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-   -   Titanium rear axle (https://www.bikeforums.net/showthread.php?t=1243274)

cjenrick 12-05-21 05:22 PM

Titanium rear axle
 
going to build a superlight rear wheel as a spare so i do not have to change innertubes in the rain at night when it is 34 degrees out.

modifying a rear blackburn type rack to carry it.

28 hole track hub with tubular tire and 320 gram racing rim,

wondering if somebody makes a titanium axle for the rear hub and if it will snap like a dry twig in a stiff desert wind if i try to use it,

i weigh 160 and the wheel only has to go about 20 miles max maybe once or twice during it's lifetime (hopefully)

rear hub not bought yet,

thanks for any help

Crankycrank 12-05-21 06:10 PM

I'll just say that yes, there are Ti replacement axles for some hubs, we need to know what exact hub, but it looks like you'll save maybe 7 grams over a hollow, steel quick release axle. Various levels of quality Ti you have to research also as I wouldn't trust an Ali Express special. Not sure there's much point to it.

Bill Kapaun 12-05-21 06:39 PM

It'd seem a bit foolish to have a Ti axle on a spare, but not on the 2 wheels you use all the time.
That would mean 3 axles.

DiabloScott 12-05-21 07:06 PM


Originally Posted by cjenrick (Post 22329862)
going to build a superlight rear wheel as a spare so i do not have to change innertubes in the rain at night when it is 34 degrees out.

modifying a rear blackburn type rack to carry it.

You're planning on carrying a whole extra rear wheel on your bike?
What happens if you get a front flat?
And if the spare is a tubular with latex tube you'll have to keep it pumped up pretty regularly.
I don't understand this at all.

cxwrench 12-05-21 08:07 PM

You actually think putting a Ti axle (which isn't made) into some random hub will make enough difference in total weight you'd notice it? When it's raining, dark, and 34*?And you're going to carry an entire spare wheel?!? I've heard of some wacky ideas but this might take the cake.

cjenrick 12-05-21 08:20 PM

changing a flat with numb hands is a pain. and i like to blow up the tube when i get a flat and see where the leak is. i always mount the tire with the label over the stem hole so i have a ref. point for finding glass and nails. then i trace the area of the leak back to the tire to see if there is anything that might cause the new tube to go flat again. thereby saving me from a situation where i have no other options but to walk 15 miles in the rain at night in deadly temps. it seems to me that it would be very hard to diagnose a leak in the rain at night. i would rather do a 15 second wheel change like you see in the TDF. that way i maintain body heat. i am 67 so not as tough as i use to be when it comes to hypothermia why am i out there in the first place? well i still like to ride.

there are a few threads on the idea of a spare wheel idea so this is nothing new. 90 percent of the flats are on the back tire so we are playing the odds by taking only one wheel.

re-thinking this, i have decided to forgo the titanium axle idea, opting instead for a steel axle and a Ti quick release on a freehub with single Ti cog. should be light enough with the tubular rim and tire.

Trakhak 12-05-21 08:38 PM

I'm 70, and for any rides where the temp is likely to be below about 50 degrees F, I switch from my skinny-tired bikes to a hybrid with heavy-duty 32-mm tires. Since I have clip-on aero bars on the hybrid, I can get just as good (and enjoyable) a workout as on my various road and track bikes, and I have almost no chance of flatting. You're not racing when you go out in the cold---why not use a bike that's better suited to those rides?

I've been riding racing bikes since the mid-'60s, back when tubular tires were all that were available, and I'd be embarrassed to admit how long it took me to come to the realization that riding fragile tires in the cold and wet was a bad choice. I hope you figure that out eventually, too.

Andrew R Stewart 12-05-21 08:56 PM


Originally Posted by cjenrick (Post 22330023)
changing a flat with numb hands is a pain. and i like to blow up the tube when i get a flat and see where the leak is. i always mount the tire with the label over the stem hole so i have a ref. point for finding glass and nails. then i trace the area of the leak back to the tire to see if there is anything that might cause the new tube to go flat again. thereby saving me from a situation where i have no other options but to walk 15 miles in the rain at night in deadly temps. it seems to me that it would be very hard to diagnose a leak in the rain at night. i would rather do a 15 second wheel change like you see in the TDF. that way i maintain body heat. i am 67 so not as tough as i use to be when it comes to hypothermia why am i out there in the first place? well i still like to ride.

there are a few threads on the idea of a spare wheel idea so this is nothing new. 90 percent of the flats are on the back tire so we are playing the odds by taking only one wheel.

re-thinking this, i have decided to forgo the titanium axle idea, opting instead for a steel axle and a Ti quick release on a freehub with single Ti cog. should be light enough with the tubular rim and tire.

I think the spare wheel's weight is the least of the problems. The space it takes up and it's sticking either up or out to the sides a bunch is my first negative take away from this idea. Plus I would not choose a sew up as my spare tire. (And I have mounted a sew up on a clincher rim to get by for the rest of a century club ride a long time ago.)

You might do a bit of research on the British wheel carrying methods used back in the 1950s and 60s. It was not uncommon for riders to have only one bike they used for everything. They would ride the bike to the race/time trial with the event wheels carried, to be exchanged for the race, then switch back to the daily wheels for the ride home.

