Steering head check

[grossohc]

I have my petrol tank off at the minute and thought i may as well check/ adjust my steering head bearings. I measured the very thin adjusting nut at 32mm (is this a special tool), when i take the upper cap off what should i torque the nut to . has anyone done this before.

Gary

[Paul Minnaert]

I think you can only feel if the bearings are right, if tou take the fork legs off, at least the wheel out. The 32 mm isn't special, it's supposed the the top clamp is gone when adjusting, then there is room for a normal tool.

 

This what you do on feeling, if there is no play at the moment it's right. If not then adjust it until it feels not free frotating, and then slightly back.

[pete roper]

I have my petrol tank off at the minute and thought i may as well check/ adjust my steering head bearings. I measured the very thin adjusting nut at 32mm (is this a special tool), when i take the upper cap off what should i torque the nut to . has anyone done this before.

Gary

 

 

 

Gary. There is effectively no special torque. The book may specify one but since steering stems tend to get dust and grit on the threads any 'true' torque figure is unlikely to be accurate. Also does a book specified torque apply to just the yokes in the frame? or the yokes plus fork legs? Or the whole lot with the wheel in place? The greater the weight on the yokes the less effect a specific torque will have as turning the nut will mean lifting more weight so resistance will be greater.

 

The way to check head bearings is very simple. Get the front wheel off the ground by lifting the bike under its sump. Grab the bottom of the fork legs and try and pull the forks back and forth so the steering stem tries to rock in the headstock. There should be no discernable play. Then swing the handlebars and therefore the forks from lock to lock. There should be no notchiness or roughness and the forks should fall under their own weight, just, with the steeing damper disconnected.

 

The commonest form of wear in steering head bearings is for them to wear a 'notch' in the straight ahead position. If you have to exert more than the slightest nudge to the bars to get them moving or worse still if they try and drop back to the 'Straight ahead' position or 'Index' anywhere then they need replacement.

 

If you get a rocking movement at the head stem when you move the forks back and forth you can try to remedy it by simply tightening the adjuster nut to take out the play. Just turn it clockwise and keep checking the forks will go lock to lock. If they start to feel *tight* you've gone too far. If they start to *index* at any point? They need replacing. If you can't remove all the play from the stem and the headstock before the spanner offers more than a few ft/lbs resistance then there is an issue and the bearings need replacement.

 

Unless they've changed them big-block head stem bearings are #30205's and cost about $15 a piece. If in doubt? Throw 'em away and get new ones.

 

Pete

[Guest ratchethack]

Wot Pete said. The following may add something -- or not?

 

There are nice specialty 32 mm open-end wrenches of ~2mm thickness designed specifically for bicycle headsets, which allow headset bearing adjustment without taking off the top triple clamp. I got one from a local bicycle shop on the recommendation of someone on this Forum from Park Tool, USA that works like a champ.

 

From a post I submitted on this under an unrelated topic way back last April:

 

On p. C 15 of my Guzzi Service manual, it has STEERING ADJUSTMENT instructions, with a nice photo and letters for parts in sequence of a procedure.

 

The "critical part" of the 4-bullet procedure is:

 

"Tighten or unscrew the adjustment nut "C" until the backlash is correct."

 

Any guesses how many possible interpretations of "backlash" can be imagined here by backwards translation into Italian?

 

One might assume that since there's no torque spec'd., that zero torque is called for. I ain't prepared to make that assumption -- but that's just me.

 

Tapered rollers have been industry standard in steering heads for about 30 years now and they’re pretty much all the same WRT maintenance and adjustment. The following is a generic write-up for Harley cruisers, though it’s hard to conceive how it wouldn’t apply to V11’s.

 

It’s a pretty good write-up and it’s lengthy (the link is gone now) but the gist of it is this:

The bearings must be preloaded to the manufacturer's specifications. In some cases that means tightening the nut to some initial torque, backing it off and then resetting it to the suggested preload. If no specs are provided or they seem vague, you'll need to use a little Kentucky Windage. Using moderate pressure, bottom the adjusting nut until the steering stem starts to bind. Rotate the steering stem back and forth a few times, then back the nut off half a turn. Repeat the tighten, turn, loosen cycle several times, always turning the steering stem from side to side. For the final adjustment, draw the nut up snugly and then back it off a turn. Don't be too concerned if the stem feels a little tight at this point—it'll free up as you install the rest of the front-end parts.

