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-   -   20" rear wheel advice please (http://www.bikeforums.net/folding-bikes/939331-20-rear-wheel-advice-please.html)

saddlesores 03-21-14 10:49 AM

20" rear wheel advice please
 
howdy all. i've got a friend with a dahon folding bike, 20" wheels.
used for local commuting and some light touring.
riding mainly on pavement, with the occasional dirt road.
he weighs around 200+ pounds, with another 25 pounds or so on the rack.
the orginal 20-spoke wheels had too much spoke breakage, so we
upgraded to a 28-spoke rear, but still breaking spokes.

could just be a bad build, or maybe need a stronger wheel.
i've never ridden this sort of bike, so need some advice.
y'all that carry a decent amount of weight....wheel problems?
what would you suggest?

i could buy some new high-quality spokes and rebuild his wheel.
in that case, anyone recommend spoke brand/type and lacing?

or i could just build him a stronger wheel. i was thinking of a novatek
sealed bearing hub (130mm) with 32 spokes. not enough? how about
a shimano dura-ace/ultegra with 36 spokes? thinking of going with an
alex rims DH-19.

fietsbob 03-21-14 11:03 AM

for stunt riding there are 406 20" rims made with a 48 spoke drilling ..

My Bike Friday has a Rohloff hub , 32 spoke rim is a Sun CR18..


wider spread hub flanges symmetrical will be stronger in general , triangulation,

Vs, a dished wheel with a narrow spread between hub flanges, to make space on the right end,
for a Cassette or multispeed freewheel ..

spokes ? European Sapim and DT and Japan's wheelsmith have a good reputation.

little wheels dont really allow many crosses between hub and rim 1 or 2 cross , most likely.

of course with more spokes there are more to cross ..

saddlesores 03-21-14 11:15 AM

thanks for the quick reply.

i'm sorta limited with what i can find on the local economy here in chinaland.
the bike has an aluminum frame, so we're limited to 130mm hubs.

he's got v-brakes, which limits the possible hubs even more. we don't want
a disc mount as that would lessen the spread between the spokes.

thinking of this novatek F172SB. max spokes is 32 which should be fine. i hope.

NOVATEC F172SB 久裕 4培林四轴承公路车大行折叠车升级后花鼓-淘宝网

fietsbob 03-21-14 11:31 AM

Guess you decided you have to have a derailleur shifting drive train then. so be it .

S-A has 36 and a 28 hole hubshell . using a rim not easily divided as 36/24 for example
gets complicated as not all spokes can be the same length..


just have them stop by more often and keep the whole wheel tensioned ,

looser spokes fatigue and break faster..

saddlesores 03-21-14 12:08 PM

Quote:

Originally Posted by fietsbob (Post 16598636)
Guess you decided you have to have a derailleur shifting drive train then. so be it .

48 spokes would be awesome, but not likely able to find anything suitable.
i've seen a few here, but either too wide or single speed.

pretty sure he wants to stick with the current gearing setup.

how much weight do you carry on your friday?

fietsbob 03-21-14 12:21 PM

so far , mostly my 200 pound arse..

I can tow my Burly flat bed trailer with it , for more stuff .

the company makes special rear Pannier racks, I don't own.

and the front one I actually use , with 2 small front Panniers ..

their racks come apart so as to minimize the pack down size ..


others have toured on theirs around the world.

fietsbob 03-21-14 12:26 PM

BTW Shimano's tandem cassette hubs are made in 40 & 48 hole ..

Uses same axle hardware around those 10x1 axles , so they can be narrowed ..

IDK about sourcing it where you are , HK may be Better .

cycle_maven 03-21-14 01:29 PM

Yes- if the rim and hub are in good shape and of good quality, then rebuild the wheel. I'd use DT, wheelsmith, sapin or other quality 2.0/1.8/2.0 stainless butted spokes, and not lace it more crosses than tangential (3 cross on small flanges on a 20" wheel). Use spoke-head washers and tension to 110 KGF on the drive side- make sure to stress-relieve the spokes! But you might be happier with a 32-36 hole Shimano road hub laced to a CR-18, or other eyeletted rim. I like Tiagra for the money; nice strong smooth cup-and-cone hub.

saddlesores 03-23-14 08:09 PM

thanks for the advice.

we'll try rebuilding the wheel first. all the wheels i've had built in china have been
total poop. not centered, not stress-relieved, crappy cast-iron spokes. i'm no wheel-
building sensei, but the few mtb wheels i've built have held up to light touring in rough
conditions.

we'll go with stainless pillar sr14, 2.2/2.0/2.2. 2- or 3-cross, depending on whether
it would overlap the spoke heads. won't know until he brings the bike over tomorrow.

if 28 spokes just won't support his weight, then we can try a 32 rear.

fietsbob 03-24-14 02:11 PM

As I said, I use a 32 hole Rohloff in the center of mine.

