Rob, thanks for the tips. Sorry to have delayed my reply. You are correct, these cranks are new. I had also wondered about the condition of the crank arms, but thankfully they seem to be in great shape. I can torque the arms down to 30 ft lbs and based on my eyeball measurements, I'd say I have 3-4 mm between the end of the spindle and the end of the crank arms. So the crank bolts aren't bottoming out or anything. (I used some 'normal' crank bolts, not the self extracting, so i just unscrewed them and could see how far the cranks had been pushed onto the spindle).
I'd say that at this point, I can definitively say that my problem is simply that the chain stays on the Atlantis do not accomodate chain rings as large as 46/36 without having at least a 122-124mm bottom bracket. Currently I have a 127.5 and there is about 3-4mm between the chain stay and chainring bolts. If I double that and subtract it from the spindle length, it suggests a 121.5mm spindle would cause the bolts to just touch the frame. I've ordered new rings for the cranks - 44/30. That will allow for a much narrower spindle since the chain ring and bolts will have a smaller radius. A 121 would easily work. Mark from Riv used a 118mm bb with 44/30 rings and the road VBC crank arms on his Hunqapillar and while it technically worked, he said the crank arms were a bit too close to the frame for comfort. They currently reside on his Homer with a 113mm bb. Using the ENO arms, I will have more clearance and anticipate a 118mm will be fine on the Atlantis. On Friday, May 23, 2014 6:17:57 PM UTC-5, rperks wrote: > > Mark, > I am correct in thinking that you picked up these cranks used? and if you > have a 113 bb spindle, new or in good shape, can you put the arms on said > spindle out of the bike, so that the arms are across from each other, and > torque down to spec of 30 ft lbs? From there it should be easy to measure > the Q factor with a tape measure or ruler. I am wondering if the arms had > previously been off and on, or run loose and the tapers are slightly > buggered. This could cause them to run up on the spindle tapers and give > you a false impression of fit with a specified spindle. This still puts > you back at a point of trial and error to get them working. > > My only concern is if you are needing a bb spindle that long it means you > quite possible are having 14.5 mm of creep split up in some portion of each > arm. I am guessing these have the self extracting bolts, and yo may not be > seeing how close these are to having the bolt bottom out on the spindle > end. You may get these to work on a longer spindle, but is the tapers are > that far out of spec you may honestly want to start thinking about safety > of use. > > That all said, even with the math WI recommends, a 36 inner ring is pretty > big and may be a portion of the multi faceted problem. First thing I would > do is confirm Q on a known accurate spindle, and make sure you are remotely > within tolerance. From there if you want to use the cranks you will also > have a new baseline for you calculations on where it all sits in space. > > Another thing to consider is the differences between spindles. I have > installed the VBC on WI, SKF, Shimano and IRD 113 bottom brackets. They > are all close, but there is still a bit over a mm in spread of where the > chain line ends up. That said, once the chain is on and you are rolling it > is all about the same. > > Rob > (the only thing worse than professional liability for answering questions, > is answering questions about used parts and stuff you talk about on the > internet ;-) ) > Ventura, Ca > > > On Thursday, May 22, 2014 2:50:59 PM UTC-7, Mark Reimer wrote: >> >> Realized after posting that you likely were referring to the 46/36 chain >> ring sizes as being a road double, not the actual crank arms. My mistake. >> Ride your bike! >> >> On Thursday, May 22, 2014 4:47:57 PM UTC-5, Mark Reimer wrote: >>> >>> The ENO crank is not a road double actually, it is a mountain double >>> crank. VBC cranks are offered in two variations - road and mountain. ENO >>> cranks are the single speed and mountain double arms. The cranks I have are >>> designed with wide chain stays in mind, so this should work. I always knew >>> the Atlantis had wide stays, but after seeing a few photos of this >>> combination online, I wasn't expecting any troubles. >>> >>> The only reason this is getting complicated is because the instructions >>> provided by White Industries themselves generated a BB length that simply >>> made no sense - well over 140mm. >>> >>> So in some ways, I agree - my first step was to use the >>> manufacturer-provided guidelines for calculating bottom brackets. This >>> generated questionable results, so that lead me to option two: ask the >>> owners group if anyone is running the same combination and can share their >>> BB length. Since that didn't turn anything up either, I asked the >>> manufacturer if I was using their formula