Drive side spokes
 

Why not use thicker spokes on the drive side?

If I am ordering two different length spokes for the back already and building the wheel myself. Is there a downside to this? I have heard people say its unnecessary and i would have to agree that it is most likely overkill but considering there would be no extra expense, should make the build easier, and result in a stronger wheel....

Why not?

what did you have in mind ?

No reason. I and many experienced wheel builders do exactly that as a way to compensate for the difference in tension.

(though I like to look at the bright side and think of in terms of using lighter spokes on the NDS)

2.0x1.5 NDS and 2.0x1.8 DS or 2.0x1.8 NDS and 2.0 DS**********?

Either is reasonable, but if you're going to make these types of decisions, you should have the basis set in your head first.

I prefer to use DB spokes all the way around, so I'd lean to the first option, but my actual choice always depends on the specifics of the wheel, ie. rim, rider weight, putpose, etc.

My belief is that thinnner spokes have value for balancing tensile stress, but not thicker spokes. Here is the simplified answer: If you start with heavy gauge spokes for some reason, you will get better wheel durability by going thinner on the NDS. But if you are already using light gauge spokes all around, there is no advantage except a little stiffness gain to using thicker spokes on the DS. Different gauge spokes on the two sides does not balance spoke tension. It balances the tensile stress which is different. Lighter gauge = higher tensile stress. Higher stress is better because it leades to more spoke stretch. That is better because it protects the spokes from going slack when the rim is compressed. So lighter spokes are always better. That is what I mean when I say it makes sense to go lighter on the NDS if you insist on heavier everywhere else. But it doesn't make sense to go heavier on the DS for any reason except a little stiffness.

This is a case of raising the bridge or lowering the water. It's simply a question of outlook. Since the wheel has no way of knowing where you started, either action is functionally identical.

I agree with the res (unquoted) of the post. Using lighter spokes increases the elongation at the same tension, increasing the working distance in the spokes elastic range as the rim flexes inward.

What rim, what hub, how many spokes, what do you weigh, what size tire, what type of road conditions.....

mixed spokes
 

Yes the actions are functionally identical. It's the thought process that is different. If you have some reason to insist on heavy DS spokes, then I would encourage you to make a better wheel by lightening up AT LEAST the NDS spokes. But if the wheel is already planned to be light spokes all around, I wouldn't bother to make the DS spokes heavier. It serves no purpose IMO. Hard to explain, but it boils down to this: I recommend Revolution, Laser or CX-Ray spokes exclusively. You can't build a more durable wheel. You want a little stiffer wheel, use a few more spokes. But I wouldn't use heavier spokes.

You just "think" the thought process is different.

I tawt I taw a putty tat.

I built up a rear for my Heron with 15 gauge double butted spokes and it does fine. There is very little difference in the ultimate tensile strength of the two sizes. What makes for a strong wheel is the right number of spokes for the weight of the vehicle and proper tension.

Here is what I just posted on the other current spoke choice thread. IMO it is what choosing spoke gauge is all about:

The correct choice of spokes is very simple. Spokes do not routinely break in the center, only at the J bend and near the threads. There is plenty of tensile strength in even 1.5 mm spoke sections to accommodate very heavy riders. Even the lightest SS spokes available these days have the same gauge J bends and thread areas as the heaviest, so have the same inherent resistance to breakage at those points. There is no strength-based rationale for using any spoke heavier than 2.0/1.5/2.0. Because the lighter spoke stretches more at any tension than a heavier spoke, it has more "return travel" before going slack when the rim is rhythmically compressed at every point on every revolution routinely and compressed by accidental stresses like hitting a pothole occasionally. That helps to keep the spoke from fatiguing and failing at the previously mentioned spots, the J bend and just below the threads. For the vast majority of riders the most durable and most comfortable wheels they can possibly ride will be built only with such spokes like Revoutions, Lasers, and CX-Rays.

The one reason to use heavier spokes than that is to obtain greater stiffness, which according to Rob at Psimet is not best accomplished in that way. The lighter spokes do result in some loss in wheel stiffness. Some of this lost stiffness can be regained by using more spokes rather than fewer, but probably not the entire amount. If stiffness is an issue for you that can't be resolved by more spokes and a stiffer rim, then perhaps a heavier spoke is proper for you. And in that case using the heavier spoke first only on the DS and maybe the front would be the smart plan. It is imperative to preserve the high level of stretch in the less tensioned, NDS spokes. Using heavier spokes on the NDS should be avoided if at all possible.

To give you some idea of the quantities of stretch we are talking about, a 2.0 mm diameter spoke stretches ~1.0 mm at 120 kgF, the common DS tension or 0.5 mm at 60 kgF a common NDS tension. That NDS stretch is not sufficient to protect the spoke from going slack periodically when the wheel is in use. The greatest popularity of 2.0 mm spokes was back in the day when wheels were not so heavily dished and DS and NDS tensions were commonly much closer. So the NDS stretch was closer to the 1.0 mm on the DS. That is not the case now. Revolution spokes however stretch about twice as much, so even at 60 kgF on the NDS they are stretched about 1.0 mm, plenty to protect against most instances of rim compression which could cause slackening of the spokes.

This is it in a nutshell: lightest spokes = best wheels unless desired stiffness cannot be achieved by spoke count and rim properties. If the DS and front wheel stretch is too high and the nipples bottom out before full tension is achieved, just go to a slightly shorter spoke. Don't change to a heavier spoke to moderate the stretching.

Yes, that post made Spock cry.