This all seems to make pretty good sense except for this sentence - "For the final adjustment, draw the nut up snugly and then back it off a turn." Now backing it off a FULL TURN afterward is beyond me, and I seek further guidance from higher expertise for an explanation?! If I did this, it would NOT feel at all "tight", it'd be er, loose as a goose (so to speak), and have an audible clunkiness and easily felt play that I wouldn't want any part of!!!!

 

In any case, on most of a dozen bikes (all the ones I've owned with tapered rollers), I've always used the manual spec'd ~20 lbs-ft, torque and left it right there without backing off any. This is also wot's spec'd for my XT600.

 

On th e Guzzi, with the wheel off the ground, at ~20 lbs-ft., and with damper backed off, the bars flop against the stops anywhere past halfway there from straight. When I put more torque on the adjuster nut -- I'm figuring around 25 lbs-ft. -- cycle it a few times, loosening and tightening between cycles, it shows a tad more resistance to turning, but will still flop against the stops on its own within 10 or so degrees of the stops, either side.

 

Hope this helps.

[dlaing]

Don't forget to loosen the triples before taking out any bearing freeplay.

I tighten upper triples with my weight and the bike's weight bearing straight down.

[Guest ratchethack]

Don't forget to loosen the triples before taking out any bearing freeplay.

I tighten upper triples with my weight and the bike's weight bearing straight down.

CORRECTION:

 

Using a headset wrench, the only thing necessary to loosen for steering head adjustment beforehand is the top steering head pinch-bolt. That's the center one in the top triple clamp.

 

Why (or even how! ) anyone would ever as much as think about "loosening the triples", and then attempt to tighten them whilst sitting on the bike in order to adjust the steering head bearings is beyond me, but I'm sure we're less than hours away from the full "cosmic rationale". . .

 

Y'all might want to pull up a chair, 'cause this oughtta be... er, somewhat amusing. I'm goin' to bed. zzz.

[dlaing]

CORRECTION:

 

Using a headset wrench, the only thing necessary to loosen for steering head adjustment beforehand is the top steering head pinch-bolt. That's the center one in the top triple clamp.

 

Why (or even how! ) anyone would ever as much as think about "loosening the triples", and then attempt to tighten them whilst sitting on the bike in order to adjust the steering head bearings is beyond me, but I'm sure we're less than hours away from the full "cosmic rationale". . .

 

Y'all might want to pull up a chair, 'cause this oughtta be... er, somewhat amusing. I'm goin' to bed. zzz.

You could be correct about not needing to loosen the triples.

I'll look into it and get back to you in a few years...

[grossohc]

Thanks for all the info, did a check and no adjustment required

Gary

[BrianG]

It has been my understanding that ball bearing require preload to create the necessary elipitical small contact patches of the balls in the groove of the race(s). This preload is dependent upon bearing size. If the preload is applied excessively, Bearing Fatigue Life will be short and will increase raceway noise as well. Bearing starting and running torque will also be high. If the applied preload is insufficient, fretting corrosion can occur. This happens as a result of vibration causing the balls to resonate and abrade on the raceways. Therefore, obtaining the correct preload is very important.

 

It has been my understanding that roller bearings must avoid axial loads, and thus require zero preload.

 

It has been my understanding that tapered roller bearings are a design compromise between the two previous types require light preload. Only enough to create a mild elastic compressive distortion, to positively locate the rollers in their races. This creates a very rigid bearing that resists displacement, and runs very true.

 

I have generally used an old Honda preload method to accomplish "enough" tapered bearing preload. The exercise is to load the steering stem nut enough to result in a 4 lb. ft. resistance to steering stem turning. I do this by hanging a 4 lb weight on a cord, over a pulley, attached to a lever running across the fork leg clamps on the lower triple clamp, 1' from the center of the steering stem. This is simple and effective for a double tapered roller bearing steering stem assembly.

 

You want some fun..... figure out how to preload an old VFR steering head, with a tapered roller lower and a ball bearing upper!! <_>

[dlaing]

This article compares tapered and ball in a Honda ST1100

http://home.insightbb.com/~mmartin36/Taper.htm

It was a little unclear but I read it to indicate 3.3 to 4.4 lb torque for tapered and 20 foot pounds for ball.

