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Drop out spacing
#1
Just ordered a new carbon fiber frame. I still run 7 speed equipment, but my steel frame has a 130 mm drop out spacing. The over locknut dimension on my rear axle is 125mm and I have no trouble cinching up the wheel. What I need to know is if there will be enough 'give' in the carbon fiber frame to accomodate the 5mm pull in, or should I use a stainless washer to make up some of the difference. I'm assuming that it is certain that the new frame will have the standard 130mm drop out spacing.
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#2
Use precision shims (look like washers but are held to very tight tolerances), not standard washers. Measure the frame when you get it, and use shim to bring the OLD up to 1.5 to 0.5mm less than the frame drop out spacing. The shims should go inside the lock nuts on the axle.

Washer are not flat nor uniform thickness, which will lead to bearing issues if used in this application. An industrial supply house will have shims of varying thicknesses with Ø10mm ID.

You should consider putting all of the shims on the left side (NDS) and re-dishing the wheel, which will lower the stress on the right side (DS) spokes, and increase it on the NDS spokes, balancing them out closer to even.
Nigel
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#3
Short answer is "no", there is definitely not enough give in a carbon frame for this. Shim the axle with 5mm of extra spacers. There should be enough axle length to do this without getting a longer axle.

I'm pretty sure just using decent, stainless washers would be fine. But nfmisso is correct that the proper way to do this is to use precision parts. It kind of depends on what quality level the hub is anyway. Based on what I've seen on some even mid-level hubs, I doubt the precision of the axle parts is much higher than a standard washer anyway.

He's also right that putting the spacers on the left and re-dishing the wheel will make the whole wheel stronger. But the quick way is just to add equal spacers to each side.
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#4
Thanks guys, special thanks to nfmisso for your input on all of my postings over the months. I was pretty sure that was the answer. I have a friend who loves to produce intricate items on his small lathe, once I know the exact spacing of the dropouts, I'll have him machine me a couple of spacers in stainless.
Just to cover all of the bases, how much flex would be acceptable in carbon ?
Thanks guys, special thanks to nfmisso for your input on all of my postings over the months. I was pretty sure that was the answer. I have a friend who loves to produce intricate items on his small lathe, once I know the exact spacing of the dropouts, I'll have him machine me a couple of spacers in stainless.
Just to cover all of the bases, how much flex would be acceptable in carbon ?
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#5
WOW That is mighty tricky lathe work. Precision shims are stamped then double disk ground to thickness, flatness and parallelism.
http://www.mcmaster.com/#metric-shim-washers/=rynuru

Regarding carbon frame allowable deflection - it depends. The carbon fiber resin matrix is usually almost perfectly brittle (no plastic deformation). Which means that it gives no warning before breaking. When it breaks is dependent on the exact composition, how it was assembled, curing process, environmental history (temperature, humidity and pollution) and mechanical history. To really know, you'd have to get a statistically significant sample, subject them to the same histories and test to destruction. The sample size is based on the confidence interval you desire; three is the absolute minimum. 32 is generally considered a "safe" sample size.
Nigel
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#6
Larry machines everything to +- half a thou. He will part halfway with enough clearance to mic the thickness, adjust and then complete the parting. He said that I could have a milled edge if I want it and I don't think he was joking. I guess I'll just aim to get to a neat fit, size to size.
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#7
Sometimes I feel you need to get a new rear axle when doing this. I don't care what anyone says or how expert they are, I get really nervous when there isn't a couple of mm riding in the drop out.
I've also (with loose ball, not cartridge bearing hubs) used two spare lock nuts, with a bit of sanding (on a flat glass substrate) they easily move you from 130 to 135mm. 126 to 130mm would be a bit more work. I've also used grade 8 washers as spacers & found them to be very uniform. I can't remember how thick they were, right at 1mm I think.
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#8
According to the delivery time given to me, I still have 33 days, 12 hours, six minutes and fourteen seconds to go before I have to worry. As usual, there seems to be a problem around every corner. The wheel i will be using has a campy hub with a thread on block. So to put the washers behind the locknuts or to replace the axle (if I could find one !!!) means removing the block. I have made a pretty good tool to do that, but they are never happy when you want them off, always a hassle. Plus something else to think about for me, is that the Campy locknuts are almost dead in line with the edge of the hub and I don't see any way to get to the flat on the cones. I guess I hang on to one locknut and try to break the other, then put the axle in the vice to break the other end. Then it will be difficult to get the adjustment right when it goes back ummmmm. I've used a washer on a badly dished borrowed Shimano wheel and it still had enough axle to safely locate in the dropout, but now I'm thinking that the Campy, from memory, looks a little more stubby. Anyway, I've got 33 days, 12 hours ........ and you guys to sort it all out.
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#9
Axles are usually no big deal, I don't know Campy, I thought it was the standard 10mm x 1.0 thread pitch, but it looks like it may be different at http://wheelsmfg.com/products/axles-cones-hub-parts/all-axles.html, you could try the 146mm here.
To get access to the cones you may have to pull the freewheel, and work from the drive side.
If you know a wheel guy (I trust NO locals around here, I ship it out) you could do as nfmisso suggested and put most of the spacer width on the offside and have the wheel redished or relaced.
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#10
(05-15-2014, 11:32 AM)limey Wrote:  ... the Campy locknuts are almost dead in line with the edge of the hub and I don't see any way to get to the flat on the cones. I guess I hang on to one locknut and try to break the other, then put the axle in the vice to break the other end. Then it will be difficult to get the adjustment right when it goes back ....

