Difference in steering stems
I was wondering, I know that there is a difference at the top of the stem. Some are straight up and some are at the same angle as the stem. But does one have more bump steer than another? I've been racing/riding one of my dads Cannondales lately and it doesn't have the original stem on it, we had to switch it out when he bought it. I think we put an older one in it. Anyways the quad has ridiculous bump steer compared to mine. Everything is tight in the front end, ball joints are great, tie rod ends are fine, I have no idea why it has so much more bump steer. Neither have a dampner or anything, but it feels like mine does when comparing the 2 quads. I don't really want to switch stems unless that is the cause. Anybody know?
There are at least 3 different bottom plates . The fx400 one has less leverage but more throw which will make your quad turn very sharp but give wicked bump steer. Then there is the moto one which has the plate mounted right at the bottom of the stem to allow for long travel without the tie rods hitting the frame. The standard travel stem has the plate mounted a half inch higher for the standard a arms. I have been converting all my stems to the moto setup which will work on all suspensions.
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wayneschofield
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QUOTE (yamadjs08 @ Aug 2 2007, 12:00 PM) <{POST_SNAPBACK}>
I was wondering, I know that there is a difference at the top of the stem. Some are straight up and some are at the same angle as the stem. But does one have more bump steer than another? I've been racing/riding one of my dads Cannondales lately and it doesn't have the original stem on it, we had to switch it out when he bought it. I think we put an older one in it. Anyways the quad has ridiculous bump steer compared to mine. Everything is tight in the front end, ball joints are great, tie rod ends are fine, I have no idea why it has so much more bump steer. Neither have a dampner or anything, but it feels like mine does when comparing the 2 quads. I don't really want to switch stems unless that is the cause. Anybody know?
Compare the relative hights of the inner and outer ends of the tie rods. Strictly speaking it's the position of the centre of the ball inside the joint that matters.
Make sure the rod end isn't on the wrong side of the plate at the bottom of the steering stem. They should go on the top of the steering stem plate but underneath the steering arms on the hubs.
You may be able to 'shim' the joints with some washers to improve things. Generally speaking, if you've got to live with a bit of bump-steer, then have it so it tows out on compression at the front as this generates 'roll understeer', which is a stable condition.
Tow-in on compression creates 'roll-oversteer' and this is generally undesirable as, when you turn in, the outer wheel tends to turn greater due to roll movement, and this makes the thing very 'pointy' and unstable. Roll oversteer is sometimes deliberately employed, but it is unusual.
I figured I could add .02 on this now that I've just measured the 3 different versions I have. I'll go chronologically...
#1. I assume this is the oldest, the tie rod plate has a crossbar welded across it on the bottom side, no dampener mounts, and the handlebar mounts are tilted forward
#2. I'm guessing this may be the middle aged one, is a new take off- never used. It doesn't have any type of gusset or stiffener on the tie rod plate, but does have the dampener mounts. The handlebar mounts are tilted forward.
#3. This I believe is the newest, which came off of a re-furb Cannibal that left the factory just before the doors got locked. It has a gusset welded from the tube down to the top of the tie rod plate and does have dampener mounts. The handlebar mounts are parallel with the main tube, unlike the other 2. This is what most people see as the difference between "02" and "03" stems. This stem is probably the same as what Wistech was calling the Moto stem (I imagine early Moto stems changed like the rest did with gussets or stiffeners added and removed) and I'd be willing to bet Cdale may have standardized to using this design on all models somewhere along the way. I say this because I have another stock 03 Cannibal with this same stem on it.
The dimensions for each are as follows...
The top plate dim is from the bottom of the bolt to the top of the plate with the stem standing up level on my work bench.
The h2h (hole to hole) is measuring the distance straight across between the tie rod holes not center to center, good for reference only as the plate has a bend in it that isn't accounted for.
