RoadBikeReview.com's Forum Archives - Fixed Gear


Archive Home >> Fixed Gear


Rear wheel building.........(18 posts)

Rear wheel building.........Dave Hickey
Nov 14, 2002 9:43 AM
I just picked up an old Dura Ace 7400 freewheel rear hub. I want to build a fixed wheel out of it. I have no problems centering the axle but I have a question regarding centering the hub body. Do I center the wheel using the flanges? The reason I ask is because the hub body is not symetrical. The left side(non-drive) has slightly more protrusion outside the flange than the driveside. Also, the flanges are a lot closer together than a track hub. Is the wheel going to be strong enough?
i would thinkSteve_0
Nov 14, 2002 10:12 AM
it doesnt matter WHAT you center, as long as you properly space the axle afterwards to center the wheel. If the protrusions is only `slight`, I cant imagine youd be affecting axle integrity either way.
It's not a lot......Dave Hickey
Nov 14, 2002 10:27 AM
The left side of the hub body protrudes beyond the flange about 5mm more than the right.
A very sophisticated drawing of what I'm trying to ask.Dave Hickey
Nov 14, 2002 10:48 AM
Do I center the rim halfway between A or halfway between B?
eitherSteve_0
Nov 14, 2002 11:01 AM
If you center between B, then the hub will be off-center 5mm, In order to center the wheel between the drops you'll need to offset the axle by 5mm using spacers.

If you center between A, you'll wont need to offset the spacers, but you'll need 5mm of dish in order to center the wheel between the drops.

I think. This, coming from a guy who never built up an asymetrical hub.
That makes sense. Now, which is preferred?Dave Hickey
Nov 14, 2002 11:15 AM
We're also not even considering chainline..
Center the rim on AAllez Rouge
Nov 14, 2002 11:04 AM
That's what "dish" is all about ... the spokes running to one hub flange run at a steeper angle than those going to the other flange. The purpose is to allow the wheel to be centered in the frame while allowing room for the cassette on the drive side. If you center on B, there will be no dish and the wheel will not be centered in the frame.
But on a track wheel, the dish is equalDave Hickey
Nov 14, 2002 11:12 AM
on both sides. I can center the wheel in the frame either way by adjusting the axle spacers. That's why I'm confused.
Maybe it's ME who's confused.Allez Rouge
Nov 14, 2002 11:25 AM
Maybe I'm misinterpreting your sketch. Which is the drive side? I assumed the large extension to the left is the spined shaft where a cassette goes. No?

Also, is the sketch more or less accurate proportionately? There appears to be a very large difference between A and B but maybe this is where the 5mm you mentioned comes in. If so I think Steve_0 is *mostly* correct in saying that it won't matter. "Mostly" because if the difference is only 5mm TOTAL, you should only have to move the wheel a maximum of 2.5cm to center it. That's 1/10", probably not enough to matter unless it screws up the chain line.
The right side is the drive side..Dave Hickey
Nov 14, 2002 11:28 AM
I want to screw a single cog on. I'm probably overthinking this.
Okay, I think I understand now.Allez Rouge
Nov 14, 2002 12:17 PM
Just went back and reread the whole thread, and had another look at your sketch. I think Steve_0 is right: the stresses are theoretically different with each method but in practice it won't be enough to matter. I still think (if I am, in fact, understanding all this correctly) that the most off-center the rim can possibly be is 2.5mm since you will only need to compensate for half the 5mm difference. So, yeah, you may be overthinking it.

If you're really antsy about either method, I suppose you could put the rim off-center by 1.25mm and then make up the other 1.25mm with the axle adjusters ...
Thanks for all your help. nmDave Hickey
Nov 14, 2002 12:27 PM
(unless you play with the axle spacers)Steve_0
Nov 14, 2002 11:21 AM
not saying centering on B is preferred, just that its possible. Centering on 'B' would (theoretically) result in a weakspot on the axle. Centering on 'A' would (theoretically) result in a 'weak' side of the wheel.

In actuality, I dont think 5mm is will make a diff either way.
I may be misinterpreting this,madstork
Nov 14, 2002 12:38 PM
and I may be telling you stuff you already know, but here goes.

The rim should be centered between the axle locknuts, using the outside locknut distance as the guide. I'm not sure that A in your drawing is locknut to locknut. If it is center on that.

No matter where the hub ends up on the axle after chainline is established, the rim should still be centered between the locknuts whick leaves the wheel centered in the frame. This may mean that you don't have a dishless wheel, but that's o.k. Look at a 9/10 speed wheel. The rim almost hangs over the drive side flange, but it is centered - between the locknuts.

Based on my limited experience of converting a built wheel with a freewheel hub, I would do this:

Since you haven't built the wheel yet, get the chainline correct first. Put the hub in the frame and play with the axle spacers until you've got satisfactory chainline. Then build up the wheel which will include centering it between the locknuts.

Hope this helps.

madstork
I may be misinterpreting this,Dave Hickey
Nov 14, 2002 12:48 PM
madstork says:

"Since you haven't built the wheel yet, get the chainline correct first. Put the hub in the frame and play with the axle spacers until you've got satisfactory chainline. Then build up the wheel which will include centering it between the locknuts."

This make sense. I think chainline is most important and let the dish take care of itself.
That's rightbrider
Nov 14, 2002 3:13 PM
Chain line first. That's probably going to put the hub farther into the spacing. You may not even be able to do this, as the freehub may interfere. It would be better if you could get an old threaded freewheel hub (what I used to build up a SS rear wheel) and play around with the spacers to get the proper chainline, THEN build up the wheel to center the rim properly.
What Madstork said. nmeddie m
Nov 15, 2002 6:11 AM
Update.......Dave Hickey
Nov 15, 2002 9:41 AM
I went home last night and played with the axle spacers and centered the hub in the dropouts. Chainline is perfect and the dish will almost be symetrical. Thanks for everyones advise.