I would like to add another link to my drive chain to bring the rear axle back as far as I can. The problem is, the bolts that extends out to push the rear axle backward won't extend far enough. The size is M8-50 (grade 11). I found the size that will fit (M8-60), but its only a grade 8 bolt. Why does this boly have to be grade 11? Why couldn't it be a lower grade bolt? Does it really see that much stress? If this isn't good enough, where can I find a M8-60 in a higher grade?
The tech side of me tells me there must be a reason to use such a high strenght bolt, the pratical side of me can't figure out what that reason is. Bolt strenght is somewhat related to shear load and I can't see that much stress being put on that bolt, especially since the axle nut carries a significant clamp load.
Another thing is that the swingarm is aluminium. There's no way that any grade of steel bolt would cause a problem, especially fastened to aluminium. There's an 11 stamped on the bolt head. This is the only thing that makes me think it's a grade 11. The bolt head itself is a 10mm.
usually metric bolts are x.x rated ... 8.8 or 10.9 etc imperial are rated with small //// marks, 3 /// marks being grade 5, 5 ///// marks being grade 8 etc etc.. I've never seen a bolt with an 11 stamped on it. I would stop in at a bolt or industrial supply store, Fastenal would like be your best bet, and ask them what they think it is, I think any high strength bolt will do... engine mounts and frame sliders are 10.9, I can't see you needing aything that special.
Bolt Strength Schoey - I think the lower grade bolt will be fine. As long as your axle is adequately torqued there won't be an issue. Nick
Grade 8.8 Yield Strength 660 MPa min. Tensile Strength 830 MPa min. Grade 10.9 Yield Strength 940 MPa min. Tensile Strength 1040 MPa min. No info on grade 11 ???? Your call Here's a handy link for those challenged by the metric system. :roflmao::roflmao::roflmao: http://web.archive.org/web/20071031104609/http://www.blm.gov/nhp/efoia/wo/handbook/h9102.html#8. Scroll down to, Fastener Data. Tables 9 and 10 pro
I invested $3 in some Home Depot M8-60 bolts that I think will do. I'll visit fastenall on the weekend to find out what the 11 stamped in there means. Being fastened into aluminum, I don't think it matters what strength it is. The aluminum will fail first.
That will work fine, the chain adjusters don't really have any load if the axle is tightened properly.
Found out today from Pacific Fasteners that the 11 marking is a manufacturers symbol and judging by the hardness of the bolt, it's not a high grade steel. A steel bolt will do, but don't stainless. Thanks for all the info people. I have what I need.