I usualy use about 1 to 3 foot pounds, but I do it without ropes, weights or torque wrench, so accuracy is not present.

I think Brian makes a good point and 4 foot pounds may be more appropriate.

And Pete made a good point or two about the problems associated with measuring torque.

[BrianG]

This article compares tapered and ball in a Honda ST1100

http://home.insightbb.com/~mmartin36/Taper.htm

It was a little unclear but I read it to indicate 3.3 to 4.4 lb torque for tapered and 20 foot pounds for ball.

I usualy use about 1 to 3 foot pounds, but I do it without ropes, weights or torque wrench, so accuracy is not present.

I think Brian makes a good point and 4 foot pounds may be more appropriate.

And Pete made a good point or two about the problems associated with measuring torque.

 

When you think about it, steering-head stem nut torque values are worse than valueless unless this value is attached to a particular motorcycle. The value at question is "bearing preload". Stem-nut torque translates to bearing preload by the multiplication factor of the steering stem thread pitch. I have seen much variation in steering stem thread pitches.

 

I think the upshot of this discussion is to go one of two ways for tapered roller bearing equipped steering heads:

 

FACT = Tapered roller bearing equipped steering heads REQUIRE some preload.

 

Near enough estimate = torque the steering stem nut enough to slightly restrict the turning of the triple clamp.

 

Measured estimate = torque the steering stem nut enough to create 4 lb ft torque resistance to steering head movement.

 

Note........... both are estimates of the required values.

[Guest ratchethack]

Brian, as discussed "way back when" when you did your "Rube Goldberg" ropes and pulleys torque measurements, and I used a ball-point pen retractor button to detect actual changes in resistance to turn at the bar-ends at different torques on the adjuster nut, I b'lieve your assessment is still right on target. With ~20 ft.-lb on the adjuster nut and the front wheel off the floor, my fork will freely flop against its stops with next to no resistance felt at the bars. My experience has been that when torqued up another ~5 ft.-lb., it just starts to have a perceptible effect on resistance at the bar ends. I reckon that ~20 ft.-lb is about right, and that +/- ~5ft.-lb ought to be an acceptable operating tolerance.

 

If anyone's inclined to be squeamish about putting this much torque on a headset, imagine the combination of axial and radial loads at the bearings through the wedge effect of the races when the bike is fully loaded, underway, and it hits a square-edged bump full-wallop, that brings the fork to its full compression stroke, and then consider that those forces must spike up by at least two or three orders of magnitude or more over the forces when the bike is at rest with the wheel off the ground -- with no ill effects (by design), and well within operating tolerances.

[BrianG]

Brian, as discussed "way back when" when you did your "Rube Goldberg" ropes and pulleys torque measurements, and I used a ball-point pen retractor button to detect actual changes in resistance to turn at the bar-ends at different torques on the adjuster nut, I b'lieve your assessment is still right on target. With ~20 ft.-lb on the adjuster nut and the front wheel off the floor, my fork will freely flop against its stops with next to no resistance felt at the bars. My experience has been that when torqued up another ~5 ft.-lb., it just starts to have a perceptible effect on resistance at the bar ends. I reckon that ~20 ft.-lb is about right, and that +/- ~5ft.-lb ought to be an acceptable operating tolerance.

 

Good info!

 

If anyone's inclined to be squeamish about putting this much torque on a headset, imagine the combination of axial and radial loads at the bearings through the wedge effect of the races when the bike is fully loaded, underway, and it hits a square-edged bump full-wallop, that brings the fork to its full compression stroke, and then consider that those forces must spike up by at least two or three orders of magnitude or more over the forces when the bike is at rest with the wheel off the ground -- with no ill effects (by design), and well within operating tolerances.

 

+1 - some preload is critical to achieve appropriate assembly rigidity.

[Jazzamoto]

Can anyone tell me how to remove the silver cap that covers the top steering head pinch bolt on a 2004 Cafe Sport? I've loosened the top triple clamp bolt as per the service manual but can't remove the cap.

 

Thanks!

[docc]

You're speaking of the center chrome cap in the top of the headset shown just left of the Agostini key fob?

Gently slip something thin under its edge and pry it up being careful not to scratch the surfaces. There is a hex drive under that, as I recall.