Front Wheel Pinch Bolt(s) Torque - 2011 V7C

[mthydro]

Would anyone happen to know what the torque setting is for the 2 pinch bolts on the right side of the fork? Would 7.37ft/lbs be correct??

Thanks!

[Perazzimx14]

Unless you have a calibrated "low value" torque wrench DO NOT try and torque them or your next post will be "how to remove a broken bolt". This is the same for 99% of the bolts and/or fasteners you will encounter. Simply snug the pinch bolts and call it a day.

 

[sib]

Unless you have a calibrated "low value" torque wrench DO NOT try and torque them or your next post will be "how to remove a broken bolt". This is the same for 99% of the bolts and/or fasteners you will encounter. Simply snug the pinch bolts and call it a day.

I totally disagree.  The above advice is for someone who doesn't know how to use a torque wrench.
I'm not sure about the 2011, but the '13 and later V7's call for 10 Nm (do your own conversion to whatever units you're comfortable with).  You do need a torque wrench with a scale that goes that low.  The trick with these cinch bolts is to tighten them EVENLY.  The same goes for unscrewing them.  Turn each a little at a time until they both reach the spec torque value.  It also is a good idea to use Loctite, not to keep them tight, but to prevent corrosion in the threads.  Finally, make sure that the hex (Allan) wrench bit is inserted fully into the bolt heads, to prevent stripping of the heads.

[John A]

Isn't the real problem cracking the fork leg? I'm not familiar with that particular bike but generally in that area I've seen no published torque values and if you use the torque for the fastener size you will probly crack the leg. Just snug them evenly

[malik]

Yes, the book says 7.37 ft lbs/ 10Nm.

[jpv7]

Just did mine to 10 Nm as Sib points out, and no problem.  Torque one, then the other, then come back to first. Easy really...

[Perazzimx14]

I totally disagree.  The above advice is for someone who doesn't know how to use a torque wrench.
I'm not sure about the 2011, but the '13 and later V7's call for 10 Nm (do your own conversion to whatever units you're comfortable with).  You do need a torque wrench with a scale that goes that low.  The trick with these cinch bolts is to tighten them EVENLY.  The same goes for unscrewing them.  Turn each a little at a time until they both reach the spec torque value.  It also is a good idea to use Loctite, not to keep them tight, but to prevent corrosion in the threads.  Finally, make sure that the hex (Allan) wrench bit is inserted fully into the bolt heads, to prevent stripping of the heads.

Pretty easy to use a torque wrench especially a "click" type. Set the value and then tighten fastener until there is a "click". Sometimes this is audible and other time its more a felt thing. The Problem is almost no one especially shade tree mechanics have a low value torque wrench. I have what most do a 1/2 drive click type that has a range of about 20 to 200 ft/lbs that is about 20 inches long. I can guarantee if I hold it at the far end and apply pressure with my finger tip I have exceeded 20 ft/lb of force on the fastener and it will not have come close to "clicking".

Your comment "The above advice is for someone who doesn't know how to use a torque wrench." actually applies to you to some degree. Torque values are always factored with the threads being "dry". If you lube the threads (yes Loctite will act as a lubricant when wet) the torque value is skewed.

[Phang]

The Problem is almost no one especially shade tree mechanics have a low value torque wrench. I have what most do a 1/2 drive click type that has a range of about 20 to 200 ft/lbs that is about 20 inches long. I can guarantee if I hold it at the far end and apply pressure with my finger tip I have exceeded 20 ft/lb of force on the fastener and it will not have come close to "clicking".

I have three, covering range from 6Nm to 200Nm (4.4 ft/lb to 147 ft/lb) but I still practice going by feel for torque settings at 10Nm (7.4 ft/lb) or lower.

[Chuck in Indiana]

Ed the Rocket Scientist told me that NASA did a study, and found the most reliable torque wrench on small fasteners was the hand of an experienced mechanic.
At any rate, be careful with dual pinch bolts.. especially with a torque wrench. After you torque the second, the first will be loose again. Then the second will be loose, etc.
Snug em up and call it good. It takes very little torque to do that job..just MHO.

[mthydro]

Thanks for the advice!

