TREK 520 gearing
 

I've recently purchased a new TREK 520 (48/36/26 and 11/32) and prior to this purchase studied that many recommend the 26T chain ring be swapped for a 24T chain ring for climbing. My thought was that I would wait and see if I really needed the 24T or not and maybe those folks suggesting this are just outta shape. When I discussed this with my LBS, they were concerned about how well it would shift from a 24T ring to the middle ring, which is currently 36T and weren't too enthused about the idea. I will be taking a 600 mile trip this Spring that will be all mountainous through Appalachia. So, following my testing unloaded and seated, sure enough I must be outta shape, because it seems to me I will need just a smidgen lower gear than what the current 26T chain ring offers me loaded (unless I’m going to stand and push it all day. (at least this is my current hypothesis)). Based on what I’ve read this must be where this 24T ring comes in, correct? Can anyone give me a recommendation on what I need to do/buy/install or the most seamless way to get to where I need to be on this? Do I just change out that one chain ring or is this going to get more complicated and costly than that. Again, I’m trying to minimize my learning curve based upon your experience. Thanks again for all your help on this and other topics. Sport

I swapped out my small chainring and it was pretty easy. I just remove the crank arm, unbolted the chainring, bolted the new one on and checked chain length. Remember to periodically check the bolt torque.

Be sure to buy a chainring with same bolt circle diameter (BCD). My crankset is an FSA and FSA didn't make a small enough chainring, so I replaced it with a Salsa chainring.

It is very easy to swap out a chainring, as mentioned above.

What cassette range are you using?

I have a 48/38/22 triple crank that started off life as a 48/38/28 (I pulled the crank, took off the old granny, put on the new one, and put the crank back on). When I drop into the granny gear, I simultaneously shift the rear derailleur up 2 or 3 gears so I'm not spinning out. When I made the change, I found my chain would sometimes pop off, so I installed an N-Gear Jump Stop and the problem stopped.

I very much like my current arrangement. I don't go down to my granny gear very often, but when I do, I'm very glad to have it.

Cheers,
Charles

p.s. Your derailleur may not be big enough to handle the new length of chain. I shortened the chain (although still long enough to get into big-big) and kept the derailleur as is. A long cage derailleur would not be crazy in this case.

First, it's best not to start a thread by insulting people. Maybe those of us with low gearing...24 teeth on the front isn't all that low...are just more experienced. When the road turns upward, trying to struggle along at 3 mph in a gear that you can barely turn over is a whole lot harder to do and harder on the rider then spinning up the same hill in a lower gear. You'll still get to the top and arrive in the same amount of time but one is going way is going to leave you breathless and the other is going to let the scenery take your breath away.

Appalachia is going to teach you a whole lot about climbing and gearing. Be prepared. It will kick your butt, take your lunch money, kick you down the stairs, remove any organs that it sell on the black market and then turn around and stuff your hide to hang on it's wall. In 600 miles you will probably be going up more and down less than you'll do anywhere else in the US. It's incredibly odd how that area can have uphills that go on forever followed by downhills that are more up than down.

As to the ring, you crank can take a 22 (actually it can take a 20T ring which you can find on Fleabay). Shifting from the 36 to a 22 (or even a 20) isn't that difficult nor outside of the Deore front derailer's ability. I'm currently running a 20 tooth inner with a 34 tooth outer and shifting it with a Tiagra front derailer. I've never had a missed shift or thrown the chain off to the inside. It shifts up and down just fine. The Deore, coming from mountain biking, is even better optimized for the task.

Changing the ring is a piece of cake. With the Deore crank, you loosen the two fixing bolts on the left side, wiggle the left arm off and gently tap the right arm out. Now you can remove the ring bolts and swap the chainring. Reassembling the crank should be obvious. Tighten the fixing bolts to manufacturer specification. You may need to shorten the chain but I doubt it.

48:11 seems over geared, 12-34 more practical.. maybe even a 46, 34, 22, is do able?

You might want to look into a 34 in the back. Better to have it and not need it than to need it and not have it. Some tests are one thing. Day after day in Appalachia is another thing. Do you even know whether or not your test(s) included the ruling grade you will encounter during your planned trip?

