climbing Berkeley's Marin Avenue: MTB versus road bike
 

Hi folks,

My first-ever post on the BikeForums! :)

My standard route up into the Berkeley Hills from the flats is to climb straight up Marin Avenue (from the Marin Circle to Grizzly Peak).

My bike is a 13-year-old Specialized Rockhopper MTB. To climb Marin, I stay in my middle chain ring (32 teeth) but move to the largest sprocket in back (30 teeth). I think my cranks are standard MTB length. Standard MTB rims too (though my tires are 1-inch-wide Tom Slick tires instead of knobbies, so the total diameter of the wheel is a tad smaller).

I've been toying for years with the idea of getting a road bike. But I've been postponing because I worry that a road bike won't give me gears low enough for tackling Marin. I've never seen a road bike go up it. (And I refuse to give that ride up!)

So I'm hoping somebody might be able to help me out. If I were to get a road bike, with its larger-diameter wheels, what size chain ring and back sprocket would I need to get the equivalent of 32-30 on my MTB? Do they even make gears this low?

Thanks in advance. I'm embarassed to say I know almost nothing about road bikes, or the math required to do this. <blushes>

Why, yes - yes, they do. :)

In my case, I have a couple of options. On three of my road bikes, I have the standard Campy triple 52/42/30 with a Campy 13/29 cassette in the rear. One one of my road bikes, I have a Campy compact double 50/34 with an IRD 13/34 cassette.

In both cases, my lowest gear is a tad lower than your lowest gear.

A triple with a 30/29 low gear (175 cranks,700x23) will almost get you 32/30 on your MTB (175 cranks, 26x1").
The road bike is lighter with lighter wheels so getting the exact same gearing may not be necessary.

Thanks for the replies gents! :)

It's good to know that road bikes can get that low.

But I guess I'm still confused. Since mountain bikes have smaller wheels, wouldn't that mean that 30/29 or 34/34 on road wheels will still be higher (in terms of distance travelled per revolution) than a 32/30 on 26" wheels? Or do the lighter wheels and frame of a road bike make up for that?

The math is easy. The formulas is:

# of teeth on front chainwheel divided by #of teeth on back cog times diameter of rear wheel. Easy-peasy-lemon-squeazy with any calculator. The result is a constant, apples-to-apples comparison of the gearing regardless of wheel size.


In the case of your MTB, that is (32 divided by 30) times 26 inches (standard MTB wheel diameter - don't worry about the slight variation in tires sizes, as it is not enough to worry about) or, voila, a 27.733 inch gear.

Bigbossman's example is (34 divided by 34) times 27 inches (used for both 27 inch and 700c road wheels; it's close enough) or a 27.00 inch gear. So BBM is correct - a 34x34 gear on a road bike will be very close to, but a hair lower, than your current low gear.

Note that a 30x30 gear or a 28x28 gear would give you the same result - a 27" gear. All of these options are easy to arrange on a road bike, but you will need a compact double or a triple crankset.


I'll wave at you as I pass by Marin on Spruce. Riding up Marin? You must be strong as hell :eek: and/or insane :twitchy:.

See my previous post - in terms of the gear size (or "gear development" if you want to be picky) it is all about the ratios between the cogs and the size of the wheel. That formula allows for gear comparisons between road bikes, mountain bikes, recumbents, kid's bikes, pretty much anything that doesn't use a internally geared hub (like the classic Sturmey Archer three speed), which use the internal gears to increase or decrease the base gear ratio by a set percentage. But that doesn't apply to your bike.

That last section before Grizzly would be the nail in my coffin. I rode down it once on a bet with a coaster brake. Wasn't sane, but I was the first one down. Going up? I'm just not feeling it.

Link to the 2009 Beaker's Berkeley Hills Suffer Fest.
I wasn't insane enough to participate. :rolleyes:

http://www.bikeforums.net/showthread...bay+death+ride

ahhh Marin, it's been a while. I've ridden it with a 34x26 and 34x27 - both times were the closest I've come to passing out on a bike. Brutal.

