Trim Motorbike spokes on newly built wheel?

[RichardM]

That's a huge barrel of worms to open. There are two schools of thought, 1) Perfectly aligned is the only acceptable set up. 2) It doesn't matter as long as the rider is unlikely to notice and they'll adapt.

Just FYI, many manufacturers have offset rear wheels. Kawasaki for example can be 20 mm offset, and that's on modern bikes.

My personal preference and aim when building or modifying is bang on inline front and rear. That usually involves a fair bit of lathe and mill work to achieve though.

Rob North Works Tridents were supposed to be 1/2" out of line.

The XT nipples are proud of the rim slightly on one side, but there is no way I'd fit that wheel as is. Get a Dremel with a cutting wheel on it and take the spokes down flush with the nipple and then file smooth.

 

[brightspark]

i had my ally wheels rebuilt and have stainless spokes they are 100 percent . a few of the spokes needed grinding back slightly but its no big deal if the guy had ground them back you would have been none no wiser and as happy as a pig in pi.ss

 

[More Amps]

How much were you charged for that "high quality work undertaken by a time-served mastercraftsman with over 40 years experience"?

 

[Screwdriver]

Finger sander would make a neat job out of that. Take only minutes.

 

[Chris152]

i had my ally wheels rebuilt and have stainless spokes they are 100 percent . a few of the spokes needed grinding back slightly but its no big deal if the guy had ground them back you would have been none no wiser and as happy as a pig in pi.ss

So Cato's point about the nuts/ nipples being too proud of the rims is not an issue?

 

[voipio]

Aye, though as @Seadog has said fretting would be the likely mode of failure: the tube is subject to various forces - vibration on undulating road surfaces, short duration high loads when hitting a pothole or road defect, centrifugal force and increase in pressure with heat if used hard which will result in fretting between the spoke sitting proud and the rim tape then tube. I have never used spokes sticking proud like that, so have never had a failure - no way would I risk those protruding spokes.

I'm intrigued. In my experience, the tyre bead seems to stay fairly firmly in place, relative to the rim, under normal road use conditions. I've never seen evidence of a tyre bead having moved relative to the rim, except once, when we were kids, riding on an underinflated tyre on a pushbike, going up a steep hill. That did lead to a loss of air in the tyre, as a result of the inner tube being pulled around by the tyre slipping on the rim, pulling against the inflation valve, causing its seal to the inner tube to fail. I know the original poster mentioned using the wheels for tarmac hill climbs, with low tyre pressures, so this experience may be relevant. Going back to normal road use, though, I don't think much happens to the part of the inner tube that's inside of the circles formed by the tyre beads, in terms of movement. The part of the inner tube that sits beyond those circles is a different matter.

 

[RichardM]

I've seen tyre beads which have moved, which is the reason I leave the nuts loose on the valve stem. Valve stem at a angle means the tyre has moved and needs to be reset. Security bolts used to be fitted to counteract tyre creep.

 

[RichardM]

So Cato's point about the nuts/ nipples being too proud of the rims is not an issue?

XT600 rear pic from the internet, to give you an idea of OEM standards (without so much rust). Put a good rim tape over the nipples.

 

[Cato]

View attachment 534498
XT600 rear pic from the internet, to give you an idea of OEM standards (without so much rust). Put a good rim tape over the nipples.

That's a great picture to illustrate fretting/chaffing. See the shiny/clean bits on the high parts of the nuts? That's where they've been rubbed in use.

 

[RichardM]

Is it that someone has had a wire brush on it to clean some of the rust off, or that the rim tape has protected those parts (including parts of the rim) from rust?

 

[Cato]

Or is it that someone has had a wire brush on it to clean some of the rust off?

Just the high spots?

Thing is people can debate it all they want, fortunately facts and physics trumps opinions every time. A high spot of any kind pressing against a rubber tube that's moving will cause friction, that friction will cause localised heat build up, and that will happen with or without rim tape in between the high spot and the inner tube. It's just a fact.

Whether someone feels that the risk of failure is low is utterly irrelevant to the fact that the risk exists, that risk is due to poor work/preparation, and that there's a very basic principle of physics creating the potential point of failure.

This is what the well looks like in a properly built wheel. Spokes cut to length before fitting, the correct nuts/nipples selected to suit the rim dimples, valve hole countersunk, and nothing protruding above the rim well.

 

[RichardM]

Who made the rim (manufacturer)?

 

[Cato]

Who made the rim (manufacturer)?

No idea TBH. I sent the hubs to Staffordshire Wheelworks with a request for stainless rims and spokes to convert from 18" rear and 19" front to 17" on both. He knows what's suitable and what's not for a given application so I just leave the details to him.

