Are motorcycles easier or harder to handle depending on rider's weight?
January 20, 2018 8:38 AM Subscribe
I'd like to know if there's a significant difference in how a motorcycle handles depending on the weight of the rider. How would a smaller rider fare versus a larger rider in terms of maneuvering or extreme acceleration? Let's say we're talking about a cruiser, and also that we're talking about the limits of performance.
Without being too specific, let's say our riders fit your description of a little guy and big guy, respectively. We can imagine that the motorcycle might be a Harley Sportster or Softail, or something along those lines.
Without being too specific, let's say our riders fit your description of a little guy and big guy, respectively. We can imagine that the motorcycle might be a Harley Sportster or Softail, or something along those lines.
Response by poster: Thank you both for these thorough and thoughtful responses. Too-Ticky, I only meant the limits of performance for the cruiser, but that detail is helpful and appreciated.
I should have mentioned that this is research for a scene in a work of fiction. The idea I'm exploring here is whether an inexperienced rider who is very slight of build and who is inclined to feel out the extremes of what he can do on a motorcycle might find that his size puts him at a disadvantage.
posted by millions at 9:24 AM on January 20, 2018
I should have mentioned that this is research for a scene in a work of fiction. The idea I'm exploring here is whether an inexperienced rider who is very slight of build and who is inclined to feel out the extremes of what he can do on a motorcycle might find that his size puts him at a disadvantage.
posted by millions at 9:24 AM on January 20, 2018
"...an inexperienced rider..."
I agree with Sokka shot first that inexperience is going to be the biggest problem. When I was an inexperienced rider, I wiped out on a bit of gravel on the road going less than 30mph. A couple of years later, with more experience under my belt, I hit a large patch of gravel on a mountain road going closer to 70mph and rode through it. By that time, my instincts were good enough to know to instantly disengage my clutch and not try to steer. (Thankfully, that stretch of road was straight.)
In my experience, it's all about nudging the steering wheel, not about throwing your weight around. This is especially true at speed. I'd expect a larger rider to have slightly more problems, because they're trying to move back-and-forth a larger weight which is higher off the ground; there's more inertia to deal with. To be honest, though, I'm not sure how different weights of rider would interact with the physics of push steering.
I'd also agree that a smaller rider - or a weaker rider, anyway - is going to experience the most problems with a big bike when they're not riding it. Your inexperienced rider will wipe out whether they're on a big bike or a small one; the problem that they'll have with a big bike is lifting it back upright after the wipeout.
posted by clawsoon at 10:31 AM on January 20, 2018 [1 favorite]
I agree with Sokka shot first that inexperience is going to be the biggest problem. When I was an inexperienced rider, I wiped out on a bit of gravel on the road going less than 30mph. A couple of years later, with more experience under my belt, I hit a large patch of gravel on a mountain road going closer to 70mph and rode through it. By that time, my instincts were good enough to know to instantly disengage my clutch and not try to steer. (Thankfully, that stretch of road was straight.)
In my experience, it's all about nudging the steering wheel, not about throwing your weight around. This is especially true at speed. I'd expect a larger rider to have slightly more problems, because they're trying to move back-and-forth a larger weight which is higher off the ground; there's more inertia to deal with. To be honest, though, I'm not sure how different weights of rider would interact with the physics of push steering.
I'd also agree that a smaller rider - or a weaker rider, anyway - is going to experience the most problems with a big bike when they're not riding it. Your inexperienced rider will wipe out whether they're on a big bike or a small one; the problem that they'll have with a big bike is lifting it back upright after the wipeout.
posted by clawsoon at 10:31 AM on January 20, 2018 [1 favorite]
It may help to note that professional riders who really push their bikes to the extreme are pretty light in general: the upper end of MotoGP riders is about 160 lbs.
This all comes down to the weight of the overall package: a Harley Sportster is about 550 lbs + so a difference of 20-30 lbs can be significant.
As others have said skill plays a great role but if you want to reach the limits of performance, the lighter the better - to a degree of course, i.e. Pedrosa who only weighs 112 lbs has some challenges of his own. I imagine this has to do with how nimbly the rider can respond to changing conditions and obstacles/opponents, though in professional racing it also has to do with acceleration and fuel consumption being advantageous for lighter riders since there is no refueling.