TW based, SA has some Wide and High flanged hubs too ..

Rob_E 03-24-14 02:48 PM

I'm over 200 pounds and ride on 20" wheels quite a bit. I've yet to break a spoke, but I always:

Use 36 spokes when possible
Use a gear hub so that my wheels are not dished

Maybe not an option for you, and maybe overkill. I would build a 32 spoke wheel if I had to, and I would be willing to try a dished wheel, too. But if your friend is already having a problem with spokes breaking, then a sturdier wheel might be in order.

Wheelsmith are my spokes of choice, but there are certainly other options that are well-regarded.

saddlesores 03-28-14 10:17 PM

welcome to china, land of the counterfeit fakes.

ordered a 20" alex DH19. contacted a few sellers to get the ERD so's i could
calculate spokes. nobody knew what an ERD was. they just sell stuff. emailed
alexrims.......they don't make that model in 20". website only lists 700C and 26".
ok....maybe the usa salesman doesn't know what they sell in foreign markets?

well, my alex rim arrived today. looks nice. but. the label says "ETRTO-559x18"
oops. if the chinese are good at anything, it's copy-n-paste in photoshop.

it would seem somebody somewhere used a chinese production JP brand "power
circle" DP25D, and switched labels.

note the exactful similarity?

POWER 双层车圈|自行车|铝圈|铝合金车圈|DP25D-淘宝网
正品特价ALEX DH19亚猎士20寸 26寸 32孔36孔v刹白色 黑色V刹车圈-淘宝网

guess i'll just build it up and see what happens. what could go wrong, right?

Violinfish 04-25-14 12:35 PM

1 Attachment(s)
Hi, saddlesores.I'm from Guangxi China, not far away from Hainan.
I'm using power circle's P19, a single wall 406 rim,for my Dahon HSL.
I built the wheels by myself, using a 20-holes front hub (Novatech A551) and a 28-holes rear hub (by Starhubs).
http://bikeforums.net/attachment.php...hmentid=376624
my HSL is mainly used for commuting and light touring. I weigh around 70kg. It seems that 48 spokes work well, till now for about 1 yr.
I think most of the spoke breakage is caused by poor wheel-buliding. e.g. I used to have a 2010 Dahon SP8,with factory-mass-produced 16-spoke front wheel. after 1 year's riding,some spokes losed their tension, and the others got extremely high tension, that cause the wheel swings when rolling in high speed. I guess that if I didn't have repaired the wheel,sooner or later one spoke would have been broken, this never happens on my hand-made wheels.I rebuilt the front wheel and it works well again ,for a relatively long time.
If you want to build strong and reliable wheels , the most important thing is to make sure all of the spokes have been tightened by nearly equal tension.
and before a wheel is ready for road, it must be stress-relieved, and tuning. most factory-mass-produced wheels may not have been stress-relieved and tuned,for productive efficiency and cost-saving. after heavy loaded usage, difference of spoke tension will cause the wheel unstable.(for more info,refer to Sheldon Brown's website.Wheelbuilding)

you can also visit my Taobao online store,首页-阳光海健康生活馆-淘宝网。there're some wheels i had built and sold in my spare time. one of them had been sold to Hainan, bought by a young rider. enjoy it.

saddlesores 04-25-14 08:35 PM

update.

sent the counterfeit rim back, seller even agreed to pay the return shipping cost.
i think like many taobao sellers, he didn't know what he was selling.

rebuilt the big dude's (100kg+) wheels, both front and rear. 28-spoke 2X with
the original hubs and power circle rims, using pillar spokes. so far, no problems
on his return ride to haikou.

also ordered the power circle P25D (extra heavy duty!), laced up to a shimano
deore (130mm, 8spd) hub, 32-spoke 2X also using pillar spokes.

just waiting for him to come pick it up, will be used for a circle-the-island tour
this summer. maybe i can convince him to take the ferry to beihai, and then
do a tour through guangxi province.

in the meantime, it's on display in my living room. so pretty!

User1 04-26-14 04:51 PM

+1 on a good quality rebuild. I had my rear wheel rebuilt after breaking one too many spokes. It's doing good after ~300 miles. It's a 28h, cross two, with DT spokes on it. Oh also the poor thing is carrying +250lbs.


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