rear wheel woes

[Guest ratchethack]

Oh, and Ratchet, thanks for dropping by and helping me with something as simple as measuring sag.

After you left, I set it to ~2mm bike only and ~27-28mm with my @ss in the saddle...assuming what we discussed regarding ratios, etc.

I still have to see if it bottoms too easily.

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Por nada, mi compadre.

 

Sure sounds like a LOT of preload, Dave. But maybe it'll work perfectly for you. Lemme know. Me? I'm starting to like my stock rear spring more & more... At 100 degrees F, it's too frickin' hot to ride, & to hot to do the new fork springs/tap the lowers this weekend (no air in the workshop ), think I'll be catching up on some office work with the air on full blast.

[txrider]

I was poking around McMaster-Carr and find two possibilities of pipe that should work. Both are 0.824", 0.113" wall thickness. Check p/n 7750k232, black welded seam steel, $18.30 for 50" length and p/n 44985k14, stainless, seamless pipe at $63.75 for 72". Od for both looks to be 1.050".

[dlaing]

I was poking around McMaster-Carr and find two possibilities of pipe that should work.  Both are 0.824", 0.113" wall thickness.  Check p/n 7750k232, black welded seam steel, $18.30 for 50" length and p/n 44985k14, stainless, seamless pipe at $63.75 for 72".  Od for both looks to be 1.050".

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The dimensions are perfect.

The welded seam may not be good.

And the stainless may be too soft.

Yah, I am still trying to build a space shuttle...

Getting back to Aluminum, the big gotcha is that if you want the right dimensions, you have to go with pipe rather than tubing. But the pipe is only available in at best, Schedule 40, while the tubing is available in 2024, but is thin walled.

Wall Thickness .065"

Inside Diameter .87"

Outside Diameter 1"

Rockwell B is about 65

Another option is the seamless carbon steel

50295K431

Metric Seamless Carbon Steel Tubing 25 mm OD, 21 mm ID, 2 mm Wall

Rockwell B is about 75

or for less money and a thinner wall

9220K431

Seamless Carbon Steel Tubing 1" OD, .87" ID, .065" Wall Thickness or converted to metric 25.4 mm OD, 22.1 mm ID, 1.65 mm Wall

 

PS Yo Ratchet! Yah, that might be too much sag....but the good news is that after a short ride over some kidney breaking bumps, it was nearly a cm short of hitting the bumper.

So, I'll back it off 3mm. The 475# spring may be fine after all.

[jrt]

Time to step up.

 

So who wants to be the guinea pig? I don't have time to do these myself, so I'll get my father in law (aka 'Bob') to run a few off for those who want one. He's a far better machinist than I am (I'm a hack, he's a pro) and he really, really likes motorcycles. Most of his work is making restoration parts for Excelsior's and such.

 

The spacer in my bike is fine- I'll buy one off Bob just to have a spare. Because the one on my bike is fine and because my Eldorado needs my attention right now and a thousand other things, I don't have time to take the rear wheel off my Sport and make the requisite measurements. I won't have time for 2-3 months.

 

Cost will be the cost of making it. I won't make but Bob needs to be paid for his time and the raw material. I was speaking with him last night and he recommended I look at metalexpress.net for materials. They are considerably cheaper than McMaster-Carr. Cool. However, the majority of the cost will be in work, not materials. C'mon, we're talking $20-$40 in material for 7 pieces. I would estimate an hour for each piece, simply because it will take longer than Pete's 5 minutes, and you won't find any machinist that will charge you for just 30. So, the bottom line cost will be $40 or less- I suspect less, but I don't want to lie and I don't want to end up subsidizing this and I'm not a businessman.

Would anyone be interested in paying a surcharge (2-3$) and donating that to v11lemans.com? I haven't asked Jaap about this, and it would be completely independant of him- so he has no liablility in this matter.

 

It's really a toss-up in materials between 6061, 2024 Alu and cold-rolled steel. The amount of material in each: a cylinder 113 mm long, 25.4 mm outer diameter, 2.5 mm thick is 22.5 cm^3. I approximated the volume of material as the surface area of outside wall X thickness. The density of alu is 2.6 g/cm^3 so the mass of the piece is 59 g. In steel, the mass of the piece will be 158 g. 2oz. vs. 5oz. So really, no difference. Pete addressed this point earlier.

Dave, the DOM (drawn over mandrel) steel is just as strong as seamless. There is considerably less dimensional variation as well, so it is a superior choice. I'm leaning toward steel at this point for strength, ease of work and cost (2024 alu- $40, 1026 dom steel- $17).

Txrider, the 7750k232 pipe is just black pipe- very maleable. It's also only 3/4", so I wonder if it would even fit???

