Cycling UK Forum

I don't know if this has been mentioned already or not but it has always seemed to me that the typical Campy triple chainline worked out so that the middle ring wasn't lined up with the middle cog quite, but one of the smaller ones. This means thats shifting onto the the little ring is more likely to happen with a big inward angle on the chain. Big gaps between ring sizes, the 'hurling' action of STi's, narrower/more flexible chains, more cogs at the back, tighter back ends, softer tension springs, etc all contribute to this problem .

I have a feeling that if the force required to start unshipping the chain is low, it is less likely to be 'hurled' with STis (was it pushed, or did it jump?). Hence a used chain (despite extra flexibility, which might be bad) may give less trouble than a new one. The worst trouble I have had with a triple in recent years was when I ran a chain that was fractionally too narrow on a middle ring that was fractionally too thick; the chain simply would not unship and when it finally went it had to be pushed very hard and therefore 'flew' to its resting place -wherever that might be.... Incidentally the chain ran very well indeed on the middle ring, but was simply too snug to shift off the thing easily. I daresay you might get this effect running (say) a 10speed chain on 8 speed chainrings or something....

cheers

robinlh wrote:I'm coming to the view slowly that old bikes should be kept period,especially English ones.
Trouble is,upgrading and general bike bodging is such fun.............
R

agreed, and agreed... but the result is inevitably a burgeoning stable of period bikes that are not necessarily altogether suitable for everyday use.... Ask me how I know this... I guess if you have just one or two bikes, they need to be as good as they can be, whatever period the bits are that go on...

BTW I'm told that Weinmann CPs go well with 'V' blocks these days; I used to make my own special shoes with the blocks spaced inwards for using Weinmann CPs with skinny rims; no need for this any more I guess....

cheers

I agree they are underrated and a flatter straddle (I've made my own for several centre-pulls) makes all the difference. Since it was a weak spot even back in the day, I keep meaning to try them with a more modern pad, too; I'm thinking of one with an offset post, maybe the Clarks XT cartridge copy or something similar; not wishing to hijack this thread or anything but I'd welcome anyone's experience on this and I'm sure the OP might benefit too.

cheers

+1 on that. Also, note that the Cylone Mk1 was one of the lightest rear mechs ever made (only a few lighter and these use titanium and/or carbon...) and the long-arm GT version is barely any heavier.

Quality kit. For slightly better shifting with a more modern (narrower) chain you could try a set of narrower replacement pulleys, but note that the bolt size may be slightly larger diameter than some other mechs, so not all pulleys swap in easily.

cheers

good diagram here;

http://www.sjscycles.com/Instructions/Sturmey_Archer/Sturmey_Archer_X_RD8_Hub_Instructions.pdf

Q. it looks as if it is a very different part to the older 3/5speed part but is it possible that the outer diamter is similar to another SA part? If so maybe a little grinding to open up the hole on another dust cover could yield a working part?

-just a thought-

cheers

is the part identifiable here?

http://www.rideyourbike.com/sturmeyarcherIGH.shtml

(need to scroll down a way to find the 8 speed, maybe its different to yours?)

cheers

do you know the part number, or have approximate dimensions?

have you tried 'oldbiketrader'?

cheers

with only one set of frame eyes in order to reduce the bending load I usually put the rack against the frame and put the mudguard stays outside of that, or mounted onto the rack somehow. The latter is the only good way if there is a plastic clip as is found on many mudguards these days; if the bolt is tight enough to hold the rack its tight enough to start crushing the plastic. I normally use a long bolt for the rack with the head filed down thin (if there is room) put through from the inside so that it sticks out like a stud, and then a nyloc to hold it all on the outside. I have found this to be very secure indeed even with a full camping load; it can be disassembled if required, is extremely unlikely to come loose and there is no real danger of stripping the threads in the dropout.

'P' clips are obviously not all created equal but even so I wouldn't trust them not to slide down the seat stays if there was any load on them for any length of time. Many of the mudguards I have mounted to ex-race frames using 'p' clips have worked loose so IMHO a rack (with anything on it) is a non-starter really. Plenty of other ways of securing the lower rack mounts as detailed in this thread, and 'p' clips are fine for the top mounts of course.

cheers

it may not be sensible because of the power input to the lights vs the generator output.

If the generator makes 3W and you are using 3W in the lights, there is nothing left over.
If the generator can make 4W and you use 3W in the lights, you have 1W left over.

1W at 5V is 200mA (and that is if your circuit is 100% efficient, which it won't be).

200mA will charge a typical device that is 'off' in, oh, er, a few hours I expect. But it might not be enough to even keep up with a device that is 'on' depending on the power it uses. Compare your likely power surplus with the ratings on your chargers before you start building something, you might be surprised.

hth

cheers

I reckon you have two problems;

1) the mudguard is very strained, (almost kinked in fact) near the brake bridge, because the forward section of the mudguard is mounted too far forwards at the chainstay bridge and the natural curve of the mudguard is not retained. This will cause the mudguard to crack from the inside out, as it were. If you use a smaller rear sprocket and move the wheel and mudguard backwards with longer stays, clips etc it'll make it worse, guaranteed to break again and again. The cure is to use a spacer of some kind to move the mudguard backwards at the chainstay mount and this will reduce the strain it sees. It will also help if you always can use the shortest chain length for any given gear, if necessary by using a half-link.