If you're on the road, agility would help with stray patches of unseen gravel, leaves, and oil slicks - so the ideal is lightness, all else being equal (same bike setup, skill level, surface, etc.).
Experienced riders are usually able to use a light touch to guide their bike, whereas many inexperienced riders try too hard and end up fighting the natural dynamics of the bike. For some people it does come more naturally, and others never learn that riding can be pretty easy.
posted by pants tent at 11:14 AM on January 20, 2018 [1 favorite]
This all comes down to the weight of the overall package: a Harley Sportster is about 550 lbs + so a difference of 20-30 lbs can be significant.
As others have said skill plays a great role but if you want to reach the limits of performance, the lighter the better - to a degree of course, i.e. Pedrosa who only weighs 112 lbs has some challenges of his own. I imagine this has to do with how nimbly the rider can respond to changing conditions and obstacles/opponents, though in professional racing it also has to do with acceleration and fuel consumption being advantageous for lighter riders since there is no refueling.
If you're on the road, agility would help with stray patches of unseen gravel, leaves, and oil slicks - so the ideal is lightness, all else being equal (same bike setup, skill level, surface, etc.).
Experienced riders are usually able to use a light touch to guide their bike, whereas many inexperienced riders try too hard and end up fighting the natural dynamics of the bike. For some people it does come more naturally, and others never learn that riding can be pretty easy.
posted by pants tent at 11:14 AM on January 20, 2018 [1 favorite]
Well, if we're talking about a small-sized rider with little experience, the main problem is putting their foot down when the bike is coming to a stop and then landing on a pebble that rolls away, or hitting a slight decline in the floor... and dropping the bike. That's a very real thing that short people do when they are new to motorcycles. Then again, cruisers tend to be on the low side, which is an advantage in this case. But your hypothetical rider is still going to drop the bike, sooner rather than later.
Being of slight build is not really going to offer specific challenges. I've seen a guy I can only describe as a fly-weight pilot a BMW K75 though rough terrain, and doing fine. It was a sight to behold. But he had skills, and experience.
Here's some good information on bikes and being short.
posted by Too-Ticky at 11:23 AM on January 20, 2018 [2 favorites]
Being of slight build is not really going to offer specific challenges. I've seen a guy I can only describe as a fly-weight pilot a BMW K75 though rough terrain, and doing fine. It was a sight to behold. But he had skills, and experience.
Here's some good information on bikes and being short.
posted by Too-Ticky at 11:23 AM on January 20, 2018 [2 favorites]
Oh, and he was definitely using his weight to steer, not just the handle bars. But maybe cruisers are different that way.
posted by Too-Ticky at 11:26 AM on January 20, 2018
posted by Too-Ticky at 11:26 AM on January 20, 2018
I'm 5'5" and my Suzuki LS650 is just right for me.
posted by KazamaSmokers at 3:12 PM on January 20, 2018 [1 favorite]
posted by KazamaSmokers at 3:12 PM on January 20, 2018 [1 favorite]
At the limits of performance, and holding rider skill to be equal, a lighter rider would fare better in just about every respect and on any type of bike. It’s basic physics. Less weight=better acceleration, shorter braking distances, and more lateral grip/can corner faster in a turn w/o losing grip.
posted by MjrMjr at 6:56 PM on January 20, 2018 [2 favorites]
posted by MjrMjr at 6:56 PM on January 20, 2018 [2 favorites]
Response by poster: These are all excellent and useful responses. Much appreciated.
One final particular scenario, for anyone who's got time for it: what if we're talking about rapid acceleration to the point that the motorcycle might wheelie, as in a drag race? It's clear now that the major issue is usually a rider's inexperience, but would a lighter rider be that much more likely to loop out, or is the engine power so overwhelmingly the consideration here that even 100+ pounds might not make much of a difference?
Would a heavier rider be able to keep the bike down better? Is weight still mostly negligible then? Or perhaps is one seated so far back on a cruiser where greater weight would scarcely make a difference?