If that's your standard route into the hills, I'd hate to hear your tough route.

Oh yes, I think your original question was answered, I'll be on my way.

What's the length/grade of that climb? I haven't done it yet....

Here's my garmin profile from gpelpel's link.

http://bikeforums.net/attachment.php...hmentid=142220

It's ~1mile, average is close to teens, but there are several sustained pitches >20%. The top 3 blocks are steeper than anything else I've ridden - my data suggests 30% - the flatter parts are me detouring down two x-streets to get my HR under control. Whatever the grade it makes the top of Diablo look like a false flat.

http://www.inl.org/bicycle/deathride.html

If you're riding straight up on the MTB, you could get a road bike with 34x28 and paperboy the steepest parts if necessary. Might not even be necessary, depending on how much lighter your chosen road bike is compared to the Rockhopper.

Holy ouch.

Gents, thanks oodles for the help! :thumb: I understand the gearing equations now (and am glad to know that the difference in size between MTB and road wheels is less than I thought).

So I think I'll pop in to the Missing Link :love: in Berkeley and ask about low/mid-range road bikes, with a triple 30/29 or compact double 34/34 setup in mind.

I'm still not sure about handlebars.... I'm so used to the straight bars on my Rockhopper..... Do most riders with drop bars really keep their hands on the hoods when climbing out of the saddle for miles at a time? The thought of climbing hills with my wrists turned 90 degrees outwards from what I'm used to on the flat bar sounds really uncomfortable, I've gotta say. :lol:

And do your knees ever hit the drops when out of the saddle?

Sorry for all the questions. :innocent:

Thanks for all the feedback too about biking up Marin. You guys make me feel like a rock star or something. <blush> But being a small guy, I know I must have a huge advantage when climbing. I'm only 5' 8", 145 pounds, so I have it easy. Flip side is I totally croak on flats, can't keep up any speed on them at all. :p

Don't be too surprised if they need to change out the rear derailleur to fit the larger cog. My Ultegra bike had a triple, and the largest I could fit in back was a 27 (although honestly the difference between a 30/29 and a 30/27 isn't that big of a deal). My SRAM bike has a compact, and I was able to make it work with a 34/30 combo, although it wasn't happy the one time I went big big by mistake:rolleyes: The cassette was from ITM. I usually use a SRAM 11-28 or 11-26 on that bike. I'm not a great climber and that's enough gearing for most rides around here, but I've never done Marin or anything that steep.

Your best bet for those kind of climbing gears with SRAM may be the new Apex group, which will have a longer cage rear derailleur and is rated to handle up to a 32 tooth cog in the back (my Rival RD is only rated to 27 but I made it work with a 30). Unfortunately SRAM only makes doubles so that would leave you with a 34/32 combo.

For both SRAM and Shimano it's pretty easy to setup a mountain bike RD to work with the shift levers and get up to a 34 back there. If the shop you're using won't or can't set it up for you, Chris at Robinson Wheel Works in San Leandro does pretty big business setting up mountain bike RD's and gearing for folks doing the Death Ride each year.

JB

I run Campagnolo 52/42/30 triples and 13/29 cassettes, and routinely use medium cage RD's. On the bike with the 50/34 and the 11/34 cassette, I needed a long cage.

Don't know much about Shimano, but I think Dan (lanceoldstrong) has a compact crank paired with an IRD 11/34 cassette on his Felt with a Shimano long cage RD.

Either way - the word "budget" doesn't match up well with either solution. :) I doubt Missing Link will have a budget Campy triple equipped bike laying about, and Shimano doesn't make a cassette that goes up to 29t in the rear. IRD makes "megarange" cassettes that are compatable with both, but the cassettes alone are $150-$170.

