| Author | Message | ||
     Lovedabueller |
me and my friend were having a discussion/argument about weight savings and the effect it has on the bike/vehicle. I THINK i read that for every ten pounds you shave you gain 1 hp... I THINk thats how it went i might be wrong. but he was saying that weight savings has no effect I KNOW BETTER!!!! THATS WHY PEOPLE LIKE THE REAL (IM DEAD SEXXXY)FT BASTARD DOESN'T RACE MOTORCYCLES. and his point was shifter carts. he was trying to tell me that a heavier person will make it around a track on a kart faster than a skinny person due to weight and the traction that takes effect. so i ask. in racing of any kind is it better to gain 10hp. or cut 50lbs from the rider/driver/bike/car.(as a whole. maybe 2 lbs rider and 48 from the vehicle GET IT??) thanks. | ||
| Xl1200r |
There will be a point where too light is, well, just too light. But I think you'd have a hell of a time getting to that point without some helium balloons or something. I would take the 50lbs, but i'm not a racer. | ||
| Slaughter |
Handling improvements are ALWAYS going to translate into better lap times than just HP. The 10 lb = 1 HP or 7 lb or whatever is a kinda/sorta explanation of the benefits of weight saving. The argument is that saving weight gets you more benefit without affecting engine reliability. Everybody seems to start looking for HP before they ever consider dialling in their handling. It's not just weight but a total "thing" of weight, suspension, braking, tires (and pressures), proper gearing. Ignore HP until the bike is completely dialled in and handling "right." | ||
| Elvis |
With all due respect . . . your friend is full of ****. Even in an extreme hypothetical in which traction was such a problem that a high normal force was required to get some traction . . . the larger mass would REQUIRE more traction to accelerate, turn, decelerate etc. Any gain in traction would be offset by the need for that increased traction by the more massive vehicle/rider. I would be surprised if there's any real racing anywhere in which greater mass is an advantage. (Message edited by elvis on June 22, 2009) | ||
| Lovedabueller |
this is not for me personally, its just a information gathering thing. ALWAYS THIRSTY FOR KNOWLEDGE! | ||
| Lovedabueller |
Elvis thats funny cause i told him that same thing. lol | ||
| Greenlantern |
he was trying to tell me that a heavier person will make it around a track on a kart faster than a skinny person due to weight and the traction that takes effect. Wow! I am inspired...New thread time | ||
| Xl1200r |
Elvis makes a really good point. If the kart was that light (as in pressure off of the tires), then it would also have just as little mass - meaning, as Elvis said, it would need very little traction because it has to move such a light object. | ||
| Gentleman_jon |
in racing of any kind is it better to gain 10hp. or cut 50lbs from the rider/driver/bike/car.(as a whole. maybe 2 lbs rider and 48 from the vehicle The simple answer to your question is.......... It depends. Reducing weight is always a good idea, as it increases the power to weight ratio. So in order to properly assess the impact of the weight reduction, one needs to know the "mission weight" of the vehicle and driver. In other words, if you remove 50 lb.s from a ultra light weight bike and rider combination of, say 300 lbs, the effect would be enormous. 50/300 = 17%. On the other hand, if you remove fifty pounds from a jet fighter, the effect would negligible , since the mission weight is over 26,500 lb.s. 50/26500 = 0.1 %. In addition, where you remove the weight from is important: unsprung weight like wheels is more important than sprung weight like the chassis. Rotating weight is more important than static weight: wheels again. How much weight is worth one horsepower, is again, a function of the power to weight ratio. On a motorcycle or go cart, it is often said seven pounds equal one horspower, but that is a simplification. If we take a 450 lb bike like a Buell XB 12, and a 150 lb rider, we have a mission weight of 600 pounds. Assuming a stock rear wheel horsepower of 75hp, we have a power to weight ratio of 450 lb/75 hp = six pounds per horsepower. See how it works? The effect on top speed is a bit more complex, but in two vehicles that have the power and proper gearing to accelerate to top speed, it makes less difference than it does on acceleration as top speed is a function of power and air and rolling resistance. OK?  | ||
| Not_purple_s2 |
I work with a guy that races go-carts. He and his son have their cart way under weight but then add more weight than necessary to race. The reason is "Mass Centralization!" but they didn't really call it that. They add extra weight down low and center (or to the left for circle tracks) of the cart to keep it balanced. Also you can shift weight forward or aft to change how the cart turns (understeer/oversteer) This is probably what has your friend confused, weight can be added to improve handling but it has to be strategically placed not just an overall increase in weight. | ||
| Froggy |
Bumper cars  | ||
| Lovedabueller |
-------------------------------------------------- ------------------------------ quote: I would be surprised if there's any real racing anywhere in which greater mass is an advantage. -------------------------------------------------- ------------------------------ Bumper cars since when is bumper cars A RACE??? | ||
| Liquorwhere |
Not Purple makes a great point, look at the last MotoGP race and if you read the articles and the press release you will see that they changed the seat for Nicky Hayden to move his weight forward more to improve the handling of the bike...here is the link http://www.superbikeplanet.com/2009/Jun/090613b.ht m Now how much of an effect it had remains to be seen, there were many other changes made as well, but Nicky did have a top ten finish, and that has been rare as of late, so in combination it may be advantageous to add weight, but moreover to arrange the weight already on the bike if possible, my Honda 450 puts out something like 55 hp or so, give or take a few, I think my 88 CI harley puts out 61 hp give or take a few, torque not withstanding, the Honda will five you the "OH $*%*" feeling when you open it up because of the very low weight, while the Harley...well it won't, although the torque is very good that springer must weight 700+ lbs, so there ya go, in a micro, over simplified, non scientific way...I would take light over heavy any day, it helps with handling, feel, and the fun factor. Good thread. | ||
