Stripped headset thread - time for a new bike?

[scottg]

For Christ's sake, if that's the length of your handlebar stem … buy a new bike. Your current frame is way too big for you.

Just a frame might be worth considering.

That bike is going to be rather twichy!

Just like flying a plane with an aft CG, load a couple KGs of ballast forward.
Rode a frienda Serotta that was notably short, would wheelie on the steeper hills,
owner just learned to lean forward on the steep ones. Custom bike, naturally.

[Brucey]

Much cheaper, more elegant solution: buy a pair of threadless cro-mo 1 inch chrome forks. Available online from £50-100. The above solution welding/threading is going to be significantly more expensive....

…..Anyone advocating to "build up" metal by welding, is mostly wrong.....

er, ahem, I have done this exact repair on multiple occasions (with complete success) and it has, of course, been less expensive than a new set of forks.

[Gattonero]

To have done such repair doesn;t mean is a good thing to do, weld material is not a good canditate to cut threads onto.
Let alone finding someone that can actually cut a thread onto the forks

[drossall]

That kind of thing is fairly common though. Frame builders would repair stripped BB threads by running solder or similar into them and recutting them (among other methods).

I had the OP's problem on a Viking frame, years ago. It wasn't even 531, but I liked it, so I had a local frame builder put in a new steerer, and went for a respray while I was at it. Cost a bit, but not too bad (I was a student at the time) - although there were more frame builders around in those days. I just don't like the waste of writing off a frame for want of matching forks.

Lasted many years, till the frame was written off completely in a collision with another cyclist.

[Brucey]

To have done such repair doesn;t mean is a good thing to do, weld material is not a good canditate to cut threads onto.
Let alone finding someone that can actually cut a thread onto the forks

It either works or it doesn't; if it works and it lasts, how can it not be a good thing to do? I don't think I 'just got lucky' as many times as I have. Believe it or not, not all weld metals are the same strength and hardness, and not all weld procedures give the same thermal cycle to the weld metal, thus the hardness can be controlled even at the same weld composition.

I've got a die that will cut fresh threads onto the built-up areas well enough. Near to me there are at least three or four others with better tools than mine that will cut threads quite happily.

Repairing parts by building them up with weldment and then remachining to suit is standard engineering practice. It just needs someone who knows what they are doing to do it.

NB when you cut threads for a repair of this type, the result can be a fair bit better than the original arrangement. The reason for this is that the threads can be cut to a tolerance that suits your headset perfectly. This contrasts with factory steerers, which are made bottom limit more or less, because that way they can be sure that any old headset will 'fit'. The result is usually that an average headset is a pretty slack fit on an average steerer, but not when you have cut the threads to fit your headset.

cheers

[9494arnold]

I am West Midlands dy8 close to Stourbridge.
And I know how to take a bike apart and put one back together.
Don't have a die to cut threads though .
I have a collection of older machines , VCC member.
Not long finished 2 trike restorations , and I have done some Dr Bike work in the past.
Pretty sure I have a top nut with an Allen screw locker on it in the bits box.
If you want to bring it to me give me an e mail paul_arnold@sandwell.gov.uk and we'll make some arrangements.

[Boyonabike]

Bit of an update as I'm keen to get a move on in preparation for spring coming.

Found a local bike shop who's willing to fit the hub motor - swapping the wheel isn't the deal, it's drilling the frame the downtube for battery mounts and swapping cranks and chainset for a chainset with integrated torque sensor that I haven't the tools for. So far so good.

Anyway, the shop agreed I should get a new fork and also advised that I should upgrade the brakes from my single pull calipers to (mechanical) disk brakes at the same time. They suggested keeping the existing rear calipers but look for new front forks with disk brake attachment and fitting a mechanical disk brake. Does that sound reasonable, and if so are my existing old-style non-aero brake levers compatible with disk brakes? Something like this looks like it fits the bill: https://www.amazon.co.uk/HYBRID-FORKS-S ... B01NALJKDV

And yes I do need a longer stem - according to bike fitting measurements at least 60mm and there are plenty of quill stems still around for these drops. I have fairly short arms and the top tube is stupidly long for the frame size hence the very short stem that was originally fitted but I agree it needs to go forwards somewhat.

