Cracked frame welding
11-10-20, 08:46 PM
#51
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Yes, I'd say that's too taut.
Edit: It's a little difficult to tell because of the angle. But try loosening it a bit more and then see how much the top sags while going backwards on the pedals. That should show total sag too, and be easier to "eye" than using a prod.
Edit: It's a little difficult to tell because of the angle. But try loosening it a bit more and then see how much the top sags while going backwards on the pedals. That should show total sag too, and be easier to "eye" than using a prod.
Last edited by CargoDane; 11-10-20 at 08:50 PM.
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11-10-20, 09:23 PM
#52
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Last edited by 5 mph; 11-10-20 at 09:27 PM.
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11-10-20, 10:30 PM
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11-10-20, 10:40 PM
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glad you got a replacement...
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Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
11-12-20, 07:46 AM
#58
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Thanks that's good information. Do you have any guidelines or information on how to set Chain slack? I switched to a bike with a CR-MO frame, a Bianchi. It was sitting in some one's garage unused for a decade I remember on the Langster the chain was so slack it would pop off at times when I hit a bump.
The chain on my Bianchi is not taut but I'd like to introduce some slack as a precaution..I'm using chain tensioners. Probably tomorrow I'll nudge the tire a bit forward as a precaution
The chain on my Bianchi is not taut but I'd like to introduce some slack as a precaution..I'm using chain tensioners. Probably tomorrow I'll nudge the tire a bit forward as a precaution
What you want to do is eliminate all tight spots. With bike off the ground spin cranks slowly and you will see that there are tight spots and loose spots. Chainrings are not perfectly concentric. Rear cogs are not perfectly concentric. Additional errors are introduced because the frame is never perfectly straight and the wheel is seldom perfectly centered in frame. To have a chance of getting it all right you simply must have good chainline. Not perfect, that does not exist, but good.
Hopefully the chain does not hang loose at any point but it might. If the chain pulls taut at any point while cranks are rotating the wheel must move forward.
I have been riding fixed wheel for 53 years and never had a chain come off. My current fixed gear road bike has 50.4 bcd Durax crank arms that are not very accurate. The TA chainring is not very accurate. With the small bolt circle errors are amplified. It is a cheap basic cog at rear and that is not accurate. To eliminate tight spots there just have to be spots where the chain hangs loose. Looser than I would wish, but it all works. Just recently made an old age personal best of 190rpm on that bike. In traffic. In distant past have done 220 on the road and used to hit 240 every time when training on rollers. That is with chains that never get taut.
I don’t even know all the bad things that can happen with a taut chain. I do know what it sounds like, having been too near guys riding that way. It will definitely make everything wear out fast. The chain wants some slack and it will grind off metal to get it. Chain coming off is either very very loose, worn out, or the chainline is not good enough.
The other thing you want to avoid is road chainrings made for derailleur bikes. Those have shift gates intended to help the chain come off. Even worse than riding on a worn out chainring.
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11-12-20, 08:54 AM
#59
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After posting I read some of the other comments accumulated on the thread. Apparently dropping a chain has become something normal and common for fixed gear riding. This is so wrong. I rode fixed for thirty years before even hearing a report of a dropped chain. It is not normal. Something is very wrong if the bike is able to drop a chain.
Someone thinks tracks are smooth and have no bumps. Someone who never rode a track. Yes, tracks have bumps. Always. The biggest bump will be a downed rider. Usually the best thing to do is to ride straight over them. No one gets hurt, no additional rider need fall and the chains stay on. Then there is the world of grass track racing. There are no Zambonis for grass track.
I am 68 years old. If my chain comes off it is very likely I fall. If I fall it is near certain I will be injured. If the chances of any of this were greater than zero I would not be out on the road riding fixed. Fixed is the safest way to ride.
In in the early years of cycling everyone rode fixed. When freewheels became available they were an expensive option. Everyone can do this. It is not that hard.
