Sunday, December 16, 2012

Limit Your Loses

A call/email/text/facebook message no wheelbuilder wants to hear/read:
I was doing some maintenance on my 29er today and found a couple of loose spokes on my rear wheel. Like no tension whatsoever. Is it possible for me to get this wheel to you sometime to get it looked at?


Crrrraaaaapppppp.  That was a message from Keith, who I built some Arch EX/Shimano XT wheels for about six months back.  Immediately the wheels started turning in my head.

Why?
Did I not build them with enough tension?
Did he bend the rim?
What did I do wrong?
HOW DID THIS HAPPEN!?!?

I got in touch with Keith to arrange for me to get the wheel and look it over and I asked a few questions.  He didn't remember hitting it hard on anything.  And no, the loose spoke isn't on the non-drive side, it's on the drive side.

What??  That didn't make any sense at all.  You see, the non-drive side (NDS) spokes only have about 60% the tension of the drive side (DS) on a rear wheel.  That means the NDS spokes only have 60% of the load capacity of the DS.  So, if the tension is too low, and the load capacity is exceeded, it'll be the NDS spokes that go slack and have their nipples loosen first.  So how in the world was there a loose spoke on the drive side of Keith's wheel???  I was perplexed.  We were both going to the SORBA-CSRA meeting so he was going to bring the wheel then.

A day or so after getting Keith's e-mail I received this Facebook message from Kai:
Hey while looking over the bike I noticed a slight wobble in the front rim.  How bad does it need to be before I make an appointment with The Wheel Doctor?
Man! Talk about a kick in the balls!  Two back to back?  What in the world was going on?  We swapped some messages, Kai said the wobble is tiny, he just wants to keep the wheels perfect because he really likes them.  Fair enough.  I was hoping it was just an optical illusion, maybe the tire is just wobbly - most tires aren't perfectly straight.  He was going to bring it over on the weekend.


There's your problem right there.
 
I got Keith's wheel at the meeting and immediately noticed the elbows-out spokes on the drive side were mangled up, apparently at some point his chain jumped the cassette and brought fury upon the spokes.  Once I got it home and really looked it over it had quite a few spokes with low tension, and one with no tension at all.  My theory is that when the spokes got bent on the DS the bend increased the tension on those spokes a lot - the bend essentially shortened the spokes.  That increased tension on a handful of spokes upset the balance on the rest, and things started getting out of whack.  There wasn't any damage to the rim however, no bends or dents or cracks at the nipple holes.  I replaced the 8 outboard spokes on the DS and retensioned the wheel, and now it's good as new.


The offending spokes removed from the wheel.
 
Check your limit screws people!  Keep those chains where they belong.

Saturday I met up with a few other riders and we did a little ride through the woods.  And of all the people to run into, we ran into Kai!  He spun his wheel for me, and sure enough it looks pretty dang straight to me.  I'm guessing it's just a slightly wobbly tire, the wheel itself is fine.


That's the result of uneven tension.
 
Oh, and sometime this weekend I replaced another broken spoke on Mark's Arch EX wheelset.  I'm predicting it's not the last one to pop either.  He rode it with whacky tension for a while, and that's not good for the longevity of the spokes.  But, we can rebuild it.  We have the technology.

That's it for this update.  Keep turning those pedals!




Saturday, December 8, 2012

Prototypes and Last Minute Repair

This is a quick post.

Recently built up a pair of wheels for David, using some prototype carbon rims, White Industry hubs, and Wheelsmith spokes.  The rims are not terribly light (430g), and are on the narrow side.  But, they are tubeless ready and are STIFF as can be and should be indestructible.  They were a pain to build though, the spoke bed thickness varied a good bit, meaning my initial round of tightening with the nipple driver resulted in way uneven tightness.  Both rims also had a 1mm low spot that I simply couldn't round out.  It's not enough to feel while riding, but it still irritated me.  These were prototypes, so hopefully they next round will fix those two issues.

Yummm.....carbon.....the black magic material of cycling.
 
A dirty White Industries front hub.  This thing spins FOREVER.
 