 

Dimensions I've been able to glean off this discussion:

113 mm long

25.4 mm OD

2.5 mm thickness

gives an ID of 20.4 (what's the diameter of the rear axle? I've asked before but never gotten a response)

I'll make sure the ends are chamfered.

 

So it's time to step up. If anyone is interested, send me a note off-list (pm or email). I can order materials tomorrow if needed. I welcome any suggestions you might have.

 

Jason

[txrider]

Jason, if you'll recheck my post I checked the id of the 3/4" black pipe and it was in fact 0.824" which was one reason I selected it for review. As to properties I've looked for some tables for compressive strength of cold rolled,stainless and aluminum and strangely did not find the data I was searching for. I'm surely not a metals/engineer type so can't comment on maleability of the black pipe but seems any steel would be stronger than alumunum for the application.

I think you're doing a service by offering this possibility, most of us don't have access to a lathe and the cost seems reasonable. For myself I'll wait until I can do the measurements on my own bike just in case there is some variation bike to bike. There goes the anal retentive again...

[jrt]

Txrider,

Sorry, I didn't notice the ID you gave. I don't have numbers on black pipe, but that stuff is soft. Like butta. Several aluminum alloys are much more brittle.

Here is a reasonably unconnected bit of trivia. Pipe dimensions change depending on whether you are talking to a plumber or an air conditioning guy. Plumbers use ID, AC folks use OD. So, 3/8" copper for me (former plumber) is 1/2" for someone else. Sigh. You can't imagine how many wasted discussions I've had with people over this.

 

If anyone can find ANY data on compressibility, I'd like to see it. I coudn't find anything either, but all the machinists I've spoken to say it's going to be negligible- just don't put a wopping big cheater on the axle. The axle torque should only be 28-30 N m or 20-21 ft lb.

[Guest ratchethack]

Jason, I agree that black pipe is more'n likely too soft. I sure wouldn't use it. Many aluminum alloys are more than hard enough for what we're looking for in this application, but I defer to the Pro's on which alloys in both steel and Alu are suitable. Need more Pro input here. Also the rear spindle torque from the factory manual is 120 Nm, or 88.5 ft-lb.

 

EDIT: I just recalled that black pipe (also galvanized, I think) is inadvisable from another standpoint notwithstanding it's low-grade soft steel: It's rolled from sheet stock and welded along a seam, leaving an obviously vulnerable path of potential failure when exposed to end compression, for which it was not designed. How I happened to remember this is beyond me. I wouldn't use anything with a seam in it for a spacer, but then again, that's just me...

[txrider]

The numbers for steel and aluminum metal alloys properties (compressive strength) are available in Machinery's Handbook if any of you engineers have a copy. Since my "redundancy" I no longer have access to that tome.

[jrt]

Also the rear spindle torque from the factory manual is 120 Nm, or 88.5 ft-lb.

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Hmm, I better look this up when I get home, but on the downloadable CD, section F, page 5, it indicates 28-30 N m. 120 sounds a bit much. But I'll double check against the printed factory manual.

J

 

Edit- I see where you're getting that 120 value (front of the book). Dang, that still sounds like a lot. I'll look at a couple other manuals I have at home.

[Guest ratchethack]

Jason, I just cross-checked it against a torque spec list for a "Guzzi Big Twin G5", and the rear spindle nut on these is 100-108 ft-lb.

 

20-21 ft-lb is what I use for spark plugs. Sounds more'n a mite puny for a big 27 mm spindle nut.

[jrt]

I just cross-referenced against my G5 manual. Too funny.

You're right, of course- 100+ft lbs is specified. I guess the section of the manual is incorrect. Thanks for pointing that out to me.

J

[Guest ratchethack]

por nada

[pete roper]

    I just cross-referenced against my G5 manual.  Too funny.

You're right, of course- 100+ft lbs is specified.  I guess the section of the manual is incorrect.  Thanks for pointing that out to me.

J

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Surely nobody actually uses a torque wrench on axle nuts???? Unless of course they have weedy spacers when I suppose there is an un-necessary need.

 

Good lord, it's a wheel spindle, you do it up until just before you fart! All it's got to do is clamp a few bits together and not fall out, how hard is that. I believe the V11's even have a nylock type nut to stop it falling to bits of it's own accord but honestly If you can't work out how tight an axle nut should be then I suggest that you shouldn't be allowed out in public without a leash, and you certainly shouldn't be allowed to ride a motorbike, never mind work on it

 

Pete

[Steve G.]

Geez Pete, we all can't have vast reserviors of flammable hot air like you in which to properly guage 'your' version of the proper torque, never mind the torque values given by the company that actually made the bloody machines!

I guess when you have an engine build in front of you, you must fill up with lovely stuff like chili, broccolli, and other notable gas boosters.

What's the torque when you piss your pants?

Ciao, Steve G.

[Guest ratchethack]

Reckon he dropped another Ambo flywheel on the same foot?!