Originally Posted by Amt0571

Hi!

I'm a mountain biker just about to buy a road bike. I'm looking for a cheap bike for occasional use, so I'm leaning towards Decathlon's Triban 3A.

However, I've been looking at road bikes gearing and I feel that all of them have way too high gears. In the area were I live, there are also lots of steep road climbs, some of them reach a 30% slope, and I'm trying to understand how can anyone climb this with the high gearing that road bikes have. The Triban 3A I'm looking for, for example, has a lowest gear of 30/25, and the Specialized Allez doesn't fare much better.

Currently I do 5000km/year on a mountain bike and around 2000 in my commute with a folding bike. Based on my climbs in group rides I feel that I'm a good climber, and I'm used to long, steep and technical climbs where I'm forced to use my MTB granny gear (22/32) to maintain a reasonable cadence. On most races I've done this year I usually finished among the first 15%, so I think I'm in good shape.

Do road bikes really roll that much better to compensate such a high gearing? even my Dahon Mu P27 has lower gears (and curiously, also higher)!! I feel that with this gearing I may as well call the bike a knee breaker!

How are you supposed to climb using such high gearing? I feel it's either standing and mashing or being extremely strong to avoid slowing down and maintain a reasonable cadence.

Is it possible to fit smaller chainrings in a road bike?

Thanks

Originally Posted by jeff@work

Yes, road bikes really do roll much better than mountain bikes. It should be noticeable just taking one even for a quick spin in a parking lot or down the street.

30x25 is a pretty low gear already, that said 8 speed cassettes are pretty cheap ($20-30 USD). If you do find that the 30x25 isn't working for you you could easily swap to a 28 or 32 cassette... no need to mess with the crankset.

Originally Posted by indyfabz

I once spent 7 weeks touring in Andalucia, Spain. Some nasty, nasty climbing. You are right about donkey paths. Some of the roads seemed like they simply widened a donkey path and put blacktop over it. Another sometimes ordeal was getting into the center of town. Many old towns were built on steep hillsides, probably so they could throw hot oil down on the invading Moors. Had to walk a couple of times even with my MTB gearing. The funniest hill experience was seeing two kids on a moped trying to get up a hill towards Andujar. One of them had to get off and push the thing while the other worked the throttle.

Originally Posted by gsa103

As pointed out above, most roads are graded at <8% for any significant distance (>1 km). Short bursts require basically grinding it out. Mt. Diablo is the standard local torture test. The final wall is about 200m at 17% grade. With a 34/28 compact I can alternate between standing and spinning for the ~1 min climb duration, and I doubt I'm in significantly better shape that the OP.

I also mountain bike, and climbing on a road bike is significantly easier, because its totally non-technical. On a MTB, you frequently have local obstacles that require rolling over, where roads are basically graded smooth, so the average grade is a good representation. Think of it like climbing stairs vs walking up a ramp.

I suspect there's something wrong with your GPS. On a 30% grade, you're going to fall over backwards. A good number of pedestrians would literally be on hands and knees up a 30% grade. As a good estimate, what the total elevation gain and distance of the climb?

Originally Posted by Amt0571

The climb in question climbs 350m in 3km, and has an area that almost reaches 30%.

I can assure you that you don't fall backwards. And I regularly climb such steep climbs with my mountain bike and have never had this problem. Mostly the problems with the mtb are that you can't stand up if it's not paved and that the steering barely responds due to the low load on front wheel. If you're strong enough and know how to sit, it's climbable with a 22/32 at around 5kph.

On a paved road where you can stand with proper gearing it's easy providing you have the strength. I'm just not sure about the proper gearing part in road bikes.

Descending is a blast, BTW.

Originally Posted by banerjek

What kind of shape are you in, and do you have only this one difficult 3km section or do you frequently encounter really steep extended sections? If this is the only doozy, I'd be tempted to go with a straight road triple and 11/32. This isn't crazy long so you have some options if you're in decent shape and you can suffer a bit.

If you have lots of awful climbs, I'd say go with the MTB triple. I would suggest using your current gearing, but the issue you may run into is that if your smallest ring is a 22, you may find yourself wishing for taller gears on slight descents or on flats when winds are chasing you. So a 48-36-26 might be a better match.

Note that even if you use your current gearing on a road bike, your cadence will drop because the wheels are bigger on the road bike. So you'll have to mash more if you use the gears I suggest. If mashing doesn't appeal, duplicate your current gearing on the road bike.

Originally Posted by Amt0571

This is a worst case, but there are lots of roads here which have sections around 20%. Even a street close to my apartment reaches 25%.

I'm not really willing to mash because lately I've been having some problems with my left knee, so I tend to spin fast whenever possible to avoid problems.