Paul I agree with you that Nitto designed approx 1mm clearance for the hex nut to shelf. I also agree it's a marginal design, and could be improved, but it does work.
I should have cautioned Leah to look for 'excessive play' in the nut to shelf which allows the nut to almost rotate fully. Alternatively, one could use feeler gauges to verify the play. John Hawrylak Woodstown NJ On Friday, June 26, 2020 at 11:56:49 PM UTC-4, Paul Brodek wrote: > > The nut likely will not fit tightly against the shelf on a new replacement > stem. That's not how it's designed. I've wrenched hundreds, owned dozens, > and every one of them was exactly the same. You've got about 1mm of space > between the top of the nut and shelf/ledge, which allows the nut to rotate > slightly. That is how they're made. > > Paul Brodek > Hillsdale, NJ USA > > On Friday, June 26, 2020 at 3:02:36 PM UTC-4, John Hawrylak wrote: >> >> Leah >> >> You should not be left holding the bag on this. I suggest contacting >> RBW, struggling or not, and see what they can do for you. RBW and Soma are >> not at fault if the stem did not meet design, but RBW or Soma should step >> up and see what they can do for you. Soma seems to be not responding very >> well, so it's time time to ask RBW . >> >> I think we would all like to now why this happened and Nitto is the only >> one who could do it, since its their product, their design. >> >> When you buy the new stem, please inspect it very carefully for tight fit >> of the hex nut to the shelf/ledge and also ensure the interior of the clamp >> is clean and smooth, with no signs of gouging or any visible burrs existing >> above the surface. >> >> John Hawrylak >> Woodstown NJ >> >> On Friday, June 26, 2020 at 1:49:19 PM UTC-4, Bicycle Belle Ding Ding! >> wrote: >>> >>> Thanks, Rob. I’m pretty small potatoes, but I’m flattered that you think >>> I have a social media presence. 😊 >>> >>> Paul, I know, I feel conflicted, too. I really should talk to Riv but >>> can’t bring myself to do it. I ordered the stem at a time that Riv was >>> struggling and needed business. Instead of getting it through SomaFab, I >>> had Riv order it. I just can’t make them handle it! I’v gone to Soma, and >>> if the Soma route doesn’t work, I’ll be spending another $130 on the same >>> stem, I suppose (when it comes back in stock). And what of my bar? I have >>> to hope it’s not compromised from the damage the stem inflicted. Sigh. >>> >>> I know user error could certainly be a factor here, but honestly, I >>> doubt if I’m capable of over-tightening a bolt. And it’s pretty >>> straightforward how to clamp stem to bar, so I am confident I did that >>> right, too. Unbelievable as it is, I think it’s just a faulty stem. >>> >>> It’s 2020 - we’re used to being disappointed! >>> Leah >>> >>> Sent from my iPad >>> >>> On Jun 26, 2020, at 9:47 AM, Paul Brodek <pcb....@gmail.com> wrote: >>> >>> >>> Having been in the bicycle components business, I'm a little out of >>> sorts thinking about how to address this post. >>> >>> I'll start out by saying that I think Nitto is one of the best parts >>> mfrs in terms of design, QC and attention to detail. >>> >>> I'll also say that I've used Nitto stems with this design for decades, >>> both on my own bikes and hundreds/thousands of builds/repairs, and never >>> seen this happen before. There has always been enough space between the nut >>> and ledge to allow slight rotation of the nut. But I've never seen the nut >>> as much as score the ledge, much less wear away enough metal to allow the >>> nut to rotate. >>> >>> From being on the mfr side, I know that the observations of one, or even >>> many, humans to hundreds/thousands of examples may mean little compared to >>> the hundreds of thousands of units the mfr has produced and shipped. Well, >>> my saying "I've never seen that before" means little in the big picture. Me >>> or someone else saying "I've seen that often" would mean something. "I've >>> never seen that happen before" doesn't mean much, because there's always >>> the chance the item in question has QC issues, and maybe there's a first >>> time for everything. But even though I know my saying "I've never seen that >>> before" doesn't necessarily have much meaning, I do want to say I've never >>> seen that happen before. I did say I'm out of sorts here... >>> >>> I've always thought the nut/ledge dimensions and fit were sub-optimal, >>> but I never saw it cause a problem, and I assumed Nitto designed it that >>> way for a reason. But I always wished that fit were better/tighter, that >>> the nut had very little room to rotate. I always thought the ledge should >>> 1-2mm closer to the top of the nut, and maybe a little taller/deeper as >>> well. >>> >>> Looking at it kinda forensically, I can think of a few possibilities >>> here: >>> 1. Bolt hole is drilled too low >>> 2. Hole position is correct, but casting is off, with too much space >>> between nut/ledge, or ledge is too shallow to resist nut turning >>> 3. Stem hardness is below spec, softer metal more susceptible to >>> allowing nut rotation >>> 4. Nut is undersized, so too much space between nut/ledge >>> 5. Bolt was significantly over-torqued during installation >>> 6. Bolt was initially tightened without ensuring nut was flush with stem >>> face, with the nut point digging/fretting into the stem, starting the gouge >>> that allowed the nut to rotate >>> >>> I might have missed something, but that's all that comes to mind. I >>> don't know enough about how Nitto mfrs stems, acquires parts and does QC to >>> know which of the mfr-related issues are possibilities. >>> >>> The hole in OP's stem doesn't look any lower than the hole in the >>> half-a-dozen Technomics I've got scattered around my desk, but