Discs or V Brakes?
- Thread starter SilverSurfer
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JonGW
New Member
- Location
- Sunny Ol' England
Only get discs if you feel you need them, Obviously, Disc brakes are 100 times better, but if you just potter around on bridleways, It's not really worth spending loads on a set of disc brakes, when you can get away with v-brakes.
Pottering around on bridleways, especially around here at the moment is exactly one reason to have discs. Not for there improved stopping etc, but the fact not having V's helps with the mud clearance and keeping the wheels rotating. And for working when you do need them.
Mr Pig
New Member
- Location
- North Lanarkshire
Four of us were out on Saturday morning and some of what we rode through could only be described as filth. At one point one of the guys with rim brakes, a guy who'd never been with us before, said that coming down a hill his brakes had not worked. Basically his wheels were covered in mud and his brakes just slid.
So buy disks? Naa. He lived. Just had to pull harder. If I had a good bike with rim brakes I would not bother fitting disks. All of this extra kit ads weight and lightness is a great thing to have on a bike. Disks might have their advantages but they have down sides too. If they come on a bike, fine, but I wouldn't rush out to buy them.
So buy disks? Naa. He lived. Just had to pull harder. If I had a good bike with rim brakes I would not bother fitting disks. All of this extra kit ads weight and lightness is a great thing to have on a bike. Disks might have their advantages but they have down sides too. If they come on a bike, fine, but I wouldn't rush out to buy them.
jpembroke
New Member
- Location
- Cheltenham
If I lived in Provence then I don't think I'd bother with disks - V-brakes work just fine in dry climates - but here in the wet and cold of the UK disks are definitely an advantage.
02GF74
Über Member
Mr Pig said:
I am not so sure that there is that much of a wieght disadvantage.
- rotor, for sure add to unsprung wieght but then you can get disc specific rim wihtout the braking surface thatwould make up of it.
- hub; be a bit heavier for the rotor mount
- spokes, heavier on disc wheels due to lacing, i.e. no radial spokes
- caliper vs brake arms, weight would be about the same
- lever about the same
- hydraulic line vs steel inner and steel outer cable, disc has got to be lighter
be interesting if someone can post weights for comparison.
JonGW
New Member
- Location
- Sunny Ol' England
They can make Disc brakes lighter than V-brakes nowadays anyway, So weight really doesn't come into it.
Mr Pig
New Member
- Location
- North Lanarkshire
Are the disk wheels less strong?
I ask because they are narrower. Or to be more correct, because of the space on the hub taken up by the disk, the spokes are further in on the hub. Has to be less strong?
My disks are now silent so I think disk brakes are great, this week ;0)
I ask because they are narrower. Or to be more correct, because of the space on the hub taken up by the disk, the spokes are further in on the hub. Has to be less strong?
My disks are now silent so I think disk brakes are great, this week ;0)
02GF74
Über Member
^^^ correct - the wheel will have less dish, a bit like hte drive side on the rear wheel.
so compared to non disc wheel, whcih has more dish it will be less strong in theory.
in practice I doubt there is any problem - again look at the drive side of rear wheel and tell me how many problems are caused by the smaller dish to accomodate the cassette.
so compared to non disc wheel, whcih has more dish it will be less strong in theory.
in practice I doubt there is any problem - again look at the drive side of rear wheel and tell me how many problems are caused by the smaller dish to accomodate the cassette.
jpembroke
New Member
- Location
- Cheltenham
Surely a wheel that has less dish is stronger. A dished wheel has a large disparity in spoke tension between drive side (high tension) and non-drive side (lower tension). Because of this, rear (dished) wheels are more prone to going out of true than front (non-dished) wheels. Some companies (Campag, American Classic) have produced asymmetric rims to allow rear wheels to be built with less dish in order to make them stronger (spoke holes are offset from centre of the rim).
02GF74
Über Member
what exacty do you mean by stronger?
The wider the hub flanges, the deeper the dishes, and the stronger the wheel can be laterally; but vertical stiffness will be low.
The more vertical the spokes, i.e. the shallower the dish, and the less stiff and strong the wheel will be laterally.
it is a compromise. it is more important to have dish since a lot of the strnght comes from the rim.
The wider the hub flanges, the deeper the dishes, and the stronger the wheel can be laterally; but vertical stiffness will be low.
The more vertical the spokes, i.e. the shallower the dish, and the less stiff and strong the wheel will be laterally.
it is a compromise. it is more important to have dish since a lot of the strnght comes from the rim.
jpembroke
New Member
- Location
- Cheltenham
Dishing is not to do with the angle of the spokes, it's to do with the different angle of spokes between drive and non-drive side. A front wheel isn't dished because the spokes on either side of the wheel are at the same angle. A rear wheel, which has vertical spokes on the drive side and angle spokes on the left side, is dished. Imagine the wheels placed on their side: a front wheel looks like one of those sherbet flying saucers in section, whereas the rear wheel looks like a shallow bowl i.e. a dish.
Dishing is done to accommodate the cassette but compromises the strength of the wheel. This is why, as I mentioned before, certain manufacturers use asymmetric rims (i.e. spoke holes offset from the centre of rim) for their back wheels. This reduces dishing and makes for a stronger wheel.
Dishing is done to accommodate the cassette but compromises the strength of the wheel. This is why, as I mentioned before, certain manufacturers use asymmetric rims (i.e. spoke holes offset from the centre of rim) for their back wheels. This reduces dishing and makes for a stronger wheel.
jpembroke
New Member
- Location
- Cheltenham
From Sheldon Brown:
"When rear wheels are built properly, the spokes on the right side are made tighter than those on the left side. This pulls the rim to the right, so that it is centered with respect to the axle (and to the frame.) Viewed edgewise, a rear wheel built this way resembles a dish, or bowl, since the left spokes form a broad cone, while the right spokes are nearly flat."
and, to be fair, dishing is also a term applied to centering a wheel on the hub, so I suppose one does 'dish' a front wheel using a dishing tool. However, it's usually only rear wheels that are described as 'dished' or having 'dish'.
another good link here:
http://www.gtgtandems.com/tech/wheandhub.html
Discusses dishing and strength.
"When rear wheels are built properly, the spokes on the right side are made tighter than those on the left side. This pulls the rim to the right, so that it is centered with respect to the axle (and to the frame.) Viewed edgewise, a rear wheel built this way resembles a dish, or bowl, since the left spokes form a broad cone, while the right spokes are nearly flat."
and, to be fair, dishing is also a term applied to centering a wheel on the hub, so I suppose one does 'dish' a front wheel using a dishing tool. However, it's usually only rear wheels that are described as 'dished' or having 'dish'.
another good link here:
http://www.gtgtandems.com/tech/wheandhub.html
Discusses dishing and strength.
Mr Pig
New Member
- Location
- North Lanarkshire
I would have thought that the closer together the hub-end of the spokes are the less strong the wheels would be.
If you think about it, the spokes on each side are only about a couple of inches away from the centre of the hub. If the spokes were in the centre of the hub the wheel would have very little lateral stiffness at all. I think small changes here would be quite significant.
However, the changes of length and angle of the spokes relative to the rim would be small enough to have little impact on vertical strength, I don't think.
If you think about it, the spokes on each side are only about a couple of inches away from the centre of the hub. If the spokes were in the centre of the hub the wheel would have very little lateral stiffness at all. I think small changes here would be quite significant.
However, the changes of length and angle of the spokes relative to the rim would be small enough to have little impact on vertical strength, I don't think.
