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post #21 of 25 (permalink) Old Aug 3rd, 2019, 9:29 am
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Excellent thread ... very useful information even though some of the weights on the latest tire types isn't filled in.

I've known about the effect of lighter tires since the mid 1970s when I was racing BMX. Back then (for at least a minute and a half) the undisputed lightest 20 inch BMX tire was the Schwinn "chevron" white sidewall tire.

During the week many of us would run "super heavy duty" inner tubes (4x thicker on the outside circumference) which were also known known as "thorn proof" tubes. We'd also run heavier knobbies during the week, as well as thicker spokes and heftier rims. Come race day on the weekends, we'd switch over to our race day wheelsets (lightest rims, 60/80 dual thickness spokes, those Schwinn gumwall tires, and the thinnest cheapo inner tubes that we could find at the local department stores like "Fed Mart").

The difference between our weekday wheel sets and race day wheel sets was enormously obvious. The bicycle felt like a completely different machine with the race day wheel/tire combos. The heavy wheel/tire/tube/spokes during the week was like doing a physical workout since every aspect of the heavier wheelsets would really make all of the muscle groups used to propel and maneuver the bikes work far harder.

Point being is that the lighter wheelsets was something that produced a very profound difference in how the bike would accelerate and handle ... something that you could really feel in every way without having to "convince yourself" with obscure mathematical formulas. The most profound difference was noticed with the light weight Schwinn gumwall "chevron" tires. If all you did was adopt those tires without switching tubes, spokes, and rims you could still really feel the difference. Switching from thorn proof tubes to $1.98 thinwall tubes made the 2nd greatest difference.

Outside rotational weight produces the most noticeable change over things like titanium rotor bolts that are so close to the rotational center of the wheelset. I know that for absolute certain. However it's also true that going with the lightest tires/rotors/rotor bolts/caliper bolts (et al) has a large effect on unsprung weight. Back when I raced in S.C.O.R.E. off road desert racing in race prepped 4x4s the old rule of thumb regarding unsprung weight was "1:10" ... meaning removing 1 pound of unsprung weight was equal to removing 10 pounds of sprung weight when it comes to overall handling and suspension efficiency in the high speed rough.

Given a choice between super-high-buck light weight wheels or lighter tires I'll opt for the lighter tires every time for my motorcycle. It's the obvious choice for the privateer racing their motorcycle on a budget as well.


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post #22 of 25 (permalink) Old Aug 3rd, 2019, 9:46 am
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Given a choice between super-high-buck light weight wheels or lighter tires I'll opt for the lighter tires every time for my motorcycle. It's the obvious choice for the privateer racing their motorcycle on a budget as well...
Or you can opt for both... I've got Marchesini 5 spoke Mg wheels mounted with Pirelli Diablo Rosso Corsa tires front and rear on my R. The difference between this setup, and the OEM Marchesini 5 spokes, is quite literally eye opening.

However, hands down the most efficient weight savings on these bikes, from a cost per lb standpoint, is making the switch from the OEM Yuasa batteries to a Shorai (or equivalent) LiFePO4 unit.

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post #23 of 25 (permalink) Old Aug 3rd, 2019, 10:18 am
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Quote:
Originally Posted by Rex Coil 7 View Post
Given a choice between super-high-buck light weight wheels or lighter tires I'll opt for the lighter tires every time for my motorcycle. It's the obvious choice for the privateer racing their motorcycle on a budget as well.
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Originally Posted by ProphetPVD View Post
Or you can opt for both... I've got Marchesini 5 spoke Mg wheels mounted with Pirelli Diablo Rosso Corsa tires front and rear on my R. The difference between this setup, and the OEM Marchesini 5 spokes, is quite literally eye opening.
I would argue that going with a lighter tire, and lighter brake rotors w/titanium rotor bolts and titanium caliper bolts would be better spent money. You'd reduce rotational weight, unsprung weight, as well as (perhaps) upgrading the performance of the front brakes.

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However, hands down the most efficient weight savings on these bikes, from a cost per lb standpoint, is making the switch from the OEM Yuasa batteries to a Shorai (or equivalent) LiFePO4 unit.
I went with the Anti Gravity ~LION~ battery. Compared with the lead/acid lump that my bike was outfitted with, the Anti Gravity unit provided a 10+ pound weight reduction.

** The stock lead/acid battery weight in at 12 pounds 9 ounces.
** The Anti Grav weighs 2 pounds 7 ounces.

But let's remember that the battery is sprung weight.


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Last edited by Rex Coil 7; Aug 3rd, 2019 at 10:23 am.
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post #24 of 25 (permalink) Old Aug 3rd, 2019, 11:30 am
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I would argue that going with a lighter tire, and lighter brake rotors w/titanium rotor bolts and titanium caliper bolts would be better spent money. You'd reduce rotational weight, unsprung weight, as well as (perhaps) upgrading the performance of the front brakes...
The R has the 4 pot Brembo's with floating rotors... 2 fingers is all that I've ever needed, and even with a light pull these things haul the bike down QUICKLY.





As far as Ti fasteners are concerned, the cost per pound of mass removal is simply too high IMO, unless we're talking about M8 and larger... We investigated that route with the Mono R, and ended up swapping only the largest fasteners, and changing the battery to an aforementioned LiFePO4 unit.

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But let's remember that the battery is sprung weight...
Yep... and I totally see your point of view and understand the advantage of mass removal from specific areas of the machine, but in general, any weight reduction is a good thing. I grew up riding dirt bikes... there is just something more comforting to me when the lump between my legs is lighter.

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post #25 of 25 (permalink) Old Aug 10th, 2019, 3:03 am
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