Shimano Crank Spider Spline Pattern

[cdn-dave]

Hey all,

I'm over in Germany and there's a shop up in Sweden Experimental Prototype that I'm asking to make a spiderless chainring for an LX M570 crank that I have. Can anyone say whether all Shimano crank spider spline patterns are the same?

Does anyone have a scaled drawing or CAD geometry of the pattern? See attached for a scan of the spider. lx570 spider 1.pdf

Other than the above shop and HBC, are there any other companies you'd recommend?

Thanks!

cheers,
dave

[What&son]

I don´t have a cad drawing of that pattern, but I can tell you that the middleburn spider I fitted on my XTR 952 cranks was rather "loose" in tolerances. I thought there was something wrong, becouse found the fitting really poor (there was rotational play, and tabs would not be the same height than the dents where they fitted), but I´ve been using it for more than one year already and no problem.

[cdn-dave]

Do you think all Shimano cranks have the same spider spline pattern? (I googled Shimano spline and keep getting hits re bottom brackets)

[What&son]

Xtr 950 and xt 750 (the ones right before going with hollow arms, that is 751) have the same spider pattern and they are actually interchangeable. You can google and easily find xtr 950, 952 crankarms retrofited with xt 750 spiders. The LX cranks of that time (the one you have) also share the same pattern, but the spider is actually thicker (that is maybe becouse softer aluminum was used, or maybe shimano wanted to keep them as less compatible as possible) So in case you would want to fit an Lx spider onto either an Xt or Xtr some material would have to be removed to make it thinner, and maybe unsafe,otherwise the lock ring would just not reach the threads. To do it the other way around, that is to fit a xt or xtr spider on a lx crank, maybe you need some extra thickness to tighten the lockring against, but I am speculating here. What is for sure is that the pattern is the same, regardless of the thicness.
Hope helped¡

[cdn-dave]

Sweet, thanks for the help! Yah, I noticed the spider on my LX is rather thick, so just need to figure out a spacer when I eventually find a spiderless chainring over here.