[sib]

Ed the Rocket Scientist told me that NASA did a study, and found the most reliable torque wrench on small fasteners was the hand of an experienced mechanic.

They sell lots of Helicoils to those folks.

[Chuck in Indiana]

They sell lots of Helicoils to those folks.

Naa, they're A&Ps. They'll not be reefing on an AN3..

[Lannis]

Ed the Rocket Scientist told me that NASA did a study, and found the most reliable torque wrench on small fasteners was the hand of an experienced mechanic.
At any rate, be careful with dual pinch bolts.. especially with a torque wrench. After you torque the second, the first will be loose again. Then the second will be loose, etc.
Snug em up and call it good. It takes very little torque to do that job..just MHO.

That's exactly right.   When it comes to dual pinch bolts, the "Must Use Torque Wrench" people are wrong, and they are the ones breaking the clamp metal, for the reason you mention.

A torque wrench cannot work with two bolts clamping the same connection.   You will literally snap the connection in two, and will not have exceeded the torque reading on EITHER bolt.

You have to have some mechanical sympathy, and not demand that both bolts be torqued alternatively by one torque wrench.    If there were TWO people with TWO torque wrenches operating simultaneously, it would work, but not otherwise.

Mechanical sympathy will also tell you that "just snug" is right for this job.   As people have found, the axle will stay in place and the bike can be ridden with the clamp broken completely away.   It's there only to keep the axle from moving and sliding, not to hold it against a load ....

Lannis

[Kev m]

Why wouldn't the two pinch bolts reach a point of equal clamp load if tightened alternately and evenly?

I would think the split on the fork would seat on the axle preventing further movement and therefore allowing equal clamp loads even if not tightened simultaneously.

Certainly I've never had a problem with one and I normally use one of my torque wrenches on such fasteners when specs are available.

For such a low range either the Craftsman inch lbs or more likely the Snap-On low range ft lbs wrench.

[Lannis]

I would think the split on the fork would seat on the axle preventing further movement and therefore allowing equal clamp loads even if not tightened simultaneously.

Maybe the fit on the axle isn't that great.   Maybe the metal is a little thin for the application.   

But it's scary when you use a torque wrench (like I did the first time I did it) and realize how far you are pulling those little bolts down, going from one to the other and one to the other and one to the other, never quite getting there ...

.... and then loosen it up and just snug the bolts down good, without a final going-back-and-checking.

It's no wonder some of them end up cracked.   There's no significant load on them from the road, no shock ... no reason for the fork to break other than too much tightening ....

Lannis

[Kev m]

Are you sure the ones that crack aren't the result of:

A. Bad technique - not alternating.

Or

B. Bad calibration on wrench?

[Lannis]

Are you sure the ones that crack aren't the result of:

A. Bad technique - not alternating.

Or

B. Bad calibration on wrench?

They could be.   I'm just giving my opinion (rather strongly) on what's happening to these bikes, based on "trying" to do it right, and in the process, realizing what was going on before I actually broke mine.

I can't change anyone else's mind; all I can do is testify that I'm trusting MY life to my judgment of what's going on there on those clamps.  I can't be more sure than that!!   

[Kev m]

Guess I'm looking at it from the point of view of the OEM or my day job when I actually write a repair procedure.

I can't see the OEM's purposely giving a spec (over and over on different bikes) that's impossible or dangerous to achieve.

I also don't understand how a pinch setup would physically work unless the clamping component would physically bottom on the shaft in question (axle) thereby allowing both to be tightened equally.

Mistakes may be made in casting, or bolt manufacturer, or maybe even spec, but more often than not it should be ok if using decent tools and techniques?

<shrugs>

That said I'm fully confident that MOST at home or in shops don't bother with the torque wrench anyway.

I especially love the torque values for non-critical fasteners that would require a crow foot adapter and some math, no way 99% of people are bothering with that...

[Lannis]

Guess I'm looking at it from the point of view of the OEM or my day job when I actually write a repair procedure.

I can't see the OEM's purposely giving a spec (over and over on different bikes) that's impossible or dangerous to achieve.

That sounds reasonable ... BUT (instead of going to bed which is what I usually do around this time) I went out to the shop and

1) Put a small (4") wrench on the bolts and tugged to make sure they're secure since the last time I installed them (8000 miles).   They are.