correctly. And then, like you >>> suggested, I'm on to option 3 - go to a shop, and trial and error. >>> >>> I am well aware that bike shops charge for labour by the hour and it's a >>> valuable service. I spend a significant amount of my money employing my >>> local shops for this exact service, so there is no need to preach the value >>> of paying skilled craftspeople to me. I am part of the choir. The reason >>> why this thread has rambled on is that there never should have been a need >>> to employ any skilled mechanic, much less go into a trail and error mode >>> and waste money buying a bunch of cheap bottom brackets as a means of >>> finding the right length, because calculating BB length is easy with some >>> simple math. I've done it for all my bikes for over a decade. I pay my bike >>> shop to do things I can't do, and order components locally whenever >>> possible. I'm building the Atlantis myself because I enjoy it, not simply >>> to save money or because I don't value skilled work. >>> >>> I manage a graphic design studio and have the exact same understanding >>> of the value of time as you do in architecture. That's why I came to an >>> owner/enthusiast group first, which doesn't cost anyone anything, then >>> contacted the manufacturer of the crank second (simply asking if I was >>> using their published guidelines for calculations correctly) and only >>> contacted Riv for advice after even my own local shop mechanics (who I pay) >>> were scratching their heads. >>> >>> Anyway, you may be glad to know I now have a pile of unused bottom >>> brackets as well as a number of other components for the build purchased >>> from my local shop (shop wins), some new, smaller white industries rings >>> and BB on the way that will enable a much narrower BB (White Ind wins), >>> already had ordered a number of the components for the Atlantis from >>> Rivendell directly (Riv wins), and will soon be spending my time riding >>> blissfully into the sunset instead of justifying my query here (we both >>> win!) >>> >>> Problem solved, now lets go ride some bikes. >>> >>> >>> On Thursday, May 22, 2014 4:04:37 PM UTC-5, bicyc...@gmail.com wrote: >>>> >>>> This is being over complicated. You are trying to equip a road double, >>>> with way too high of an inner ring, on a bike with 60mm tire clearances. >>>> You will need a crazy wide bb to do so. 125 isn't very long, old mountain >>>> bikes with high profile cranks used them (early 80s mb-1s among them). >>>> >>>> The solution to bottom bracket issues is to, a) search for an answer b) >>>> try out combinations. A bike shop, in which you pay for hourly rates of >>>> labor, will have a variety of these bb lengths to try in order to find the >>>> correct length for the application. If you are doing your own work, in >>>> order to save money, don't expect that the answer will be there or that >>>> paid craftspeople will be able to help you without you taking your bike >>>> into a shop and allowing them to swap combinations (and hopefully, paying >>>> for that work). This is part of the craft of the mechanic work you elected >>>> to avoid by doing it yourself. DIY is often more expensive, when starting >>>> out. >>>> >>>> In architecture, we charge to answer requests for information from the >>>> contractor, because it takes a lot of time (imagine answering the phone on >>>> the thousands of custom setups that go out the door of shops like riv, >>>> that's a lot of hours). I wonder what an RFI system would mean for shops, >>>> but I digress. >>>> >>>> So, since your custom build means a) didn't work, you've finally >>>> arrived at b) which was the place to probably start in the first place as >>>> all hand made frames are slightly different. You will likely find that >>>> 36x48 works ok with a 125mm bb, but that your chainline is pretty bad. >>>> This >>>> is why wide range doubles, not road doubles, are what riv recommends and >>>> what the bikes are designed around. Instead of returning those bottom >>>> brackets, keep them for the next time you or your friends need to try out >>>> combinations. Super cheap bb's make the world go round, and are used on >>>> all >>>> of my bicycles, since this is a constant question for people who tweak >>>> their setups. Next time, if you don't know, just go with a crank that is >>>> recommended or prepare yourself for similar headaches. >>>> >>>> Not trying to run on about this, but at a certain point the answers are >>>> only to be found in practice. Custom parts on custom builds = custom >>>> headaches. >>>> >>>> Put on the 127.5 and ride your bike, it's working and you're on your >>>> way. When you wear out those rings, drop down your sizing and put on a >>>> smaller bb, or get a low profile triple if the 46 is important, or get a >>>> 30 >>>> if the 46 is important, or or or ad infinitum. >>>> >>>> e >>>> >>> -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. 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