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42 to 39 chainring or 12-25 cassette?
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Hey folks,

I've got a race in Ohio this year that is on the same course as the American Triple-T (little smokies 1/2). They recommend a 42-25 setup for their big climb out of the park (which you do twice).

I'm on a P2k 650c with the standard 53-42 chainring and 23-11 cassette. I have a 39 chainring that I can take from my road bike. Any guru's out there know if a 39-23 would be similar to a 42-25 setup? Easier or harder?

PS: I'm a hill-wuss. I'm in pancake-flat Indiana where there are no hills.

Thanks in advance,

Gill
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Re: 42 to 39 chainring or 12-25 cassette? [Gill] [ In reply to ]
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A 39-23 is a tiny bit harder than a 42-25, but they are very close. Do you know if their 42-25 recommentation is based on 650c or 700c wheels? If based on a 700c, then I would think you'd be fine with your current setup.

Pesonally, I'd stay with the 53-42 and maybe swap out your cassette for a 12-25. Well actually since the bike is 650, and unless the hill is killer, I'd go with a 12-23 to get tighter gearing and leave my easiest gear at 42-23.

Then again, if you just go to your 39 you won't have to spend any cash. (That's no fun though.) This is going to wind up being a personal preference thing.
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Re: 42 to 39 chainring or 12-25 cassette? [Gill] [ In reply to ]
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Just a note: If you have Ultegra components, there are two 53 big rings (A and B). I believe the A is supposed to be matched with the 42 and the B with the 39. The teeth on the B are machined a little better for smoother shifting, since it has further to travel because the 39 is smaller in diameter. I am in the process of changing my P2K 42 to a 39 and am told that there really should not be that big of difference.




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Re: 42 to 39 chainring or 12-25 cassette? [Gill] [ In reply to ]
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The difference between 1st gear ratios is less than 1%. I would go with which ever gives a closer spacing because it's easier to maintain the right gear and a good cadence.
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Re: 42 to 39 chainring or 12-25 cassette? [Pooks] [ In reply to ]
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If the wheels are 650 - and he has to get a new cassette... why not an 11/25 just to cover the range?
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Re: 42 to 39 chainring or 12-25 cassette? [MS.kansan] [ In reply to ]
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I'd get a 12-25 instead of a 11-25 just so I could have a little bit tighter gearing. It woud be one less two tooth jump between cogs. I tend to think it's more important to have the climbing gears you need rather than an 11 tooth cog. Besides, I'm not sure you can get an 11/25 without combining two cassettes. I don't believe Shimano makes one although somebody probably does.
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Just ride! [ In reply to ]
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Gill:

Not to sound cynical...but just RIDE! Go out and play the hills right. Don't blow your HR out of it's range going up. Keep it easy on the uphill. Then just pour it on during the downhill! No need to go swapping out casseete and chain rings. If you can control HR, you'll be better off and you'll drop people like crazy. Ride your normal set up and be smart on the hills. Triathlon is a thinking man's sport!

I remember when I first got my 56 tooth big ring, I was all bent up about racing on hilly courses and such, but then it ocurred to me...I was wasting time worrying about small things. Just ride my friend!
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Re: Just ride! [Graz] [ In reply to ]
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Graz,

I'm with you, but this is a 16% hill for about 300 feet. Then it "levels off" a bit into a difficult 1.2 mile climb to the highest point in all of Ohio. I'm told that the hill begins with a curve, so you can't build speed before getting to it. I don't mind 50-60 rpm on a hill, but I'm guessing this could be slower.

I'm all for "riding", but even when I hit a 12% grade on a computrainer, I'm barely going. 16% is something else. Haven't even seen that yet. I don't plan on going out of Zone 3 on the hill, although I may not have a choice. The point is, I'd rather have an escape gear that doesn't blow my legs out.

Thanks all for the advice, it's been great. I think I'll try the 39 to see if it works, although it seems the 12-25 will probably be the solution of choice.

-Gill
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Re: Just ride! [Gill] [ In reply to ]
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yeah im a big believer in an emergency cog---you never know how your legs are going to feel coming out of T1. Its better to have a gear you dont think you'll need then hit the hill and kick yourself for not having that "unnecessary" gear.

Wildflower is the same way, with a tough hill out of T1, and my friend said that a 11-23 was plenty, the next yr i returned with a 12-27---i've now settled with a 12-25. I could have killed myself for listening to my friend. So my new rule is, no taking advice on the day or day before the race. I'll soak up race advice weeks or months before, but i wont change my set up if i know what i'm running works for me.

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Re: Just ride! [Gill] [ In reply to ]
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16% is almost unheard of in the US. I would get a lower gear like 39-25 or 27 if you don't have hills to train on. You may have a hard time keeping your front wheel on the ground at 16% grade. You may find yourself more limited by the amount of force you can generate than by heart rate.
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Re: Just ride! [Gill] [ In reply to ]
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16% is pretty insane. Here in PA, I've found about an 11 - 12% grade max in my travels so I can see where you're coming from. I agree then, the 12-25 will give you peice of mind.

Good luckl!
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Re: 42 to 39 chainring or 12-25 cassette? [Gill] [ In reply to ]
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Get the gearing that you need - but don't count on it.

I find that on some steep hills... a few more teeth on't really help that much. If you are already spinning at a high cadence the differnce might be minimal from a 25 to say a 27 and just lengthen the time you are climbing.

Find any incline you can and climb a lot. Increase the resistance on your trianer and raise the front wheel. No amount of gearing makes up for the hard work early in the season.
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16%, are you serious? [ In reply to ]
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If you are serious about a 16% climb, you need all the gearing you can get. Well, at least I would.

Figure out the lowest you could possibly need and go at least one gear lower. Remember you have to run afterwards.

I can't even imagine doing a 16% grade. I am not even sure I have ever seen a paved 16% grade. Hmm, I went down Lombard Street a couple of times. It trashed the power steering in the rent a car, but I got down. Maybe that was 16%.
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Re: 16%, are you serious? [ajfranke] [ In reply to ]
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I believe Fillmore Street in SF is around 18%. It's hit 10 times in the SF Grand Prix. Taylor Street, which is hit 15 times in the race is right around 16%. These are certainly not the steepest grades in the city. There's tons and tons of nasty grades off the beaten path. (That's not to say I can ride them. Driveways make me work up a sweat.) Damn, I miss that city.
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