Thursday, July 15, 2010

Araya Rims, Gold 16b to RC-540; No More Tubulars!


Well obviously it has been too long since I posted on this blog. I have been doing all my postings on my political blog OSB Politico and just riding. I also see I picked up a couple more followers; welcome and thank you. Anyway it was time to clean up the Soma NJS bike The Soma Bike is Done . My original build used wheels built with Araya Gold Tubular rims; Keirin bikes only use tubular tires. I have never used tubular tires, but they were once very common, so I figured I could embrace the retro side of me, and add one more NJS component. Well it didn’t work out so well. I wasn’t about to spend the $270 @ for Soyo NJS tires (and those are the cheap ones), so I went with $80 Vittoria CX. This is where I went wrong. What I failed to notice was the NJS tires are 1 1/8 wide, that’s over 28.9 mm! Yikes. I bought the Vittoria’s at a standard 21mm and they were a mis-match. I did not really know it at the time so I tried gluing them anyway but the tire would not lie down against the outside edges of the rim surface no matter what I did. After three tries I just hung up the bike and moved on to other projects.

Well the time has come to fix this problem. I could look for some wider, ie Vittoria Pave EVO CG in 27 mm or the Continental Tempo in 1”, both about $100 @. They are pretty much on the opposite side of the spectrum with the Vittoria being a ride it till it wears out and the Conty a quick and sketchy race tire, but good on the track. I decided to do neither and punt.

I sold the rims and tubulars on ebay and bought some really cool Araya RC-540 rims. The RC-540 is considered a clincher version of the Araya Gold. They are really just a very nice race rim similar to the classic Mavic Open Pro. What sets them apart is the top surface of the rim was polished before it was anodized. It’s nowhere near the finish of a the un-anodized Araya Gold, but it is also more durable. They are also impossible to get outside of Japan, so I used an ebay importer and they were delivered straight away.

Here's the rear wheel hanging in the garage. I laced the rims with the longer spokes for practice; just waiting for the shorter spokes. I’ll admit I am not an experienced wheel maker. I’ve made maybe 7-8 wheels but I’m getting faster. I held the slimmest of hopes that the old spokes would work, but my doubts were realized. Since the clinchers rims are about 50% taller at the spoke, this made the spokes too long.

I fumbled around with a spoke calculator and finally came up with 289 for the front and 299 for the back. The fumbling was figuring the ERD, or Effective Rim Diameter. The spoke calculator asks for this measurement, which is the inside rim diameter plus the additional length the spoke would need to thread into an installed nipple. Since the nipple is up, inside the rim cavity, it's not always and easy measurement to take accurately. I finally came close using the rod end of a caliper, adding 3mm x2, or 606 mm (there are also web pages with ERD ratings for most rims, but it is recommended you measure it yourself; the rim database said the Araya RC-540 had an ERD of 606.3mm) . The Suzue hubs have 36 spoke holes, have a 67mm spoke hole diameter (circle) and the flange spacing is 74mm for the front and 67mm for the rear; again the front is 3 cross and the rear 4 cross. I used this simple spoke calculator and came up with 288.8 front and 299.6 rear; try it yourself. This calculator only works with same size flanges and doesn't take into account the dishing of a rear wheel with a freehub for a gear cluster. Spoke Calculators can get very involved such as this one from machinehead but this one from wheelpro will handle most wheel builds.

I had a second hope that the shorter 3 cross spokes might work with the rear 4 cross pattern, but no luck, they were 295mm and as I said I needed 289mm. The spoke size might be a little off, since the old spokes were 295 and 302 respectively; 7mm difference where my spoke calculator showed a 10mm difference. My LBS didn’t have the spokes I needed so I had to order them. I did notice the 302mm rear spokes were a little short (or just barely covered the spoke threads) when I removed the old rim, so if they had been a millimeter or two, it would have been more consistent with the spoke calculator; just to be sure I also ordered some spokes 287 and 298. Like I said, I am not a boy wonder wheel builder, but I figured I can return the spokes I don’t use.


Okay I'm back. Why did I do that? Why did I round 288.8 up and 299.6 down? Well guess what? The 299 spokes were a little short. I don't know if most wheel makers want the spoke threads completely covered with the nipples, but I do. When I built up the rear 4x wheel, there was about .5 mm of threads showing. By simply rounding up I would have spokes the right length (300mm). So I bit the bullet and went out and bought the right length spokes. They say that the money you pay to make up for your mistakes wrenching bikes, is tuition. I am a bit perturbed about the info I found on some of the forums I checked trying to nail down the spoke size. There were several that recommended rounding down, or even going for a millimeter shorter if they don't have the size you need. Most spoke nipples have 3mm lead way once the spoke threads are covered. The only way would want to round smaller is if you don't mind the threads showing, or you are going to use 16mm nipples opposed to the standard 12mm. While I'm not a perfectionist, I do like to think what I do is done the right way. I did return the 287/ 298 spokes I ordered, but I still had to pay for shipping both ways. I also have a nice collection of spokes; 287mm, 295mm, 298mm and 302mm. Hopefully they'll come in handy some day.

And here they are! Suzue Pro Max NJS hubs with Araya RC-40 rims and DT Champion 15g spokes; 3 cross in the front and 4 cross in the back.

I chose the Specialized Pro Roubaix for two reasons, primarily they were the only non-committed road tires I had. So a better question is why I bought the tires to begin with. The reason is these are some of the sweetest tires on the market. The reason why, is the tires are made by Vittoria. The Roubiax-Pro is similar Rubio Pro and the Roubiax S-Works is similar to the Open Corsa Evo, both with a slightly lower thread count. Both designs are referred to as Open Tubular construction, meaning like tubulars they are hand made, have an inner latex tube with an outer casing; they are rated 700x23/25c, meaning the volume of a 25c and the tread of a 23c. I also like these tires because you can get then very cheap because the come stock on Specialized race bikes, and every one wants to switch them out for something else so I got them at half price on the take off table. I have actually not tried the Ruobiax Pro, But I have tried both the Roubiax S-Works and Vottoria Open Corsa Evo. I would not place them on the same level as a tubular, but they are a very comfortable tire. Hopefully the Roubiax will not disappoint.

The final build (so far) :
Frame: Soma Rush (55cm);
Fork: Threaded Tange steel;
Headset: Tange Levin (NJS);
Bottom Bracket: Hatta R9400 (NJS);
Crank: Shimano Dura Ace Track (NJS);
Pedals: MKS (NJS);
Toeclips: MKS aluminum (NJS);
Straps: Toshi (NJS);
Handlebars: Nitto B125 CroMo (NJS);
Stem: Nitto Pearl (NJS);
Rims: Araya RC540; Spokes/Nipples: DT 15g; Hubs: Suzue Pro Max (NJS)
Tires: Specialized Pro Roubiax;
Wheels: 3 cross front/ 4 cross rear;
Cog: 16T Shimano (NJS);
Seat post: Nitto Jaguar SP72 NJS;
Seat: Brooks B-17 Champion Sprinter
Brake caliper: Tektro;
Brake lever: Soma.

1 comment:

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