Here you can see how the spoke bed thickness varied.  Notice how much more of the middle nipple you can see compared to the one on the top of the picture.

Thursday night Mark called with an emergency repair, he had a broken spoke on his rear wheel (a stock Stan's Arch EX wheel) and was scheduled to head out of town the next morning for a weekend riding trip at Raccoon Mountain and the Snake Creek Gap pre-ride.  Lucky for him I had several spokes of the correct length on hand, so he brought it over and I swapped in the new spoke.  I also did a quick overall look at the wheel and discovered many of the non-drive side spokes were pretty loose.  I checked the dish and sure enough, the rim was ~5mm off center, towards the drive side.  The NDS spokes (which have a lower tension, and therefore less load capacity) have apparently been slowly losing tension as he rides.  I corrected the dish by increasing and evening out the tension on the NDS, then increased tension on the whole wheel.

The Snake...can you hear it calling?

Monday, November 26, 2012

It's Been A While

It's been a while since my last post, but that doesn't mean I've been idle.  I've had a few repairs come in and out of the shop, been riding a ton, raising baby fishes, and built a set of wheels for Scott's wife Rochelle.  They wanted to use Hope Pro II Evo hubs, just like we did on Scott's build a little while back.  Stan's Crest 29er rims were used because Rochelle is light and isn't going to be hucking road gaps or anything, so the Crest will be plenty stiff and strong enough and will keep weight down.  DT Swiss Competition spokes and alloy nipples round out the parts.  Purple nipples were used to match her Specialized hardtail.

Sometime after the first of the year look for an announcement.  Got some things in the works.

Here's some recent pictures.  Take a look, then go for a ride!


Parts and pieces for Rochelles set.  Final weight came in at 1,711g.
 
Did an 81.5 mile long MTB ride recently, the longest I've ever done.
 
Daddy fish watching over his little ones.
 
Up and over on the Modoc trail.
 
I re-repaired a botched wheel for Keith.  A spoke broke and was replaced by a shop in Anniston, AL, but the new spoke wasn't laced correctly and no lubricant was used on the spoke threads or nipple seat.
 
 
Crashes happen.
 
Coming soon....
 

Tuesday, October 16, 2012

Red Hot for Scott

More wheels laced up and sent out onto the local mountain bike trails! Scott is a friend of Kai, who I built some wheels for a few weeks ago. Scott wanted to go tubeless, drop some weight, and have wheels to match his Specialized Hard Rock Sport Disc 29er.

Everyone knows red is the fastest color.

The build is identical to Kai’s, other than colors. The Hope hubs where chosen once again because they’re well made, easily serviced, and convertible to any axle standard. Stan’s Arch EX rims are laced to the hubs with double butted DT Swiss Competition spokes and alloy nipples. To match the black and red colorway of the bike all the components are black, except for the red nipples.  Spicy!

Scott opted to use American Classis tubeless valves.  They've got some cool features.  My personal favorite part is the small plastic spacer - it keeps the nut up off the rim so it's easier to tighten, and the spacer matches the shape of the Stan's rims perfectly. 


The spacer is a nice touch.

The only thing I'm not crazy about is the way they seal against the rim - they have a metal backing with an o-ring.  The metal backing will ensure you can't pull them through the rim, which is cool. 


Cool detail you'll never see.

But, the o-ring is flat, and it has to seal against a curved surface, so you have to tighten it down enough to squeeze in.  It does work, I'm just not sure about the longevity with that o-ring being so compressed.  Time will tell.  The red anodizing matches the nipples perfectly, and at ~3g a piece they're very light.

The o-ring doesn't match the curve of the rim perfectly, but can be tightened down enough to seal up.

All told, laced, taped, and with valves installed the wheels weighed in under 1900g, and Scott will likely see ~2lbs dropped off his bike with the wheels installed and tires mounted up tubeless.
Ready to ride!

