sometimes retro should stay in the past

[wallymann]

built up some old Sun metal rims onto disc hubs for my grinder. was chuffed to bits with the way they came out:

http://brown-snout.com/cycling/bikes/chinaman_grinder-ac024/IMG_3655.jpg
http://brown-snout.com/cycling/bikes/chinaman_grinder-ac024/IMG_20140704_213746_409.jpg
https://scontent-a-ord.xx.fbcdn.net/hphotos-xpf1/t1.0-9/10544326_10203555577281926_1793594952207274199_n.j pg

but one of the rims has "issues"...i've been riding the grinder ~2 weeks now and after *every* ride i've come back with a slight wobble on the rear that needed a touch-up. that's normal, things settle, spokes ping/unwind, etc, no biggie. but after +6 rides and no improvement?! in fact it seemed to be getting worse...

well after the local tuesday-night-worlds ride, same deal -- had a bit of a wave to deal with...threw the rear into the park stand and got it nice and true. popped it out of the stand (with aired up tyres in place) and bounced the wheel a couple times on the floor.

and this is what i got (600kb video):

http://brown-snout.com/cycling/bikes/chinaman_grinder-ac024/wobble.wmv

thats just ridiculous! a little pissed about spending all the time/money to build these up, only to have the rear show it's tendency to pringle at the slightest touch. i'm assuming the rim is toast...i'm punting on these sun rims, screw retro for the grinder -- i'm re-doing this wheelset with h-plus-son archetypes in gray.

[fogrider]

that rim was designed for 6/7 speed! I'm assuming 32 spokes, how much tension did you need on the drive side and non drive side?

[wallymann]

that rim was designed for 6/7 speed! I'm assuming 32 spokes, how much tension did you need on the drive side and non drive side?

correct 32h. no spoke tensiometer, but the rear is a PT hub which has flange specs that help equalize both spoke length and tension, spokes end up identical length on either side. the rear setup, dish wise, is much more balanced than the front.

contrast that with the front disc hub, which has significant spoke-length and dish differntial from the disc to non-disc sides. despite that, the front has stayed perfectly true.

i think the rear rim had some latent issues.

[oldpotatoe]

correct 32h. no spoke tensiometer, but the rear is a PT hub which has flange specs that help equalize both spoke length and tension, spokes end up identical length on either side. the rear setup, dish wise, is much more balanced than the front.

contrast that with the front disc hub, which has significant spoke-length and dish differntial from the disc to non-disc sides. despite that, the front has stayed perfectly true.

i think the rear rim had some latent issues.

Sometimes tough to see if a rim is 'bent' or deformed until ya build it and then ride it. Sun rims, IMHO, are kinda soft. IF the tension was too low, then you rode it, first ride, it might have bent/deformed then..erratic tension when retruing is the inevitable outcome.

You can try to take all the tension off, re-do, make sure tension is proper. Re-try..if it goes out again, it's telling you rim is ill..BUT a tension meter would tell you a lot right after you finish the wheel, before you ride it. It would tell you if the tension is high enough and how even it is. I suspect the tension is erratic around the wheel, making for the wheel to go outta true.

[Gummee]

I rode a pair of Mistrals for years. Minor issues with the rear. None in the front.

...then the ex- ran in to me when we were out riding and taco-d that rear wheel or I'd still be riding it. Grrr

You may try a Mistral with the 'aero' shape in the rear. That deeper section should help

Failing that, TB14s have the same look and shape.

M

[FlashUNC]

Shame. Those are cool looking rims.

[nathanong87]

http://brown-snout.com/cycling/bikes/chinaman_grinder-ac024/wobble.wmv

:eek:
http://upload.wikimedia.org/wikipedia/en/2/2e/Image-Tacoma_Narrows_Bridge1.gif

[Fivethumbs]

I've got a set of those hoops NOS that I have sitting waiting to build up as soon as I find a set of 6401 hubs. Now I'm having second thoughts

[wallymann]

I've got a set of those hoops NOS that I have sitting waiting to build up as soon as I find a set of 6401 hubs. Now I'm having second thoughts

i think you'll have better luck with a traditional build, plus i think my rims werent truly NOS. despite appearances, they were previously ridden/used.