Member Contributer bmart Posted April 27, 2022 Member Contributer Share Posted April 27, 2022 German good-n-tite method. Link to comment Share on other sites More sharing options...
Member Contributer Wald Posted April 27, 2022 Member Contributer Share Posted April 27, 2022 26 minutes ago, bmart said: German good-n-tite method. No, a good German always uses a torque wrench with +/- 0.001% accuracy! Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 8 hours ago, Wald said: No, a good German always uses a torque wrench with +/- 0.001% accuracy! And every bolt gets its own serial number! Link to comment Share on other sites More sharing options...
Member Contributer bmart Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 Bolt or bullet? They're trying that too! Link to comment Share on other sites More sharing options...
Member Contributer RC1237V Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 Wow, that bolt is special, it's 10 X 57 and cost $15.55 each. The 1200 has radial calipers as well, and uses a 10 X 67 and they are only $3.84 each... Link to comment Share on other sites More sharing options...
Member Contributer VFR78 Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 The Gen 8 bolts are tubular, so standard torque settings and stretch characteristics go out the window. Why are they hollow? Who knows, but there has to be a reason. Maybe it’s so they can flex under braking, just like aeroplane wings flex in flight and consequently they may fail over time. Everyone seems to be focusing on the threadlock treatment as the reason for replacing them, I can’t see that as particularly relevant, when it’s easily removed from the fittings, with a tap and die, and then replaced. I’m not suggesting they should or should not be replaced, just would like to know the rationale. Lawyers probably have an input, but there must be a concern, somewhere in Mr Honda, that they might fail after repeated stressing. There has to be more to it and it would be nice to know. Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 3 hours ago, VFR78 said: The Gen 8 bolts are tubular, so standard torque settings and stretch characteristics go out the window. Why are they hollow? Who knows, but there has to be a reason. Maybe it’s so they can flex under braking, just like aeroplane wings flex in flight and consequently they may fail over time. Everyone seems to be focusing on the threadlock treatment as the reason for replacing them, I can’t see that as particularly relevant, when it’s easily removed from the fittings, with a tap and die, and then replaced. I’m not suggesting they should or should not be replaced, just would like to know the rationale. Lawyers probably have an input, but there must be a concern, somewhere in Mr Honda, that they might fail after repeated stressing. There has to be more to it and it would be nice to know. Hi VFR78. I think there can be no doubt that Honda are protecting themself against litigation, especially given the vitally important job these bolts do, Honda can't afford to rely on good common sense and trade skills as these are not that common! Specifying a one use recommendation is there only sure way of covering themselves. Doubt you'd ever get a proper technical reason from Honda. Perhaps its over torquing and/or the rotational stress from radial mounted calipers under extreme braking conditions that might cause the stretching effect. The bolts being hollow might be to reduce unsprung weight and/or improve caliper heat dissipation. Each to their own, but the way I look at it is, if the bolts have never been over torqued, are closely inspected before installation for any sign stretching, and a small amount of Loctite blue 243 threadlocker is applied all should be fine. Can't say I've ever heard of a caliper jumping off its mount from properly installed bolts be they old or new, however, I'm sure someone will come back at me with an example! And YMMV. Link to comment Share on other sites More sharing options...
Member Contributer VFR78 Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 To add to the confusion, I compared the length of a new bolt, to a used bolt, using a digital vernier. The bloody new bolt was longer, go figure! Time to move on now, me thinks. Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 I've thought about drilling the heads and safety wiring the bolts rather than using thread lock, but never have gotten around to it. Unfortunately that's not an option on the SMC side caliper on LBS bikes. I sometimes cringe a bit at running a tap through the aluminum boss to clean out the old thread lock compound. It seems as though Honda could have designed the system so that bosses on the forks take the braking stresses directly and the bolts only retain the caliper to the boss rather than placing the forces on the bolts themselves. As pointed out though, I also don't ever recall of a failure due to a failed bolt or one backing out. Even if a bolt did back out it would be so obvious that anyone couldn't help but notice. But it takes just once . . . Link to comment Share on other sites More sharing options...
Member Contributer DannoXYZ Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 Don't use tap, thread-chaser better for cleaning existing threads. Most of load is carried on skin of bolt. Equation for torsional rigidity is 4th-power. So tiny increase in diameter increases strength tremendously. Going from 8mm bolt most commonly used on calipers to 10mm increases rigidity by 244%. To solve for loss of rigidity when hollowing out bolt, take torsional rigidity of bolt same size as hole and subtract from larger value of solid bolt. You'll see it actually loses very little being hollow. That's also why axles are hollow. And tubing used in trellis and bicycle frames are hollow. In fact, Ducatis are made from same Columbus chromoly tubing used to make racing bicycle frames. BTW, calculate tension on bolt from torque used, it's nowhere even close to yield-strength of material. In fact, it's well below fatigue-limit, meaning it can undergo infinite tightening/loosening cycles (SN) to spec torque without failure. Photo above of stretched Triumph bolt was obviously from over-tightening. Also came from land of warm beer because Lucas Electronics also makes refrigerators... Link to comment Share on other sites More sharing options...
