+1 forward a-arms any good for hillclimbing?
#1
09-06-2001, 09:46 PM
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I have a set of TimmyBoy +2+1 a-arms on order. Should have them Friday or Monday. What I'm curious of though... Are +1 forward a-arms better or worse for hillclimbing? My original thought on it was that +1 would make the front of the bike heavier, which would be better for hillclimbing. But, I also had someone point out to me that +1 a-arms makes the rear tires grab more, which could be bad. Anyone have any input on this? Any experience?
#2
09-07-2001, 12:52 AM
Your theory seems to make sense to me.
I noticed on the HuevosIII video, during the hill climb segment, one of the quads had a wide front, and the rear seemed really narrow. That seems like it would make it track straighter to me. In my experience, a wide rear axle seems to make the quad/trike want to pull one way or the other, but body english really helps that. But the wider axle helps when you get sideways on a steep hill. It is a toss up I guess.
I noticed on the HuevosIII video, during the hill climb segment, one of the quads had a wide front, and the rear seemed really narrow. That seems like it would make it track straighter to me. In my experience, a wide rear axle seems to make the quad/trike want to pull one way or the other, but body english really helps that. But the wider axle helps when you get sideways on a steep hill. It is a toss up I guess.
#3
09-07-2001, 09:48 AM
#4
09-07-2001, 02:18 PM
IceMan11,
This is an awesome topic. Theoretically you are correct. I will try to express why your thinking is correct without a bunch of charts and graphs and math formulas. For those reading who want the really short version, increasing wheelbase will increase climbing ability. Skip to end!
Okay, you decided to read on. In the simplest terms, increasing wheelbase increases the distribution of weight forwards. This could be measured if you were inclined to check. You would have to find the front to rear balance point of the quad and mark the frame at this point. Then make the a-arm changes, and then find the new balance point. Basically, the balance point would have moved forward some but not an inch (+2,+1 a-arm). Bottom line is that this will help keep the front down thus allowing more rider weight to be transferred to the rear to increase traction. The modification is what allows the rider to change positioning thus increasing climbing ability. Obviously, not everything is better though. For example, your turning radius will decrease both from moving the a-arm forward one inch and for increasing the width between the front wheels. (Those old tractors with the two front tires sitting next to each other can turn around on a dime!)
More thought provoking theory...Now once the quad is built and just sitting there, two factors can change the distribution of weight: incline and acceleration (for this discussion, let's assume acceleration and momentum are the same - they are close but not really the same). The higher an incline the more weight that is transferred rearward. Also, the greater the acceleration, the greater the transfer of weight from the front to the back. A simple test to verify the change in weight distribution due to incline changes would be to place four scales under the quads tires on level ground on a 4 X 8 sheet of plywood. Then, start increasing the incline of the plywood. More and more weight will transfer to the rear tires thus the weight on the rear scales will go up as the weight comes off the front end. The same is true of acceleration. This is why you can do a wheelie - the front end lightens up to the point gravity can't keep it down. Okay, just like in school when they told you one thing and then changed it. The distribution of weight is not only influenced by incline and acceleration but also from the positioning of weight changes. Meaning it depend where on the bike you add weight (in our case, the rider). The higher the weight (above the center of gravity) the less effective it can be transferred downward to the rear tires. Think rider positioning doesn't make a big difference. Try climbing a really steep hill. The first time, hold yourself on the bike by standing up and leaning forward and putting all your weight on your footpegs (you should only be holding the handlebars enough to steer). Next test, climb the same hill but sit forward on the seat and hold yourself on the bike by pulling your weight on the bars as much as possible thus keeping the weight off the footpegs (in fact just lift your legs off the pegs to be sure you aren't putting any weight on them). In either case, you have added the same overall weight yet its impact is dramatically different. In one case, you have a very low center of gravity because the weight is being transferred very low to the ground at the footpegs. This weight transfers rearward and downward to the tires to increase traction. In the other case, the weight is above the center of gravity. The difference is that most of the weight still transfers rearward but never really transfers as much downward on the tires. Adding weight above the center of gravity is more equivalent to just trying to pull a weight up a hill connected to the rear axle. The weight itself doesn't help increase traction and yet becomes a hindrance since more weight has to be carried up the hill against gravity. (a somewhat related topic that just came to mind. If you are trying to pull someone out of a mud hole, connect the strap as low as possible on the stuck quad and on your rear grab bar. This lightens the stuck quad and puts more downward force on the rear tires of the pulling quad to increase traction. I've seen people do it exactly wrong by connecting high on the stuck quad and down on the hitchball of the pulling quad. This effectively is pulling the stuck quad down into the mud and trying to lift the backend of the pulling quad off the ground).
