29er Crest rim, built and perfectly true, DS spokes at max tension, but non – DS spokes at singnificantly lower tension.

Any attempt to increase spoke tension on the NDS move the wheel out of alignment which I then can’t correct without violating the max rim spoke tension.

The DS is currently at 97kgf, the NDS is currently at 66kgf…they feel, well, flexy.

wrong thread, repost on bike forum 🙂

If you’re certain that your measurements are accurate there are two choices.

1 accept it as is. Maybe try riding the wheel to see if it feels flexy.

2 break the rules and ‘over tighten’ the DS spokes and tighten the nds ones until you’re happy.

I’d probably go with 2 myself.

As Nemesis says I’d go with option 2 and just tighten the DS, are you sure that’s the recommended max anyway? Sounds a bit low to me, though it may just be the particular spokes you’re using.

Sure you have the correct spoke lengths?

I had the same issue with some Iron Cross rims I built recently – once I stress relieved it from the initial build and then put a tyre on and inflated for the first time the spokes all lost some of the tension. Re-tensioned everything as the spokes at max tension measured about 2 notches less on my Park gauge after I deflated the tyre and everything seems more normal.

As a comparison I have some Hope Hoops using Crests and they have a large disparity between the two sides as well (and I’ve raced then for 2 seasons). Think it’s a function of the low overall max tension on the Crests (95kgf?) making the non drive sides appear very very loose.

Everybody bar spxxky nails it.

OP if you post up your hub and rim details (ERD, centre-flange distance on the hubs and flange PCD) plus how many spokes you’re using and what cross pattern I’d be happy to run the calculations.

We use http://www.kstoerz.com/freespoke/fullcalc which gives you an indication of the relative tensions you’ll have in each side once built – very useful when comparing potential builds as you can see what will give you the most evenly-tensioned wheel.

remember the basics: uniform tension, fully stressed, no twisting. higher tension does NOT build a better or stronger wheel. If it’s straight and true, it’s done. Ride it, check it again after that.

Deja-vu ? 🙂

I may be missing something but the two sides will not have the same spoke tension, ever, unless the angle at which they go between the hub and the rim is the same, which it generally is not for a rear wheel. The lateral force must be equa which means the tension multiplied by the sin of the angle from rim to hub. If the angle is small, as in the drive side, the tension will need to be high.

Yeah. What captaindanger said. How did we get so far through this thread before someone posted that?

Because no one states the bleedin obvious!

As above, I’m aware that spoke tension, especially on the rear will be lower on the NDS due to the dish of the wheel, but it’s more about the feel than he numbers. This isn’t my first wheel build, but is the first where I’ve run into this problem.

Again, it’s the coupling of a lightweight rim (crest 29er) with thin, lightweight spokes (DT Revs) that’s causing the issue.

The spokes are 292mm in length for both sides. The recommended length, (according to my home made excel table) for CK ISO disk hubs on Crest 29er rims using a 3 cross lacing pattern are :

NDS rear = 293.4
DS rear = 292.4
NDS front = 292.4
DS front = 293.1

So 292mm spokes were used all round.

Crest 29er rears are possibly the worst wheel i’ve ever had to build, well, since the GEL280 and GL330 went out of production…….

Freespoke gives lengths within 0.1mm of those, and I’d agree using 292 both sides is fine.

Expected tension in the NDS is 59% of the DS so you’re already over that; I’d say it’s as good as you’re going to get and you’re only going to be able to “improve” on those tensions by going over the max recommended on the DS, or swapping to a different hub/rim combo which allows for more even tensions (e.g. an offset rim).

I ended up using washers in my Alpha rims after corrosion let a nipple pull through