Surly stainless chainrings seem softer than alloy

[wqlava1]

I was on my way home from a ride at about 9pm this evening through Westerfolds park on my Velosmith, when a darkish lump on my right that I'd thought to be a rock but turned out to be couple of cubic feet of wombat muscle, wanted to go to my left at the same time as I passed him/her. It hit the chainring as my foot and right pedal were at the back of the stroke, and my chain fell off immediately as I tried to accelerate away. I suppose 115kg of me and bike had enough momentum to save me, as the bike kept going upright a little. With me stopped, and the wombat about 2 metres away, he turned & growled at me, the first noise of the encounter. I just paddled the bike down the path 20 or 30m more to stop disturbing him/her and to try to see what was wrong. Some MTBers came the other way, and stopped to give light as I had no light without the front wheel spinning. And the problem was a bit aft of there anyway. I was trying to find a good way of lining the chainring up for one judicious kick from the left under the BB, but one of them had multitool pliers with them. It worked soft of, but the chainring needs replacement. It had been bent once before when I only used a Ground Effect Body Bag on the plane home from Adelaide, but I thought then that Qantas must have been a bit brutal. With tonight's effort, I'm looking out for aluminium instead. One of the MTB guys (who for some reason thought the old Sugino GT cranks worth pointing out to one of the others) mentioned that Salsa do some nice ones. I have seen 46T and 42T online in silver, but not yet the 40T that would replace my current wiggly ring. As I said thanks to the group for the lights and assistance, they said to thank Commuter Cycles who must have been represented in the group. Thanks again guys.

[wqlava1]

So, what is the collective wisdom on the best 110mm BCD singlespeed chainrings in about 38 to 44 teeth sizes? I could see myself going up a couple of teeth maybe on the bike with a Rohloff hub, but mate a little smaller for another bike with Alfine 11 where I have 38 teeth now but wonder when that too will bend with a moderate side impact. Maybe I move the chainring to the middle position and use a guard on the outer position, but then I need to change BB.

[rifraf]

Where have you got to with regards to a solution? Have you found a suitable chainring yet?
Is your MTB 26 or 29er? Maybe worth considering is a reversible Thorn 110mm bcd 5 hole ring.
These are available from http://www.sjscycles.co.uk/110-bcd-5-ar ... pt724_pg1/
Like the Rohloff chainring the Thorn front ring is reversible for a longer life.
You sound like you prefer much higher gearing than I do. Is it pretty flat where you ride?
The 29er I'm building with have Rohloff's 16T at rear and 34T at front.

[HappyHumber]

Bit in the market myself for a 110BCD... probably a 32-34 for a SS MTB Build... Got a few square taper triple cranks laying about which should serve my purpose.

Re-reading the OP.. I guess at least you can bend & then unbend stainless... Aluminium once bent will never straigthen... well.. safely anyway.

[il padrone]

What a tandem under load can do to an alloy chainring

[HappyHumber]

Arrgh dammit....
Just pulled off the well worn original pressed steel (ie. non replaceable rings) cranks... and the &%$*# things are Octalink. Typically healthy BB

Back to scrounging something else crank wise.

[wqlava1]

Where have you got to with regards to a solution? Have you found a suitable chainring yet?
Is your MTB 26 or 29er? Maybe worth considering is a reversible Thorn 110mm bcd 5 hole ring.
These are available from http://www.sjscycles.co.uk/110-bcd-5-ar ... pt724_pg1/
Like the Rohloff chainring the Thorn front ring is reversible for a longer life.
You sound like you prefer much higher gearing than I do. Is it pretty flat where you ride?
The 29er I'm building with have Rohloff's 16T at rear and 34T at front.

I've been very slack, and still have the straightened Surly SS ring on there. For being straightened by the light of a few AyUps with a small pair of pliers, it's a fantastic job. (Thanks again to whoever it was from Commuter Cycles!) I went and chased up an alloy 42T 110 ring secondhand but little used from the LBS, but the lack of any noise or visible deviation makes it hard for me to justify the time to change yet. I'll get out the magnetic base and needle gauge when next building a wheel and mount it on the frame to check the runout out of interest.

It is not a MTB. It is a Velosmith tourer, with Rohloff sliding dropouts but somewhere in tube specification a little lighter than the Jota on Tim Stredwick's website. It currently has the ugliest mount of the shifter (on an angled accessory T-bar off the stem) that I have ever seen, though I have a beautifully made Gilles Berthoud shifter on a Velo Orange rando bar sitting here waiting to tidy things up. I'll take photos and write a bit after I get it to a less embarrassing state.

I think I could probably reverse the SS Surly ring.

Even with 42/16 driving the Rohloff hub I will still have some pretty low gears. I think the current 40/16 is right on the limit for my weight with the Rohloff warranty - unless I lose a few hundred grams more riding some more hills.

No, it's not really flat where I ride. Usually out somewhere in the arc from Lilydale around to Whittlesea starting in Eltham, with regular forays towards the city. Sometimes riding based in Apollo Bay or Woods Point (where we have cabins).

You'd want to be pretty light to be running 34/16 and Rohloff and avoiding warranty problems. Rifraf I think posted something about that recently.
viewtopic.php?f=77&t=59772

[rifraf]

You'd want to be pretty light to be running 34/16 and Rohloff and avoiding warranty problems. Rifraf I think posted something about that recently.
viewtopic.php?f=77&t=59772

Rohloff revised their ratios and now a combo of 34/16T is within limits as long as rider is below 100kgs from memory.
My current build project has a 38T but will be swapped out to 34 before I go riding anywhere loaded.