This thread has been updated. Got some of the dimensions wrong first time. The chains that come on trials bikes are typically Regina or Iris 1.8mm plate thickness chain. Almost everything available in USA is the more porky 2.2mm plate chain. I just made a mistake in ordering a chain that I wanted to make you all aware of. Avoid any "heavy duty" designated chain. I saw an RK brank 520H chain on eBay for a good price for 120 links (typically you need no more than 104 or 102). I looked up the tech specs on the RK website and found it to be 2.2mm plate. This was wrong. It's actually 2.45mm. I thought, "OK, it's just pig chain like all the rest, but it'll do." What I got was 2.45mm-plate chain and it's wider at the pins and taller in the plate. Ack! The chain barely fits the chain tensioner block, and with the swing arm fully extended, the chin goes z-z-z-z-z-z against the frame. It is even heavier than the usual porky chain. For reference: On my Factory Sherco, Regina, no master link (assembled same time as the swing arm): Plate: 1.8mm, Tall: 13.8mm, Wide: 16,3mm This is what we can't get here, unless we pay $100 for the D.I.D. 520 ERS chain! Typical chain available in USA from many brands: Plate: 2.2mm, Tall: 14.4mm, Wide: 16.5mm Porkmeister 'heavy-duty' chains (avoid like the friggin plague): Plate: 2.4mm, Tall: 15.0mm, Wide: 16.8mm Argh! All that added pork for no good reason, as it is pretty much impossible to ever so-called 'stretch' chain plates even at 1.8mm. The load to plastically deform chain plates is just HUGE. Chain specs for D.I.D. are here: http://www.didchain.com/chainSpecs.html I have found two places in USA to buy the ERS2 1.8mm plate chain. Accu-Products, or on eBay from the same: http://www.ebay.com/itm/D-I-D-DID-5...0-Links-RS250-TZ250-DID-520-ERS-/262239211590 The following guys are a bit more expensive. http://www.moto-chains.com/site/898528/product/d520ers $100 for 'light duty' chain! This is a great chain and not crap like Iris. Paying that much for a chain is hard to swallow to save some ounces. Anyone find a source for 1.8mm plate chain that is more reasonable? I'd love to be able to buy this in bulk roll and resell it at a reasonable price.