What about Deore? :innocent:

Ooops - yeah. I was thinking road. Shimano, of course, have a whole mtb line of stuff. Thanks for catching me. :)

This raises an interesting question. If Marin really is a regular part of your route, I'd consider getting a triple. Although I muscled up in a 34x26 (35.3 gear inches), I wouldn't want to repeat that very often. Since it's rare to find road climbs that are as steep as Marin, I much prefer more subtle transitions in my cassette for the other 99% of my riding than having to rely on an extreme cassette for the less common stupid steep climbs. If you went with a 13-29 cassette and a triple you'll get the low gears with the 30T ring, but get better transitions between your gears for "normal" climbs and riding around. Also if you decide you want to go compact or double in the future, it's not too difficult from a triple - it's much more expensive to go double to triple down the line however.

If you check out the pictures in the gpelpel's link, you'll see everyone has an exceptionally tight grip around their hoods to get maximum downward pressure on the pedals. This was true for the last 3 blocks, but I sat for a good chunk of the rest of the climb, either hands on the tops or on the hoods.

If your knees are hitting the bars then there's likely something wrong with your fit, it doesn't normally happen.

Yup - I knew Campy could handle bigger cassettes than Shimano (at least 105 and Ultegra) but didn't know the details. I have one of those IRD cassettes, but mines only an 11/30 - and that was pushing the SRAM RD to (and a little past) it's limits. It never locked up, but made all kinds of ugly noises when I went big big by accident.

I do think that the SRAM Apex group might be his answer - it's slotting in below Rival (which is priced close to 105) but has the option of a longer cage derailleur and their new 1/32 cassette. I haven't seen in shops yet, but am actually thinking of getting the RD and cassette to play with when funds allow.

JB

Yup - I knew Campy could handle bigger cassettes than Shimano (at least 105 and Ultegra) but didn't know the details. I have one of those IRD cassettes, but mines only an 11/30 - and that was pushing the SRAM RD to (and a little past) it's limits. It never locked up, but made all kinds of ugly noises when I went big big by accident.

I do think that the SRAM Apex group might be his answer - it's slotting in below Rival (which is priced close to 105) but has the option of a longer cage derailleur and their new 11/32 cassette. I haven't seen in shops yet, but am actually thinking of getting the RD and cassette to play with when funds allow.

JB

PS - if Dan is running an 11/34 on a Shimano bike, he must be running a MB RD. I know lots of folks who do longer climbing rides that use that solution.

if you went with a triple you could always swap the inner chainring with a smaller tooth count mtb one. it may compromise some of the shifting between inner/middle rings but it's cheap and preserves the quality of shifting in the rear. if you went down to say 26 teeth in the front you could use a tighter and probably better shifting 12-25 or 12-27 cassette. 26x27 is a pretty low gear ;)

For the Death Ride I had a 12-32 IRD cassette using my regular (medium cage) Campy Chorus derailleur. Campy derailleurs have a small adjustment screw that allow the use of greater than 29 teeth cogs. 32 is the limit however, and I really mean limit.

If you can climb for miles at a time whist out of the saddle, you are an animal :eek: and should hie thee to the Tour de France post haste. :p

On looooong climbs, you will be seated more than you are standing. As for the handlebars, give drop bars a try. You still have the flats for riding the way you are used to now, but I think you will find that the variety of hand positions gives you more oveall comfort and more efficiency. Believe me, being able to get into the drops is a good thing when grinding into a headwind. As has already been mentioned, riding on the hoods is common in hard climbing - it just seems to lend itself naturally to alternate standing on the pedals and sitting back down.

By all means, go talk to Missing Link. (I was in there just this afternoon, and trust me, there is no way you could ask sillier questions than one or two I heard.) Either they can set you up with what you want or they can't (and I think the only issue will be price). In any event, you will be no worse off than you are now and, at worst, you will be armed with a bunch more info.

Oh, by the way: Speaking as someone who is considerably taller than you and almost double your weight, I hate you little spindly legged climbing farts. :notamused: And I mean that in the nicest possible way. :rolleyes: