weight reduction holes in the rear caliper bracket?

[98valk]

has anybody done it?

here is the GW 1500 bracket
 https://www.ebay.com/itm/276489226147?_trkparms=amclksrc%3DITM%26aid%3D777008%26algo%3DPERSONAL.TOPIC%26ao%3D1%26asc%3D20240114230242%26meid%3D0a56d334a184417cbbc7a86749c25fe1%26pid%3D101952%26rk%3D1%26rkt%3D1%26mehot%3Dnone%26itm%3D276489226147%26pmt%3D1%26noa%3D1%26pg%3D4375194%26algv%3DWatchlistVariantWithMLR%26brand%3DHonda&_trksid=p4375194.c101952.m162921&_trkparms=parentrq%3A4abd200b1900a56924052b01fffe3e40%7Cpageci%3A8f41bf7e-3239-11ef-8f8c-cae82fc07329%7Ciid%3A1%7Cvlpname%3Avlp_homepage

Here is the Valkyrie bracket which looks prime for some un-sprung weight reduction holes.  any structural engineers here to provide hole drilling location opinion?
Thanks

https://www.ebay.com/itm/204567865386?itmmeta=01J15C0175NVW857W6X127R8XH&hash=item2fa131e82a:g:xk8AAOSwxXxi9lLf&itmprp=enc%3AAQAJAAAA8MkYRwGPt1IGesyYwdGd2S3cucu3eyKwfs%2BlgdOkaxlh0qNT8UGitPYdzDQLuOZJG6HNp8zzLSiWvrLW3e7v39DqE1nhV04XDzEe8F7owZhUahn7kUU16G0cWcvrJ3nvxtXq6TDf3Grop%2F6MAz8YzaOed%2BnSVeazY4O7JxgmwikLrBL%2Fef8T9OZBTlVwx7UPUhy5RSjNWDqIPq7SZp853Y6eBTAaUnt7MFffAA9StIxJHz7iTokETQftDtpQDBXPltI5kZpD0GNrzqirypARE9%2FQpcMbpcJUNq6SvduZ03xLcjzJ9RcWDWP54qXwN%2BS67A%3D%3D%7Ctkp%3ABFBM2JOArIlk

[Chrisj CMA]

I understand drilling rotors for weight reduction (moving parts). That plate is already very lightweight metal. Is there really a need to lose an ounce or three on that static plate?

[98valk]

it is un-sprung weight, even reducing 4-8 ozs would be like removing a couple of lbs.  a pound here and there adds up. 
the c/t is a couple lbs heavier than the m/t it replaced so there would be a benefit.
 It seems Honda thought so with the lighter weight GW bracket but Honda wanted a more stylist looking bracket for the Valkyrie. also there would be less manufacturing cost leaving the valkyrie bracket solid.

[Jims99]

I wouldn’t mess with the integrity of something that important. Your talking about ounce’s and pounds, not going to make any difference. It would be easier to just fill the tank half way. There’s a few pounds there.

[Pluggy]

The flat section of that part serves as a shear panel.  That helps keep the part rigid.  (The outer skin of an airplane is similar.) 

That bracket was computer designed, prototyped and evaluated before it went into production.  An owner can't improve upon it.

[98valk]

I wouldn’t mess with the integrity of something that important. Your talking about ounce’s and pounds, not going to make any difference. It would be easier to just fill the tank half way. There’s a few pounds there.

the bracket is un-sprung weight.  tank weight is sprung weight. There is a major difference btwn the two.

[98valk]

The flat section of that part serves as a shear panel.  That helps keep the part rigid.  (The outer skin of an airplane is similar.) 

That bracket was computer designed, prototyped and evaluated before it went into production.  An owner can't improve upon it.

thanks for that info and engineering insight. 

[WintrSol]

The flat section of that part serves as a shear panel.  That helps keep the part rigid.  (The outer skin of an airplane is similar.) 

That bracket was computer designed, prototyped and evaluated before it went into production.  An owner can't improve upon it.

And, even if there were a safe place to drill, I really doubt there would be as much as an ounce saved, anyway.

