Blue Triad w/ American Classic 420s

[scott07]

I just bought a 2010 Blue Triad with American Classic 420 wheels. These wheels are 700x20 which is different than what I'm used to, 700x23. I haven't had a chance to ride the bike outside/at all yet, and I have a few questions.

First of all, being a 180 lb rider, will I be able to use these wheels? Being that they're thinner rims, I'll need to up my pressure, right? With a max pressure of 120 psi for the rims, will I be able to achieve appropriate pressure at that size rim with my size?

Secondly, if I can use these wheels, what can I do for a trainer tire? Most trainer tires are 700x23, so there's a blowout possibility according to my mechanic. I've considered getting a cheap wheel and throwing a cheap cassette on it, but I'm running a 10-speed SRAM Force cassette on the American Classic 420s.

Do I need to get rid of the 420s and get something a little wider or can I roll the 420s? If so, can I run a typical trainer tire or do I need to get a different wheel?

Thanks for the tips and advice.

 

[davereo]

You can use any old 23mm tire you have kicking around as your trainer tire.

 

[alienator]

I think you might be confusing tire width with rim width. AC 420's have the standard rim width, 19-20mm. The most popular 700c tires are almost certainly 700 x 23mm tires, meaning the tires are nominally 23mm when inflated. At 180lbs you can use 23mm wide tires, but I'd suggest considering 25mm wide tires so that you get a bit more comfortable ride and better grip via a better shaped contact patch. For you all else being equal, 25mm wide tires will last longer than 23mm tires. As for the AC 420's you may as well ride them until either they break or you decide you want something else. They're not known for being the most robust wheels, but they are popular and generally get favorable reviews.

 

[swampy1970]

They're a pretty good set of wheels and will take a fair beating before the rims ding. I rode on a set of CR-420's with Sapim cx-ray spokes for a couple of years before I discovered the weight limit was 185lbs - and I was above that for most of the time back then. It took a fair sized pothole at ~40ish mph and a 182lb me on top coming down Monitor Pass to stick a dent if the back wheel. Not a huge dent but big enough to make rear braking a pain on the rest of the Death Ride. I still use the front wheel from time to time and it still runs true. The San Marco regal saddle that was on the bike during that near ball crushing incident suffered a bent rail - that's how hard of a hit that it took. There are a couple of different weight limits for those wheels depending on the spokes you have. I think the round spokes are 225 and the flat blades are there too. The cx-Xray spoke model limit is 185. Theres a section on amclassic.com under support on this. Continental make the Gp4000 in 700x20 and if you get the black on black you get the black chilli compound just like the 700x23 GP4000S. 23's do run slightly nicer but using the powermeter says (via the Chung method and golden cheetah) there's a noticeable difference in speed for a given power with the 20 coming out better. We're talking "time trial" noticable over 40km - but not something you'd go "damn, these are way faster!!!" by the seat of the pants feel. That said, I won't be using a 23 up front on some silly long distance brevets I have coming up to get the miles (or should I say kilometers) in. 400km in one sitting is bad enough to start consider small gains worthwhile. 600km is definitely so... I don't notice any difference between the two tires when cornering like I do on my 36 spoke "stiffer the anvils" training wheel - the 420s are hardly stiff and probably flex more than the 23s sidewalls during cornering. LOL. You'll be fine on the trainer with them. I just use some cheapie specialized tires from sport chalet - tougher than nails and last a long time. By contrast the knurled roller on my trainer chews the conti's up real quick. For a trainer with a plain roller this shouldn't be an issue. Just an FYI - you need 16mm rim tape for these wheels, a size that most bike stores seem not to carry. 16mm plastic rim strip works best. Velox 17mm, despite with you local bike shop might say, absolutely does not fit and the next common size down for Velox, which is around 11mm will work ONLY if you center the tape perfectly otherwise the tape sinks into the spoke holes and the edges of the spoke holes will puncture the tube. I had that happen to me on the back wheel - but as I carry a bit of spare tire and a knife a "get out of jail" fix was made and the long walk home - or the wait of shame was avoided.