Hi Cyco I really do apologize if I insulted you or anyone else for that matter regarding my comment about being "outta shape." I thought it was pretty obvious the context was quite tongue and cheek. Regardless, I hope my comment motivates you to get yourself in better shape. As far as Appalachia is concerned, I was born and raised there, and for some strong reason I have a good feeling that I know a LOT more about what it can do to a person than what you do. Thanks for all of your input though concerning my question, I appreciate it. Sport

:popcorn

If you know about the term gear inches, that’s the measure of gearing most use. It takes into account tire size and your gears and gives you the equivalent size the outside of your tire would be if your gearing was 1 to 1. Or if you were riding an old time bike with the big wheel in the front with no chain the size of that wheel. My touring bike has a range between 17 gear inch and 101 gear inch and most will tell you to stay at least at 20 GI.
There is a nice calculator you can put your information in and get all these numbers back.
http://home.earthlink.net/~mike.sherman/shift.html

Another good read.
http://www.sheldonbrown.com/gear-theory.html

I experimented a good bit with my gears before I found what I wanted and for me I found around 15 or 16 GI was the max lowness I could even ride. My legs were going so fast just to stay upright I would spin myself out. I could climb anything but you are moving about the same speed you can get off and push and at that point pushing felt like less work. So I took things as low as I felt I would ever ride and did it with a 24t and a 12-36 cassette. My crank is a road triple and the lowest you can put on one of them is 24T. as to shifting up and down my rings are 45, 42, 24 and I have no trouble going from 24 to 42 I did add a thing called a chain catcher, there are a bunch of different kinds but what they do is when I go from 42 down to the 24 if the chain overshoots it’s a plastic finger thing that catches the chain and flips it back on the granny. I would recommend one for anyone, I didn’t know if it was working or not but after a few months I could see some signs of wear on it so it had done something. My shift between the 42 and the 45 is super smooth and I will even shift that barely letting off the crank. When you do the granny shift both ways do it as a soft shift where you turn the crank slower than what the bike is moving so there is no tension on the chain and you will be fine. Because the shift is a bit harder to the granny I tried to find a cassette that let me have a good range of granny gears. I have 6 I can use down there (not cross chaining) and most of the time it’s not the 24 36 combo I need. Like someone mentioned above I try and get more in the middle of the cassette before dropping on the granny and then if anything when I hit the hill I can start shifting down in the back as the hill gets worse. If you go all the way low (biggest) on the cassette and then drop on that small chain ring it just seems harder knowing where I’m at with the gears.

I’ll take all the help I can get with gears, and I don’t see why your bike shop had any issues with making that little change.

Mine comment about the insult was also tongue in cheek.

As to knowing a lot more about the mountains of the east, let's just say perhaps...or perhaps not. I toured the Ouachita's in 2010 which I consider to be kind of the western (and gentler) end of the Appalachias and I did 1200 miles through the heart of them this spring, so I've been rather intimate with them. Both of them kicked this western mountain boy's butt.

Isn't it funny how when you speak to someone about needing lower gearing for the eastern Apps vs the Rockies out west, they give you a look like "this guy's an idiot",.....until they've done it. I swear some of those climbs out east go straight up, there's almost never a long sloping grade like out west where you can find a rhythm.

btw, Cycco that was some funny stuff, "kick your butt and take your lunch money":)

The lowest gear you have is Ahemm, walking the bike uphill. No shame in doing that if you're out of shape. You'll get in shape in no time as soon as you ride longer.

The difference between a 26T and 24T is not much though. Eventually, the gear you are in would be so low that it looks silly spinning so fast before you topple over because the bike is so tippy heavy. Unless you are planning to climb lots of 13% to 20% hills, a 26T with a 32T is fine for the majority of 8% climbs you'll meet on the road.

Hope this helps.

Sport,

I didn't consider your request as an insult. In fact, you were honest. I had to toured one time with a lady who bought a bike from Canadian Tire (like Walmart) and was out of shape. She rode for a few months and she built up the stamina and strength to finish the trip. We live in very mountainous areas where 16 to 22% grades are kind of the norm. That's what you get when you're in the Rockies. They say that if you can ride here, you can ride anywhere in the world with enough lungs to spare. This is true.

Having said that, my advise is for you to study the elevation profile for your trip and determine how many climb sections you need to do. If you need a 16" gear or lower, than you need to have lower gears. Being out of shape is what a lot of North Americans are in today unlike some of us who ride and are in better shape.

just to say, a 26 with a 32 is 21.9 g.i.
a 24 with a 32 is 20.3 g.i.

not a hell of a lot of difference. Depending on the weight you are carrying, and all the other factors we in webzland cant evaluate, you might wanna go lower.

only you can figure out what you need in relation to what the bike is presently.

heres a pointer, use a gearing calculator (sheldons browns one is good) and see what you have now as gear inch numbers in your lower gears. Load a crapload of stuff on your bike and hit a hill and see how it is, and how the jump of "x" gear inches feels like (to see if a 1.6 gear inch lower gear is even worth doing---ie, perhaps look into getting a diff rear cassette as suggested , up to 34 or whatever.)

have fun figuring it out for you and your situation.

Why not change cassettes? 12/34 or so. Your Deore rear derailleur can handle the 34 quite nicely, and a 12 instead of an 11 seems to be a better option. I doubt you'd have to make any other changes.

Sport10y, Buy the 22T or perhaps the 20T inner chainring and even with a 12-34T on the cassette, you might walk a hill. You might want to consider a device to protect the frame when shifting to the smaller inner chainring for peace of mind.

Brad




Brad

+1. I use an N-Gear Jump Stop and since I haven't had my chain jump of when shifting from 38T middle to 22T granny. Keep the middle and high rings where they are since this is what you use most of the time. But when you need a real granny gear, they're really nice to have (particularly if you are carrying a lot of weight or towing something/someone).

Cheers,
Charles

Sorry, but I don't agree. First, traveling at slow speeds doesn't automatically mean that the rider will fall over. I've spent hours pedaling at 3 mph on-road and off-road. I even do it without weaving all over the road. It's not that hard to do. Second, pedaling at 3 mph beats walking and pushing a bike. I've done that too.

Third, what gear you want, or need, depends on the individual. I'd much rather spin up a hill at 3 to 4 mph in a 20/34 gear (my touring bike's gearing) than struggle up the same hill in a 26/34 gear. I can do both...I'm fit and strong enough...but the 20/34 is a whole lot easier.

Finally, I live in the highest part of the Rockies. I ride in the highest part of the Rockies. I've done it my whole life. Here in Colorado, you won't run across too many 8% grades. We may like skiing but we don't like to do it in our cars. From my experiences in the Appalachias, 8% is a gentle grade. I have the lung power (and thicker blood) that comes from living at altitude but those eroded stubs of mountains back east taught me a valuable lesson in respect. They may be short but they are mean.

me too.

me no like pushing heavy bike up hill. me no like hitting pedal on back of foot and me say "ouch", and when very tired, me say bad words very loudly and not be happy.

One of the worst feelings on a bike is starting to struggle on a climb, attempt to shift to a lower gear and find there is NO lower gear to bail you out.
Never pretty.
Not sure your granny can be too low?

No such thing as a granny that's too low.

OTOH, I'm not sure there's such a thing as a granny gear that'll always be low enough. At the end of a long, hard, hot day, how much or a load can you pedal up a 20% slope? You may gear low to minimize walking up a hill, but I doubt you can guarantee you'll never have to do it.

I agree as well; your observations are borne out by my experience.

If the OP wants to keep the current crankset, he could also go with a 12-36 cassette, which according to Harris Cyclery can work with a standard mountain derailleur: "Shimano recommends that this cassette is only compatible with Shimano Shadow type rear derailleurs. We've run it successfully with a basic Deore (non-shadow design) with a longer (20mm) B-tension screw all the way in. You might have to reverse it for more adjustment."

A change from a 32 tooth to a 36 tooth cog would make a noticeable difference.

One other possibility is to swap out the 26/36/46 crankset with a mountain triple 22-32-44 crankset and stick with the 11-32 cassette.

I agree, I had no problem with my 12-36 and you get a lower GI with a 24/36 than a 22/32. ( 17.7 compared to 18.3) It also helps you on the other end as hardly anyone will miss the 11t.

My stock RD on the Windsor works great with the 12-36.

Yep, I live in the Pittsburgh area, an Eastern suburb, and on my 3 mile ride to shopping and other errands I encounter 10%, 15% and if I want, 18-22% grades. My wife went riding with me on her new bike, she is from Thailand and rode a lot there, I showed her how to shift into the small ring up front and the large one in the back, saying she would need it on the hills most likely, and she responded that she didn't like having to spin so much. A quarter of a mile from home she had shifted into the granny gear, and then got off and walked. She is 28 and I am 48. I rode to the top of each hill and waited for her.

The grades here are many and steep. Appalachia is like that all over. It is beautiful but brutal, especially with a load.

Google "The Dirty Dozen" in Pittsburgh for more examples.