The TR Dist is the distance from the OS of the stem to the tie rod hole which relates to how far the tierod holes are from the center (except measured to the outside) of the stem
(The asterisks are used to keep the formatting straight)
*****Top Plate*****h2h*****TR Dist
#1.***2.620"******.883"*****3.420"
#2.***2.776"******.746"*****3.047"
#3.***2.443"******.756"*****3.055"
As Wistech noted, the tie rod plate of the newer stem is just under 3/8" lower than the middle aged stem, but only 3/16" lower than the earliest stem. However, the tie rods were 1/8" farther apart on the older stem, which is probably only a small part of the difference in steering geometry that Yamadjs08 was feeling and that Wayne had great insight into. Yama's not actually talking about true bump steer as Wayne was dissecting, I think he was talking about feeling bumps in the handlebars and jerking the bars, which would be directly affected and increased by going to the earliest stem with that long tie rod plate. Yama, take a look and tell us which 2 stems you are talking about. I bet you put on one with the crossbar on the bottom and no dampener mounts.
BTW, Don't you know the fine #3 that I measured is the one I just took out of my regular ride and has about a 3/8" bend in it!
Edit- I added the TR distance after originally posting and seeing I should've checked that, too. Now that I've edit'ed 3 times none of that probably makes any sense.
#1. I assume this is the oldest, the tie rod plate has a crossbar welded across it on the bottom side, no dampener mounts, and the handlebar mounts are tilted forward
#2. I'm guessing this may be the middle aged one, is a new take off- never used. It doesn't have any type of gusset or stiffener on the tie rod plate, but does have the dampener mounts. The handlebar mounts are tilted forward.
#3. This I believe is the newest, which came off of a re-furb Cannibal that left the factory just before the doors got locked. It has a gusset welded from the tube down to the top of the tie rod plate and does have dampener mounts. The handlebar mounts are parallel with the main tube, unlike the other 2. This is what most people see as the difference between "02" and "03" stems. This stem is probably the same as what Wistech was calling the Moto stem (I imagine early Moto stems changed like the rest did with gussets or stiffeners added and removed) and I'd be willing to bet Cdale may have standardized to using this design on all models somewhere along the way. I say this because I have another stock 03 Cannibal with this same stem on it.
The dimensions for each are as follows...
The top plate dim is from the bottom of the bolt to the top of the plate with the stem standing up level on my work bench.
The h2h (hole to hole) is measuring the distance straight across between the tie rod holes not center to center, good for reference only as the plate has a bend in it that isn't accounted for.
The TR Dist is the distance from the OS of the stem to the tie rod hole which relates to how far the tierod holes are from the center (except measured to the outside) of the stem
(The asterisks are used to keep the formatting straight)
*****Top Plate*****h2h*****TR Dist
#1.***2.620"******.883"*****3.420"
#2.***2.776"******.746"*****3.047"
#3.***2.443"******.756"*****3.055"
As Wistech noted, the tie rod plate of the newer stem is just under 3/8" lower than the middle aged stem, but only 3/16" lower than the earliest stem. However, the tie rods were 1/8" farther apart on the older stem, which is probably only a small part of the difference in steering geometry that Yamadjs08 was feeling and that Wayne had great insight into. Yama's not actually talking about true bump steer as Wayne was dissecting, I think he was talking about feeling bumps in the handlebars and jerking the bars, which would be directly affected and increased by going to the earliest stem with that long tie rod plate. Yama, take a look and tell us which 2 stems you are talking about. I bet you put on one with the crossbar on the bottom and no dampener mounts.
BTW, Don't you know the fine #3 that I measured is the one I just took out of my regular ride and has about a 3/8" bend in it!
Edit- I added the TR distance after originally posting and seeing I should've checked that, too. Now that I've edit'ed 3 times none of that probably makes any sense.
I think the reason Wistech is calling it the Moto stem is because I believe they used it first on the Moto and then migrated it to all the other models. Since I am not the racer you guys are I never noticed the difference except in the height of the bottom plate due to it having issues with tie rods hitting the frame on the Moto type front end. I believe you have documented the three types of stems very well in your reply. I think that only the early model (FX400) stems came without the damper mounts, and that all of the stems with the straight steering head angle came with the "moto" style bottom plate. What I am not sure of is whether there were two different stems with the bent angle top and different bottom plate styles.