If you can't reach the cone flats and the locknuts are not properly exposed then someone put in the wrong cones - not long enough in the cylindrical portion. Campy has nothing to do with it.
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#11
Before doing anything, measure the distance from the end of the axle to the locknuts on both sides.

Please note that you only need to remove the NDS (left) lock nuts, then you can pull the axle completely out of the hub. You should plan on repacking the bearings, which is easier with the freewheel out of the way, but not too bad with it in place.

Most bicycle axles are threaded on the ends only, and as Jef notes are usually 10 x 1 mm. You can also purchase high strength chrome-molybdenum threaded rod from industrial supply houses to make you own replacement axle if desired.

Once the axle is out of the hub, it is a simple matter to remove the remaining cone and locknut with a cone wrench and a regular wrench on the lock nut.
Nigel
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#12
I have probably repacked a thousand hubs over the years, so that's not a problem. On this hub the flat on the cone is inside the face of the hub and the only place to go with wrenches is on the two locknuts. I can wrench on both at the same time, but there will be no gurantee which one will break. I know this because I wanted to repack the hub for routine maintenance, but recognized the problem and left it alone. No idea how it was done originally.
That's not really a problem because once it's out I can remove the other side. The problem comes when I re-install, I won't be able to hold onto the cone while I tighten the locknut. Don't know why it's like this, it's the only Campy thing I have, I never have a problem with any other brand. Once I check what I have to play with on the existing protrusions, I'll know whether or not I have to consider the axle problem. Between riding, playing golf, watching the Tour of California and the Giro, everyday is jampacked, but I will schedule and inspection when I clean the bike at the weekend !!!!
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#13
(05-15-2014, 05:33 PM)limey Wrote:  No idea how it was done originally... Don't know why it's like this, it's the only Campy thing I have, I never have a problem with any other brand.
As I said, the reason it's like that is that someone installed cones that are not properly sized. It was not that way originally. It's possible to depend on the tabbed lockwasher to lock the two parts together when reassembling but would involve a few attempts to get it OK, and just plain is not right. An entire axle set would be the best solution, or at least a left side cone of the proper length and a new axle to accommodate the cone and whatever spacer width (would be less) that is requires with it.
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#14
One of my friends who runs Campy Record, told me that he has three spare axles of varying lengths, which he has collected over the years, maybe he has cones too. If on closer inspection, I cannot one way or another solve the problem, I'll check on the spare axles and hope that I get lucky with the length on one of them. There's always duct tape.
Approx 30 days, 12 hours, 6min and 4 seconds to go !!!!!!
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#15
Done all my measuring and I have 127mm over the 'nuts', so I need two 1.5mm spacers - no problem. I will still have 4mm axle into the dropouts at each side. I went in disguise to Cannondale and asked them, they just replied that the wheel and the frame need to be size and size, 130mm / 130mm.
I believe that my hub is a sealed unit, there are two completely round, smooth 'nuts' that look like cones, no flats at all and they just barely clear the face of the hub. There is a milled pattern on the top face which has to be for grip in the dropouts, too light to be anything else.
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