Someone thinks tracks are smooth and have no bumps. Someone who never rode a track. Yes, tracks have bumps. Always. The biggest bump will be a downed rider. Usually the best thing to do is to ride straight over them. No one gets hurt, no additional rider need fall and the chains stay on. Then there is the world of grass track racing. There are no Zambonis for grass track.
I am 68 years old. If my chain comes off it is very likely I fall. If I fall it is near certain I will be injured. If the chances of any of this were greater than zero I would not be out on the road riding fixed. Fixed is the safest way to ride.
In in the early years of cycling everyone rode fixed. When freewheels became available they were an expensive option. Everyone can do this. It is not that hard.
11-12-20, 01:10 PM
#60
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After posting I read some of the other comments accumulated on the thread. Apparently dropping a chain has become something normal and common for fixed gear riding. This is so wrong. I rode fixed for thirty years before even hearing a report of a dropped chain. It is not normal. Something is very wrong if the bike is able to drop a chain.
Someone thinks tracks are smooth and have no bumps. Someone who never rode a track. Yes, tracks have bumps. Always. The biggest bump will be a downed rider. Usually the best thing to do is to ride straight over them. No one gets hurt, no additional rider need fall and the chains stay on. Then there is the world of grass track racing. There are no Zambonis for grass track.
I am 68 years old. If my chain comes off it is very likely I fall. If I fall it is near certain I will be injured. If the chances of any of this were greater than zero I would not be out on the road riding fixed. Fixed is the safest way to ride.
In in the early years of cycling everyone rode fixed. When freewheels became available they were an expensive option. Everyone can do this. It is not that hard.
Someone thinks tracks are smooth and have no bumps. Someone who never rode a track. Yes, tracks have bumps. Always. The biggest bump will be a downed rider. Usually the best thing to do is to ride straight over them. No one gets hurt, no additional rider need fall and the chains stay on. Then there is the world of grass track racing. There are no Zambonis for grass track.
I am 68 years old. If my chain comes off it is very likely I fall. If I fall it is near certain I will be injured. If the chances of any of this were greater than zero I would not be out on the road riding fixed. Fixed is the safest way to ride.
In in the early years of cycling everyone rode fixed. When freewheels became available they were an expensive option. Everyone can do this. It is not that hard.
And since it seems directed to me: A track does not have bumps compared to street riding with potholes, kerbs, and whatnot.
AND, I specifically said it should NOT drop off, and if it does, the wheel has to be moved back a bit.
Sheesh! Go ride on that "bumpy" track of yours. No one is advocating for a chain so loose it will drop off the cog/chainring.
11-12-20, 04:45 PM
#61
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For those who live vicariously there are photo archives. Always a popular photo, many examples.
11-12-20, 05:29 PM
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11-12-20, 05:47 PM
#63
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I never said you couldn't avoid crashing. I said that if you run OVER someone as you suggested, you're going down. Hitting or avoiding someone is not the same. And even if you find those "amzing" saves, it is not really a bumpy track - and certainly not like actual roads, kerbs, and what have you. Maybe go for a ride outside?
It doesn't change much what I argued: That his chain should NOT be so loose it comes off as you seemed to pretend I said. I specifically said that if it came off, it was too loose and he should tighten it up.
It's amazing, it's as if the two of you have never ridden outside on potholed streets, kerbs, gravel, singletrack, and whatever else is out there. So eager to argue against so loose chains they fall off, despite me not advocating that at all.
It doesn't change much what I argued: That his chain should NOT be so loose it comes off as you seemed to pretend I said. I specifically said that if it came off, it was too loose and he should tighten it up.
It's amazing, it's as if the two of you have never ridden outside on potholed streets, kerbs, gravel, singletrack, and whatever else is out there. So eager to argue against so loose chains they fall off, despite me not advocating that at all.
