Broken Axle!
 

So I broke the rear axle on my Univega Supra Sport yesterday and am finding it to be less than straightforward to figure out the size and thread count I need to replace it.

The rear hub is a Sunshine #5345 with a Suntour "Perfect" 6sp Freewheel, laced to a 27" rim.
I removed the (solid) axle and it looks to measure 164mm long and about 9.5mm wide.
Granted im only using a regular ruler to measure this but when I looked at the Harris Cyclery website and their links to the Wheels Mfg site I have not found either any info on the Sunshine brand nor is there an axle that matches this length. All the Suntour info looks to point towards a 10mm x 174mm axle but this seems both too thick and too long for what im replacing. Im hoping to get over to the lbs with the cones hoping I can match something they have but I wanted to get some more info first. Im also debating switching over to QR so any opinions that could be had are appreciated.

Thanks.

Sansin made sunshine hubs according to Sheldon Browne.

http://www.sheldonbrown.com/japan.html#sansin

Based on that, I would feel confident going with the Sansin axles listed at Harris.

http://www.sheldonbrown.com/harris/axles.html

Good eye jsharr. I hadn't found that page with the Sunshine info. That would lead me to trust that the axle is 10x1x174 however the one I have is still 10mm shorter and doesn't seem that thick. Additionally, I downloaded the Wheels catalog and all the Sansin 6spd axles they list are either 9.5x26x137 or 10x1x137. Far too short. The axle listed on Harris for Sansin is a 10x1x174 which I don't know if it might be too long, and it seems thicker than the one I have.

My Trek MTB came with a freewheel. After 2 broken axels I changed to a freehub and haven't looked back. The new wheel and hub only cost me $60.

Ive thought about that as Ive researched but that (correct me if im wrong) presents several problems I dont want to deal with... Im running 27" wheels and dont particularly want to attempt a swap to 700 right now (which would make finding 7 spd freehub wheelsets easier id imagine)and would rather keep running the 6 spd. While I dont think i can get a 6spd freehub Ive read that I could go to a 7spd without derailer/shifter issues but I would have to either get a whole new rear wheelset or get a new hub laced to my rim. I also like the sunshine hubs and have read good things about the suntour cassettes and would resultantly like to keep both of them rather than go through conversions. Does anyone think im crazy? This is really my beater/rain/grocery hauler bike but the more I ride it the more im becoming attached to it and if it could benefit from these changes maybe it is worth it. Time and money, however, is always a concern for poor grad students.

Go to the Auto parts store and "borrow" a known 10MM nut and "test"!

The 137 mm axles are most likely hollow and intended for 6/7-speed (126 mm drop out spacing) quick release hubs. You could use one of these if you want to use a qr instead of axle nuts.

So I went to a local (not my first choice but the closest) LBS and while they didn't have extra axles or cones lying around to compare my stuff to they did have a caliper and thread measuring tool. The width of the axle came out to about 9.4mm (can we call it 9.5mm), the thread looked to be 3/8 (26tpi), nothing matches the length of 164 that I have. Now the issue is that the Wheels chart has contradicting info. One page says that the sansin solid rear axle should be Axle #13 and is 9.5x26x174, however on the next page's chart none of the sansin measurements match this and axle #13 is listed as either a suntour or shimano bmx hub with two different specs! Even worse neither matches what Harris lists for the sansin. My question now is whether it will hurt the hub to run a 9.5mm axle in it if it should be 10mm as Sheldon suggests?

A shop that doesn't have a stock of replacement hub axles is pathetic. Go to another one.
You should try to re-use the cones and spacers off your broken axle, and should just find a compatible replacement. Shouldn't be that hard. Take your old axle into a decent bike shop and let them do the work for you.

Keep in mind that a 10mm threading is always a little smaller than 10 mm in diameter. 9.4 mm diameter seems a little small but it's still within spitting range of being 10 mm. Although it's very close to 3/8 (.370) so it may be that for some odd reason they chose to use a 3/8 axle.

However 26 TPI is not the standard fine 3/8 pitch. However it IS very close to 1 mm pitch (25.4 tpi) so it's possible that you've got a slightly undersized 10 - 1.0mm axle and the 1mm pitch gauge is the one that would fit better.

There ARE other thread pitches used so be sure to take one of your cones to test on the new axles. And if you can't find the right length then just get one that's longer and either live with a few mm's sticking out or hacksaw and file it shorter to fit. Or the shop may cut it down for a small extra charge.

Haha, yeah thats b/c it was an REI. Its only a 10 minute walk from my house. Today Ill be riding over to the good shop with my bag of nuts and cones to try to find a match. I never like to go uneducated and identifying this part turned into kind of a mystery which got me more intrigued.

So you are saying even though most catalogs I've looked at the list 3/8 bolts are 26tsi there is a good chance it is rather 10mm? And even though the bolts that are 9.5mm wide are usually 26tsi it still may be 10mm? Who knew a bolt could be so elusive. My mind is blown. Too bad this info isn't stamped on the axle. Time to go to the experts at the shop. Thanks for the help guys.

So it turns out after visiting the good LBS the axle was 9.5x1.0x164mm. Turns out they had one that was a 168 which I will work with, but rather confusing as its not even on the charts!! Hopefully ill get it on the bike tomorrow and everything will go back together. Thanks for all the info guys.

Well, we both learned something. I had no idea that they had an official 9.5 mm size out there.

I do know that I've got a lot of cones and nuts that only fit specific axles but I figured that there were some thread pitch oddities.