Sorting out the triple clamp jargon


12 replies to this topic
  • Deejdubya

Posted October 03, 2010 - 01:04 AM

#1

I thought I might revise and simplify my question. Are the 06-07 YZ450 triple clamps the same as the 08-09. Some clamps list the fit as 06-09, some as 06-07 and 08-09 and some list from 07-09. I want to put the Protaper 22.5mm offset on my 08 YZ450 but the only offsets I can find are listed for 06-07.:smirk:

Edited by Deejdubya, October 07, 2010 - 12:46 AM.


  • Guntoter534

Posted October 10, 2010 - 08:18 PM

#2

If your chaging the top and bottom clamps then you can use anything from 06-09. The 06 has a 25mm offset and the 07 22mm. If you get some new clamps i recommend the zipty racing set at a 17mm offset. going from 25 to 22 doesnt make much difference. Ive put the 07 stock clamps on a 06 if didnt help all that much. The 17mm made a huge difference

  • grayracer513

Posted October 10, 2010 - 10:48 PM

#3

The 06 has a 25mm offset and the 07 22mm.

This is inaccurate. The triple clamp offset from '98-'09 is all 25mm. Trail varies slightly on the '08+ due to changes in the axle lug. Clamp geometry of all YZ models '06-'09 is the same.

  • Deejdubya

Posted October 11, 2010 - 12:26 AM

#4

This is inaccurate. The triple clamp offset from '98-'09 is all 25mm. Trail varies slightly on the '08+ due to changes in the axle lug. Clamp geometry of all YZ models '06-'09 is the same.


Finally that's the info I was looking for. So you're saying if I had a 22.5mm offset clamp for a 06-07 the geometry is all the same in regards to outer fork tube diameter and width? I know they put a 5mm shorter steering stem in the '08 450. So hypothetically speaking, if I found a killer deal on the 22.5mm clamp for the '06-'07 I could just simply press out the steering stem and press in my '08 stem?

To address the other post: I have ridden the '08 with the 22.5mm offset and it makes a HUGE difference. 17mm would be FAR too short of steering geometry.

Thanks for the help guys. Yamaha Canada couldn't even tell that.

  • grayracer513

Posted October 11, 2010 - 08:43 AM

#5

Finally that's the info I was looking for. So you're saying if I had a 22.5mm offset clamp for a 06-07 the geometry is all the same in regards to outer fork tube diameter and width? I know they put a 5mm shorter steering stem in the '08 450. So hypothetically speaking, if I found a killer deal on the 22.5mm clamp for the '06-'07 I could just simply press out the steering stem and press in my '08 stem?

To address the other post: I have ridden the '08 with the 22.5mm offset and it makes a HUGE difference. 17mm would be FAR too short of steering geometry.

First two questions, yes, and yes. Be sure to press the stem down, out the bottom of the clamp. There is a wire stop ring that prevents it from moving up.

The more the offset decreases, the more the steering trail increases. 17's seem to be pretty popular with enduro/hare scrambles racers more than MX.

  • Deejdubya

Posted October 12, 2010 - 06:01 PM

#6

Thank you so much for the input. It's greatly appreciated.

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  • KJ790

Posted October 13, 2010 - 04:39 AM

#7

The reason why the 08-09 clamp sets are some times listed with a different part number from the 06-07 is b/c a shorter steering stem was used for 08-09. The difference is very small, and you can actually get away with the 06-07 steering stem on the newer bikes.

  • Mr. Neutron

Posted October 13, 2010 - 08:27 PM

#8

Whichever offset you choose, try to find some new clamps that have the pinch bolts in the same relative position & orientation as the stock Yamaha clamping setup. This is one area where a lot of suspension experts seem to agree that Yamaha got it right.....

Some aftermarket triple clamp sets have the pinch bolts oriented differently from stock, and even when torqued to, or slightly below spec, these clamps can actually torque the fork legs in various degrees off of parallel, causing some pretty good binding & stiction. The bike might corner pretty well, but likely won't behave too well in the types of trail/track junk where low speed impacts aren't taken too well...... :smirk: Just something else to consider when ya get new triples......

Jimmie

  • grayracer513

Posted October 14, 2010 - 06:54 AM

#9

Can you cite one such suspension expert who says that?

As a career technician/machinist I'm inclined to doubt that the orientation of the pinch bolts has much effect on anything. OTOH, a poorly made clamp could, or improper torque, but far more likely a matter of distorting the tube out of round than out of alignment, and far more likely a torque issue.

  • Mr. Neutron

Posted October 14, 2010 - 10:55 AM

#10

Yes, I can "sorta" find a suspension guy that would say that, G.R.. He's out of the suspension biz now. He still rides, does his own suspension, helps others with theirs, but now teaches an aviation program at the college level....... Out of courtesy, I will withhold his name. I hope you can understand that.

I understand, coming from essentially the same background as you, why you'd think that. I'm a machinist for aerospace, and found it kinda hard to wrap my brain around. The suspension guy I'm referring to has a fairly extensive aircraft background as well. The fact is that the forks DO distort somewhat when tightened, and we're not always able to control how they do distort. I'm not too certain that I fully understand myself why pinch bolts angled differently from stock, or in a different location, would tend to distort the fork legs off in a different plane from theoretical perfect alignment. Here's something he wrote in a post at another website, back in July of this year:

"In regards to alignment, I have one of the prototypes of the Motion Pro aluminum tool. It taught me a lot about triple clamps.

