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Discussion Starter · #1 ·
Hi to all from rainy and windy Western Australia. Any info on lightweight wheels and how they compare with standard monster wheels would be much apreciated.Thanks
 
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Discussion Starter · #2 ·
I don't have exact weights posted anywhere but
I have some weights posted in our 748-998 wheel section to give you an idea of the differences between stock five spokes, 5 spoke magnesium and 10 spoke magnesium. We also have some weights posted on the CF wheels.

Simple static weight measurements are a little misleading, since it does not tell you where the weight is distributed on the wheel. Some wheels such as Marvic mill out the hubs to get a low wheel weight but takes very little weight off the lip where it really matters. BST uses a solid alum hub so the hub is about 80% of the weight of the wheel. The outer rim itself is very light.

The difference between a CF and mag wheel is huge. One of of racers is lapping 1.5-2 seconds faster than his magnesium wheels. Other racers are getting 3 seconds faster than OEM wheels.

Light weight wheels will transform your street bike and make a huge difference in turn in, acceleration, stopping and ride quality. I think it is the best bang for the buck. You want get this much improvement from a full exhaust system, piston kit or brake/suspension upgrade.

Modern magnesium and carbon whels are very strong. CF wheels are basically maintenance free and will likely outlast your bike.
 
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Discussion Starter · #3 ·
the CF wheels seem to be the way to go. My only concern would be having tires mounted by the local rim butcher.

I am wondering if there are any special considerations or things to look for in selection of a shop to mount the rubber on CF rims....in terms of type of tire mounting equipment used....not using tire irons/levers etc etc
 
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Discussion Starter · #4 ·
CF wheels won't scratch as easy as painted wheels (and if it does scratch you won'r notice it much). They are much stronger than aluminum or magnesium wheels.

The only concern is getting the tire to bead on the CF wheels. The rougher texture of CF does not allow the tire to slide onto the bead area if your shop uses soap and water as a lubricant. Their are a few very good lubricants designed for easy tire mounting that I believe are alcohol based. This is the stuff to use for magnesium wheels as well since it is not ideal to have water inside the rim on a mag wheel.
 
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Discussion Starter · #5 ·
CF wheels will not bend but crack on impact. you might want to reconsider if you will be riding your bike on rough streets (pot holes).
 

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The first bit of information was posted on an RC51 bulletin board. RC51 wheels may be different from Ducati wheels, but you can get an idea of the weight savings. The second bit was posted on the website of a Ducati 888 and 900SS owner.

Wheel Weights Courtesy of Dan Kyle Racing

The most important weight is around the outer rim, this outer weight determines the gyroscopic effect (turning) and affects the brakes the most. So even though the overall weight may not appear to be a significant savings the performance aspect is still there due to less rotating mass on the outer most part of the rim.

FRONT WHEELS NO DISCS
Blackstone carbon fiber 4.85 lbs
Dymag carbon fiber 5.6 lbs
Dymag mag center carbon rim 7.8lbs
Hi Point forged aluminum 8.2lbs (unofficial weight)
Marchesini cast mag 7.7 lbs
Marchesini forged aluminum 8 lbs
Marchesini forged mag 7 lbs
Marvic Penta II 7.5 lbs
PVM cast mag 9 lbs
PVM forged aluminum 10 lbs
PVM forged mag 7 lbs
PVM Colorline 5 spoke two piece 14 lbs
OZ forged aluminum 7.75 lbs
Stock RC51 10.5 lbs

REAR WHEEL WITH DISC AND CUSH DRIVE
Blackstone ?
Dymag carbon fiber 13 lbs
Dymag mag center carbon rim 12.8 lbs
Hi Point forged aluminum 16.3 lbs (unofficial weight)
Marchesini cast mag 12.7 lbs
Marchesini forged aluminum 16 lbs
Marchesini forged mag 13 lbs
Marvic Penta II 13.6 lbs
PVM cast mag 14.25 lbs
PVM forged aluminum 17.75 lbs
PVM forged mag 12 lbs
PVM Colorline 5 spoke two piece 6.25" 25.5 lbs
OZ forged aluminum 16.5 lbs
Stock RC51 19 lbs
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Here are the ACTUAL weights of the magnesium Marchesinis for the sizes shown. I weighed all this myself. The wheels are compared sans rotors. The rears were weighed with cush drives & sprockets (both alloy) since they both use proprietary stuff there. I also weighed the cush drives separately, in case anyone's interested in that. All bearings are in place...

Stock Brembo 3.5 x 17 front: 11lbs, 3oz.
Marchesini 3.5 x 17 front: 7lbs, 3oz.
4 lb difference.

Stock Brembo 5.5 x 17 rear with cush & sprocket: 18lbs, 13oz.
Marchesini 5.5 x 17 rear with cush & sprocket: 12lbs, 6oz.
6.5 lb difference.

Stock Brembo cush drive with sprocket: 3lbs, 3 oz.
Marchesini cush drive with sprocket: 2lbs, 4oz.
Just under 1 lb difference.
 

