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I have this interrogation about the ideal place to put the extra weight needed for XC/AM rides (hydration pack or bottles, multi-tools, spare tubes, etc.) … on my back or attached to the bike ? I guess physics is involved here, since one might want the lightest bike as possible (for maneuverability purposes when climbing technical trails), and others would rather let the bike carry the extra weight (probably easier on the muscles, leaving it to the bike frame). What do you guys think ?

Marc

2008 Specialized SJ Pro Carbon
2006 Iron Horse Warrior HT
 

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noMAD man
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If you're gonna have weight in some form like tools, parts, tube, food, etc., it's better to have it on the rider than the bike. The rider is moveable and can shift that weight to affect handling. This is even true on dirt motors.

This is all within the realm of reason, of course. I'm not advocating strapping a 50lb backpacking rig on your back and toting it on a regular ride. And I guess we're mainly talking about trail riding here and not crosscountry traveling/camping stuff.
 

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The lower the center of gravity, the better the balance. Having said that, I've tried both and didn't notice a difference in balance or maneuvarability.

My new bike has 1.5" more bottom bracket clearance, which raises my entire body by the same amount. I felt like I was on stilts for the first ride or two. And I still didnt notice a difference in balance, even with tracks stands or stationary hops and pivots. And even when I carry extra weight on my back, it still doesn't seem to affect my riding.

I don't think we're talking about enough weight to make a difference, although my personal preference is to keep my body cool and light by putting the weight on my bike when possible.
 

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whtdel said:
I have this interrogation about the ideal place to put the extra weight needed for XC/AM rides (hydration pack or bottles, multi-tools, spare tubes, etc.) … on my back or attached to the bike ? I guess physics is involved here, since one might want the lightest bike as possible (for maneuverability purposes when climbing technical trails), and others would rather let the bike carry the extra weight (probably easier on the muscles, leaving it to the bike frame). What do you guys think ?

Marc

2008 Specialized SJ Pro Carbon
2006 Iron Horse Warrior HT
On my road bike I like it on the bike, as it is more comfortable and cool, but on the mountain bike a much prefer it on me, as it makes bike maneuvers much easier.
 

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Personally, I can't stand having a little monkey riding on my back all the time. (For one thing, it's kinda sweaty). So I use a seatpack for tools and spare tube and water bottles. So much more comfortable. Same goes for commuting - messenger bags suck when your bike can carry your stuff on a rack. Obviously I am in the minority in both cases - apparently most people like stuff on their back. Weird.
 

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Thor29 said:
Personally, I can't stand having a little monkey riding on my back all the time. (For one thing, it's kinda sweaty). So I use a seatpack for tools and spare tube and water bottles. So much more comfortable. Same goes for commuting - messenger bags suck when your bike can carry your stuff on a rack. Obviously I am in the minority in both cases - apparently most people like stuff on their back. Weird.
It's not an issue of wanting it on my back, it's not wanting it on the bike (at least when mountain biking).
 

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For me, certainly, bike. The lower and more in the rear the gravity center, the better, in my opinion. Besides, doesn't your back deserve some ventilation? I carry the spare tube, pump and everything, needed for fixing a flat, in a small bag in one of bottle racks. Rest of the tools in the seat bag. One water bottle on the second rack. The rest (1.5 l. of water, first aid kit and more - in a big waist bag, which, unlike a back pack, doesn't heat my back and is placed low enough. Very convenient, never interferes with technical riding.
 

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kapusta said:
On my road bike I like it on the bike, as it is more comfortable and cool, but on the mountain bike a much prefer it on me, as it makes bike maneuvers much easier.
I've tried bottles and fanny pack vs. everything in a camelback, and didn't notice a difference, except with ventilation and comfort. Just curious - which maneuvers are easier with a higher COG? And I'm surprised you were able to notice. How much weight are you talking about?
 

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To add to TNC and kapusta's points carrying the weight on your back allows you to flow over terrain more effectively, weight on the bike has to be dealt with by the suspension. I prefer a backpack for my gear, I like minimal weight on the bike.
 

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tduro said:
I've tried bottles and fanny pack vs. everything in a camelback, and didn't notice a difference, except with ventilation and comfort. Just curious - which maneuvers are easier with a higher COG? And I'm surprised you were able to notice. How much weight are you talking about?
It's not an issue of how high the COG is, it's how heavy or light the bike is compared to me Any time I use my body's mass against that of the bikes, it is easier with me heavier and the bike lighter. Log crossings, rock features/gardens, bunny hopping, getting over roots on a steep climb are examples. How much weight? I don't know, whatever my pack weighs. I guess 5-10 lbs, depending on how much water, food and other supplies I have with me. 100 oz of water is over 6 pounds.
 

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If this necessary extra weight is on you, then you can use it to aid your body English; if it's on the bike, you have to use more of yourself to overcome it. So -- do you want it helping you, or fighting you?
 

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Spread it out. Some on the back, some on the bike.

I keep tools, tube, pump on the bike so it's always there. For a short ride I can simply grab a water bottle and go since everything else in on the bike at-the-ready. Sometimes I don't even put on bike-specific clothes other than shoes. I'm all for the no muss/no fuss quick getaway capability.

For longer rides you can take your Camelbak filled with water and food.

If you're concerned mostly about maneuverability, then the Wingnut packs are the best solution since your CoG is low (around your hips) and your "unsprung weight" (i.e., bike) stays light as possible.

http://www.wingnutgear.com/product_details.cfm?product_id=112
 

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Hmm, bike or back... I think it's really a personal preference. I'm in great shape, but sweat like a pig, so I don't like stuff on my back. But then I usually ride a hard tail with two stock holders that can carry 2 bottles totaling 50 ounces of water. For me, that's good for a 3+ hour ride. My spare, patches, CO2, etc go in a small scrotum bag under the seat.