I never realized, nor did my well known clamp manufacturer realize, that properly tightening the lower clamp bolts will make the tubes NOT parallel.

I documented this years ago in posts here. The reason is that even at proper torque, the fork tube is slightly crushed, this alters the location of the tubes center depending upon where the pinch bolts are located. This couple of thou dimension change of the tube is amplified by the tubes length. You probably are thinking the tube clamps equally, crushing equally on account of the full circle pinch. My lower clamp bolts are on the aft side of the clamps, the threads are angled fwd about 30 degrees. This design when tightened, pulls the tubes center inward. To me the best bolt location and orientation, is with the bolts otbd, heads forward. While a bit uglier, and protruding for possible contact from a knee, it will however clamp the tube equally in a front to rear direction, not changing the alignment.

Take a look at some oem Jap bike clamps. Some have the bolts this way.

Also, after finding out that my forks can not be parallel when properly torqued, on my own stuff I have since started to run very low torques on the lowers and highers torques on the uppers.

BTW, yes this was a quality torque wrench, with a recent aerospace level of calibration."


Anyway, Grayracer, I put this out not to be argumentive, but just as something that probably has some merit. It is, however, one person's findings, & I realize that's not as conclusive as most would like. Noticeable in a real world situation? Maybe not, at least probably by most folks. But some guys ARE hypersensitive to stiction issues, and generally, mis alignment of the forks is a pretty consistent cause of that.......

Jimmie

Edited by Diesel Goober, October 14, 2010 - 11:11 AM.
clarify a point, hopefully....


  • grayracer513

Posted October 14, 2010 - 12:14 PM

#11

What's interesting about that is that Yamaha had the lower clamp bolts oriented as he suggests from some time prior to 1997 up until 2004. In '04, they were moved to their current position, behind the tube bore, with the bolt centers straight out to the side. The uppers on current YZ's, as well as those made as far back as at least '01, put the bolts on the front of the bore, also facing straight out.

In order for the center of the tube to move in any direction when tightened, the bore has to be reduced in size as the bolts close up. The direction the bore centers would drift does indeed depend on the orientation of the clamp split, but less on the split itself than on the position of the most dimensionally stable portion of the bore, that portion that is inflexible. The centers will drift toward this section as the diameter closes. Since the most fixed side of the bore is always the inner side, against the center of the clamp body, this virtually always means any center drift that would occur will be toward the steering head on a vector no wider than 10 degrees at most. The bore center in the example with the split on the outboard will do this the same as in the example with the split behind or in front, because the only way the bore can drift as it shrinks is from the flexible side toward the fixed side.

That said, as a machinist, how would you prevent this? The way to prevent inward drift of the centers is to prevent the root cause, which is the shrinkage of the bores from their machined size. Assume the true dimension of the fork tube is 50mm. The clamped closed diameter of the clamp assembled to the fork then would ideally be the same 50mm. So if the clamp is bored to 50mm, the clamp will actually need to be slightly opened in order to make the assembly, then be tightened to it's original finished size when torqued.

As far as crushing the tubes is concerned, I haven't been able to measure this effect amounting to any more that 0.0002" inch when limiting torque to the specified 14 ft/lb. That would cause a center drift of only 0.0001". Not a significant amount under any circumstance. Since the top clamp bears on a section of the outer tube that is bolstered from the inside by the presence of the fork cap or cartridge and base valve, it is very much less prone to crushing the tube than the lower clamp is, and if the tube were significantly distorted, that would move the fork ends toward each other, but always inward, and only if the tube was actually shrunk a significant amount by the clamp.

I can't account for the skewing of the forks in your expert's case, but I would suspect that the clamps were either damaged or suffered from a machining error.

  • Mr. Neutron

Posted October 14, 2010 - 06:15 PM

#12

Hi, Grayracer!

First of all, I probably need to apologize to the original poster. We sorta seemed to have hijacked his thread. The more I think about it, the more I realize I was probably wrong for mentioning fork misalignment from the "crush" of the pinch bolts inthis thread. It's more than likely pretty much a non-issue, really. I think that if the clamps are engineered well, and the machining is done correctly, there should be no problem with any triples. And hopefully, the Original Poster will find a decent set of aftermarket triples, and then have a YZ that corners as he'd like it to! :smirk:

The problems that brought the whole matter up were initially linked to KTM's White Power (WP) forks. I've read that there have been a few documented cases of "bad machining" with those forks, and their triples. I believe they (WP) have actually contracted out some of their fork machining out to a Japanese firm now, to rectify some of those problems. And big-time "Stiction" was what started the whole investigation......

The guy that brought all this up felt that Yamaha, at the time, had actually done the "best job" of keeping their forks moving in the right direction as it were, with their triple clamps.... And so it was with that I gave the "warning" about this in my 1st post here. Sorry if it confuses & hijacks. But, I really do like the discussion, and feel you bring up some really valid points, Grayracer....

Jimmie

  • Deejdubya

Posted October 15, 2010 - 02:22 PM

#13

Thanks again for the input all around. Coming from a hobby machinist background I can comprehend the points made. The only point I can come up with is that all the big name suspension companies sponsor supercross and motocross teams and in doing so supply them with appropriate offsets for their riders' style. If they are quality enough for the pros then why not for the average joe? If they can really affect stiction that much then race teams would be far less likely to use them. Either way coming from Hondas to a Yami this thing turns like an old Lincoln Towncar so a different offset is my next improvement.





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