Author Topic: Roll Design Bumpsteer Issue (Read 10876 times)

Allison#51 · « **on:** October 09, 2015, 01:38:00 PM »

Why is the Bumpsteer so bad on my roll design +3's with 400ex spindles? I can get the toe equal at extended and compressed lengths by spacing the tie rod ends down some but it toes way out in the middle of the travel no matter what.

2ndmoto · « **Reply #1 on:** October 10, 2015, 12:32:57 AM »

I never checked the toe on mine through the stroke, only at dry weight. Are you using a roll steering stem? I have called roll several times on different issues, never had any luck getting info. The girl who answers the phone is nice, but can never answer my questions. Always tells me Doug will get back to me...maybe in my afterlife.

I would check mine, but unfortunately it is several states away. Are you running any camber? Pretty sure these are supposed to be ran at 0' of camber

Best regards
- Jason

Allison#51 · « **Reply #2 on:** October 10, 2015, 01:16:54 AM »

Quote from: 2ndmoto;59673

I never checked the toe on mine through the stroke, only at dry weight. Are you using a roll steering stem? I have called roll several times on different issues, never had any luck getting info. The girl who answers the phone is nice, but can never answer my questions. Always tells me Doug will get back to me...maybe in my afterlife.

I would check mine, but unfortunately it is several states away. Are you running any camber? Pretty sure these are supposed to be ran at 0' of camber

Best regards
- Jason

I'm just running the stock stem. I'm curious if the roll or other brand stems are different. And I am running like 3/16" camber so I'm sure that is playing into it. That's the first I've heard that they're supposed to be 0' camber, I'm glad you said that! Thanks man.

havinnoj · « **Reply #3 on:** October 10, 2015, 10:45:42 AM »

I can't offer measurements as I'm not with my R's but I did set them up per Roll Design instructions. I run +3 Roll arms with 400ex spindles and a Roll stem and have not noticed much bump steer in the dunes.

2ndmoto · « **Reply #4 on:** October 10, 2015, 12:31:33 PM »

I am curious how you got negative camber? I am running a Lobo and I can adjust to 0' but no farther. The only way would be to remove the jam nut on the top heim. I have been looking for a heim with a longer threaded section so I can put a jam nut on the back side.

Anyways I brought this up before and I believe it was Sidcon that told me the roll front ends are designed to run at 0'.

Best regards
- Jason

Allison#51 · « **Reply #5 on:** October 10, 2015, 08:58:05 PM »

If anything I thought my heims were out pretty far to get the negative camber that I have. I feel like they won't have a lot of threads left if I set it at 0' but I could be wrong. I'll work on it tomorrow and snap some pictures. I thought most companies recommended setting it up with negative camber though. When I set that should it just be at ride height?

hontrx265r · « **Reply #6 on:** October 11, 2015, 01:09:22 AM »

Are you 100% its roll not jrd, or similiar? Are you cycling it with no shock, or is it within the actual range of travel?

Allison#51 · « **Reply #7 on:** October 11, 2015, 02:00:04 AM »

I actually went and worked on it tonight. I set it at ride height and found that I had more negative camber then I thought. I don't have a good angle finder so I used a square and measured to the top of the tire and it was about 1/2" so I reset the camber to 0 at ride height. I double checked with a two foot level first checking the rear tires for plumb then going to the fronts. Then I reset the toe to straight up. Went back and checked camber again. Most setup instructions will say to thread your heims in all the way then back each side out an equal amount of turns but my right side has to be out like 2 or 2 1/2 turns farther than the left to get the camber correct.. Kinda weird but everything looks good on both sides. Then I went back to checking Bumpsteer. Shocks are off. I have three washers spacing the tie rods down. I raised it up to the extended length of the shock and set the toe to straight up. Dropped it down to halfway through the travel and again it toed out but not as bad. This time it was 9/16" out before it was moving 13/16". Dropped it down to the compressed length of the shock and the toe measurement returned to straight up.

Allison#51 · « **Reply #8 on:** October 11, 2015, 02:13:19 AM »

This is where the heim has to be to achieve 0' camber at 7 1/2" frame height. It's threaded out pretty far. There is a little over 3/4" of threads in the arm

2ndmoto · « **Reply #9 on:** October 11, 2015, 02:28:34 AM »

You might have a mixed set of arms. Bottoms are too long or tops are too short. Measure and post them to check against what others have. Mine are threaded all the way in and I have 0'. You are fine with that much thread, there is not that much radial loading being applied on to the threads on the top ball joint.

Also have you measured center to center on your tie rod ball joints? Pretty close on right and left?

hontrx265r · « **Reply #10 on:** October 11, 2015, 11:16:43 AM »

I noticed you are not running roll tierods and oem rod ends. That is most likely the first issue. I have found on mine washers make it worse. I would compare you misalignment height to an oem and start there as a base. I have a narrow frame but my bump steer is almost none. It just barely toes in at full bump.

Aceman · « **Reply #11 on:** October 11, 2015, 11:20:55 AM »

What offset are your wheels? Are you running spacers? The closer you can get the centerline of your tires over those heims the less bumpsteer you'll have. Basically, the farther your tires get from the steering pivot point(the heims), the more the tires act like levers when you're trying to steer.

Allison#51 · « **Reply #12 on:** October 11, 2015, 01:14:46 PM »

Quote from: 2ndmoto;59716

You might have a mixed set of arms. Bottoms are too long or tops are too short. Measure and post them to check against what others have. Mine are threaded all the way in and I have 0'. You are fine with that much thread, there is not that much radial loading being applied on to the threads on the top ball joint.

Also have you measured center to center on your tie rod ball joints? Pretty close on right and left?

Upper is roughly 12" from center of the front bolt to the end

Lower is roughly 16" from center of the bolt too the edge of the spherical bearing cup. And the tie rods are pretty close to equal lengths.

Allison#51 · « **Reply #13 on:** October 11, 2015, 01:19:19 PM »

Quote from: hontrx265r;59718

I noticed you are not running roll tierods and oem rod ends. That is most likely the first issue. I have found on mine washers make it worse. I would compare you misalignment height to an oem and start there as a base. I have a narrow frame but my bump steer is almost none. It just barely toes in at full bump.

I have quite a bit of adjustment with the spacers on these I can go either taller or shorter than stock. I'm pretty close to the stock ends height right now but I am gonna play around with it a bit more.

Allison#51 · « **Reply #14 on:** October 11, 2015, 01:20:24 PM »

Quote from: Aceman;59719

What offset are your wheels? Are you running spacers? The closer you can get the centerline of your tires over those heims the less bumpsteer you'll have. Basically, the farther your tires get from the steering pivot point(the heims), the more the tires act like levers when you're trying to steer.

They are 4:1s no spacers.