Another interesting point is that heavier people generally have an advantage when it comes to hill climbing. A large part of this is due to the fact that they can get more weight transferred downward on the rear tires to increase traction. If you don't have enough weight, the rear tires will just spin. Lighter people often need more momentum (acceleration) to counteract the fact that they do not have enough weight to get traction. Remember that acceleration puts more weight on the back end thus increasing traction. Obviously this only works to a point. If you are too fat, the tires can't get enough traction to pull your big, fat butt up the hill. If you have too much momemtum then you can flip over since too much weight is transferred from the front to the rear.
Along the same lines as climbing a hill is traversing a hill. For those of you still reading who like to traverse hills sideways, let me just say that rider positioning is critical. You should be pushing down with most of your weight on the lowside footpeg. Yep, I know this sounds wrong but it isn't. This is way better than leaning up hill with your weight on the seat and the upper footpeg. The problem with doing it this way is that most of your weight is higher than the center of gravity. You are more likely to flip this way than standing and leaning up hill but planting your weight on the lower footpeg. This is a trick that all the GNCC and Hare Scramble guys know (many can't explain why it works but it does). Don't believe it? Test it. I promise you that you will double your speed when traversing hills if you position your weight this way.
Anyhow, sorry for all the rambling. As I mentioned in another post, I am pretty much confined to bed with nothing better to do. You are lucky I couldn't get to my calculus books. Hopefully somebody got something from reading this. It takes quite a bit of time to put it into words.
As mentioned before IceMan11, theoretically, your thinking is correct. Let us know how practical experience works out.
I am looking forward to getting a set of +1+1 a-arms soon. Plan to add another inch with the wheels. Don't want to go too wide since I am an old man (37) who sees many more senior hare scrambles in his future than MX racing. I have been patiently waiting for the "real" Raptor RPM Dominator axle to come out (I know some have adapted the Banshee axle).
Later,
This is an awesome topic. Theoretically you are correct. I will try to express why your thinking is correct without a bunch of charts and graphs and math formulas. For those reading who want the really short version, increasing wheelbase will increase climbing ability. Skip to end!
Okay, you decided to read on. In the simplest terms, increasing wheelbase increases the distribution of weight forwards. This could be measured if you were inclined to check. You would have to find the front to rear balance point of the quad and mark the frame at this point. Then make the a-arm changes, and then find the new balance point. Basically, the balance point would have moved forward some but not an inch (+2,+1 a-arm). Bottom line is that this will help keep the front down thus allowing more rider weight to be transferred to the rear to increase traction. The modification is what allows the rider to change positioning thus increasing climbing ability. Obviously, not everything is better though. For example, your turning radius will decrease both from moving the a-arm forward one inch and for increasing the width between the front wheels. (Those old tractors with the two front tires sitting next to each other can turn around on a dime!)
More thought provoking theory...Now once the quad is built and just sitting there, two factors can change the distribution of weight: incline and acceleration (for this discussion, let's assume acceleration and momentum are the same - they are close but not really the same). The higher an incline the more weight that is transferred rearward. Also, the greater the acceleration, the greater the transfer of weight from the front to the back. A simple test to verify the change in weight distribution due to incline changes would be to place four scales under the quads tires on level ground on a 4 X 8 sheet of plywood. Then, start increasing the incline of the plywood. More and more weight will transfer to the rear tires thus the weight on the rear scales will go up as the weight comes off the front end. The same is true of acceleration. This is why you can do a wheelie - the front end lightens up to the point gravity can't keep it down. Okay, just like in school when they told you one thing and then changed it. The distribution of weight is not only influenced by incline and acceleration but also from the positioning of weight changes. Meaning it depend where on the bike you add weight (in our case, the rider). The higher the weight (above the center of gravity) the less effective it can be transferred downward to the rear tires. Think rider positioning doesn't make a big difference. Try climbing a really steep hill. The first time, hold yourself on the bike by standing up and leaning forward and putting all your weight on your footpegs (you should only be holding the handlebars enough to steer). Next test, climb the same hill but sit forward on the seat and hold yourself on the bike by pulling your weight on the bars as much as possible thus keeping the weight off the footpegs (in fact just lift your legs off the pegs to be sure you aren't putting any weight on them). In either case, you have added the same overall weight yet its impact is dramatically different. In one case, you have a very low center of gravity because the weight is being transferred very low to the ground at the footpegs. This weight transfers rearward and downward to the tires to increase traction. In the other case, the weight is above the center of gravity. The difference is that most of the weight still transfers rearward but never really transfers as much downward on the tires. Adding weight above the center of gravity is more equivalent to just trying to pull a weight up a hill connected to the rear axle. The weight itself doesn't help increase traction and yet becomes a hindrance since more weight has to be carried up the hill against gravity. (a somewhat related topic that just came to mind. If you are trying to pull someone out of a mud hole, connect the strap as low as possible on the stuck quad and on your rear grab bar. This lightens the stuck quad and puts more downward force on the rear tires of the pulling quad to increase traction. I've seen people do it exactly wrong by connecting high on the stuck quad and down on the hitchball of the pulling quad. This effectively is pulling the stuck quad down into the mud and trying to lift the backend of the pulling quad off the ground).