Member Contributer DannoXYZ Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 Be careful about replacing steel directly with Ti in high-load structural applications. While yield and ultimate-strength of grade-9 3al/2.5v Ti is similar to 4130 chromoly steel, Ti has only 1/2 the rigidity (young's modulus). Meaning while both can take similar loads before breaking, the Ti will flex more under same loads. Ti's modulus is only 1/2 of steel regardless of alloy composition of either. So for same loads, Ti will bend twice as much! For something like radial caliper mounting where rigidity is important, I'd stay away from Ti. Applications using Ti would be specifically designed with material's properties in mind. In this case, if Honda was to use Ti bolts, they would probably use 12mm Ti bolts to account for its higher bending amounts. Link to comment Share on other sites More sharing options...
Member Contributer DannoXYZ Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 Seems like this is perfect application for belleville or Nord-lock washer. Link to comment Share on other sites More sharing options...
Member Contributer Wald Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 1 hour ago, DannoXYZ said: Also came from land of warm beer because Lucas Electronics also makes refrigerators... Still LMAO regarding this reference. I always refer to Lucas electrics as "prince of darkness". Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 8 hours ago, Cogswell said: It seems as though Honda could have designed the system so that bosses on the forks take the braking stresses directly and the bolts only retain the caliper to the boss rather than placing the forces on the bolts themselves. The radial callipers on my MT-10 are like that; the calliper has a recess that fits over a boss on the fork leg, and the bolts just hold the two together. Link to comment Share on other sites More sharing options...
Member Contributer Grum Posted April 28, 2022 Member Contributer Share Posted April 28, 2022 10 hours ago, Cogswell said: It seems as though Honda could have designed the system so that bosses on the forks take the braking stresses directly and the bolts only retain the caliper to the boss rather than placing the forces on the bolts themselves. Hi Cogs and Terry. The 8gen front caliper is the same. There are two locating collars that lock the caliper to the mounting boss, and the bolts, as suggested, retain the caliper to the boss. Picture doesn't show it too well! Link to comment Share on other sites More sharing options...
Member Contributer MaxSwell Posted April 29, 2022 Member Contributer Share Posted April 29, 2022 7 hours ago, Wald said: Still LMAO regarding this reference. I always refer to Lucas electrics as "prince of darkness". Me Too! I had a 1980 Triumph TR8. So I 've seen the Prince Of Darkness. Our British Car Club's moto was: "But when it runs!" Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted April 29, 2022 Member Contributer Share Posted April 29, 2022 1 hour ago, Grum said: Hi Cogs and Terry. The 8gen front caliper is the same. There are two locating collars that lock the caliper to the mounting boss, and the bolts, as suggested, retain the caliper to the boss. Picture doesn't show it too well! That is, IMHO, a much better design than earlier gens. But, they all seem to work. YMMV Link to comment Share on other sites More sharing options...
Member Contributer VFR78 Posted April 29, 2022 Member Contributer Share Posted April 29, 2022 2 hours ago, MaxSwell said: Me Too! I had a 1980 Triumph TR8. So I 've seen the Prince Of Darkness. Our British Car Club's moto was: "But when it runs!" Didn’t the TR6’s catch fire occasionally too. I’ve seen a bubbling bonnet before. Link to comment Share on other sites More sharing options...
Member Contributer MaxSwell Posted April 29, 2022 Member Contributer Share Posted April 29, 2022 19 hours ago, VFR78 said: Didn’t the TR6’s catch fire occasionally too. I’ve seen a bubbling bonnet before. I never heard of that happening in our club during my membership. And we had some fine TR6's among us. Before the TR8's introduction, TR6 would have been my choice among the two-seater ragtops available at the time. Link to comment Share on other sites More sharing options...
Member Contributer VFR78 Posted April 29, 2022 Member Contributer Share Posted April 29, 2022 1 hour ago, MaxSwell said: I never heard of that happening in our club during my membership. And we had some fine TR6's among us. Before the TR8's introduction, TR6 would have been my choice among the two-seater ragtops available at the time. Sitting in traffic on Chandos St, in Sydney, in the 70s. It also cracked a rear suspension arm, maybe because of our crappy roads. A motorcycle racing buddy, from a wealthy family. He moved on to a V12 E type 2+2 after that. Now that was a proper car!! Lost his life racing a Jota. Link to comment Share on other sites More sharing options...
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