Having said that, any ride over 3 hours still requires an hydration pack. And of course riding a full sus bike with only one water bottle holder also requires a pack for anything but short rides.
 

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Nat, isn't unsprung weight those items on the bike that are not "above" or supported by the suspension?...like wheels and such? Won't the rider always be somewhat in the category of "sprung" weight? Your comment brings up a good point. I'm usually refering to full suspension bikes in my comments, but for hardtail guys, that point of unsprung weight isn't quite as clear if they have a suspension fork on front. And maybe a rigid bike is a better discussion point. In that case, the rider and the air in the tires are the "suspension". If one starts strapping weight to the bike in that example, I think most will see the advantage of the rider having the weight instead of the bike for better control.

Again, all of this should be related to a reasonable amount of weight for trail riding, and not those crosscountry travel/camping applications.
 

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TNC said:
Nat, isn't unsprung weight those items on the bike that are not "above" or supported by the suspension?...like wheels and such? Won't the rider always be somewhat in the category of "sprung" weight? Your comment brings up a good point. I'm usually refering to full suspension bikes in my comments, but for hardtail guys, that point of unsprung weight isn't quite as clear if they have a suspension fork on front. And maybe a rigid bike is a better discussion point. In that case, the rider and the air in the tires are the "suspension". If one starts strapping weight to the bike in that example, I think most will see the advantage of the rider having the weight instead of the bike for better control
I think you kind of answered your own question. We've kind of got two different suspensions, the one on the bike and the arms and legs of the rider. So, if you can keep weight on the rider it is now unsprung for that category. That was kind of what I was trying to say earlier about being able to flow over things by moving the bike below you.
 

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TNC said:
Nat, isn't unsprung weight those items on the bike that are not "above" or supported by the suspension?...like wheels and such? Won't the rider always be somewhat in the category of "sprung" weight? Your comment brings up a good point. I'm usually refering to full suspension bikes in my comments, but for hardtail guys, that point of unsprung weight isn't quite as clear if they have a suspension fork on front. And maybe a rigid bike is a better discussion point. In that case, the rider and the air in the tires are the "suspension". If one starts strapping weight to the bike in that example, I think most will see the advantage of the rider having the weight instead of the bike for better control.

Again, all of this should be related to a reasonable amount of weight for trail riding, and not those crosscountry travel/camping applications.
I don't want to overanalyze it since we shouldn't make this excessively complicated, but I was referring to anything below your legs and arms (i.e., the bike) as unsprung weight since it moves around beneath you when you ride. Pretend I left the term "unsprung weight" out of my post.
 

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I'm not convinced. Particularly since in my personal experience, I can't really notice a difference in handling. I wonder, does anyone add unnecessary weight to their upper body just to improve handling? And are there ever occasions where the higher COG is unwanted? Like steep rocky shoots?

I like to focus on riding relaxed, wasting NO energy, and maximizing efficiency. Weight on my body has to be lifted by or supported by my legs every time I move off or around the saddle. That could be thousands of times on a ride. Weight on my bike still has to be hauled up the hills, but at least my legs get a small break. It's like when I XC ski with overnight gear. It's so much easier to pull a sled than carry a backpack.

I think, in the end, 10 lbs. or less applied anywhere in the "system" is going to have its own pros and cons, which essentially offset the pros and cons of other placements.

I sweat a lot too, and prefer not to have anything inhibiting air movement over my back. A waist pack keeps the COG lower, opens the back area, and creates somewhat of a barrier to the rivulets of sweat trickling down my ass crack. In the off chance that it really does affect bike handling, it's worth it. In reality, I only notice the comfort improvement. But that's just me.
 

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tduro said:
I'm not convinced. Particularly since in my personal experience, I can't really notice a difference in handling. I wonder, does anyone add unnecessary weight to their upper body just to improve handling? And are there ever occasions where the higher COG is unwanted? Like steep rocky shoots?

I like to focus on riding relaxed, wasting NO energy, and maximizing efficiency. Weight on my body has to be lifted by or supported by my legs every time I move off or around the saddle. That could be thousands of times on a ride. Weight on my bike still has to be hauled up the hills, but at least my legs get a small break. It's like when I XC ski with overnight gear. It's so much easier to pull a sled than carry a backpack.

I think, in the end, 10 lbs. or less applied anywhere in the "system" is going to have its own pros and cons, which essentially offset the pros and cons of other placements.

I sweat a lot too, and prefer not to have anything inhibiting air movement over my back. A waist pack keeps the COG lower, opens the back area, and creates somewhat of a barrier to the rivulets of sweat trickling down my ass crack. In the off chance that it really does affect bike handling, it's worth it. In reality, I only notice the comfort improvement. But that's just me.
So, you're saying that you're a bike handling hack with spindly legs?:D

Seriously though, your last comment probably sums up a good deal of this. While there may an absolute physics based conclusion that might ultimately decide this issue decisively, the overall gains and losses are probably nothing to get one's chamois in a wad. Another issue might be riding style. I'm all over my bike like a rabid monkey, but perhaps that comes from riding a dirt motor where overt body english is somewhat required to influence handling. I never thought about the weight issue and the rising and sitting frequency. Even with body armor, 100oz Camelback, and other assorted items in a pack, it's usually not much of an issue for me. Maybe it's like weight lifting.:D
 
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