But I think the idea of carrying a spare wheel for a flat fix is a bit odd and not what I would do. Andy

sweeks 12-05-21 09:41 PM

How about concentrating on a highly flat-resistant tire? There are such things.

cpach 12-05-21 10:23 PM

To answer your question, probably the lightest hubs use aluminum axles and cartridge bearings, like https://mackhubs.com/hubs/track/low-flange-rear/ .

I would think that rather significant performance penalties would be worth it to avoid carrying an entire rear wheel. Maybe tubeless with a rather robust tire? Or even https://tannusamerica.com/pages/tannus-armour with a robust tubed tire. Or even a fully solid tire.

Tannus Armor for tubes or tubeless with most tire inserts also will run flat more or less rideably if the distance is short and the handling is relatively mellow.

cjenrick 12-06-21 02:48 AM

i do use a Bridgestone MB-2 for rain rides in the cold, it has fenders and Continental Gatorskins. Rarely do i get a flat so this is a what if type of deal.

with a rear rack, you can mount the wheel far enuff back to where it will be out of the way. picture a wheel instead of a pannier.

we just bought a wheel exactly like the wheel that is on my MB-2. this way i avoid wheel building, tubular tires, the extra expense and labor of installing titanium parts, plus i now have a reliable backup wheel in case i break a spoke or axle.
we can mount a 650 x 23 C gatorskin on there which only weighs 275 G and use a light tube but not latex. now i do not have to build a wheel and hassle with spoke length. we already have a single cog and spacer kit for the freehub that was gathering dust after a poster wisely told me not to convert the MB-2 to a single speed as the bike is plenty light already. my rain jacket gains weight out there, at least as much as the weight savings of a titainium axle.
also, we do not have to carry a 15 mm wrench for changing a track hub although we could have installed QR on the track hub which would have been an extra hassle and more money. and i do not have to pump up a tubular every 15 minutes.

a light wheel with a tubular would be nice but we want the spare to be dependable, not like a space saver spare in the back of the car.

with the light tire and single cog, we still have a pretty light wheel. and we can ditch the stuff in the saddle pack and save weight like the tube, co2 inflator and cartridge. nobody wants to ride at night in cold temps so i go it alone on the bike path which means calling uber could be tricky. and we do not want to depend on a cell phone if possible.

thanks for the input, saved me time and money.

we have a Big Blue 1300 Lumen scuba diving light coming in next week, good for 300 feet, a magnetic switch and no USB, and a Fennix handlebar mount, so we should be ok if we keep it on low so it don;t burn up. this will replace the :water resistant: nite rider lumina micro 900 and we now have a 18650 battery which means we do not have to send in the light to get a new flat pac Li-Ion soldered into the PC board. the light was 155 dollars, comes with a charger and a 300 lumen backup light, also meant for diving. the backup takes two aa batts and will fit in the saddle pack so we in fat city.


https://cimg9.ibsrv.net/gimg/bikefor...07aa6b21cd.png
i be ready spare wheel, spare light!

https://cimg1.ibsrv.net/gimg/bikefor...3d1db7dcb0.png

rosefarts 12-06-21 07:45 AM

This is strange to everyone here. With tubeless and way tough tires, you can almost guarantee no flats unless you get slashed on something.

I got a flat on a tubeless tire 3 years ago when a piece of shale sliced open the sidewall on a light tire.

That’s one, ever.

mpetry912 12-06-21 10:21 AM

why not get a can of Vittoria Pit Stop, it's a spray in goop that will get you home !

I dread the thought of a rear flat on the Ebike, especially in cold weather. So Pit Stop is the ticket

DiabloScott 12-06-21 10:31 AM


Originally Posted by cjenrick (Post 22330023)
90 percent of the flats are on the back tire

I challenge this statement.

IME, more like 60%... but I just made that number up.

mpetry912 12-06-21 10:49 AM

I'd agree "most" flats are on the rear.

remember especially for tall riders, the bike's weight bias is toward the rear.

I run a heavier rear tire on most bikes.

/markp

blacknbluebikes 12-06-21 11:41 AM

Since several mfgr's now produce sub-7kg bikes, I'm thinking I'll just put one of those bikes on my back for true, full redundancy. Kinda reduces my aero profile a bit, but I'm further dropping the stack to offset it a bit with less frontal area.

Koyote 12-06-21 12:06 PM

I'm not sure what's wackier: the ti axle idea, or the idea of carrying an entire spare wheel.

Koyote 12-06-21 12:08 PM


Originally Posted by cjenrick (Post 22330023)
90 percent of the flats are on the back tire so we are playing the odds by taking only one wheel..


Originally Posted by DiabloScott (Post 22330523)
I challenge this statement.

IME, more like 60%... but I just made that number up.

I challenge THAT statement. 127% of my punctures are on the rear tire.

canopus 12-06-21 04:00 PM

My brain on this thread....:foo:..:twitchy:..

https://cimg5.ibsrv.net/gimg/bikefor...bf4a46a175.jpg


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