Steering Head Bearings

[Guest danhunt56]

Hey:

 

I bought my Scura last October off of Ebay and riding it out of the shipping terminal I emediatly noticed it was wandering about. It pretty much went away as I got above 30 mph. I loosened everything up and bounced the front end and that seemed to align everything and it seemed fine, sort of. Loaded up the bike and took it down the pacific coast to California to visit friends and family and with the load it was wandering again at slow speeds. Through the winter I was busy and did not ride much and did not get around to doing any more about it. Last week I reset all the setting in the suspension and found the rear shock compression was 26 clikcs out instead of 15 and this made a world of difference in the handling , much more like my brother's M. Roso, but now it seemed to actually lock up the steering at slow speeds. So, I decided to check out the bearings in the Steering head and found them to be washed pretty much clean of grease and very rusted and pitted. Now with new bearings and grease it is like on rails in highspeed sweepers and is steers quicker and feels more nimble at slow speeds.

But now I have a new problem, doing a long pass on a two lane just as I hit 100 miles an hour the front end began a slow shimmy or wobble... I know it was a hundred cause the gps indicated that the highest speed was now 101 mph. It was a gentle wobble so I just backed off a little and completed the pass... So I was thinking maybe I did not get the head bearing tight enough. I used a large fat adjustable while putting it together, to make fine adjustments now would require a very thin wrench, like those used for biciycle work on the cranksets... My question is does anyone know what size wrench the nut takes and two do you think I am on the write track with this. I had the steering stabalizer crank completly off. Also the steering stablilzer seems to have a lot of stiction when I was playing with it while putting the fork back together. It is an ohlins, seems like if anything that would keep it from wobbling like the locked up bearing did. I think I put the tubes in exactly as they were before, niether higher nor lower in the tripples. Anyhow any advice would be apreciated.

 

And by the way, I have been lurking here on and off since last October, this is my firest post.

 

Thanks,

 

Daniel

[stogieBill]

Daniel,

 

Based upon similar discoveries I've made on my 2002 Scura (and other '02 MG's), I'd have to recommend a through greasing of all bearings, fitting and joints where grease could have been omitted. It probably was.

 

Must have been when Luigi was supervising the assembly line.

 

Happier trails.

[Guest ratchethack]

Dan, congrat's on getting y'er steering-head bearing problem diagnosed and fixed.

 

The adjuster nut is 32 mm.

 

Unless you fab up a custom wrench, or happen to have an ultra-thin specialty wrench on hand, the top triple clamp has to come off for access. If you find one available somewhere, please do advise! The bearings are properly set under tension. I do mine by hand and go probably ~20 ft-lbs., maybe Pete or Greg has an exact number - but I'll bet they do it by hand too.

 

Just a possibility - but it could be that your new bearings have settled in against the steering head in the frame and need re-setting. A good check is to get the front wheel off the floor, grab it from the front and shake it, feeling for any fore-aft play. Any play at all detected, it's too loose.

 

This is just me, but I'd never consider riding above about 60 mph without steering damping dialed in. Not only is this good insurance against the onset of tank-slappers and speed weaves, but to me it just feels better and tracks much more accurately. I generally use more damping the higher the speed and rougher the road. Your Ohlins steering damper should NOT be contributing ANY stiction to your fork rotation whatsoever. If it does, it's broken. It should ONLY be contributing damping according to the setting.

 

This is just me (Part II), and I know I'm a broken record on this , but I always put suspension setup at the top of the priority list on any new bike. The stock springs on V-11's are notoriously WEAK, unless you weigh in the neighborhood of 125-150 lbs.... I'm no heavyweight at 190 lbs with fully armored leathers and riding boots, but I went up-rate on fork springs by 50% to get my sags in the correct range. If you're heavier than this and riding on the stock fork springs, which I estimated at .6 kg/mm, you're riding around on the air spring at the end of fork travel and this is a HARSH ride! It's also distorting your chassis geometry, decreasing ground clearance, and throwing all the optimal range of dimensions for correct handling out o' whack. Without springing your Guzzi correctly, you have ZERO chance of achieving the superb (IMHO) handling the chassis is designed for and capable of.

 

Poorly sprung suspension and improper setup is the root of many a handling problem, IMHO - including headshakes and speed weaves. And let's face it - most riders these days don't seem to give it much of any thought whatsoever.....

 

The general sequence in setting up the chassis is:

 

1. Install springs properly matched to riding load.

 

2. Using spacers in the fork and preload adjustment in the rear, set BOTH laden and unladen sags at each end to your target range objectives, according to your weight and riding style. Set the AIR GAP in the fork (I use 100 mm).

 

3. Tune your suspension action to suit your riding style and road conditions using compression and rebound damping adjusters.

 

NOTE: Unless you do #1 first, attempting to do #'s 2 and/or 3 provides about the same benefit as whistling in the wind. . . . . .

 

There's a pretty good site here that's a useful guide IMHO:

 

http://www.strappe.com/suspension.html

 

I'd do a little reading and don't omit UNLADEN SAG SETTING (aka static sag) along with LADEN SAG SETTING. The woods are full of misinformation and outright disinformation! I recommend DO NOT use any guide that ignores UNLADEN (static) sag in the procudure.

 

A general rule o' thumb on sag settings is that LADEN SAG should be 25-33% of total travel (both front & rear) and UNLADEN SAG should be 15-20% of total travel (both front and rear). It's impossible to achieve both in range without properly matched springs, and NO amount of preload can ever make up for weak springs. Your target sag settings at both ends should be as close to the same as you can get. Getting it right literally transforms the bike. The results are magnificent, a thing of beauty, and a joy forever.......

 

Hope this helps & Have fun!