[Chrisj CMA]

Ok, I admit before this discussion I didn’t know the difference between sprung and unsprung weight.  I understand now, but most of the information I read indicated that the ratio of sprung and unsprung is important. Meaning that the heavier the bike the less small reductions in unsprung weight matters

From what I read with the weight a Valkyrie is carrying ounces won’t make a measurable difference in any vital aspect like handling, suspension rebound or tire patch contact (traction). You would have to lose several pounds of unsprung weight on a heavy bike like ours for it to be significant.

[98valk]

Ok, I admit before this discussion I didn’t know the difference between sprung and unsprung weight.  I understand now, but most of the information I read indicated that the ratio of sprung and unsprung is important. Meaning that the heavier the bike the less small reductions in unsprung weight matters

From what I read with the weight a Valkyrie is carrying ounces won’t make a measurable difference in any vital aspect like handling, suspension rebound or tire patch contact (traction). You would have to lose several pounds of unsprung weight on a heavy bike like ours for it to be significant.

my thoughts of looking into this is because car tires are a few lbs heavier than motorcycle tires. at least my 205/65-16 single ply sidewall is 2 lbs more than the E3 it replaced. My next C/T will be a 2 ply sidewall, so more unsprung weight.
I have posted before a few yrs ago that I installed a lighter GW1500 rear rotor 1lb 4ozs lighter. So I'm always looking for beneficial mods to do. right now running I/S shocks, planning to install the 416 air shocks which are 1.5lbs lighter for a total of 3 lbs total unsprung weight reduction.
so per below even a few ounces using their ratio would be a few lbs of unsprung weight loss which would have balanced out the heavier C/T.
thanks

""Studies have shown that in optimal conditions, losing 1lb of unsprung mass is equivalent to up to 20lbs of overall sprung weight reduction. In real-world scenarios, this likely is nearer to 6-10lbs but unsprung, and rotational masses should be prioritized as part of your weight reduction activities.""

https://suspensionspot.com/blogs/news/improve-your-track-car-reducing-unsprung-weight

[WintrSol]

... right now running I/S shocks, planning to install the 416 air shocks which are 1.5lbs lighter for a total of 3 lbs total unsprung weight reduction.

Is that 1.5 lbs the total weight of the shock, or just the part of it that attaches to the swingarm? If total weight, then not 3 lbs reduction, since the upper half is part of the sprung weight. Not sure if this is a spec they publish, or that one can even estimate if it is not published.

[Knapdog]

So does rider weight make a difference in all this as I've  just been wondering what the difference is between an "overweight" (I'm trying to be polite) rider with lots of weight-saving holes, drilled on the bike and an untouched "heavy" bike with a lightweight rider on it.

[rug_burn]

   I underestand the desire to reduce weightr on our Valks;   they ain't no lightweights, for sure.
    There are a lot of things tha could be lightened, mainly all the steel brackets, passenger footpegs, etc could be a lot lighter. 
    But as for running gear, there's not much you can take off.   I tried  thinning out the front wheel distance tube in the middle one time,  and ended up overly sueezing the wheel bearings.   The squeeked real bad, and loudly.   In theory I could have calculated a lower axle nut torque to give the same bearing preset sqeeze...  but I just went and ordered another stock distance tube and forgot about that.
     
   

[mello dude]

I find trying to reduce ounces of weight on a 750 lb cruiser bike laughable.
On a sportbike project sure, but the Valk?  
Maybe if I just lose my extra 20 lb gut that would work better.

[Glaserbeam]

Since we are talking rear brake and not front brake, I think you are safe in cutting the bracket to look like the Goldwing version, because the rear brake is only providing 20% of the stopping power, so I think the bracket will rarely be stressed to its limit.

I'm also concerned with unsprung weight, so I replaced my front rotors with Goldwing rotors, which are maybe a pound lighter, and even look better, and I replaced the rear rotor with an aftermarket slotted rotor.

Ken

[Chrisj CMA]

Since we are talking rear brake and not front brake, I think you are safe in cutting the bracket to look like the Goldwing version, because the rear brake is only providing 20% of the stopping power, so I think the bracket will rarely be stressed to its limit.

I'm also concerned with unsprung weight, so I replaced my front rotors with Goldwing rotors, which are maybe a pound lighter, and even look better, and I replaced the rear rotor with an aftermarket slotted rotor.

Ken

Just curious.  So if you reduced unsprung weight by three pounds, what was the benefit?

[98valk]

Since we are talking rear brake and not front brake, I think you are safe in cutting the bracket to look like the Goldwing version, because the rear brake is only providing 20% of the stopping power, so I think the bracket will rarely be stressed to its limit.

I'm also concerned with unsprung weight, so I replaced my front rotors with Goldwing rotors, which are maybe a pound lighter, and even look better, and I replaced the rear rotor with an aftermarket slotted rotor.

Ken

I use VFR800 front rotors, 2.75lbs each vs 3.25lbs valkyrie rotors 50k miles. '99-'00 CBR600F F4 are same rotors just usually more $$ on ebay.  oven cleaner takes off the anodized coating and then I just polished the center carrier.
my '98 rear rotor 40k miles is 4lbs 4ozs vs GW 1500 new rotor 3lbs.
un-sprung weight is also very important with the drive shaft assembly. So I use an early GW1500 U-joint which is 2.5lbs vs Valkyrie 2.75 lbs. some of the later ones are closer to 3lbs.

[98valk]

Since we are talking rear brake and not front brake, I think you are safe in cutting the bracket to look like the Goldwing version, because the rear brake is only providing 20% of the stopping power, so I think the bracket will rarely be stressed to its limit.

I'm also concerned with unsprung weight, so I replaced my front rotors with Goldwing rotors, which are maybe a pound lighter, and even look better, and I replaced the rear rotor with an aftermarket slotted rotor.

Ken

Just curious.  So if you reduced unsprung weight by three pounds, what was the benefit?

suspension control is improved.   wheels and rotors will increase acceleration and braking performance.

[98valk]

... right now running I/S shocks, planning to install the 416 air shocks which are 1.5lbs lighter for a total of 3 lbs total unsprung weight reduction.

Is that 1.5 lbs the total weight of the shock, or just the part of it that attaches to the swingarm? If total weight, then not 3 lbs reduction, since the upper half is part of the sprung weight. Not sure if this is a spec they publish, or that one can even estimate if it is not published.

good question.
I'm sure there is a suspension engineering report out there breaking it down like that. all I have read is that lighter shocks/struts increase unsprung weight and suspension performance increases.
since the shock moves with the suspension I would imagine the full weight would be considered the unsprung weight.

I checked my notes,
'98 std/tourer shocks 4lbs 13.5ozs each,  I/S 5lbs 7.5ozs each, progressive without air/fluid 416 4lbs 4ozs each.  Now since the '99-'03 std/tourer shocks are different I don't know their weight.

[98valk]

I find trying to reduce ounces of weight on a 750 lb cruiser bike laughable.
On a sportbike project sure, but the Valk?  
Maybe if I just lose my extra 20 lb gut that would work better.

I'm looking at unsprung weight whereas a few ozs translates into lbs of reduction in regards to suspension, acceleration and braking performance.

when doing overall weight reduction ozs add up and location of weight also affects the center of gravity which can translate into a better handling motorcycle.

[Knapdog]

Well, I'm delighted to say, that the thought of trying to lose a few grams on a 349kg motorcycle has never entered my mind and never will.

[WintrSol]

since the shock moves with the suspension I would imagine the full weight would be considered the unsprung weight.

Only the bottom 'half' of the shock moves with the suspension, the upper half is fixed to the frame and is part of the sprung weight, so not all the weight of the shock is moving with the swing arm. Hard to say how much of the weight of the shock is in the moving part; probably more than half, unless the fluid chamber and valves are at the top.

[98valk]

since the shock moves with the suspension I would imagine the full weight would be considered the unsprung weight.

Only the bottom 'half' of the shock moves with the suspension, the upper half is fixed to the frame and is part of the sprung weight, so not all the weight of the shock is moving with the swing arm. Hard to say how much of the weight of the shock is in the moving part; probably more than half, unless the fluid chamber and valves are at the top.

ahh, but the shock is installed on an angle so how much of the shock is actually being lifted?  it can be calculated I'm sure in race circles it is. Then one could calculate how much of the shocks resistance to movement can be consider weight resistance I would think.
All I know is every suspension info I've read states its a benefit if lighter shocks/struts can be used to reduce unsprung weight.

[dago mooserider]

Interesting. Thanks for putting up that lighter brake rotor  info. When it’s time I’ll use the those options. I have noticed while working on the valk that many things seem overly robust. The bracket you are talking about is ridiculous sized and even the wheels themselves seem like they are made for a tank. I guess they get called fat ladies for more than just the engine poking out lol. For those who like to ride like the wind,  Acceleration, braking, handling the twisties, yes a few ounces can make difference. Dudes on the C rockets - switching to carbon fiber wheels instantly equals faster lap times.

[98valk]

Interesting. Thanks for putting up that lighter brake rotor  info. When it’s time I’ll use the those options. I have noticed while working on the valk that many things seem overly robust. The bracket you are talking about is ridiculous sized and even the wheels themselves seem like they are made for a tank. I guess they get called fat ladies for more than just the engine poking out lol. For those who like to ride like the wind,  Acceleration, braking, handling the twisties, yes a few ounces can make difference. Dudes on the C rockets - switching to carbon fiber wheels instantly equals faster lap times.

since many crash the CBR and VFR, very low mileage rotors are avail on ebay.  the ones I bought were usually two for around $100 (2 yrs ago). one set was 4.44 mm and spare set is 4.48 mm.
  New OEM thickness is 4.4 - 4.6 mm, minimum 3.5 mm.
There is a nice difference in braking performance with them.

[HayHauler]

Interesting. Thanks for putting up that lighter brake rotor  info. When it’s time I’ll use the those options. I have noticed while working on the valk that many things seem overly robust. The bracket you are talking about is ridiculous sized and even the wheels themselves seem like they are made for a tank. I guess they get called fat ladies for more than just the engine poking out lol. For those who like to ride like the wind,  Acceleration, braking, handling the twisties, yes a few ounces can make difference. Dudes on the C rockets - switching to carbon fiber wheels instantly equals faster lap times.

since many crash the CBR and VFR, very low mileage rotors are avail on ebay.  the ones I bought were usually two for around $100 (2 yrs ago). one set was 4.44 mm and spare set is 4.48 mm.
  New OEM thickness is 4.4 - 4.6 mm, minimum 3.5 mm.
There is a nice difference in braking performance with them.

Do you use OEM pads on your CBR rotors?


Hay 
Jimmyt

[98valk]

Interesting. Thanks for putting up that lighter brake rotor  info. When it’s time I’ll use the those options. I have noticed while working on the valk that many things seem overly robust. The bracket you are talking about is ridiculous sized and even the wheels themselves seem like they are made for a tank. I guess they get called fat ladies for more than just the engine poking out lol. For those who like to ride like the wind,  Acceleration, braking, handling the twisties, yes a few ounces can make difference. Dudes on the C rockets - switching to carbon fiber wheels instantly equals faster lap times.

since many crash the CBR and VFR, very low mileage rotors are avail on ebay.  the ones I bought were usually two for around $100 (2 yrs ago). one set was 4.44 mm and spare set is 4.48 mm.
  New OEM thickness is 4.4 - 4.6 mm, minimum 3.5 mm.
There is a nice difference in braking performance with them.

Do you use OEM pads on your CBR rotors?


Hay 
Jimmyt

Had existing Vesrah pads at first until fork oil contaminated the one side so then replaced them with the 10mm thk rear I/S pads.  I have the VFR rotors but they are the same as the CBR ones. VFRs are lower $$$ on ebay.
can't beat Honda quality for around $100.
there are different CBR rotors out there different bolt circle so make sure look at the exact name I posted earlier. Also later models had ABS rings, just remove bolted on rings.