2) Took a go-nogo feeler gauge and slipped it into the gap between the two sides of the clamp, between the bolts.   .058" would go, .060" would not.   

So it's pretty obvious to me that if someone tried to make those two "mating" surfaces meet by pulling that 1/16" gap shut, they'd snap that bit of metal right off.   And nibbling down on it 7 foot pounds at a time from one side to the other would do just that, I believe ....  7 on this side, check the other.   Oops, it WAS 7, now it's 4, tighten to 7 check the other.  Oops it's 4.2, tighten to 7 check the other.   Oops it WAS 7 now it's 4.5, tighten it to 7 check the other.   I'll bet it asymptotically approaches 7 until the thing breaks.  At least that's the way it was headed when I did it.   I saw no end except pain.

BUT, absent a destructive evaluation of the fork, I can't really prove it, just throw it out there for observation, with Chuck's sort-of-agreement ... !

Lannis

[Kev m]

Someone correct me if I'm wrong but THE FEELER GAUGE tells us nothing.

The pinching occurs by creating interference between the inner diameter of the clamp and the outer diameter of the shaft.

The split line of the pinch doesn't have to and probably shouldn't join for there to be a measurable and even clamp load on the bolts.

[sib]

Kev, you can't argue with those folks.  Perhaps this forum should include torque wrenches in its no-no topic list, along with religion and politics (and maybe also include oil).

[Lannis]

Kev, you can't argue with those folks. 

Sounds like he's doing a pretty good job of it, though.   Certainly better than just making a snotty, dismissive remark and strutting away with one's nose in the air ....

Lannis

[Kev m]

Yeah it's just a discussion. I don't think we're taking it personally.

[Wayne Orwig]

More importantly, don't use synthetic oil in the forks.

[Lannis]

Yeah it's just a discussion. I don't think we're taking it personally.

I appreciate the insight from someone who's had to deal with "How It Is Done" for consumers.

I continue to think, despite the questions, that torque measurements are meaningful when the bolt you are torquing is snugged down against something solid, like bolting flanges to cases, bolting heads to cylinders, etc, and you are using torque as an indirect indication of bolt stretch.

But when you are NOT torquing against something solid, but every turn stretches the metal of the clamp and NOT the bolt, then torque doesn't mean much, at least not in terms of clamping pressure.

As to why it's like that in the manual ... perhaps legally they felt like they HAD to put something in there or they wouldn't be seen as taking enough care?    After I read my Centauro manual saying that I MUST (under penalty of some unspecified horrible thing happening) replace my entire drive shaft every 18,000 miles, I've looked at manuals with a different, more jaded eye ... 

Lannis

[sib]

...As to why it's like that in the manual ... perhaps legally they felt like they HAD to put something in there or they wouldn't be seen as taking enough care?...

If they applied that reasoning consistently, then one would expect them to have torque specs for the rear drive drain bolt and vent, which they don't.

[Lannis]

If they applied that reasoning consistently, then one would expect them to have torque specs for the rear drive drain bolt and vent, which they don't.

I expect Kevin could explain that better than I could.   Maybe you don't normally have torque values with the kind of crush washers they use?   I do know that there are some manifestly silly statements, like the drive shaft replacement, in owner's manuals.   Why they're not consistent, considering all the EU regulations they have to watch out for before exporting, I don't know.

At least we don't get "Beware the Skid Demon Lurking in Muddy Road" any more unless we buy a 1962 Benly ....

Lannis

[Kev m]

I wish I could explain it.

I suspect half of it is perceived liability and they know it's ignored.

[Chuck in Indiana]

A guy would have to be pretty anal to look for the torque specs on the rear drive vent.. yer not a beemer guy, are ya?
Ask the guys with the early Stelvio forks about torquing those pinch bolts..

[sib]

A guy would have to be pretty anal to look for the torque specs on the rear drive vent.. yer not a beemer guy, are ya?
Ask the guys with the early Stelvio forks about torquing those pinch bolts..

Call me anal, but I use the vent hole to fill my rear drive, as fill hole is pretty useless for this function.  I'm also anal to make sure I put in the correct amount of the correct oil.