Take a look at this video, which I found during my research and prompted me to wonder.
https://youtu.be/pu64lSdqyeQ
posted by millions at 3:00 PM on January 21, 2018
One final particular scenario, for anyone who's got time for it: what if we're talking about rapid acceleration to the point that the motorcycle might wheelie, as in a drag race? It's clear now that the major issue is usually a rider's inexperience, but would a lighter rider be that much more likely to loop out, or is the engine power so overwhelmingly the consideration here that even 100+ pounds might not make much of a difference?
Would a heavier rider be able to keep the bike down better? Is weight still mostly negligible then? Or perhaps is one seated so far back on a cruiser where greater weight would scarcely make a difference?
Take a look at this video, which I found during my research and prompted me to wonder.
https://youtu.be/pu64lSdqyeQ
posted by millions at 3:00 PM on January 21, 2018
It's typically much harder to get a cruiser to do a wheelie at all because of their length, weight, and weight distribution. I suspect that a heavier rider would have more trouble getting the front wheel off the ground at all, though it would likely be easier on the Sportster given that it's 150 lbs lighter than the Softail. Compare your Softail video to this Sportster wheelie video (one of many).
posted by clawsoon at 3:34 PM on January 21, 2018 [1 favorite]
posted by clawsoon at 3:34 PM on January 21, 2018 [1 favorite]
That bike in the video is not something you can buy at the Harley shop - seems like it has more power and more traction.
It would help to know what kind of bike you are talking about. A normal Harley is not gonna flip and walk away off the starting line - it's just not balanced that way. It will look more like this. Maybe the wheel would leave the ground for a moment but it won't do much.
To get a regular Harley to wheelie, you need to do some special stuff, like rebound off the front suspension in addition to a clutch drop.
And 100 lbs is probably 15% of the total weight, so it will make a huge difference once the bike gets going. As most people have said, weight is not negligible!
posted by pants tent at 3:41 PM on January 21, 2018 [2 favorites]
It would help to know what kind of bike you are talking about. A normal Harley is not gonna flip and walk away off the starting line - it's just not balanced that way. It will look more like this. Maybe the wheel would leave the ground for a moment but it won't do much.
To get a regular Harley to wheelie, you need to do some special stuff, like rebound off the front suspension in addition to a clutch drop.
And 100 lbs is probably 15% of the total weight, so it will make a huge difference once the bike gets going. As most people have said, weight is not negligible!
posted by pants tent at 3:41 PM on January 21, 2018 [2 favorites]
Response by poster: The uploader of the softail wheelie video mentions that it has a new tire that "hook[ed]". I didn't catch that, so thanks for pointing it out. And you're right pants, most responses don't say that weight is negligible.
posted by millions at 3:48 PM on January 21, 2018
posted by millions at 3:48 PM on January 21, 2018
More on weight: The typical wheelie bike is a 450 lb sportbike (or "crotch rocket"). A Softail is closer to 700 lbs. Power for both is typically in the 50-70 hp range. So doing a wheelie on a Softail would be like doing a wheelie on a sportbike but with a 250 lb guy riding on your back.
posted by clawsoon at 3:56 PM on January 21, 2018 [1 favorite]
posted by clawsoon at 3:56 PM on January 21, 2018 [1 favorite]
Response by poster: @pants tent: the comments for the video I posted show the rider made an engine upgrade as well. Good call.
posted by millions at 7:37 PM on January 21, 2018
posted by millions at 7:37 PM on January 21, 2018
Response by poster: Thank you sincerely to everyone who contributed an answer here. Everything you all wrote illuminated the scene a little bit more for me, and I truly appreciate the help.
posted by millions at 7:25 PM on January 25, 2018
posted by millions at 7:25 PM on January 25, 2018
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On the other hand, when accelerating rapidly, a heavier rider will experience more mass inertia and so they will need to hold on to the handlebars that much tighter.
All in all I don't believe it matters that much. And frankly I'm having difficulty matching the concepts 'cruiser' and 'the limits of performance'. People who care a lot about performance rarely choose a cruiser, and there are reasons for that. Horses for courses, as they say.
posted by Too-Ticky at 9:11 AM on January 20, 2018 [3 favorites]