If the existing brake levers are not compatible with disks, are there any other improvements I could make to the front brakes without chucking the levers? To be fair the brakes have never been fantastic (though as I also have a coaster brake I haven't been that bothered as together they can stop me on a sixpense...) and I take the point that by adding a low powered motor plus the extra weight, upgrading the brakes is a sensible suggestion if possible. Double pivot calipers are out because of the mudguard and tyre thickness (currently 28mm, but I would quite like to move to 32 or 35mm if mudguard permits). How about cantilevers, or are there any better single pull calipers that would fit over 35mm tyre and guards?

Please bear in mind this is a "vintage" style bike but with 22mm drop bars and "non-aero" brake levers so if I have to change the brake levers I will need new bars, new stem, new bracket for gear shifter etc etc so I'd prefer to switch over as little as possible.

[Brucey]

I would counsel caution if you are thinking of adding an electric conversion to your bike. In the simplest terms it was never designed for what you are planning to do with it. The electric gubbins will weigh about 15-20kg (i.e. doubling the weight of the bike) and because it is connected securely to the bike then the loads passing through the frame whenever you go over a bump will be many times higher than normal.

Drilling holes in your down tube to mount the battery sounds like the stupidest thing I have ever heard TBH; this might be fair game if you are converting a BSO made of gas pipe but your bike is made from tubes which are between 0.8 and 0.5mm thickness; drilling holes willy-nilly is simply not a good idea.

Also in the category of catastrophically dumb ideas (IMHO) is fitting a disc brake fork to a frame with a 1" steerer. IME the frame will, if regularly subjected to the (much higher) possible loads from using a disc brake on a heavy bike, soon fail.


The reason you like your bike now is most probably because the frame is light and fairly springy, and rides well. If you strap 15-20kg of crap onto it, all that will be lost; whatever ride qualities the bike has at present will be gone forever, even if the frameset doesn't soon break (which I think is very probable).

If you want an e-bike conversion for utility use, then really you should start with a frameset which is more suited to this. I would suggest a steel frame with oversized tubes and a 1-1/8" steerer, ideally using a rear hub motor or a BB drive conversion, not a front hub motor.

cheers

[Boyonabike]

Actually the frame is a cheap but heavy steel so part of the benefit of conversion is just making it roll better! Kit weighs around 7kg of which half is the motor and half is the battery. As there are already two holes in the downtube for a bottleholder only one extra needs to be inserted.

The purpose of adding a relatively lightweight and not very powerful motor is not so I can go breaking speed records. It is to make a 30 mile round commute something that doesn't leave me tired and sweaty.

Returning to the earlier question therefore, can I improve upon the existing single pivot caliper brakes in any way if I'm replacing the fork with a new steel fork that may have canti or disk attachment points whilst keeping my existing brake levers? The more extra kit that I'd need to add, like new bars, new levers etc, the more expense and closer to cost of a new bike it gets which I'm trying to avoid as I quite like the existing bike.

[Brucey]

If you drill a hole in a tube then it immediately sees at least x3 the stress. Some frames are fitted with threaded nutserts in drilled holes from the start (which I don't think is the best idea) and these don't do much to alleviate the stress concentration. In fact they don't do anything to mitigate the stress concentration unless the fastening is pretty securely tightened in the threaded fitting, and even then they don't do much. The saving grace for most such fittings is that they holes are not drilled near the ends of the tubes, so don't see the worst bending stresses. However it doesn't matter where the holes are drilled they will always see the torsional stresses, of which there are plenty in a down tube. Just drilling a small hole for a dynamo wire in a down tube is quite sufficient to cause a frame to fail by fatigue.

FWIW I still would counsel caution re. such a conversion, even if the claimed weight is less than 10kg. IME when the batteries are not contributing (which will be quite often if you ride far and the batteries have a small capacity) the bike may be draggier than normal as well as much heavier than normal. If you like, it turns itself into the worst bike in the world, one you would never choose to buy, own, ride or work on.

Re the brake levers; the levers you have at present are 'old road' type and have a short cable pull/ high MA (mechanical advantage). They will work OK with single pivot side pulls, centre pulls, cantilevers, Sturmey Archer drum brakes, and some (not all) 'road' type cable disc brakes. Some folk use them with early dual pivot brakes and in this pairing the power is good but the brakes need to be kept set closer than normal to the rims.