[dlaing]

The bearings are properly set under tension.  I do mine by hand and go probably ~20 ft-lbs., maybe Pete or Greg have an exact number - but I'll bet they do it by hand too.

92512[/snapback]

Pete, Greg, or someone else would know better than I, but I think 20 foot pounds is too much.

I set mine just till snug. Once it is snug there should be no freeplay....but I suppose bad threads could mislead.

Ideally, I lift the wheel in the air and move the steering back and forth to make sure it is not too tight. Snugging it till steering resistance is felt and then backing it off a little, I believe gives the best result.

[Guest Nogbad]

Snugging it till steering resistance is felt and then backing it off a little, I believe gives the best result.

92518[/snapback]

That's the way I've always done it anyway.

[BrianG]

Are the head bearing ball-type or tapered rollers?

 

Ball type are set to 0 (zero) preload. (and zero play)

 

Tapered-roller type require preload. (20 lbs should be close)

[Guest ratchethack]

Thanks, Brian. They're tapered rollers.

[BrianG]

LET'S AMMEND THAT TORQUE VALUE FOR THE STEERING HEAD BEARINGS.

 

Honda's recommended setting for their tapered-roller type steering head stem nut is 15 lb.

 

20 lb. might make things a tad sluggish.

[Troy]

RE Thin 32mm Wrench

 

Ratchet wrote in post #3:

 

"The adjuster nut is 32 mm.

Unless you fab up a custom wrench, or happen to have an ultra-thin specialty wrench on hand, the top triple clamp has to come off for access. If you find one available somewhere, please do advise!"

 

Here's a thin 32mm wrench on sale for $8.00. It looks like 8-side, but one might grind the back out to make it 6-side.

 

http://www.icyclesusa.com/catalog/new/park...dset-wrench.htm

 

Troy

[Guest ratchethack]

Here's a thin 32mm wrench on sale for $8.00.

http://www.icyclesusa.com/catalog/new/park...dset-wrench.htm

Hey Troy, somehow it never dawned on me to check a bicycle tool supplier.

 

However,

 

I tried to add the wrench to my "cart" 3 times in an hour and the Icycles site wouldn't take my order.

 

Of course, at the "CONTACT US" link, there's no phone number, just FAQ's. The only to way contact them is via e-mail. MAN, I hate that!

 

I'll be checking with the local bicycle folks.

 

Many thanks for the great suggestion!

[Guest danhunt56]

Thanks Troy, the bicycle wrench was exactly what I was gona try and you go and find me one on sale even... Ratchethack, I did not have any problem ordering mine although finding the cart was not quite as obvious as the usual.

 

Also I checked out the spring rate on the stock Ohlins and it is for a 170 to 190 lb rider, I am 170, but with gear closer to 190. Add anything else as I usually do and the set up would be a little soft. When things settle down work wise I will talk to an Ohlins dealer and see about upping the spring rates on the shock and fork and maybe having a remote preload adjuster added to the shock. Right now I am pretty happy with the feel of the bike, except for the wobble thing, so there is no hurry. Still need to set the preload, I am using the factory suggustions for preload till I get the time to even ride the thing.

 

And I rechecked the steering stabilizer and there is no initial stiction now.

 

Thanks to all for your comments and suggestions.

 

Daniel

[Guest ratchethack]

. . . . I checked out the spring rate on the stock Ohlins and it is for a 170 to 190 lb rider, I am 170, but with gear closer to 190.  Add anything else as I usually do and the set up would be a little soft.  When things settle down work wise I will talk to an Ohlins dealer and see about upping the spring rates on the shock and fork and maybe having a remote preload adjuster added to the shock.  Right now I am pretty happy with the feel of the bike, except for the wobble thing, so there is no hurry.  Still need to set the preload, I am using the factory suggustions for preload till I get the time to even ride the thing.

 

And I rechecked the steering stabilizer and there is no initial stiction now.

Dan, reading your post, I just tried the Icycle order again - no go. . . . I give up.

 

It wasn't clear to me that you had Ohlins forks. It HAS been clear to me that the Ohlins forks that come from Mandello have springs in the neighborhood of 50% higher rate than the Marzocchis.

 

The difference in spring rates between the Ohlins and Marz forks has created a horrendous confusion for many years that many still seem to suffer from. It's resulted in many Marz fork owners making the assumption that the Marz fork is "crap", causing many to "throw the baby out with the bathwater" and ditch them altogether by replacing the entire fork with an upgrade to Ohlins, or having the entire fork rebuilt and re-valved (which of course includes new up-rated springs) - when a simple re-spring would be 99% of the solution, IMHO. . . . . But to each his own. . . . . IMHO, the Marz forks have been and continue to be grossly and unfairly underrated due to this confusion.

 

I reckon you're just about exactly where you need to be with spring rate according to Ohlins.

 

BAA, TJM & YMMV

[Guest danhunt56]

Dan, reading your post, I just tried the Icycle order again - no go. . . . I give up.

 

REI has bike wrenchs for about 12 bucks.

 

I have never ridden on a bike equipted with Marz forks, my brothers Roso Mandolo has Sachs, I think, which feel pretty much the same as the Ohlins, though I think he has them set up too stiff in some way. But he likes it and won't touch it.

 

Thanks, Daniel

[docc]

The Sachs would be the rear shock. Bikes with the Sachs rear have the Marzocchi front forks.

[Troy]

Dan, reading your post, I just tried the Icycle order again - no go. . . . I give up.

 

If you have any patience left for ICYCLESUSA, they have another 32mm wrench near the end of Closeouts, page 2, for $4.99.

I can get to it from the homepage, ( http://www.icyclesusa.com/ ), by searching on ( X-Axis Headset Wrench ) and choosing option 121B for the 32mm size.

Troy