Surly hubs & ISO vs. English, what gives?
 

Long time since I've posted (kids, work, etc), but I hope y'all can help me figure something out.

After getting tired of busting spokes commuting on my stock Rush Hour wheels, I'm building up a new wheelset: Surly hubs, Open Pro hoops, and DT spokes. On my current wheel (stock hubs, I assume Formula or something similar) I'm running an IRO cog.

Surly's manual for their hubs (http://www.surlybikes.com/files/NewHubs_07.pdf) states, under the heading "Two reasons why our track hubs don’t always fit perfectly with other track cogs":

Fair enough. But the next sentence says:

So does that mean that Surly does not endorse taking my IRO cog off the hub it is on now (with what are presumably English 1.370"x24 threads) and placing it on their hub? I cannot imagine that the Al threads on the hub have so distorted the steel threads on the cog that it will screw up the Surly hub, but then, I'm not a mechanical engineer.

Of course, Surly offers up:

I could order a Surly cog (I already have two, but not in the 17t size I prefer to commute on), and sell the IRO cog, but that's a PITA if I don't have too. I could also just go for it, since I have two fixed sides on the hub, but it would suck to ruin half of a hub on a brand new $150+ wheel.

Thoughts (besides call Surly, which I might try)?

OK, a quick call to Surly answer the question, but maybe the information will be useful to someone:

An English threaded cog works fine on their hub, regardless of where it was before. What they do not recommend doing is putting an English cog on and then replacing it with an ISO cog, because the tiny (5 thousandths) difference between the threads could cause the hub to strip. (Presumably, the same would apply to swapping back and forth between English and ISO cogs on an English-threaded hub.)

So, a revised question for the masses: Are IRO cogs English or ISO? (The IRO website doesn't say, but I haven't tried searching yet either.)

I shot the service department at IRO a message asking about the threading. I'll update when I get a reply. It doesn't mention anything about threading in their shop manual online (real lame IRO). However, I would imagine it would be ISO, but that's just a guess.

Edit: I kinda doubt the .005 difference in threading would remove enough metal to cause the threads to weaken enough to strip, especially if the lockring is tightened properly, but then again that's just an opinion and I'm not the master of Surly engineering.

Thanks - it'd be cool if it is ISO. I am also skeptical of the difference, but other than trying to prove them wrong, it's hard to know if Surly is talking from experience or just covering their butts.

I would imagine a combination of covering their butts/not wanting you to inadvertently damage your new gear.

Got this reply today.
Thank you for your interest in Irocycle. The IRO cogs are english
threaded. Thanks.

--
Nicole
Irocycle, Inc.
Middleburg, PA.
570-374-4631
www.irocycle.com

Do not get Surly hubs. The bearings are shot after a few months, poor threading, and has a whole are not that great.

I guess I got a freaky one as it has been used for 2 years, been through 2 winters and has the original bearings, cogs thread on perfectly, never had a cog slip once and on the whole, has been an excellent hub, one that I would gladly buy again.

Please elaborate.

Thanks. Of course, as a materials engineer at work point out, just how good are the tolerances on a $25 cog? The spec is 5 thousandths different, but what is the +/- that they are machined to? It could mean they are closer, or it could mean the difference is even worse.

Now I just have to decide if I drop $30 on a Surly cog and sell the IRO for $20 on eBay, or if I say the hell with it, and put it on the hub. For the $10 difference, I think peace of mind might be worth it.

I've used surly, dura ace and miche cogs on my surly hub, never had a problem. Probably just cursed the hub now.

I picked up a Surly at my LBS cheaper than I could find it on the net. It was like 24 clams or something. Always try your LBS first.

does it have 6000 series bearings or the 7900s? surly switched to new bearings that seem to be the suck. i hate the bearings in mine, but ive never had any other problem with the hub, wish i could somehow convert it to loose ball.

I have personally never owned any Surly hubs. I do however have friends that own them and the bearings in all of them have been bad news.

I also have multiple friends who work in different bike shops that have nothing good to say about them and have actually NOT let me buy them before. When multiple wrenches, whom I trust, tell me to avoid something - I do.

Now, Im sure some of their hubs are fine and will serve you very well but I would rather go with something else in the same price range based on the amount of negative things Ive heard about them and save myself time and money.

Like I said, mine is awesome. 135mm fixed free mtb hub. Not sure on the bearings, but it is from 2005.