Trek520 gearing change

Since 2001, over 90,000 cyclist's have joined Cycling Forums to discuss topics from general cycling to equipment, training, racing and travel or vacation destinations (especially in europe during the tour de france). We also feature an great deals in our online store, 100's of articles, classifieds and product reviews.

Yes, I know this is a popular one and most people do it by changing to an mtb crankset. Well, I don't want to do that. I'm riding a 2007 Trek520 and am very happy with the two larger chainrings (52/40 they suit most of my riding perfectly) but as I'm running out of puff on some of the nastier hills around here, a smaller granny gear (from the current 30) would be appreciated. If I'm going to change the small chainring, I'd might as well change it for something suitable for heavy touring (not that I'm planning it but while I'm doing the change ...).

Any suggestions on what sized chainring to go for?
As I said, I'm keeping the Ultegra cranks and 105 derailleur, so the new ring has to be compatible with that. A mate has suggested going to a 24 (which looks good on the gear chart - nice overlap, a few more ratios) but the lbs reckons the 105 shifter won't handle the 52-24 range. Any thoughts?

Better still, has anyone done it?

Richard

I bought a TA 26 tooth inner for my Felt. It worked ok but I went back to the 30. Have you thought about a 11-30 cassette?

I bought a TA 26 tooth inner for my Felt. It worked ok but I went back to the 30. Have you thought about a 11-30 cassette?It's already running an 11-32 George ;)

I'm guessing you'd be happy putting the 26 on my Trek then? (that's how I read it).

I'm 50 with a fairly typical 50 year old girth :o Looking at some charts (thanks for the calculator Sheldon) 26 gives me a more useful spread of gears. At the moment, I really only use the small chainring for nasty hills yet that only gives me two more ratios (on a 9 speed cassette) - the third (largest) freewheel actually gives the same gearing as largest on the middle ring. Typically, I work my way down the middle chainring and if the hill dictates something lower, will change then, or two cogs earlier if I predict I'll need it which isn't difficult on two of my regular rides :rolleyes:, so at best, I'm using five of the 7 useable cogs on the cassette (I don't use the two smallest on the small chainring tp avoid excessive chain crossover). But on too many of my rides here, I'm on the bottom ratio and mashing - no longer able to maintain a decent cadence. Okay, loose some weight and become stronger and fitter and that'll change, but I'd still like to have operative knees when I get there (okay, exageration, but the bike's supposed to make life easier, not harder). The 26 gives the same ratio (middle chainring to low chainring), four from the end. That gives an overlap of four gears with the middle chainring and three new lower gears, with the improvement in bottom gear going from a gain ratio of 1.9 to 1.6.

Basically, changing to a 26 just shifts my cassette up one gear (the matches across the cassette are fairly close) and that, if nothing else, will make it more useable, plus I'll use more of the rear cassette when on the small chainring.

The alternative is to change all three chainrings, but that's starting to sound expensive and it's not something I'm in a hurry to do because at the moment, the middle chainring is almost perfect for me - I only need the other two for high speed or steep hills, with rolling country being handled nicely on the middle :D

Arrrrrggggghhhhhh - methinks I'm starting to suffer from 'gear-itis'.

So, if buying a 26 tooth chainring is relatively cheap, and it'll work without problems, it's worth doing. If I need anymore than that though, I might just work on getting thinner, stronger and fitter.

Richard

I got my 26t TA from Sheldon Brown, he has tried it too. ;)

Where are you? Aus, UK, USA?

I can buy a Sugino 28/38/48 crankset in alloy for not much more than a single TA chain ring.

I went through the exact same set of questions you are raising only a few months ago. I have a relatively new Randonee Novara, which is similar to the Trek 520. It came with a wide range of gears which is more than adequate for the areas where I live, but I noticed that I wanted a slightly lower ratio for touring loaded through the hills. I don't do that a lot, but I wanted the bike set up for whenever I decided to take the trip.

