I finally got round to replacing the two broken spokes in the back wheel on my Cinzia folding bike, and found that three spokes had broken, not two! Mind you, the longer you leave a broken spoke, the more stress there is on the rest, so the more likely further breaks are.
The root of the problem is three-fold:
a) I have fairly lightly-built wheels, with only 28 spokes. A modern "general purpose" wheel has 36 spokes in it. More spokes, generally, equals stronger wheels. Folding bikes, in attempt to shave off a few ounces (grammes) often have only 28 spokes, although in the case of folders with a heavy steel frame like mine it is as much about fashion as it is about weight;
b) I am not a light person! I weigh a good 100kg (220 lbs), and I can be carrying up to 15kg (33 lbs) of shopping on top of that;
c) My folding bike has a sloping seat tube so that as the seat is adjusted upwards it moves back quite a bit too. This is so that taller riders get extra "arm" room between the seat and the handlebars, and is a good idea. However, as I am tall (about 6 foot 2 inches, aka 190 cm), the seat is quite far back as well as quite high. Therefore I am sitting pretty much over the rear wheel, which is taking a MUCH heavier loading than the front wheel (additionally, I now have a 36-spoke front wheel, because that was what was fitted to the hub dynamo I bought a while back)
So, all in all, the lightly built (28 spokes, remember) back wheel is taking a weight which is rather more than average.
Result = broken spokes.
But spokes are cheap, and a new (36 spoke) wheel is either expensive (if I get a bike shop to build it) or fiddly and very time-consuming (if I build it myself). So, for the time being, I'll keep going as I am, just replacing a few odd spokes ever now and then.
I have now broken 5 spokes in just under two years of daily usage, so it's not that many really.
Of the five, I have broken three at the "elbow" - where the spoke bends and goes into the hub flange, and two have broken on the threads that go into the nipple that slots into the wheel rim.
I get my replacement spokes from SJS Cyles, in Bridgewater.
The spokes that break are the "original" ones, not the replacements, so I am possibly getting better replacement spokes, too!
But of course, the "originals" are twenty years old, and the "new" ones are, well, "new"
SJS sell spokes in a number of designs, and a VERY wide range of lengths (mine are an unusual 190mm length), and I buy the "plain and simple" aka "cheap" version - SJS describe them as 14 gauge British-made stainless steel "plain gauge" spokes, and they come with "12mm brass nipples"
I paid £1.84 for a packet of 6, with £2.50 for postage, and they came in about two days.
Because of the shipping, I bought two packets, so it was a total of £6.18 (US$9.88, Euro 7.42) for 12 spokes including delivery.
That's only just over 50 pence (80 US cents, 60 Euro cents) a spoke!
I took out the rear wheel to change the spokes, and while i was there I inspected the rear tyre - a few extra cuts, but no sharp stuff stuck in it.
Then, of course, I put the wheel back in, tensioned the chain, giving it a quick rub down with a cloth to get debris off it, and set the correct cable adjustment for the Sturmey-Archer three-speed hub gear.
Suitably repaired, I took it for a quick spin to check it was all OK, and then put the bike back in the garage ready for the daily commute to work.
I did a photo summary of what is required to fix a broken spoke just over a year ago, and you can see that here:
fixing a broken spoke - pictures
The root of the problem is three-fold:
a) I have fairly lightly-built wheels, with only 28 spokes. A modern "general purpose" wheel has 36 spokes in it. More spokes, generally, equals stronger wheels. Folding bikes, in attempt to shave off a few ounces (grammes) often have only 28 spokes, although in the case of folders with a heavy steel frame like mine it is as much about fashion as it is about weight;
b) I am not a light person! I weigh a good 100kg (220 lbs), and I can be carrying up to 15kg (33 lbs) of shopping on top of that;
c) My folding bike has a sloping seat tube so that as the seat is adjusted upwards it moves back quite a bit too. This is so that taller riders get extra "arm" room between the seat and the handlebars, and is a good idea. However, as I am tall (about 6 foot 2 inches, aka 190 cm), the seat is quite far back as well as quite high. Therefore I am sitting pretty much over the rear wheel, which is taking a MUCH heavier loading than the front wheel (additionally, I now have a 36-spoke front wheel, because that was what was fitted to the hub dynamo I bought a while back)
So, all in all, the lightly built (28 spokes, remember) back wheel is taking a weight which is rather more than average.Result = broken spokes.
But spokes are cheap, and a new (36 spoke) wheel is either expensive (if I get a bike shop to build it) or fiddly and very time-consuming (if I build it myself). So, for the time being, I'll keep going as I am, just replacing a few odd spokes ever now and then.
I have now broken 5 spokes in just under two years of daily usage, so it's not that many really.
Of the five, I have broken three at the "elbow" - where the spoke bends and goes into the hub flange, and two have broken on the threads that go into the nipple that slots into the wheel rim.
I get my replacement spokes from SJS Cyles, in Bridgewater.
The spokes that break are the "original" ones, not the replacements, so I am possibly getting better replacement spokes, too!
But of course, the "originals" are twenty years old, and the "new" ones are, well, "new"
SJS sell spokes in a number of designs, and a VERY wide range of lengths (mine are an unusual 190mm length), and I buy the "plain and simple" aka "cheap" version - SJS describe them as 14 gauge British-made stainless steel "plain gauge" spokes, and they come with "12mm brass nipples"
I paid £1.84 for a packet of 6, with £2.50 for postage, and they came in about two days.
Because of the shipping, I bought two packets, so it was a total of £6.18 (US$9.88, Euro 7.42) for 12 spokes including delivery.
That's only just over 50 pence (80 US cents, 60 Euro cents) a spoke!
I took out the rear wheel to change the spokes, and while i was there I inspected the rear tyre - a few extra cuts, but no sharp stuff stuck in it.
Then, of course, I put the wheel back in, tensioned the chain, giving it a quick rub down with a cloth to get debris off it, and set the correct cable adjustment for the Sturmey-Archer three-speed hub gear.
Suitably repaired, I took it for a quick spin to check it was all OK, and then put the bike back in the garage ready for the daily commute to work.
I did a photo summary of what is required to fix a broken spoke just over a year ago, and you can see that here:
fixing a broken spoke - pictures
How long did it take you?
ReplyDeleteIt sounds like a hard job.
Katya
not sure how long it took.
Deleteallow at least an hour.
summary of work:
1) take wheel off bike
2) take tyre off wheel
3) take off rim tape
4) take out broken spoke(s)
5) put in new spokes, making sure they go in with the same pattern as the rest of the spokes on the wheel
6) tighten up new spokes until the wheel is fairly straight
7) put rim tape back on
8) put tyre back on
9) put wheel back on
10) reconnect anything you had to undo to get the wheel off in the first place (such as brakes or mudguards)
11) go for a quick test up and down the road just to make sure everything looks and feels right.
Or, of course, you could ask your Dad to do it for you :-)