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cannondale27
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thedeatons
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So I have a 2002 Moto with the vertical upper handlebar mounts (zero back angle for a 1" longer cockpit) and a 2003 Glamis with the angled back upper handlebar mounts (angled at ~45 degrees for a 1" shorter cockpit).
I ride nearly exclusively sand so far with these, and my Moto is perfect for turns of any kind. I have noticed that the Glamis with the shorter cockpit comes out of sharp turns wheelying a lot more, as in so much I have to let off and lose ground when playing cat and mouse, when I can stay in the throttle with my Moto. The Glamis is a stocker with 45hp, and the Moto is a ported 450 with 52hp.
I really enjoy the Moto steering stem because of this alone. I go faster with it and can ride harder. If I pull myself way forward on the Glamis I can do nearly the same turns, but it is much harder on my body. Everything on the bikes is the same suspension wise. Same Moto front and rear ends, same paddles, pressure and settings. Only difference is the steering stem.
I ride nearly exclusively sand so far with these, and my Moto is perfect for turns of any kind. I have noticed that the Glamis with the shorter cockpit comes out of sharp turns wheelying a lot more, as in so much I have to let off and lose ground when playing cat and mouse, when I can stay in the throttle with my Moto. The Glamis is a stocker with 45hp, and the Moto is a ported 450 with 52hp.
I really enjoy the Moto steering stem because of this alone. I go faster with it and can ride harder. If I pull myself way forward on the Glamis I can do nearly the same turns, but it is much harder on my body. Everything on the bikes is the same suspension wise. Same Moto front and rear ends, same paddles, pressure and settings. Only difference is the steering stem.
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cannondale27
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QUOTE (thedeatons @ Jan 2 2008, 06:37 PM) <{POST_SNAPBACK}>
So I have a 2002 Moto with the vertical upper handlebar mounts (zero back angle for a 1" longer cockpit) and a 2003 Glamis with the angled back upper handlebar mounts (angled at ~45 degrees for a 1" shorter cockpit).
I ride nearly exclusively sand so far with these, and my Moto is perfect for turns of any kind. I have noticed that the Glamis with the shorter cockpit comes out of sharp turns wheelying a lot more, as in so much I have to let off and lose ground when playing cat and mouse, when I can stay in the throttle with my Moto. The Glamis is a stocker with 45hp, and the Moto is a ported 450 with 52hp.
I really enjoy the Moto steering stem because of this alone. I go faster with it and can ride harder. If I pull myself way forward on the Glamis I can do nearly the same turns, but it is much harder on my body. Everything on the bikes is the same suspension wise. Same Moto front and rear ends, same paddles, pressure and settings. Only difference is the steering stem.
I ride nearly exclusively sand so far with these, and my Moto is perfect for turns of any kind. I have noticed that the Glamis with the shorter cockpit comes out of sharp turns wheelying a lot more, as in so much I have to let off and lose ground when playing cat and mouse, when I can stay in the throttle with my Moto. The Glamis is a stocker with 45hp, and the Moto is a ported 450 with 52hp.
I really enjoy the Moto steering stem because of this alone. I go faster with it and can ride harder. If I pull myself way forward on the Glamis I can do nearly the same turns, but it is much harder on my body. Everything on the bikes is the same suspension wise. Same Moto front and rear ends, same paddles, pressure and settings. Only difference is the steering stem.
That stem was not stock on a Glamis. All of the Glamis bikes should have the last stem made ("03 style with straight angle). That stem must have been replaced somewhere down the road.
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thedeatons
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I don't think so Ken.... I bought it from the first owner who was also a former Dale dealer. Perhaps I mislead you with my babbling - The Glamis bar clamps are on the same plane as the steering stem. Making the bars more rearward, shorter cockpit. My Moto bar clamps are on a vertical clamp, angled straight up and away from the steering stem's rearward angle. These are both original bikes, bought from original owners, in original condition. The Moto has the OEM Tag bars, the Glamis has the OEM Magura bars. Once again, logic tells me it is the shorter cockpit though, cuz like I said when I pull up close to the tank on the Glamis it feels similar....