Tuesday, October 2, 2012

First Impressions: Crest Rims

When I built up some Stan's Crest 29er rims I wasn't sure if I'd like them.  The interwebs are full of people complaining about them not being stiff enough, or not tough enough.  Folding in one ride, losing tension and needing constant attention to stay true.  There are also lots of people who love them and have no issues with durability.  So to find out how they really are for myself, when built properly, I laced some up.


The Jabber is weighing in under 23 pounds these days.

I've logged about 60 miles on them now, all on my Jabberwocky.  It's single speed, and rigid - wheels aren't babied on this bike.  Sixty miles is hardly enough for a proper review, these are just first impressions.


A few rocks at Horn Creek.  Photo: Brian Williams

The first ride was three relatively hard laps at Horn Creek.  Each lap was right around 40 minutes - faster than any lap I did at last year's Baker's Dozen. Horn is rooty and rough, good place to beat on wheels.


One of the step ups on the short track course (not me in the photo obviously)

The next ride was two days of racing at the Georgia State Single Speed Championships.  Saturday was the short track, balls to wall for just a few minutes around the campground.  There were several places you had to hop some railroad ties....I couldn't focus 100% on the hop (I was partially focusing on keeping my lunch down) and slammed the rear rim once or twice. 

The short track was followed by a night time time trial around the single track.  I rode the 7 miles in 34 minutes, which earned me 3rd in my class.  Sunday was the cross country race, 15.5 miles in 1hr and 10minutes - hauling balls!  Good enough for 4th in my class.


I spent the entire XC race in a train.  It was a blast, but also really hard.  It was full throttle the whole race, no resting allowed.

Racing is a good way to test parts - I typically beat on my bikes (and myself) way harder at a race than a regular ride. 

So what do I think?  So far so good.  No dents after a few rim strikes, they haven't folded up yet, and they're still perfectly true.  The light weight is nice, but not ground breaking.  I'm used to riding fairly light wheels though, for someone with a heavy set of stock wheels these would make a huge difference in how their bike rides.  I can't feel any weird flex either, but I'll eventually move them to the geared bike which is a better test bed for that - with a suspension fork and a thru-axle that bike gets driven harder over rough terrain.  I also haven't made any big mistakes (aka crashed) on them yet for durability testing...give it time.

Monday, September 24, 2012

Cool New Wheels For Kai

The latest hoops out of the shop are for Kai.  He wanted to upgrade his Trek Mamba to drop some weight and go tubeless easier.  He had previously used a ghetto tubeless set up, using a 24" tube as a rim strip, but it proved problematic when it was time to add fresh Stan's.

The major parts.

Kai was originally looking at the Stan's No Tubes Flow rims, but the more we talked the more the Arch EX made sense.  Kai isn't that heavy, and isn't particularly hard on parts, so the Arch EX is plenty strong and will save some grams compared to the Flows.  He wanted to make sure the wheels were future proof, and could be moved to his next bike whenever that time comes.  We went with some Pro2 Evo hubs from the UK manufacturer Hope.  They have a good reputation for reliability, can be rebuilt easily if need be, and are convertible to pretty much any and all axle standards.  So if Kai's next bike has through axles, his wheels will still be usable.  Hubs for the long haul so to speak. 


Lots of beautiful machining on these hubs.
 
Kai was originally thinking of getting some cool colors to match his bike, but decided instead to go with a black and silver color scheme that will look good on any bike.  Silver hubs, black spokes, silver nipples, black rims.  The set weighed in at 1,864g, 556g lighter than the stock wheels. Combined with a new front tire and no more tubes Kai dropped a total of 807g - 1.78lbs.  NICE!  Enjoy the pics.

The spoke holes on the Hope hubs are chamfered, which allow the elbow and head of the spoke to fit into the hole better.

 These things look great, and I love the sound of the Hope freewheel.  Not a good choice if you don't like noisy hubs however.

 Laced, taped, and ready to get dirty.

Stan’s tells you not inflate tires more than 45psi on their rims. I had heard that only applied if you were not using a tube – with a tube you can go as high as you want. I like using a tube to press down the tape really well...and more air pressure pressed down harder. As a public service announcement – follow Stan’s advice!!! I took this one to almost 60psi before the tire blew off the rim and the tube exploded. It’s really loud. Especially inside a bonus room. My wife was not amused.
 