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I agree with everything said regarding the importance of rotational mass: with respect to the difference in turn-in performance, the important factor to consider is mass near the rim as it will contribute much more to the rotational intertia (and hence gyro effect) than mass at the hub.

What's not been mentioned in this thread, is that TOTAL mass does matter for another reason. The ability of your suspension to track uneven pavement is a factor of the "unsprung" weight. The wheels, tires, disks, calipers and all that stuff are unsprung weight. The suspension is trying to allow the tires to track over bumps and quickly recover after the bump has passed. The unsprung weight causes inertia that resists the suspension's restoring action.

Sooo, if two wheels weigh the same, but one has more mass concentrated in the hub and less in the rim, it will turn more easily. It will not, however track bumps any better. A wheel must be lighter overall for that.
 
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Discussion Starter · #8 ·
CF wheels will not bend but crack on impact. you might want to reconsider if you will be riding your bike on rough streets (pot holes).

Most people are relating their experience with the low tech carbon they have seen.

The BST wheels tested stronger than the OEM aluminum or aftermarket magnesium wheels. The BST wheels actually broke the machine when testing for impact at RIM technologies in the UK. They submitted one wheel for all the individual tests where all the other companies submit one wheel for each test.

We had a GSXR customer curb his wheel straight on at over 40 miles an hour. It "bent" the lip slightly but held air. The fiber was not broken. there was slight delamination that allowed the lip to deform about 1/4 inch. The tire was cut but he rode home. He was so impressed that he bought another set for his other bike.

We've been bouncing the wheels on the ground at shows. They don't crack, bend or distort in any way.

If you damage these wheels in a pot hole, the wheels will be the last thing to worry about because the pot hole will have to be big enough to swallow you up...
 

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I think Jerome's point was that the failure modes for these materials is different. WHEN they reach their limits, they react differently. A CF wheel breaks and cannot be repaired. An alloy wheel will bend (first) and might be repaired.

Your point is that the impact that will break the BST wheel is FAR above the bending impact for an alloy wheel. That impact would thoroughly trash the alloy (and forks and tripple and...)
 

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I can't believe no one has mentioned cost. What are the typical prices for the various types of wheels?
 
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Discussion Starter · #11 ·
go to motowheels.com to see prices...
cost goes:

OEM rims = cheapest
cast aluminum is next (like the 5 spoke marchesini's)
cast magnesium and forged aluminum are similar in price (i went with magnesium, personally)
forged magnesium starts getting really spendy
carbon fiber rims (BST's) are silly-expensive (in my oppinion) although i was reeeeaaaaaalllly tempted by martin when i was buying my piuma's to go for the gusto with BST's. *sigh*... if i was only made of money...


now a quick comment on the differences between cast and forged rims. the quick story is that forged rims are as strong (if not stronger) than cast rims, but because of the difference in the process, less material can be used so they weigh less than their cast counterparts.
 

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SO what is the effects of lightweight wheels on STABILITY? such as mid corner bumps?
 
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Discussion Starter · #13 ·
your suspension has to work less with lighter weight wheels... so your bike handles better. stability is more of a factor of your suspension settings and steering geometry... heavy wheels only make it harder to turn.

anyway saw on the big list where marvic is jumping onto the forged bandwagon also... http://www.marvic.it/catalogocerchi/forgiato2ing.htm all i can say is sweeeeeet.
 

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My unsprung weight comments above were intended to address the stability question.

Look at it this way:

In the ideal case, you want your bike (with you on it) to track dead level over all road surfaces, whether turning or in a straight line. Then the wheels and tires (unsprung weight) will move up and down to track over the irregularities without transferring any of that motion to the frame (the sprung weight) of the bike. That's what your suspension is attempting to do for you. The less mass (inertia) in the usnprung portion of the chassis, the easier it is to do that.

Now your suspension has to be dialed in for the mass you end up with. I'd expect preload to ramain unchanged since that's set to match the sprung weight, but you'll probably end up with less compression and rebound damping.

Taking compression as an example:

the bump will kick the wheel up, but since it now has less mass, it will have less tendency to keep going up after the kick has passed, so you need less compression damping to control it.
 
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Discussion Starter · #15 ·
We import and sell Marvic wheels but that new wheel looks fragile...scary thin. I hope it has been subjected to adequate testing...
 

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[/URL][/IMG]put in a search "lightweight motorcycle wheel tests" see although old from 2006 sportrider.com compares and explains in detail lightweight wheels, a great article. its good with sportbikes finding lighter wheels, i want lighter wheels for my 13 victory hammer, manufacturers will NOT say what their custom wheels weigh. i guess they are heavy to accommodate the bigger load bikes well over 1,000 lb with rider-s bags and travel gear. my 675 lb stripped cruiser gets the same good lookin but overweight wheels. i contacted BST and they replied they are getting setup for bigger V-twin applications mid 2014 meanwhile i will start a BST savings fund $$$$
 
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