What do Wheels Weigh?

I recall seeing discussion several times on the forum about wheel weights, so I thought I'd start this thread to collect data in one place. I weighed the following wheels, picking ones that could be used on Commandos, as well as a couple of TZ250 ones for comparison. I have some others that I'd like to weigh, but they all have tires on them at this time. Maybe later. Feel free to add more data on other wheels.

Unless otherwise stated, the weights are with spacers and bearings, but without axles or disks.

First, a stock MKIII Commando 1.85x19 - 12 lbs. 7.2 oz.



Next a period Morris Mag aluminum wheel in 2.15x19 - 11 lbs. 14.2 oz.



The next two are wheels I am prepping for my street bike. They are period EPM magnesium wheels that I used on my race bike years ago.

The front 2.15x18 weighs 8 lbs 5.0 oz.



And the rear 3.0x18 is 10 lbs. 2.6 oz.



Just for interest, this is a Harley front wheel in 2.5x19 that I thought about using, until I weighed it at 15 lbs. 14.2 oz.



For a comparison to more modern casting technology, I've also included a pair of TZ250 racing wheels

The front Asahi 3.5x17 is aluminum and weighs in at 8 lbs. 4.4 oz.



And the rear is a Marvic 5.5x17 in magnesium at 8 lbs. 3.0 oz.



Ken

The modern wheels obviously benefit from years of development an computer aided design to use the least amount of metal. This is probably as much to do with saving money in production costs that performance gains. The older wheels where in their day cutting edge untried technology designed by hand so there is definitely room to improve them.
SO ITS TRUE YOU CAN REINVENT THE WHEEL :lol:

Do you (or anyone) know the difference in weight of an alloy rim over the standard steel rim? Or lighter thinner spokes? (Wonder if you could get titanium spokes)

I run apprillia pegaso / BMW f650 wheels much lighter than the stock commando wheels ,next time it's apart I will weigh them cheers

toppy said:

The modern wheels obviously benefit from years of development an computer aided design to use the least amount of metal. This is probably as much to do with saving money in production costs that performance gains. The older wheels where in their day cutting edge untried technology designed by hand so there is definitely room to improve them.
SO ITS TRUE YOU CAN REINVENT THE WHEEL :lol:

Do you (or anyone) know the difference in weight of an alloy rim over the standard steel rim? Or lighter thinner spokes? (Wonder if you could get titanium spokes)

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Buchanan's Spoke and Wheel here in SoCal made titanium spokes for a while, but will no longer do so. I asked Kenny Buchanan about it at the Quincy rally, and he explained why, but I've already forgotten the reasons! A friend of mine had some made for his Norton wheels back in 1999 or 2000. He sent a batch of grade 5 (6Al-4V) titanium welding rod to Buchanan's, and they turned it into spokes. Might have been the first ones Buchanan made.

Ken

I've forgotten how much weight can be dropped just by switching from stock chrome steel to flanged alloy Morads. I seem to recall 2 and a bit pounds per wheel, which if correct is a nice light wheel, maybe comparable with modern aluminium 3-6 spoke, but still heavier than modern wheels in magnesium. The flanged alloys win the beauty contest over all others IMHO, especially on a Norton.

I've heard that the safe shelf life of a Magnesium wheel is not terribly long.
Is this correct Ken?



Glen

I had a magnesium Dymag wheel crack between two of the spokes on a T160 while I was in Spain.
I've had better days, just glad I discovered it while parking the bike up for the night.
Recovered home to UK, and replaced the wheels with alloy Lesters.
sam

What do the flanged alloys from back in the day weigh?

Is this string intended for racing Nortons or for road use. If road use is there any significant advantage of lighter wheels?

Don P. ( madass ) made me a set of OEM size flanged alloys with SS spokes etc. this spring ..... was surprised how much lighter they were compared to chrome wheels I took off ..... in hind sight I should have weighed them before mounting the tires and hitting the road .... maybe Don will post up weight one of his flanged wheels for comparison .... Don ?
Craig

illf8ed said:

Is this string intended for racing Nortons or for road use. If road use is there any significant advantage of lighter wheels?