 

[Rannsachair]

I'm intrigued. In my experience, the tyre bead seems to stay fairly firmly in place, relative to the rim, under normal road use conditions. I've never seen evidence of a tyre bead having moved relative to the rim, except once, when we were kids, riding on an underinflated tyre on a pushbike, going up a steep hill. That did lead to a loss of air in the tyre, as a result of the inner tube being pulled around by the tyre slipping on the rim, pulling against the inflation valve, causing its seal to the inner tube to fail. I know the original poster mentioned using the wheels for tarmac hill climbs, with low tyre pressures, so this experience may be relevant. Going back to normal road use, though, I don't think much happens to the part of the inner tube that's inside of the circles formed by the tyre beads, in terms of movement. The part of the inner tube that sits beyond those circles is a different matter.

I used to work with steering systems for articulated vehicles and modelling of tyres deforming under load was a complex model: our original computer model was created by an ex NASA scientist, a Professor. Not my area of expertise, though I recall some of the factors.

The carcass of the tyre deforms giving the vehicle its contact patch with the road, as the wheel rotates the deformed area constantly moves, so the tube is continuously deforming as the wheel rotates - so the tube is being deformed and recovering hundreds of times a minute. On top of that you have centrifugal force pushing the tyre and tube outwards at higher speeds, there is also friction between the tube and rim and tube and tyre, it is not fixed, it can move slightly. Then there are braking, acceleration and impacts (road defects).

My understanding is that a tube will experience low amplitude high frequency creep that lead to tube failure if it is against localised high spots - spokes, though I have never studied this in enough detail to say conclusively. So even if I am not correct, I would err on the side of caution for a potentially life critical risk.

 

[Chris152]

Just the high spots?

Thing is people can debate it all they want, fortunately facts and physics trumps opinions every time. A high spot of any kind pressing against a rubber tube that's moving will cause friction, that friction will cause localised heat build up, and that will happen with or without rim tape in between the high spot and the inner tube. It's just a fact.

Whether someone feels that the risk of failure is low is utterly irrelevant to the fact that the risk exists, that risk is due to poor work/preparation, and that there's a very basic principle of physics creating the potential point of failure.

This is what the well looks like in a properly built wheel. Spokes cut to length before fitting, the correct nuts/nipples selected to suit the rim dimples, valve hole countersunk, and nothing protruding above the rim well.

View attachment 534515

I've spent the morning looking for info on how the nipples seat within the rim, surprisingly little on it that I can find. I can see different gauge nipples being sold, but they don't specify the head size, so it's hard to tell if they'll seat properly in the dimples, as in the photo.

Does anyone specify the head sizes, or is it just a matter of different manufacturers making different size heads?

ps Some good news, a friend who's an old-school motorcycle mechanic has agreed to redo the wheels for us - he doesn't offer it as a service but knows what he's doing and will set them correctly.

 

[Seadog]

if all the spokes are tight the wheel runs true and is properly centralized just grind the excess back and fit the rim tape dont make a mountain out of a mole hill , you can buy spoke dies if u want to make your own up

Spoke dies? No, no, no! The threads should be rolled so that the nipple doesn't run up to the end of the thread, and it is also stronger.

"I've never seen evidence of a tyre bead having moved relative to the rim, except once, when we were kids, riding on an underinflated tyre on a pushbike, going up a steep hill. That did lead to a loss of air in the tyre, as a result of the inner tube being pulled around by the tyre slipping on the rim, pulling against the inflation valve, causing its seal to the inner tube to fail."


Hence the use of one, sometimes two security bolts on off-road bikes' rear wheels where you run lower pressures.

 

[Cato]

I've spent the morning looking for info on how the nipples seat within the rim, surprisingly little on it that I can find. I can see different gauge nipples being sold, but they don't specify the head size, so it's hard to tell if they'll seat properly in the dimples, as in the photo.

Does anyone specify the head sizes, or is it just a matter of different manufacturers making different size heads?

ps Some good news, a friend who's an old-school motorcycle mechanic has agreed to redo the wheels for us - he doesn't offer it as a service but knows what he's doing and will set them correctly.

Probably best to have a word with someone who rebuilds wheels and/or supplies the bits. From the little I know the nipple selection is based around the rim type and spoke angle, but I have no idea which ones for what.

 

[voipio]

I've never seen evidence of a tyre bead having moved relative to the rim, except once, when we were kids.....

Memory can be a poor servant :-)

I've seen tyre beads which have moved, which is the reason I leave the nuts loose on the valve stem. Valve stem at a angle means the tyre has moved and needs to be reset. Security bolts used to be fitted to counteract tyre creep.

@RichardM 's post reminded me that I have seen tyre bead movement on pushbikes several times. But not on motorbikes (admittedly not performance machines) nor on four wheeled vehicles (tubeless tyres).

 

[bricol]

Moved tyres on trials cars, but running silly low pressures, off-road, for grip. Security bolts not allowed in the classes I run in.