11-12-20, 06:54 PM
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Not sure how this turned into an argument. I posted the link to the velodrome crash and near-crash simply because one of the posts reminded me of it and thought that you guys might find it interesting.
For what it's worth, I have a Langster that I bought the first year it was in production, and I had the chain derail repeatedly out on the road (glad I had a front brake when it happened). Very unnerving.
I finally traced the problem to the soft aluminum track ends, which the axle locknuts caused to deform over time, enough to let the axle slip regardless of how much I tightened the track nuts. I stuck some very thin stainless steel washers on the axle, on the inner side and outer side of each fork end, and added a axle retainer on the drive side that's all I have left from my first track bike, bought back in 1964. (Specialized added steel plates to the faces of the fork ends on later Langsters, so I clearly wasn't the only one who encountered that problem.)
Somewhere on Sheldon Brown's site, I believe he says that you can compensate for the eccentricity of a track bike's chain ring by loosening the bolts a little, finding the spot on the chain ring where the chain is tightest, and then smacking the chain ring with a rubber mallet. Sounds like wishful thinking to me. I just wish it were easier to get the chain tension right with the Langster's cheap drivetrain, which always seems to be either too tight or on the verge of dropping the chain. My other two track bikes have high-end cranks, and it's a breeze to get the chain tension right on those.
For what it's worth, I have a Langster that I bought the first year it was in production, and I had the chain derail repeatedly out on the road (glad I had a front brake when it happened). Very unnerving.
I finally traced the problem to the soft aluminum track ends, which the axle locknuts caused to deform over time, enough to let the axle slip regardless of how much I tightened the track nuts. I stuck some very thin stainless steel washers on the axle, on the inner side and outer side of each fork end, and added a axle retainer on the drive side that's all I have left from my first track bike, bought back in 1964. (Specialized added steel plates to the faces of the fork ends on later Langsters, so I clearly wasn't the only one who encountered that problem.)
Somewhere on Sheldon Brown's site, I believe he says that you can compensate for the eccentricity of a track bike's chain ring by loosening the bolts a little, finding the spot on the chain ring where the chain is tightest, and then smacking the chain ring with a rubber mallet. Sounds like wishful thinking to me. I just wish it were easier to get the chain tension right with the Langster's cheap drivetrain, which always seems to be either too tight or on the verge of dropping the chain. My other two track bikes have high-end cranks, and it's a breeze to get the chain tension right on those.
11-12-20, 07:00 PM
#65
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Sorry for that trackhat. I got annoyed on another poster who thought I was arguing for slack chains that falls off, when I clearly didn't advocate that at all. My apologies.
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11-13-20, 10:35 AM
#66
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I never said you couldn't avoid crashing. I said that if you run OVER someone as you suggested, you're going down. Hitting or avoiding someone is not the same. And even if you find those "amzing" saves, it is not really a bumpy track - and certainly not like actual roads, kerbs, and what have you. Maybe go for a ride outside?
It doesn't change much what I argued: That his chain should NOT be so loose it comes off as you seemed to pretend I said. I specifically said that if it came off, it was too loose and he should tighten it up.
It's amazing, it's as if the two of you have never ridden outside on potholed streets, kerbs, gravel, singletrack, and whatever else is out there. So eager to argue against so loose chains they fall off, despite me not advocating that at all.
It doesn't change much what I argued: That his chain should NOT be so loose it comes off as you seemed to pretend I said. I specifically said that if it came off, it was too loose and he should tighten it up.
It's amazing, it's as if the two of you have never ridden outside on potholed streets, kerbs, gravel, singletrack, and whatever else is out there. So eager to argue against so loose chains they fall off, despite me not advocating that at all.
You have never been on a track. Why pretend to know things? Yes, tracks are used with potholes. Do you even know what grass track is?
How many posts did this thread go before someone pointed out drivetrain eccentricity? OP posted photos of chain slack and got opinions, who asked if that was the tight spot or loose spot?
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