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Definitely.
Reduction of rotating, unsprung weight means improved handling, plus every 7 lbs=1 bhp.

Glen

Getting rid of unsprung weight (everything that moves when you hit a bump) is the best thing you can do to improve an otherwise good-handling motorcycle.

Correction to my earlier post, flanged alloy Morads are almost exactly one pound lighter than stock rims, however that is stepping up to WM3 from WM2.
The Madass single front disc is also about one pound lighter than the stock disc, so there is another pound saved while going to a much improved brake.
A lighter or drilled rear disc could save another pound.
Finally, tubeless conversion saves another pound, so there is 6 pounds eliminated right where it matters most.

Glen

worntorn said:

I've forgotten how much weight can be dropped just by switching from stock chrome steel to flanged alloy Morads. I seem to recall 2 and a bit pounds per wheel, which if correct is a nice light wheel, maybe comparable with modern aluminium 3-6 spoke, but still heavier than modern wheels in magnesium. The flanged alloys win the beauty contest over all others IMHO, especially on a Norton.

I've heard that the safe shelf life of a Magnesium wheel is not terribly long.
Is this correct Ken?



Glen

Click to expand...

Depends. In dry storage they are good pretty much forever. In use, a lot depends on environment and maintenance. The problem with mag wheels is in two areas. They are very subject to corrosion if not properly treated, and the corrosion causes stress cracks, which can lead to failure. Clean magnesium, with proper conversion coating and good paint, will take care of the problem when new. The difficulty with mag wheels is that they always end up with scratches and dings in use, and that can lead to corrosion and failure. The problem gets worse if you live near the ocean. Touching up damaged areas immediately will maintain the wheels integrity, but who really does that? The other problem with mag wheels is that they are not as strong as aluminum, so are more easily damaged from pot holes and hitting curbs. I think that's one of the principal reasons they are not ussally recommended for street use. I will have the EPM wheels inspected after I get them completely stripped of paint. If there are no cracks, I will touch them up with an Iridite coating, and apply a good urethane paint. If they are cracked, they will be trashed. I'd really like to use them for the period appearance, but not enough to risk it without checking them. If I can't use them, I'll probably go with a pair of Morris or similar cast wheels.

Ken

For those who might be interested (and wealthy?), I should point out that Marvic are making new repops in magnesium of the original Morris mag wheels, including the 19" sizes. Unfortunately, they are something like £2500 a pair.

Ken

When aluminium is exposed to the atmosphere it immediately forms it's own protective coating of oxide. Is the metallurgy of magnesium similar or can a mag wheel look beautiful and have no cracks, yet still be fundamentally weak ?

The first mag wheels in Victoria were made using wheels from the UK as a pattern. The entrepreneur failed to allow for shrinkage, so some cracked in service. He went back to the foundry at Commonwealth Aircraft Corporation and complained. After that it was almost impossible to get anything for motorcycles cast in magnesium by that company. These days there is another company working with magnesium, however I don't believe anyone is having wheels made there.
There is also another consideration - the mass of the wheel affects the gyroscopic effect - might change the handling and if the steering is already very quick ... ?

Back when, light gauge painted steel spokes with alloy nipples were a standard part of a roadracing wheel package with Borranis being lighter than Akronts. The San Remo flanged rims were also very light. Light gauge spokes had to be painted because if they were plated, then they were too weak, having been weakened by electrolysis.

I'm always frustrated by the failure of magazine testers to weigh tires, or to publish, their respective weights.

A new Morad 2.15x19 flanged alloy rim weighs just 2.2 kgs. It's not much is it? I wonder how much better than that one can do and maintain enough strength to endure potholes 2 up?
According to Central Wheel, their flanged Morads are their strongest wheel type.

Glen

I've got a non-flanged alloy Exel 18" rim with SS spokes fitted to a 1971 front hub (minus the disc) that weighs in at 4.8 Kg on my bathroom scales. That works out at about 10 lb 9 oz.

My bare Excel flanged WM3 x 19 front rim weighs 2.18 kg compared to a new bare chromed steel WM2 x 19 at 2.53 kg.

Ed