unsprung weight? Tire weight..?

[TwentyThreeMX]

I've been looking into what I want to do as far as new wheels and such go and obviously I'm taking weight into consideration. Then I figured I should check into the weight of tires. Why spent $1400 on a set of light hubs if I could save the same amount of weight by switching to a different tire?

I've looked into some weights, and for example there is a 1.5 pound difference in a rear tire for a kenda washougal compared to a dunlop geomax 51. Here I was worried about adding a pound to my rear wheel with a cheaper hub.. switch tires and buy cheaper hubs, not any heavier!

Realistically, I doubt I would ever notice a difference.. I guess that's my question. At this level, has anyone ever noticed a difference? I hear that a pound of unsprung weight is about equal to 7 pounds.. So saving 3 pounds would be like saving 21 pounds. Thats interesting??

I've ran the same tires pretty much since on big bikes, but I got the chance now to switch brands and get just as good of a deal, so its really debatable.

 

[jeffro667]

I bet you would be suprised at the difference you may notice. I rode Husqvarna's in 96, and they came with Metzler tires, and heavy duty tubes, when I switched out to Bridgestones and regular tubes it was very noticable.

I did at one point try Michelin Starcross tires, because they were very light. I hated the tires, so it wasn't worth the weight savings. You just have to find a happy medium between weight and how well you like the tires.

What wheels did you decide to go with? It really is tough to beat the durability/weight of the stock wheels, but I gather that you are a bit of a harder rider than I am, so you may be tougher on your wheels.

 

[PitRacer]

Funny you post this because there is all this banter about powdercoating recently. Powdercoating is HEAVY.

Whenever you can save weight it is a good thing. One of the big selling points in those Tubliss tire systems is the amount of weight they save over tubes.

 

[jeffro667]

Hey pit, funny that you mention the tubliss system. I ordered a set of those in order to save unsprung weight. I weighed them vs my standard duty tubes and rimlocks, as they also replace the rimlocks. They tubliss was actually heavier than the set up that I was running. If you run heavy duty tubes, they will save you some weight, but they are not lighter than regular tubes.

 

[tfarrar134]

I don't think it is necessarily just any pound unsprung weight that equates to about a 7 pound difference...it has to be rotating. However, in the case of a dirtbike, the majority of the unsprung weight is in the wheels (I'm not sure if the swingarm and forks are considered sprung or unsprung). The reason removing one pound of a rotating body is equal to 7 pounds has to do with the rotational inertia. By reducing the weight of the wheel, the inertia is lowered which creates the effect of removing more weight than you actually did.

 

[KTMkarl794]

While I might not be an expert on unsprung weight, I DO have an opinion on the Geomax 51's.

Don't buy the Dunlops, barely got half a season out of mine, they chunked and wore really quickly and I HATED the front tire in corners.

As far as the hubs and weight saving goes, think of it this way, the heavier the bike is, the better shape you're going to be in after riding all summer!

You and I are gonna have to do some running (well maybe biking with your foot, how bout rays!) after we both heal up, until then, I'll keep your fridge full of beer if you keep the supercross parties coming. Thanks again for having me over man!

 

[GeorgiePorgie]

While I might not be an expert on unsprung weight, I DO have an opinion on the Geomax 51's.

Don't buy the Dunlops, barely got half a season out of mine, they chunked and wore really quickly and I HATED the front tire in corners.

What's half a season to you? (In seat-time hours). I could easily go through 5-8 rear tires in a season just practicing 3 times a week. Not to mention if i'm racing about twice that figure.

 

[TwentyThreeMX]

Any time man.. im sure ill have another soon!

So I guess it sounds like maybe I should make the switch. A lot of what I read (dont know how much of it to believe) said people prefer the 31's on the front and the 51's on the rear.. maybe that would have helped your washing situation. Powder is definitely heavy. I haven't gone with any wheels yet. Knowing the weight I'll save in tires I could always get little heavier (cheaper) hubs and still be where I was at now. We'll see though. I've dented up every set of wheels I've ever had, but never had an issue with hubs. This is more so just for the looks, and becase I want to get black wheels so I might as well do it all instead of just half of it. I figure this is probably the last new bike I'll buy for a while, might as well do it right.

I just wasnt sure if it was worth it or not. I know I'm not real fast or anything, so I don't watn to come on here acting like I think I'm some pro worried about saving ounces to gain seconds off my lap times lol.. but if a rider at our level would notice a difference then it might be worth it i guess.

And yeah.. whats a half season? I go through like 3-5 rears an outdoor season, usually 2-3 fronts. ANd then A fresh set before indoors usually lasts until spring.