Another interesting point is that heavier people generally have an advantage when it comes to hill climbing. A large part of this is due to the fact that they can get more weight transferred downward on the rear tires to increase traction. If you don't have enough weight, the rear tires will just spin. Lighter people often need more momentum (acceleration) to counteract the fact that they do not have enough weight to get traction. Remember that acceleration puts more weight on the back end thus increasing traction. Obviously this only works to a point. If you are too fat, the tires can't get enough traction to pull your big, fat butt up the hill. If you have too much momemtum then you can flip over since too much weight is transferred from the front to the rear.
Along the same lines as climbing a hill is traversing a hill. For those of you still reading who like to traverse hills sideways, let me just say that rider positioning is critical. You should be pushing down with most of your weight on the lowside footpeg. Yep, I know this sounds wrong but it isn't. This is way better than leaning up hill with your weight on the seat and the upper footpeg. The problem with doing it this way is that most of your weight is higher than the center of gravity. You are more likely to flip this way than standing and leaning up hill but planting your weight on the lower footpeg. This is a trick that all the GNCC and Hare Scramble guys know (many can't explain why it works but it does). Don't believe it? Test it. I promise you that you will double your speed when traversing hills if you position your weight this way.
Anyhow, sorry for all the rambling. As I mentioned in another post, I am pretty much confined to bed with nothing better to do. You are lucky I couldn't get to my calculus books. Hopefully somebody got something from reading this. It takes quite a bit of time to put it into words.
As mentioned before IceMan11, theoretically, your thinking is correct. Let us know how practical experience works out.
I am looking forward to getting a set of +1+1 a-arms soon. Plan to add another inch with the wheels. Don't want to go too wide since I am an old man (37) who sees many more senior hare scrambles in his future than MX racing. I have been patiently waiting for the "real" Raptor RPM Dominator axle to come out (I know some have adapted the Banshee axle).
Later,
#5
09-07-2001, 06:56 PM
#7
09-08-2001, 02:12 AM
NotuRaptor........ you have way too much time on your hands to write that! good post though. i'm glad everyone doesn't write that much or i'd never get any time riding. wheelbase helps keep front wheels down for hill shooting. i don't know about the wider axle pulling you off to one side though. the wider axle should do the same thing it does for normal riding, extra stability.
laterz
laterz
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#8
09-08-2001, 08:22 AM
Yea, I agree with that the wider stance should help! The only reason it might throw the bike around more is because the hill climbs are heavily rutted and a wider quad doesn't fit in the ruts as well; therefore, the side of the tires grab a traction on the side of the rut. Or like mentioned in a previous post, the tire pressure is off.
See, much shorter.
See, much shorter.
#9
09-08-2001, 12:58 PM
The hills I climb are not usually smooth, like dunes, they are rutted out. Obviously that is a contributing factor to wander. I like a wide rear axle because when you do stop, or turn around, it is so much more stable. I notice the hill wander more on my 350X, than my widened 400EX. When I used to ride a wide Blaster, I don't recall a problem with wander. But, the Blaster didn't have the power to get too far out of hand either! When the 350X is spinning, and one wheel gets more traction, WATCH OUT! Mostly I think because the front wheel is just skimming the dirt, nothing to keep it tracking straight.
I HATE having to let off the throttle because the trike is shooting off toward a tree. If the rideable part of the hill is wide enough, you can stay on the juice, and just steer, and lean it where you need to go (with practice). Oh yeah, have at least one reliable friend around! [img]i/expressions/face-icon-small-smile.gif[/img]
I HATE having to let off the throttle because the trike is shooting off toward a tree. If the rideable part of the hill is wide enough, you can stay on the juice, and just steer, and lean it where you need to go (with practice). Oh yeah, have at least one reliable friend around! [img]i/expressions/face-icon-small-smile.gif[/img]
#10
09-09-2001, 01:06 AM
This is one of the best posts I've seen in awhile. But what should I do in my situation? Every rider is different and we are all here for answers. I have a 2001 Warrior. I ride 75% rocky trails and 25% motocross. I like to do hillclimbs it's just I never find enough of them to challenge me. Should I go for wider a-arms or not? I'm going to order a set of aftermarket shocks for the Warrior so that doesn't matter. The wider a-arms are the question. I like to hit the turns fast. Would the wider a-arms help?