75/7 steering head bearings and torque

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Peter Bowles
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75/7 steering head bearings and torque

Post by Peter Bowles »

Following my previous post, here’s the first of a whole barrage of things to come..

I’m just putting the steering head together and have a question about how much torque is needed on the top nut. (R75/7)

I’m finding that if tighten as hard as I think I should, I lose the smoothness in the arc of the steering bracket (the forks are still removed). It feels like how someone has previously posted about notching in the bearings and bearing races. Am I over tightening or is this just an indication of worn bearings? Whilst I’ve got this apart – should I just assume its worth replacing bearings and races?

Thanks
Duane Ausherman
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Re: 75/7 steering head bearings and torque

Post by Duane Ausherman »

There is no useful figure of torque. Do you know about fork alignment? You better, as you are approaching that issue.
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ME 109
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Re: 75/7 steering head bearings and torque

Post by ME 109 »

Duane, where has the link to your site gone?
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Airbear
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Re: 75/7 steering head bearings and torque

Post by Airbear »

Hullo Peter. If it is feeling lumpy (with clean, freshly-oiled bearings - temporarily for now) I'd replace them. That lumpiness is likely to lead to uncomfortable handling.

Replacing the bearings is not too hard and the bearings are cheap enough from your local bearing shoppe - take a sample. If you are going to proceed down that path let us know - there are some tricks worth knowing about removal technique.

And Duane is correct of course. Reassembling the forks and getting things right takes a bit of fiddling. It's also straightforward once you see how. Well worth reading about it on Duane's site.
Have a look here: http://w6rec.com/duane/bmw/forks.htm

ps: No torque and no play is what you are looking for with the steering head bearings. A good indicator is that the wheel falls to the stop at left or right with a slight push, but it moves kind of slowly because of the grease, if you get my drift. The steering head lock-nut needs to be tightly locked. Not sure of the torque - I just do it really tight.
Charlie
and Brunhilde - 1974 R90/6
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Peter Bowles
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Re: 75/7 steering head bearings and torque

Post by Peter Bowles »

So it looks like I'll be replacing the bearings and racers. I had always assumed that they were a specific bmw part, is it really possible to get them from an industrial bearing supplier? I don't want to scrimp on this project but very happy to find and use less expensive parts if they are up to the job.

I've read the previous threads about removing the races so will see how I go.
Chuey
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Re: 75/7 steering head bearings and torque

Post by Chuey »

Peter Bowles wrote:So it looks like I'll be replacing the bearings and racers. I had always assumed that they were a specific bmw part, is it really possible to get them from an industrial bearing supplier? I don't want to scrimp on this project but very happy to find and use less expensive parts if they are up to the job.

I've read the previous threads about removing the races so will see how I go.
Last year I bought some bearings from the dealer and they were $27.00 each, I think. (Edit) Oh, I see that I should say US dollars. Welcome.

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Airbear
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Re: 75/7 steering head bearings and torque

Post by Airbear »

I got mine from a bearing shop on the main street for $16.50 each. And that's OZ dollars.
Charlie
and Brunhilde - 1974 R90/6
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Graduate, Wallace and Gromit School of Engineering and Design (Pending)
Peter Bowles
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Re: 75/7 steering head bearings and torque

Post by Peter Bowles »

well thats certainly less spendy than the $60 each listed on Munich. And just found a set on ebay for $40 +pp including races and seals. mmmmm
Roy Gavin
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Re: 75/7 steering head bearings and torque

Post by Roy Gavin »

Going back to the original question, I have had mixed responses to tightening down the centre nut.

On my low mileage /7 the bearings were adjusted and the nut tightened to the 80+ ft lbs as per the book, no problems.

But on my well worn G/S forks tightening the nut changed the adjustment of the bearings, enough to, err, damage them beyond further use use.

The G/S had seen a lot of off road miles, fully laden, and the flat top plate was twisting and flexing, even with correct torque the centre nut would still loosen.

I dont have a welder to remove the bearings so I bought the bearing puller, and bearings, from Cycleworks, probably less for both the Munich is ask for the bearings alone.
There was no visible lip at the bearing so removal would have been impossible without the tool, or a welder.

I replaced the flat plate top yoke with a SJBMW billet top yoke - makes aligning the forks easier and doesn't flex as much as the old beat out flat plate - I tightened the nut to 55 lbs and it hasn't slackened off yet.
Adelaide, Oz. 77 R75/7. 86 R80 G/S PD, 93 R100 GS, 70 BSA B44 VS ,BMW F650 Classic
Duane Ausherman
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Re: 75/7 steering head bearings and torque

Post by Duane Ausherman »

ME 109 wrote:Duane, where has the link to your site gone?
When Matt came up with this new website, my old signature file disappeared. I imagine that there is some way to put it back on, but I don't have the time/interest just now. I had completely forgotten about it, thanks.
Ask the Indians what happens when you don't control immigration.
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