[In a nutshell there are three other cable pulls which you can encounter
a) Dual Pivot. Very close to 'old road' but not quite the same, often with slightly longer cable pull and slightly lower MA. This covers most road bike equipment made between ~1992 and 2008, as well as some current stuff from SRAM and Campagnolo. b) current standard pull on shimano (and some other) road brakes is 'New Super SLR' (NSSLR) which is longer cable pull/lower MA again and is designed to work with NSSLR brake calipers and some (not all) 'road' cable disc brakes. These levers also work OK with 'mini-V' brakes in many cases. c) V -brake cable pull. Even lower MA and longer cable pull. These levers work with some mini-Vs, all full V's, and 'MTB-type' cable disc brakes. ]

Anyway I can understand that you might want to keep the old brake levers but I'd guess that if that is going to be a make or break issue then you are going to be in trouble with other aspects of the conversion.

FWIW the 'no sweat' speed you will acheive (without electricty involved) will vary with the rider, clothing, gearing etc. But for me it is at least 12mph. In practice I have not tended to commute without at least expecting to change my clothes at the other end so I have usually accepted some sweating rather than none. 'No Sweat' rides have usually been done when it is raining hard enough that I have had to don a full waterproof; it is just not possible to exert myself normally (in a non breathable, everyday use waterproof) without there being something a 'boil in the bag' syndrome. Given that e-bike assistance is legally limited to 15mph, if you can do 12mph without sweating anyway, then you are not going to gain that much; swings and roundabouts really; you will get useful assistance up hills and into headwinds but that should be balanced against the fact that the bike is worse bike the rest of the time as well as heavy, expensive, and practically parasitical in terms of needing to be charged up /stored in a particular way if the batteries are not to die prematurely.

cheers

[niggle]

I converted a hybrid with a hub gear to an ebike using a front hub kit. It has been an effective tool for no sweat commuting and for helping pulling loads in a trailer or panniers full of shopping up the hills round here. I had a carbon fork so obviously that had to be changed, so I got a steel canti/disc fork from Bankrupt Bike Parts, and fitted a TRP Spyre front brake, but my frame uses 1 1/8" forks and has a noticeable strengthening gusset around the headtube/downtube joint. Brake levers are Tektro RL340s and work very well with the Spyre, and I am pretty sure they would fit on your 22.2mm bars, just need to be screwed down more.

However much of what Brucey says rings true for me, if it was not so hilly the electric assist would not be all that helpful to be honest and there are penalties to pay in terms of a big increase in the bike's weight, it is an unwieldy lump to lift even without the battery, the front hub's unsprung weight is noticeable along with the stiffer fork, but running a size bigger tyre has helped. Also I have had quite a few issues with damp getting into the electrics, the Chinese made components don't seem very well sealed at all, and if the bike loses the electric assist it is indeed a very slow, heavy thing to ride, you can feel quite noticeable drag from the motor when it is not running. In hilly Cornwall my range is more like 20 miles on a full charge with a 10.5Ah battery.

Also I did not drill a third hole in the down tube, I adapted the battery holder to fit the two bottle cage mounts properly instead. A rear hub is probably preferable in some ways but you would have to change to derailleur gears for that, a mid motor kit is quite a lot more expensive and may cause damage to your hub gear as it was not designed for the extra torque. There is a new uprated Nexus 7 for ebikes and most people agree that all the Nexus and Alfine 8 hubs are OK with mid drive.

One more thing- I also fitted drop bars to a flat bar frame necessitating a very short stem, the handling absolutely fine, in fact really good at speed, so ignore those who think they know more than they do

[Boyonabike]

Thanks Brucey that's very helpful. Of course retrofitting a road legal and therefore relatively tame motor to an existing bike forces compromises, but so too does buying an off the shelf ebike that doesn't come with a spec you want yet is at a price you don't really wish to pay. If there's a choice between cantis and disks that allows me to continue using the original brake levers and bars then I'm happy so long as I can find a suitable fork and this looks to fit the bill perfectly whilst letting me use all the rest of the existing kit:
https://www.amazon.co.uk/HYBRID-FORKS-S ... B01NALJKDV

Niggle - just what I was looking for (other than that I can't stand derailleurs and am a hubbie through and through). Just practical, eases the long commute whilst allowing a gentle workout and kills the hills. If I could only feel like I was always cycling along a slight downhill thanks to the motor assist I'd be very happy with the conversion. In my case though I do need a slightly longer stem I think - I have a lovely view of the front axle miles in front of the bars and I thought they were supposed to hide the axle. Holding a broomstick in the position I think they need to come out to was very comfortable hence I'll be looking for a 60mm threaded quill stem too.

[niggle]

I think these are exactly the same forks for less: https://www.bankruptbikeparts.co.uk/700 ... sc%20forks