2) the way the mudguards, eyes, and seatstay angle are has left a long length of mudguard unsupported between the brake bridge and the first set of stays. This will jiggle up and down and this will also help to break the mudguard at the seatstay bridge (again and again...). The cure here is to bring that set of stays nearer to vertical. You can do this by either remounting those stays on the mudguard, or shortening the whole mudguard at the front which will move both sets round to a better angle. If you do the latter and you ride in groups, you might want a rear mudflap for the benefit of others. A skinny one 'stortford style' would be fine.

hth

cheers

Vladimir,
you don't say where you are (unless I've missed it...) if anyone is local maybe they could help you out. I have a load of useful good used parts for upgrades etc and I'm sure others do too, much less expensive than new.

cheers

rjb wrote:Has anyone tried this - it looks to be an ideal compromise. Cheap mtb thumbies mounted below the brake lever. I haven't tried this - i just had the idea after seeing them in my shed. The lever works in the opposite direction to down tube levers with this arrangement but it will be at it's most aerodynamic when you are going faster in top gear
These are 7 speed - did they come in other speeds?

DSCF0166.JPG

DSCF0165.JPG

-oh yeah, I did this about ten years ago, works fine. Cable routes are horrible BTW. I used the very cheapest shimano friction thumbshifters that were put on cheap bikes at the time. These are OK but because the diameter is quite large where the cable wraps round the lever movement for a shift is rather small. I've also run indexed ones and actually you pretty soon get used to having the shifters on the wrong side if this is how you set them up. I've also made special brackets for mounting that lose the pinch bolt but this is a right faff TBH.

If anyone is interested I can post pictures I expect.

cheers

lots of good suggestions here; I guess (as with many things) there are several different ways you could go and personal preference will be a major factor.

I'd certainly want to ride the frame before I put any real effort into it, but if you are having it resprayed it makes sense to get any brazing or frame mods done first.

cheers

Mick F wrote:

Brucey wrote:When the range was rebranded in the early eighties the changes were more than skin deep............ On the minus side ............ Costs were cut too; the cold drawn seamless butted steerer tube disappeared, to be replaced by a heavier, thicker walled (but weaker, and seemingly seamed) steerer tube.

Just picking out your thoughts here, sorry for not quoting the rest of your post.

I have a 1986 531c frame - ie post "early eighties" - and it has a cold drawn seamless steerer. No doubt "older" tube sets were still being used, so you cannot say "early eighties" specifically.

Also, when I had my frame refurbished for its 21st birthday, the original stickers weren't available, so I had to have the "wrong" ones. I wonder about the wisdom of this, perhaps I'd have been better not having stickers at all as the serial number is recorded at Mercian and they know the frame as well as I do and its providence and pedigree could be proved.

I think that Reynolds, their stockholders, and various framebuilders all had stocks of tube and as you say there is no guarantee by date alone...also not all changes happened at the same time...

Before there was 'designer select' framebuilders could still order tubes of many different gauges; AFAIK the 'designer select' name was a rebranding exercise for the most part.

All you can say without accurate records or careful examination is what was most likely to be used at any given time. The vast majority of frames were built with 'standard' tubesets (with roughly the gauges indicated by PW, ta) but there are no guarantees... I've examined quite a few frames and many are not as advertised by the stickers- some are 'better' than expected which is a pleasant surprise but many are not.

IIRC 0.3mm tube wall was used in some 753 top tubes back in the 70's. I have fixed a top tube dent in a 653 frame with a similar wall thickness and it was like massaging a dent out of a beer can. I only rode the frame for 20 years with the dent in before I couldn't stick it any more....



cheers

ooh yes, I should think you have ~75mm reach onto the 27" wheels there.... and a bit less at the front.

The Mafacs will reach 700c depth I expect but any brake that deep is not going to work all that well.

I would question what you are trying to achieve with the rebuild; you have a vintage early 70's bike there which will soon (if not already) be at least 'interesting' if not actually 'collectable' just yet.

If you 'modernise' it fully it'll be 'just another bike'. I'd think about doing something different maybe....

Back in the day one route ahead was to fit cantis. Mafac cantis were the thing, and you already have the right levers and cable hangars.... If you have bosses put on just right you will be able to run Mafacs or more modern cantis with 700c or 27" wheels.

Another idea is one I've seen on a couple of custom French bikes; basically they braze on canti mounts much higher up, and then mount the Mafac centre-pull arms on the high bosses without the usual back frame. I suppose it is a bit like a Gallic 'U' brake . The arms can be mounted to give good mechanical advantage even on a 'gappy' frame.

I also note that you appear to have a classic 'airlite' front hub (although I cannot be certain from the picture). If so the front width will likely be ~90-95mm instead of the modern 100mm.

You probably know this already but the colour scheme you have there is a nod to the classic 60's Holdsworth colour scheme which is (roughly) VW 'signal orange' and a blue panel.

cheers