Hornplayer

FWIW, my Defy 1 came with a 105 RD and a Tiara 12-30 cassette. I don't think you'll have any issues with a 30.

1986raleigh

Ok chain and cog it is... thanks

rm -rf

That's an unusually long, steep climb. It would be a 9.5 mile climb at 9% average. If the ride distance is longer than that, the average grade has to be lower. (I'd be surprised if it was all 9%). Calculate: Grade = (elevation in feet) / (miles * 5280) *100

I have a 34/29 low gear, just a little easier than a 34/28. I really like it. I can climb a 7-8% grade sitting down, and handle a 11-12% grade that's pretty long.

You should be okay with a 34/28. Do some mile or longer climbs, and get a feel for how hard you can go without having to slow down or stop to recover. Pacing is good on long climbs. ( I have a heart rate monitor which helps me to stay in a range that I can maintain.)

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I did a climb this year that was 4-mile, 1700 feet, 7.8% average. It took 55 minutes (at about 4.5 mph!). But climbing 4500 feet (2.6 times as far) at a similar grade would have been difficult for me.

Here it is: Cullowhee Mtn Road, at mile 44.6. ridewithgps link

rm -rf

Test to see if your chain is long enough.

You can swap the cassette, and keep the same chain. With the rear wheel off the ground, and the chain on the 34 chainring, turn the cranks by hand, and "carefully" shift to the 30 cog.

Does it shift okay?

Does the top pulley have a little clearance so it doesn't touch the cog?

And there should be at least a small angle downward on the chain between the pulleys on the rear derailleur--you don't want it stretched straight out.

Shift up and down a few times. If it looks good, go test ride it at slow speeds.

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Then, check the small chainring--small cog combination. The pulleys should be almost folded all the way back, but the goal is to not have the top pulley rubbing the chain coming from the bottom of the front chainring. (It actually still works--my LBS had the chain a link or two too long, and this small-small combination was rubbing. But I didn't notice until I had the bike on a stand)

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I like Wipperman Connex quick links. They are extremely easy to use, and I don't need to worry about pressing in the link pins correctly. And it's lasted at least two chains.

401flava

Yes,the 5701 is what you'd need afaik,it will handle the extra teeth that the 5700 will not. On the plus side,I got the 5701 new for $42 from Nashbar, so you could actually sell a used 5700 for enough to buy a NEW 5701,strange but true. (Scored the Sram PG-990 11/32 for $63 from CRC,nice cassette,and again cheaper than used 990's on eBizzle) Coincidentally, I too have a 39/53 double,and I know that an 11-25 or -28 just isn't gonna get me up the big hills. Idk why this is even an issue...there's loads of 39/53's out there,they can't all live in flatlands lol. Why is anything with more than 28t a 'MTB' part? I'm a newb,so labels like 'Mountain' put me off when I need a road bike part. Only to find out, it's not reeeeally mountain it's just uuuuusually used that way. A long cage road derailleur is made to go well over 28t, but there's no 'road' cassette over 28t?! I've learned a lot about bike parts lately,and I have to say the biggest hurdle for a new gearhead is cutting through the bs and marketing and proprietary nonsense and so on. "Well,we call it 10 speed,but it's really 8/9/10 speed", "it says MTB but don't mind that,it's for road too","oh no,that's not ISIS it's Octalink...wait,v1 or v2?". It's maddening. Lucky that bike people are cool and help out the newcomers. Lucky that the Sheldon's of the world make sense of it for the confused. I will of course keep you posted on how I make out,but I don't foresee any troubles. I grilled the tech/customer support pretty good at every step along the way to make sure each drivetrain component would play nice with the others. It may be awhile before I have it all together,the brifters are backordered.

1986raleigh

Great I'll try that, thanks

401flava

Quick update... I just received the 5701-gs and it says right on the front of the box that for triples it's 30t max and for doubles it's 32t max. So Shimano themselves call a 32t within spec, that's good enough for me. Also, that probably means you can actually run a 34t without a hassle afaik.