 

[Jason145]

Funny you post this because there is all this banter about powdercoating recently. Powdercoating is HEAVY.

Whenever you can save weight it is a good thing. One of the big selling points in those Tubliss tire systems is the amount of weight they save over tubes.

as for powdercoating, its virtually nothing. 4 ounces is insignificant and the average rider wouldnt even notice the difference. hell I doubt even a pro or a dyno machine would pick up a 4oz drop in the rear wheels weight.

this was copy pasted from thumper and not my own words but i do agree! I mean if it really made a bike feel heavy then why did Chad have a powdercoated frame and swingarm? My current build will have a powder coated frame and swingarm, hubs, tripple trees, and other misc. parts

 

[PitRacer]

I mean if it really made a bike feel heavy then why did Chad have a powdercoated frame and swingarm?

He didn't. If you re-read that whole auction you'll see the lister said that was a mistake and they were anodized, not powdercoated.
I have a 1983 RM125 with powdercoating everywhere. I can't list exact numbers but I know it added a significant amount of weight. If I had to guess I would say it added 5 lbs to the bike.

 

[BriarcliffMx]

He didn't. If you re-read that whole auction you'll see the lister said that was a mistake and they were anodized, not powdercoated.
I have a 1983 RM125 with powdercoating everywhere. I can't list exact numbers but I know it added a significant amount of weight. If I had to guess I would say it added 5 lbs to the bike.

Way too much thought here. PC difference is neglible, maybe 5 pounds, doubtful. Whats that mean my quad is 10 pounds heavier with everything pc'd, doubt it. Whats chrome wiegh? Well winter is def. here. Take out every other sprocket bolt and rotor bolt, that should save a bunch of rotating mass.

 

[PitRacer]

Take out every other sprocket bolt and rotor bolt, that should save a bunch of rotating mass.

Well you can't do that.....but I do have titanium ones! You'd be amazed at the difference!

When did people stop caring about how much bikes weigh? Is that a side-bar of the move to pigs?

 

[PitRacer]

I did some googling around and it seems like 5% weight add is a generalized amount people agreed on.
I also saw an instance where someone weighed original factory automotive wheels and after powdercoating they weighed LESS. How? Well, they stripped off all the factory chrome finish first before PC.

I have some extra RM125 parts that are coated, I could weigh them to see if any difference.

 

[mshafer62]

I think it's interesting the aftermarket companies don't show how much their products weigh.

The bicycle sites I visit show weight (in grams!) and the cost allowing you the ability to determine is it worth it for unobtanium...

 

[BriarcliffMx]

Even if it were 5 lbs, and you do notice it on the "first ride", you will have long forgot it by the 5th-6th-7th ride. After you figure out how to use the power to get the boat anchor up to speed, it will be a non-issue. This aint the salt flats.

 

[John250]

I really doubt there is more than one person on Pitracer that would notice any difference in unsprug weight or tire weight of tires on their bikes......I've been racing and riding for 38 of my 42 years, and have never worried about things like that. I think Jason is on the right track.....no one is going to notice the difference. I always think it is kind of funny when your at the track and you hear a couple guys riding in say C class talking about something like this, and you just say to yourself, "really"......

 

[NQ1965]

When do I notice the weight of my bikes?
A) when I get jammed up on a hill climb.
B) when I get that sucker stuck in the mud.
C) when lifting up on the stand after a full day of riding.

Most of the time I'm lucky if I can remember which bike I'm on when I'm riding, say nothing about if it weighs more or less.

 

[Jason145]

So the real question is "does a anodized billet hub weigh more than an oem powder coated hub"? I personally do not know

 

[Tom]

All you guys need to start on a diet, so you all will be ready for spring. 5lbs I sweat that out in a day. LOL

 

[TwentyThreeMX]

i can crap out at least 3lbs in the morning before i ride.. im not trying to say i would or wouldnt notice it. i guess IMO it cant hurt... so why intentionally add weight. might as well do the best ya can.

i dont think the weight of powder would stop me from PC'ing a part. Thats minimal.

But heres what I'm thinking for my bike
new battery, save ~ 3 pounds (only 80 bucks. go try to save 3 lbs with titainum parts.. cost you 2 grand probably!!)
already have the ti/carbon exhaust, sve like 2 pounds i think
diff tires, save 3 pounds

thats like 8 pounds right there, 3 being at the wheels. possibly even more depending on if i get nicer hubs or cheaper ones

sounds stupid, but when everyone talks bad on this bike or that bike, like the 350 for example people saying they think its stpiud that it weighs the same as a 450.. well that drops it a bit under the 450s then.

do i think itll make me a faster rider? not at all. but why NOT pay attention to stuff like that?? every little bits gotta help