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Discussion Starter · #41 ·
Anyone have a link to some tasty titanium axles?
So since JDGUNs question about finding Titanium axles I have looked and found nothing for the '17-19 bike. So I started looking into having a set made.

If the front axle is 383g (13.5oz) and the rear axle is 465g (16.4oz) then the titanium is 43% of that, so front axle would be 165g (5.8oz) and the rear axle 200g (7.07oz), for a weight loss of 483g (17oz), just over a pound.

Just the material is expensive. To do one set with Grade 5 (6AL-4V) it would be $584, with Grade 23 (6AL-4V Eli) it would be $674, but for 5 sets each would be $484 in grade 5 and $580 in grade 23.

Then there is the machining and heat treating cost. So I will take dimensions of the original axles and talk to a few machine shops to see if I can find one experienced turning titanium and how much it will cost.

So I need to do more investigation but is anyone interested in a set of titanium axles if the cost is $800 to $1000.
 

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Discussion Starter · #42 ·
I was looking for less expensive sources for grade 5 titanium and found a place with cutoffs that are long enough to turn an axle from such that it might be possible to reach $100 for materials for a set of axles. So it is even more intriguing. Tomorrow I will be calling machine shops. :)
 

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Discussion Starter · #43 ·
So San Diego used to be a hot bed for the Aerospace industry so there are lots of machine shops that work with Titanium but most of the machine shops I talked to can turn the outside diameter of the axle but can't drill through the length of the axle. I found other machine shops that specialize in gun drilling so they can do that. So it looks like I will have the axles turned to shape at one shop then, after inspecting for accurate diameters and lengths, take them to a gun drill shop to have them finished. Depending on how smooth the drilling is one shop that does the drilling can also hone smooth the internal diameter to remove anything that could end in a stress fracture. I have spare stock axles coming from Ebay so I can make a good drawing for each and provide a sample to the machine shops. Once I receive the axles and do the drawings I will get quotes, purchase some stock of Grade 5 Titanium, and have one set of axles made, then I can post pictures and costs.
 

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While I personally don't think the weight savings from titanium axles are worth the cost/effort/risk, I commend you for your efforts!

When you get quotes, ask if they can quote for 1,5, and 10 sets. If you could get a group buy going, the price per might come down to a reasonable level... and I might have to get in on it :)
 

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Discussion Starter · #45 ·
Titanium for any part on the bike is kind of esoteric but there aren't many ways to lose a pound of unsprung weight on the newer CBR1000RRs. I have carbon fiber fenders, lighter rear brake rotor, and have lighter wheels coming.
Titanium rods for crank to piston is normal for high performance but axles is a bit over the top but then there is no such thing as over kill when it is your toy.
I will use machine shops that can do CNC so once they make the first one I can ask for quotes of greater quantities and see is there is a better volume cost. Guessing the numbers who really want a set will be small but we will see once we know the real cost.
 

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You notice much braking performance difference with the lightweight rear rotor? I use mostly front brake anyway, but I like to have a solid rear brake too.

And even a shop that does it by hand will give a volume price break. I know a guy who does good work at good prices in the SD area (I think he's up in oceanside). You want his contact info? Again he does really quality work.
 

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Titanium for any part on the bike is kind of esoteric but there aren't many ways to lose a pound of unsprung weight on the newer CBR1000RRs. I have carbon fiber fenders, lighter rear brake rotor, and have lighter wheels coming.
Titanium rods for crank to piston is normal for high performance but axles is a bit over the top but then there is no such thing as over kill when it is your toy.
I will use machine shops that can do CNC so once they make the first one I can ask for quotes of greater quantities and see is there is a better volume cost. Guessing the numbers who really want a set will be small but we will see once we know the real cost.
I had an axle turned up for the Ohlins RVP's to match the HRC triples for the other bike and the facility in EU that supplies a number of race teams that did the work said they wont do Ti axles for heavier bikes, so I got it done in the standard steel they do them.

I trusted their judgement call - FWIW they were OK doing one for either of my 200lb 250 GP bikes.
 

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Discussion Starter · #48 ·
You notice much braking performance difference with the lightweight rear rotor? I use mostly front brake anyway, but I like to have a solid rear brake too.

And even a shop that does it by hand will give a volume price break. I know a guy who does good work at good prices in the SD area (I think he's up in oceanside). You want his contact info? Again he does really quality work.
I noticed a slight reduction in braking power but that is fine as it occasionally had too much. I tend to use the front heavily also and that moves the weight forward and lightens the tail. I almost blow a corner when the ABS kicked in for a locking rear brake. Unfortunately the ABS releases ALL brakes slightly so surprize...

Yes I would like the contact info on the machine shop, Oceanside isn't far from here, the gun drill shop is in Van Nuys.
 

