old road bikes AFAIK but not what the opening post said.

I agree on binning suicide levers. Interrupters are better.

[merseymouth]

Hi Again, 26" x 1.125" was a "Senior Moment! That was meant to be "Twenty-Six x One & a Quarter Inches" . "The Pen Is Mightier Than The Computer" for daft duffers like me! But otherwise I believe I make sense? TTFN MM

[Valbrona]

I would question the logic of throwing a modest amount of money at doing up an historic artefact when that modest amount of money might buy a new and more useful bike.

[mjr]

Any new bike you can buy for the price of a rear wheel, shifters and possibly rear sprockets and mechanism, isn't going to be great, is it?

[pete75]

I would question the logic of throwing a modest amount of money at doing up an historic artefact when that modest amount of money might buy a new and more useful bike.

Some people have no soul

[Brucey]

if you have ~12mm of upwards movement of the brake blocks available then when you change from 597 to 622mm rims then you will be able to re-use the old centre pulls.

Personally I'd try the suicide levers with the new wheels before ditching them; if you change to alloy rims the brakes will instantly work x3 better in the wet or so.

It looks as if you have a Simplex friction lever gear there; this should be assembled bone-dry. The slightest trace of grease or oil will cause the lever to slip, so degrease it before assembling it. Note that if the backplate moves (even slightly) when the lever is moved, or the front plate moves slightly either, then the tension screw will gradually back out as the lever is moved back and forth.

A final comment is that I would suggest a different saddle, chosen by your GF to be comfy; that one looks pretty dreadful to me.

cheers

[fastpedaller]

Whoops..... my senior moment, I'm so used to seeing 27 x 1 1/4 that my brain (or eyes?) missed the 26!!!

[531colin]

Warning....reality check below....I am telling it as I see it, not as I think you might want to read it.....

".......beautiful old road bike......."
Sorry, but it isn't any of those things except old. If your GF has been riding it with the saddle at that height, it isn't even near the right size for her, with the bars much lower than the saddle she is never likely to be comfortable or safe.
You seem to be looking to "rescue" an old bike that you feel attached to, without spending too much.....there are 2 problems with this, firstly I don't see any reference to what your GF might want, and secondly I don't think you have the skills or tools to do the job,,,,what will you do if the stem or bottom bracket are corroded into the frame? If you start paying somebody to do the job, it gets expensive.
If there was even the faintest possibility that my woman might ride with me, I would be searching for the exact bike she needs and wants, not trying to bodge something up just because it happened to be knocking around.
Modern "aero" brake levers have the wrong cable pull for your old centrepulls, they are optimised for dual pivot sidepulls.
What is "slipping" with the gearing? "Friction" gearing requires the rider to put the lever in the right position. If this isn't done, you will get ghost shifting. If the lever is simply being pulled round by the spring, you only need to tighten the friction nut in the middle of the lever.

Edit...most towns have some sort of charitable/volunteer bike repair/recycling thing going on. The sort of place where you might be able to use tools, get help and information.....and maybe a more promising bike to start from.