fractions of >>> a mm that my eye might not spot might matter here. None of my stems are >>> crappy enough that I'd be tempted to try to duplicate making a gouge like >>> that myself, but by eyeball it doesn't look like my gouge would be any >>> deeper. >>> >>> If it were my stem, I'd reckon there's plenty of metal there, and use a >>> new nut/bolt, install with two wrenches, and be aware of proper nut >>> orientation and proper torque. Using the triangular beveled nut, and >>> matching bolt, from a Tech Deluxe doesn't work at my end, either. The bolt >>> is definitely too short. If I leave out the thin washer that goes under the >>> bolt head, I can get maybe half a turn, not nearly enough threads, even >>> with a bar in the stem. And even if the bolt were long enough, that wedge >>> is beveled at the top, and the Tech stem ledge is beveled to match, and the >>> Tech stem ledge is deeper. It's not as clean a fit on the Std. I'd feel >>> better with standard nut on the standard Technomic. >>> >>> But I'd also understand if somebody else would want to replace the stem. >>> >>> I would be interested to hear what Nitto would have to say if they >>> examined the stem. I'd be thrilled if Nitto redesigned the stem to make >>> that nut/ledge fit tighter. >>> >>> Paul Brodek >>> Hillsdale, NJ USA >>> >>> >>> On Friday, June 26, 2020 at 9:07:51 AM UTC-4, John Hawrylak wrote: >>>> >>>> Leah >>>> >>>> The pictures of the stem shelf were perfect. Sorry to hear the bolt >>>> was too short. >>>> >>>> The *direct cause *of the of the circular divot is Nitto drilled the >>>> hole for the Stem Bolt *TOO LOW* in the stem clamp . The lower stem >>>> bolt/hex nut resulted in the hex nut not being close to the shelf for it's >>>> flat to have a large surface area to resist the turning force of the bolt. >>>> The hex nut flat rotated through the shelf as you tightened the bolt, >>>> producing the small circular divot, resulting in the 'stripped' feeling in >>>> you stated in your original post. >>>> >>>> The stem was not manufactured to the correct tolerances for the stem >>>> bolt hole to stem clap shelf distance. It's useable with a correctly >>>> tightened nut. However, I would recommend perusing a replacement stem via >>>> Soma/Nitto due to the manufacturing problem. Hopefully, Nitto takes this >>>> as a 'learning opportunity' and adjusts their process. >>>> >>>> The gouging on the inside of the stem and bar clamp area is troubling. >>>> Most likely it was due to the bars rotating in the stem clamp due to >>>> insufficient tightening torque resulting from the stem bolt hole problem >>>> above. It is possible Nitto had the gouged in the interior surface of the >>>> stem clamp during manufacture or left foreign material side the stem >>>> clamp. >>>> >>>> John Hawrylak >>>> Woodstown NJ >>>> >>>> >>>> On Friday, June 26, 2020 at 12:25:17 AM UTC-4, Bicycle Belle Ding Ding! >>>> wrote: >>>>> >>>>> John asked for a photo when I swapped the bolts. I tried that >>>>> tonight...bolt is too short. Sigh. But he asked for photos that show the >>>>> shelf that the nut is supposed to rest against. (I think.) >>>>> >>>>> Here are photos of the area in question. I hope you can see what you >>>>> were looking for because I’m never taking that nut off again. I’m worried >>>>> I’m going to wear it out and it will let me know on my way down Killer >>>>> Hill. >>>>> >>>>> >>>>> Sent from my iPhone >>>>> >>>>> On Jun 23, 2020, at 10:32 PM, CB <tuolum...@gmail.com> wrote: >>>>> >>>>> Aside from BBDD's stem issue, a number have noted that the sleeved >>>>> bars sometimes creak. I would expect that the sleeve is inflexible when >>>>> clamped properly in the stem. The bars flex quite a bit, and the flexing >>>>> may deform the inner bar a tiny bit at the ends of the sleeve and cause >>>>> the >>>>> creak. >>>>> >>>>> A similar effect might be expected between the stem clamp and bars for >>>>> non-sleeved bars, but in that case tightening the clamp would reduce the >>>>> deformation. >>>>> -- >>>>> Carl >>>>> >>>>> On June 23, 2020 6:04:56 PM PDT, Joe Bernard <joer...@gmail.com> >>>>> wrote: >>>>>> >>>>>> The stem worked fine on her steel bar, I don't know if it has that burr >>>>>> mark on it and I think it's long gone now. I don't imagine even my >>>>>> slightly obsessive bike detective skills are going to ever solve how the >>>>>> dang thing got in there, but I'd sure like to grab a piece of sandpaper >>>>>> and knock it down! >>>>>> >>>>>> -- >>>>> You received this message because you are subscribed to a topic in the >>>>> Google Groups "RBW Owners Bunch" group. >>>>> To unsubscribe from this topic, visit >>>>> https://groups.google.com/d/topic/rbw-owners-bunch/FHIW1F5qAE0/unsubscribe >>>>> . >>>>> To unsubscribe from this group and all its topics, send an email to >>>>> rbw-owne...@googlegroups.com. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/rbw-owners-bunch/C7B77792-357C-4EFB-BD5D-98BFE72DC947%40gmail.com >>>>> >>>>> <https://groups.google.com/d/msgid/rbw-owners-bunch/C7B77792-357C-4EFB-BD5D-98BFE72DC947%40gmail.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>>> -- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "RBW Owners Bunch" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/rbw-owners-bunch/FHIW1F5qAE0/unsubscribe >>> . >>> To unsubscribe from this group and all its topics, send an email to >>> rbw-owne...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/rbw-owners-bunch/4f4c4db6-0f48-42c7-b04f-3e8133178e85o%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/rbw-owners-bunch/4f4c4db6-0f48-42c7-b04f-3e8133178e85o%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >>> -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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