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M. Hausknecht

Lightweight Rear Disc

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M. Hausknecht
Posted (edited)

No one appears to market a lightweight rear disc for the stock 07 rear wheel. For those of us who ride exclusively on race tracks, the stock rear disc is a lot beefier and heavier than necessary. I recently learned that Norton Motorsports sells a significantly lightened rear disc for the R7. https://www.norton-motorsports.com/product/norton-racing-lightweight-rear-brake-rotor-yamaha-r7/ Upon inquiry, Norton doesn't know if they fit an 07.

It should fit; I hope it fits. I've read the wheels are the same dimensionally, and I know the rear caliper and caliper mount are the same on both the R7 and the 07. The distance between mounting bolt centers is the same.

I've ordered two, one for each rear wheel I use with slicks. I have rain tires on a third set of wheels but extra weight on a wheel is the least of my challenges when trying to ride fast in the rain. If they don't fit, I might have to get an R7 to put them on. I wonder if my wife will notice?

I'll post again once they show up and I return from this weekend at NC Bike.

Edited by M. Hausknecht
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shinyribs

Man, that is one snazzy looking rotor. I wouldn't feel guilty buying that just for the looks! Seems like quite the weight savings as well.

Reminds me of a '76 CB750 I converted to dual disc. Those old discs were completely solid and about 4x the thickness of what you see now. I drilled them and I think it was something like 180 holes between the pair. Ended up being worth a whole pound per rotor. I was shocked. 

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M. Hausknecht

 

Just now, shinyribs said:

Man, that is one snazzy looking rotor. I wouldn't feel guilty buying that just for the looks! Seems like quite the weight savings as well.

Reminds me of a '76 CB750 I converted to dual disc. Those old discs were completely solid and about 4x the thickness of what you see now. I drilled them and I think it was something like 180 holes between the pair. Ended up being worth a whole pound per rotor. I was shocked. 

Good on you. Must've looked pretty cool. I've opened up the holes on my stock discs. Even with a drill press and cutting oil I went through 3 bits for maybe several ounces a disc. Yeah, pretty silly. When I raced karts, I drilled my discs; had a really nice pattern I got out of a magazine. Remember magazines? Kart discs were much softer steel than what Yami uses; seemed to have helped although plenty of people made fun of me.

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shinyribs

I enjoyed the people that made fun of me when I was racing. It gave me clearcut goals of who's ass to outrun next 😁

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cosp600rr

Following for sure to see the outcome. If they fit the stock wheels Ill probably order a couple for mine.

 

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Pursuvant
Just now, shinyribs said:

I enjoyed the people that made fun of me when I was racing. It gave me clearcut goals of who's ass to outrun next <img src=">

And not trying to pass on that last corner before the finish line for first 6 laps, let your nemesis get comfortable on that one corner, until the last lap of the race and you passed 'em where they thought they we safe and took the flag before they recovered

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bartman5impson

Wow, I've been looking at these rotors for years hoping they made one for the 07 so I'm excited to see if this one fits.

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FrodoFZ

It should fit without promblem. I crossed referenced the wheel part numbers between the FZ07/09’s, XSR’s, and R7’s a few weeks ago for this exact reason. Aside from color code and model code differences they are interchangeable between those models. I believe only difference between abs and non-abs wheels is the surface where the speed rings mounts has a machined surface and drilled/tapped to accept the screws used to mount the ring. So in theory they’re all interchangeable, minus the loss of abs function if using non-abs wheels on an abs model 

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M. Hausknecht

Today I received my two lightened rear rotors from Norton Motorsports. I can confirm that they fit the FZ/MT 07 rear wheel. They are the same diameter and, for what it is worth, about .002" thicker, which means they'll fit with no modification to anything. The stock disc I removed weighs 2lb, 1.75ounces; the Norton disc weighs 1lb, 2 7/8 ounces. Removing rotating weight is "free torque" because before the motor can accelerate the bike, it needs to accelerate the drive train and rear wheel assembly. I let Norton know they fit so they may now start to market them for 07s.

One thing to be aware of. There is Loctite on the stock socket head bolts so you're going to need something beyond a wimpy allen wrench to remove them and, be careful not to booger the socket in the bolts or you'll be ordering new ones from Yamaha. I will not be reinstalling the bolts with Loctite. I'll just mark them with an oil-based marker and visually check them regularly (race bike so I check lots of things regularly).  

 

rear disc.jpg

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bartman5impson

I'd like to see what it looks like on the bike

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M. Hausknecht
Just now, bartman5impson said:

I'd like to see what it looks like on the bike

Just one man's opinion but I wouldn't put it on a street bike. I expect it severely compromises use of the rear brake. On track, I rarely use the rear brake, and rarely ride when its wet. On those occasions I end up off track (in the grass), that is a good time to stay away from the front brake and rely solely on the rear which, in this situation, doesn't need to do much. It should be fine in that context.

Road riding, in my experience, more often leads to sketchy traction circumstances whether it is rain, gravel, sand, or something else that encourages more use of the rear brake than when on a warm, dry race track with sticky slicks. Moreover, if you ride two up, you definitely want a rear brake with some power.    

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