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Discussion Starter #1

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So is this something that can be simply machined on a lathe or mill to trim away any "extra" that may be rubbing on the seals?

Half a horsepower seems like a huge amount of drag to me.
Certainly seems that way... Wonder how much an extra set of OEM spacers is. Would be a fun experiment.
 

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From Grom Father's Youtube video: "stock rolled 25 seconds speed spacers 7+ mins"


I'm sure that all changes once you slap the caliper back on and start rolling without the wheel suspended in the air... but it doesn't hurt.
 

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From Grom Father's Youtube video: "stock rolled 25 seconds speed spacers 7+ mins"


I'm sure that all changes once you slap the caliper back on and start rolling without the wheel suspended in the air... but it doesn't hurt.
from the unscientific test I did, once I slapped the caliper on the front, it stopped in roughly the same amount of time as with the stock spacers. Too much brake drag. The rear did spin more freely though.
 

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Discussion Starter #6
I still don't know about this. If there was that much friction it seems like we would be wearing holes in the seals pretty quickly. What are we missing?

I haven't had my wheels out yet to see what's going on, is there a rubber seal that slides on the spacer? Or is this the seal on the bearing that rubs (RS or rubber seal series bearing).

And yes I am still doubting this, seems like a reported lot of horsepower from something that shouldn't be robbing power in the first place.
 

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You'd only get 0.5 hp if you eliminated ALL the friction in the wheels and their interfaces (contact patch areas) with the road surface. The TOTAL such friction is between 1 and 2% of the weight of the bike plus rider, depending on which on motorcycle design book you believe, and the vast majority of that is friction within the tire which is deforming at the contact patch continuously, PLUS the brajke drag, NOT in the bearings.

Even that 1 or 2% of total weight for a rider plus Z125 is only 1 or 2% of about 400 lb, which is 4 to 8 lb force.

Power = force x distance per unit time

So that 2% total friction, at its highest at an estimated speed of 60 mph is about 4 to 8 lb force x 88 ft/sec = 352 to 704 ft lb/sec = 0.64 hp to 1.28 hp. So getting 1/2 hp out of spacers seems like a pretty pie in the sky claim.

Jim G
 

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The Major Friction loss of a bearing is the seal @ 60%

Second is the Grease/lubricant @ 28 %
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Rolling friction /

Cage @ 7 %
Ball Deformation @ 3 %
Raceway Deformation @ 2 %
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So YES' the SPEED SPACERS reduced diameter at the seal interface is more beneficial than ceramic bearings in terms of gains ... Per the Great Hambini anyways ...
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Drag racers will completely remove the seals and use the thinnest and least amount of lubricant they can get away with .
 

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Probably worthwhile if you want just a wee bit more speed. I'd do this and skip ceramic bearings. Ceramic bearings are overrated, IMHO. Not to mention ceramic bearings on a bike like this seems a bit stupid anyway, but I've wasted my time with them on other bikes.

I'd say get these speed spacers and stay non-oring chain for the best shot at minimizing hp loss.
 

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Discussion Starter #10
Eventually I'll deal with the bearings, there is a Chevron salt water rated lube that you can get in some of them, but these in my Buell and never had an issue with them. I think the lube is SR2 but might be wrong.

A light teflon bearing oil like you can get for inline skates would make a good single day lube, and if you run metal shields (ZZ) or only the external facing metal shield you can reduce friction at the cost of replacing bearings often.

You can also use larger final gears for the chain, there is less energy spent going around a 15 tooth gear than a 13 tooth gear, the same applies to a lesser amount on the large gear on the wheel. Eventually weight would cancel the benefit from the reduced friction.

I still find it hard to believe that the spacers are rubbing on the seals. Guess I'll need to take a critical look myself and then decide if buying a set is worth the time saved from machining my own out of aluminum.
 

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The spacers def improves spin time on my bike. Rear wheel was the improvement. Even with the caliper and chain on the wheel spun much longer with the speed spacers. The front was spinning for much much longer until I put the caliper on. Then It stopped in about the same amount of time as with the stock spacers. Brake drag killed it. I’m not sure if that is the case for every z or it’s because of my p34 caliper.

I am going to look into a floating rotor that will work with the brembo caliber. That should help reduce brake drag I would think.
 

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IMHO the spacers themselves are responsible for some friction, yes. But any claims that it gains 0.5hp are BS I think.

At the drag strip I have seen some guys go without seals entirely, ceramic bearings, and a non sealed chain. As a package involving those three yeah I can see it equating to a measurable result. On the Z125 I think you would see a bigger gain by going up 1 PSI in your tires.

Under-inflated tires, a sealed chain, and dragging brakes are your largest parasitic drag factors on any bike. Unless you're counting (and accurately measuring) hundreth's or thousandth's of a second I see no benefit. (Except for machined and anodized aluminum that always looks cool)
For any bike that's not on a track regularly (mine included) remember that we are trading a nearly immeasurable amount of stiction for a substantially reduced seal.

Greg_E; It may be easier to take a couple thou off the existing one's than making some from scratch? I'd like to hear your results if you go through with this.
 

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Open discussion on this topic,
One thing that should be mentioned is that its not recommended to Power Wash your bike anymore or stay away from the seals . Dont think many people hand wash there bike these days ? But myself the left rear over chain lubed swingarm and sprocket is the main reason for power washing :rolleyes:
 

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One thing that should be mentioned is that its not recommended to Power Wash your bike anymore or stay away from the seals . Dont think many people hand wash there bike these days ? But myself the left rear over chain lubed swingarm and sprocket is the main reason for power washing :rolleyes:
Excellent point, especially since at least a regular city-pressure hose spray is pretty much needed to rinse the bike as you wash its individual components and areas. I don't think you can effectively rinse without spraying.

Jim G
 

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Wash? If it doesn't come off with a garden hose, it will probably stay there.
Agree, IF you are using the right automotive wash soap with the garden hose.

Pressure washing also does NOT truly "clean" a surface. You cna prove this to yourself by pressure washing a surface and then running your finger, or a white piece of paper towel, over it. The finger or paper towel will come off dirty. To really clean a surface, you need to use a good soap designed for exterior automotive use and a cloth that you rinse in the wash bucket frequently.

The GOOD commercial car washes all use an initial spray only to "loosen" and remove the obvious dirt that would otherwise clog their water recycling system too quickly. They then apply soap and use power-agitated felt pads to actually remove "bonded" dirt, and then rinse with a spray using SOFTENED water (If you use unsoftened city or well water, you will have spots where the water drops dry and leave their mineral residue). Then, they dry, first with hot blowers, and then with handcloths.

Car wash soaps that are harsh enough to get at least some of the bonded dirt are also unfortunately harsh enough to significantly degrade the paint and plastics. You don't get something for nothing.

High pressure spray washing is just a poor shortcut method that gives results that at first APPARENTLY look fine, but don't stand the test of time at all.

Jim G
 

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With the spacers the wheels spin longer and the bike rolls easier. With so little power anything that lowers rolling resistance has benefits.
 
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