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Discussion Starter · #49 ·
I had an axle turned up for the Ohlins RVP's to match the HRC triples for the other bike and the facility in EU that supplies a number of race teams that did the work said they wont do Ti axles for heavier bikes, so I got it done in the standard steel they do them.
The diameter of the center hole could be varied, thicker for greater strength. Once I get the spare axles and take measurements I will be able to determine thickness required. If the Axle is only 50% lighter rather than 43% of original then not a big deal but Aerospace industries does things like landing struts on airplanes with Titanium since it doesn't fracture a easily as steel alloys.

BTW, I see on EBay, I think it was, a set of Chromoly axles from Japan for $650, a bit too expensive for me.
 

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I noticed a slight reduction in braking power but that is fine as it occasionally had too much. I tend to use the front heavily also and that moves the weight forward and lightens the tail. I almost blow a corner when the ABS kicked in for a locking rear brake. Unfortunately the ABS releases ALL brakes slightly so surprize...

Yes I would like the contact info on the machine shop, Oceanside isn't far from here, the gun drill shop is in Van Nuys.
Glad I don't have ABS ;) . PM sent.
 

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The diameter of the center hole could be varied, thicker for greater strength. Once I get the spare axles and take measurements I will be able to determine thickness required. If the Axle is only 50% lighter rather than 43% of original then not a big deal but Aerospace industries does things like landing struts on airplanes with Titanium since it doesn't fracture a easily as steel alloys.

BTW, I see on EBay, I think it was, a set of Chromoly axles from Japan for $650, a bit too expensive for me.
Yeah, if I didn't have a hookup, the axle would have cost 950 Euros - I think I ended up paying $300 for it. STill I had no choice really, I didn't have any axle LOL

Once you get the production process down I might reach out to get a couple Ti axles turned up for my 250 GP bikes.
 

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Discussion Starter · #52 ·
So today I rode to Cycle Gear to take advantage of there big sell to pick up a new jacket and a pair of boots. On the ride I concentrated on the rear brake with the racing rotor trying to use the rear only for some turns to see exactly how much power loss. I would have to swap back to the original to be sure but I think it is about 50% of the braking power of the stock rotor, never really noticed since the front brakes are so impressive. The good news is I couldn't get it to lock so no chance of the ABS kicking in at a bad time.
 

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Discussion Starter · #54 ·
There are lots of things that are banned in certain racing organizations that are regularly used outside of those organizations. Take the McLaren active aero elements, they are not allowed in one racing organization but, it you have the money, can buy it for other uses. Titanium axles might be banned in MotoGP because racers might shave too much weight from the axle making it fragile and a risky application. It is all in how it is designed, it can be made to last.
 

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I was considering a custom titanium axle to fit 30mm Ohlins fork bottoms and after much research decided against it due to accumulated stress on the material, especially if the titanium is not from a reputable source. There are so many different types of stresses on the front axle such as torsion, impact, and even some suspensions have separate rebound/compression fork tubes. Scary part is the stress may not be immediately visible until it fails at the worst possible moment.

That axle supports so much more than the weight of the bike and for the weight saved it was not worth it to me. Plus it's one of those parts on your bike where if it fails it's a complete catastrophic failure.
 

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Discussion Starter · #56 ·
I agree with all your points. I will be sourcing the Grade 5 titanium round stock from a US supplier to aerospace which will cost a bit more, about $100 for front and $130 for rear axle material. So a situation that is stressful enough to cause a steel axle to crack with deform a titanium axle of similar strength, higher elasticity for titanium. Titanium connecting rods used in high output engines are under a lot of stress and are engineered to reduce failure which would be catastrophic to the engine.

The wall thickness of the titanium axle will be increased and the finish such as to eliminate points of stress. The axles will be inspected after a couple hundred miles of used then every 5000 miles with tire changes.

So any modification comes with risk. Add an aftermarket exhaust and lean the engine and risk failure. Change the rims to whatever material and risk a failure. A ECU flash not optimal for your engine setup risks failure. As an engineer I know it is all about risk and remediating the risk to the point of acceptability, and I might even have another engineer check my work. Everyday is a risk, from catching a virus to getting hit by a truck while on a ride, you try to minimize the risk but you can't eliminate them completely. Riding a motorcycle is risky but we do it anyways. ;)
 

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Discussion Starter · #60 ·
I probably could do pull cups but that would mean a larger diameter of round stock to start with and more machining of diameter so much more expensive in material and labor.
For my bike I just unscrew the front axle bolt out half way and tap it with a rubber mallet, remove the bolt, then put a Phillips screwdriver through the end hole in the big end of the axle and pull.
Anything added to the axle is extra weight and cost, have to see how much of each.
 
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