I asked a similar question on this thread a few months ago: what's the best way to lower the gear ratio? My initial preference was to get a smaller chainring up front. I got a lot of feedback from this forum, but the advice was split down the middle: about half said I should get a smaller chainring and the other half said I should get a larger cassette in the back. At the advice of a local bike mechanic, I bought a larger cassette. Iwent from 11-28 to a 12 - 32. He warned me that I "might" have to get a new derailleur and chain. He was right. I replaced cassette, derailleur, cable and chain. It took awhile shopping for the parts on ebay, but I eventually found what I needed. It also took me time awhile to get the shifting set up properly, but I eventually did so. Looking back, it might have been easier to take the other route: getting a smaller chainring.

I'm not sure if any of this helps. Good luck. Keefe.

G'day Keefe,

She already comes with an 11-32 cassette. Very nice. It means I can more or less live on the middle chainring for most of my riding (which is rather undulating to say the least), with the large chainring for the rare downhill run or when I'm feeling especially energetic (or trying to keep up with my son :rolleyes: ) and the small one for the hills. I won't be touching the middle chainring gearing at all ;)

The small chainring is the issue. If I were stronger, fitter and half my weight, it wouldn't be an issue until I started to haul heavy weights around. Well, I believe a bike should carry you now, not in some mythical future. With nine cogs on the rear, there are plenty of options back there. Okay, you loose two because of chain angle (small to small), but the current 30 tooth chainring gives only two more ratios - middle chainring to large cog is identical to small chainring and third cog. After firing up Sheldon Brown's gear calculator and putting in a few numbers, the 26 tooth ring gives me that common gear at the fourth cog - this allows me to use all the middle ring, change to the small with three lower ratios (instead of two) plus three usuable ratios the other way (overrlapping and roughly matching the middle ring). I reckon this makes better use of the cassette.

Shimano don't make an ultegra ring in 26 teeth, but there are alternatives (again, good ol' Sheldon Brown lists some) so I'll make the change. Others who have done it reckon the shifting becomes a tad more cumbersome (because of the extra jump in teeth) but it's workable and I may find I need to fit a 'jump stop' - a wee gadget that stops the chain flicking off the small ring during the change, but considering I don't need to go onto the small ring except for big hills (ie, I'm not on and off it all the time), I don't consider these a negative.

Now it's just a matter of saving a few pennies and making the change :D

Richard

G'day Keefe,

She already comes with an 11-32 cassette. Very nice. It means I can more or less live on the middle chainring for most of my riding (which is rather undulating to say the least), with the large chainring for the rare downhill run or when I'm feeling especially energetic (or trying to keep up with my son :rolleyes: ) and the small one for the hills. I won't be touching the middle chainring gearing at all ;)

The small chainring is the issue. If I were stronger, fitter and half my weight, it wouldn't be an issue until I started to haul heavy weights around. Well, I believe a bike should carry you now, not in some mythical future. With nine cogs on the rear, there are plenty of options back there. Okay, you loose two because of chain angle (small to small), but the current 30 tooth chainring gives only two more ratios - middle chainring to large cog is identical to small chainring and third cog. After firing up Sheldon Brown's gear calculator and putting in a few numbers, the 26 tooth ring gives me that common gear at the fourth cog - this allows me to use all the middle ring, change to the small with three lower ratios (instead of two) plus three usuable ratios the other way (overrlapping and roughly matching the middle ring). I reckon this makes better use of the cassette.

Shimano don't make an ultegra ring in 26 teeth, but there are alternatives (again, good ol' Sheldon Brown lists some) so I'll make the change. Others who have done it reckon the shifting becomes a tad more cumbersome (because of the extra jump in teeth) but it's workable and I may find I need to fit a 'jump stop' - a wee gadget that stops the chain flicking off the small ring during the change, but considering I don't need to go onto the small ring except for big hills (ie, I'm not on and off it all the time), I don't consider these a negative.

Now it's just a matter of saving a few pennies and making the change :D

Richard
I went with a 28 and is great! didn't have to change anything else.