| Wolfridgerider |
Tom Reiser and I had a conversation about racing.... and how my girth was a issue when it came to road racing. He said the ideal rider weight for his near 200 hp hill climbers would be about 200 lbs. http://www.motohistory.net/featuredstory/reiser_fe ature1.html I would still need to drop a few pounds...  | ||
| No_rice |
I would be surprised if there's any real racing anywhere in which greater mass is an advantage. demo derby, and its not to bad in figure 8 to have a few extra pounds in the right places. plus it helps shove you through with the extra momentum you build up. | ||
| Spatten1 |
Weight bias (front vs. rear) is important. They did not add weight to Nick's bike on the front, they just moved his weight to the front. For ROADRACING (NOT tractor pulls, hill climbing, etc): Lighter is always better, period. If there is only a miniscule amount of weight pushing down, the same miniscule amount of weight will be forcing the bike toward the outside of the turn's radius. There is no such thing as a point where you need more weight to get traction, unless the rider is lighter than air and pulls the bike up into the sky. | ||
| Fast1075 |
Go to the drag strip and ask how much difference a few pounds makes on a bike. Back in my street racing days, I was sought after to ride other people's bikes. Some though I was some sort of wizard to make their bike run that good...it was very simple...I weighed 115 pounds...the owners usually weighed 175+ pounds...it was all in the weight difference...but I let them THINK it was me  | ||
| Oddball |
Bumper cars can be a race. It takes reading the flow of all the crashing idiots. Smoothly finding the holes without stopping and thus becoming a target in the pile up. Maybe pulling a pit maneuver on someone to get a clear path or jam everyone behind you. LOL It's good survival training for the DC beltway. And just fun to have circled the same people over and over again without being touched. While they're all jammed in a pile behind some old woman or kid who can't figure out how to turn the wheel to get off the wall. On topic, I'd rather be too light and have to strategically add weight. | ||
| Badlionsfan |
I would be surprised if there's any real racing anywhere in which greater mass is an advantage. The only one I can think of would be soap box derby. Also, in stock car racing a few more pounds can be an advantage if it's put in the right place. I was a tech inspector years ago at a local short track. It was a very tight 1/4 mile, like a mini martinsville. The fastest guys weren't the lightest in the class, the fast guys had the maximum left side weight % allowed. | ||
| 46champ |
There is one place that rewards extra weight and that is the salt flats. A lot of cars and bikes have enough power to overpower the track so they have taken to adding lead weight, a lot of weight. Most of the bikes that run over 200mph have about 70lbs of lead shot in their swing arms at least those that have hollow swing arms. I know Leslie Porterfield weighs about 120 if that but the reason women go fast is they punch a small hole in the air. The cars with big motors go to the line weighing upwards of 5000 lbs, I don't know why they don't call it adhesive weight like the railroads do. | ||
| Ourdee |
I like the 2 stick bumper cars. | ||
| No_rice |
my anorexic feeling 145 pounds since ive lost so much weight in the last 2 months, sure did have a good time making laps at blackhawk on the 1125  knocking 20+ pounds off of me and then just not really giving a crap about much, seems to make me faster for some reason... im still surprised by the times i was running in full street trim. apparently the instructors were also, well atleast enough to stick me with all the damn race bikes... and ya i was they guy growing up that had to do all the top speed runs when we built stuff simply because i didnt weigh half as much as most of my friends. and most of them were scared $hitless to get much past 120-130 on a bike, and sure werent willing to ride the thing when we were trying to tag 200 on it. so i always got elected. but then again at a certain point you really float alot also... | ||
| Fahren |
basic physics: F=ma (force = mass x acceleration). The less mass, the greater the acceleration with a given force. | ||
| Court |
And acceleration has ZERO impact at Bonneville. Rider skill and size do . . . likely the reason Susan Wilson broke one of the longest standing records (something like 167 on an UNFAIRED) S1. Bonneville presents many unintuitive challenges. | ||
| Skinstains |
At the Mugelo GP the 125's were flying off the wet track all race long where as the 250's did a lot better on the same track that was probably even wetter than when the 125's were out. | ||
| Xb9ser |
As a former land speed racer even in the rule book they said lighter was not allways better. | ||
| Madduck |
I raced snowmobiles for three years back in the late 60's. Weight gets you to the first turn quicker, acceleration from 0 to 75 mph in an 1/16th of a mile needs traction. 215lbs was about 1.5 seconds faster than 165lbs. Teammates on identical sleds. Cornering was also an advantage as greater mass moving to inside could get much better bite with front ski. After a couple of laps all of the advantages go away as the surface becomes less than ideal. I would bet that short dirt tracks would also show some advantage to 200lb riders over 160 lb riders as they would get the same sort of benefit on weight shifting. Unfortuately there are no advantages to racers of my current bulk. | ||
| Wolfridgerider |
Unfortuately there are no advantages to racers of my current bulk. What if there was a race to terminal velocity jumping out of a airplane? | ||
| Ceejay |
Here we go!? |