Checking out the new set up.
 

The black and silver match the bike nicely.  By the time you read this, the red and white decals are probably already peeled off.
 
 

Wednesday, September 19, 2012

This Is A Test. A 1,557g Test

How light is too light?  That is the question.

The Stan's NoTubes Crest 29er rims are light.  Very light.  380g light, that's 85g lighter than the already light Arch EX 29er rim.  Dimensionally they're similar - both have the same basic shape, and the same inner width.  The Arch EX outer width is a whole 0.02mm wider than the Crest rim.  The weight reduction comes from getting rid of some internal supports found on the Arch EX, and thinning the spoke bed.  Well, actually they used to have the same spoke bed thickness, but Stan's has recently increased the thickness on the Arch EX's to increase the spoke tension spec up to 125kgf.  The Crests are still pretty thin though, and carry a 100kgf spec.


Reviews on the Crest rims are all over the place.  Some riders sing their praises, others say they're too flexy and weak.  There are stories of clydesdales beating on them with no issues at all, and there are also stories of 130lbs riders folding them in one ride.  The main complaint however seems to be that they lose tension over time and need regular attention from a spoke wrench.  I'm highly skeptical of this, that sounds more like a wheel that wasn't built well than it does a poor rim.  I've seen first hand how the tension will drop on Stan's rims when a tire is mounted - lacing them up with proper tension is extremely important.  I typically go a little over the recommended spec for this very reason.  Once the tire is mounted the tension will drop down just below spec.  The higher the tension, the more load carrying capacity the wheel has.

I'm weighing in around 170lbs in my birthday suite these days.  I know the Arch EX rims work well for me - they are great rims that will work really well for most XC riders, in fact.  But what about the Crest?  I'm on the heavy side for the Crest rims, but I have a suspicion they'll hold up just fine with a quality build - but there's only one way to find out.  So I tore down the first pair of wheels I ever built (which have seen 3+yrs of use on a rigid SS and never needed truing) and am re-lacing the hubs to a pair of Crest rims to try them myself.


The rear hub after removing the old Arch rim.

The hubs are American Classic.  Much like the Crest rims they're very light - 225g for the rear and only 130g for the front.  Paired with the light rims they make for a very light wheelset.  The completed rear weighed in at only 838g, the front at only 719g, for a total weight of 1557g.  That's the naked weight, doesn't include tape, valves, or skewers.

The rear hub has an aluminum freehub body for light weight, and a few steel inserts help prevent cassettes from gouging the aluminum - it's the best of both worlds.

I like to build so that the top of the spoke is flush with the top of the nipple, whereas many other builders and manufacturers want the spoke to be flush with the bottom of the slot in the nipple.  Their method leaves the slot available for quicker removal of the nipple if need be (you can use a flathead bit in a drill to remove the nipple instead of manually using a spoke wrench), and reduces the chance of bottoming out the nipple (running out of threads on the spoke) before proper tension is achieved.  It's not uncommon for spokes to be even shorter than this in pre-built wheels. 

Proper spoke lengths.

My method ensures the maximum thread engagement, and better supports the head of the nipple preventing it from collapsing and failing (especially important when using aluminum nipples).  I'll trade quicker removal for reliability any day.  To make sure I get the proper spoke lengths I measure the ERD (effective rim diameter - a number used to calculate spoke lengths) myself, and don't just go off the manufacturers number.  Stan's ERD is sized to put the spoke flush with the slot in the nipple, so my measurement is typically 2mm larger than theirs.  On these rims the decal shows an ERD of 540mm, which is a typo .  Their website shows 605mm.  I measured 607mm.

The lightness of the rims is apparent when building them up, they are finicky.  The Arch EX rims build very easily, but these Crests are particularly sensitive to spoke tension and small variances easily pull the rim out of true, I can see how a first time builder could have trouble with them.

I'll report back with some first impressions after I get them dirty this weekend. 

No more decals.  Looks better, and is easier to true.