01-05-07, 10:47 PM
Hi all - my first post :) I'm fascinated with the idea of touring and I am looking into buying a trek 520 for a fully loaded tour with a buddy from Pittsburgh to DC. Never really been into biking before... but touring looks like it could be quite an experience. I've been reading the posts about switching out the crank and/or lowering the gearing on the trek 520 and I've found a wealth of information - thank you. I was wondering, however, has anyone tried to add a 4th cog with the Mountain Tamer Quad? Someone had mentioned that they did so with their tandem, but I didn't see anything about the trek 520. Anyway, I tried reading what the manufacturer of the Mountain Tamer Quad (Abundant Adventures) had to say regarding if the product would be compatible with a bike or not, but I really wasn't able to figure it out. (Like I said, I'm new to bikes and not really familiar with all the different variety of parts and stuff yet - sorry). Thank you in advance.
I had that, or something like it on a Canondale mountain bike about 15-20 years back, I think I read something about it in Outside and sent away for the gear. That bike was stolen so I only got about a year or two use out of it. I recall thinking it was worth having. In retrospect I wonder how useful it really was, these were early days in MTBs, and there are probably better tactics than the micro gear.
In touring I think it would not help. On trails one can sometimes grind through a short rough section with just the low enough gear.
On the road:
- The surface is smooth and the gearing provided on the current granny of something like a 24-34 is already low enough one may struggle to keep the bike upright;
- A long section in the Quad would tend to really wear you out. One is spinning so fast that even if one didn't fall over, the cadence would blow you up anyway;
- There really can't be any doubt that if the going gets this bad then pushing the bike is the non-heroic, but more efficient option. The idea that one can always ride (though one pretty much can) is a little primative. We need to accept the cyclocross approach that sometimes riding isn't the most efficient option. In less advanced countries pushing is not looked down on, it's normal;
- The quad I had, did no harm, it was steel I think, but it was so small in diameter that I never knew it was there. It fit over the BB area and didn't require any changes to the bike, so one could try it and use it where it helped;
- I do recognize that your part of the world is really tough on the hills. You gain strength rapidly on a bike, but you need to go by yourself, or with a weaker or very understanding partner. Nothing is so discouraging as being hauled up hills by a faster rider when you have your own pace.
It doesn't seem to always work to slow down (into ever smaller gears) on hills. You just loose more and more momentum until you fall over. Within the bounds of one's own ability one needs to attack a little on hills, and I do not say that as a strong climber myself.
01-06-07, 01:52 AM
You should do the crank swap and the installation of the Mountain Tamer at the same time.
If you do the crank swap before you get the Mountain Tamer you might end up having to replace the bottom bracket with a wider bottom bracket when you go to install the Mountain Tamer.
I assume you are not going to be doing this work yourself since you are new to bikes.
You are also going to have to replace the front derailleur with one compatible with a 44/32/22 crank.
Mountain Tamers may not work with integrated cranks. A splined or a square taper bottom bracket is more likely to work because they are available in different widths. So, the replacement crank that you buy should be compatible with a splined or a square taper bottom bracket.
If you do the Mountain Tamer you'll have to run the front shifter in the friction mode. In other words, there will be no clicks, you'll have to guesstimate when making a shift. There's nothing wrong with this. You would get the hang of it.
Another alternative is to go to a bike with 26" wheels rather than the 700c wheels of the Trek 520, like the REI Novara Safari. 26" wheels give substantially lower gearing. The Safari comes with a 48/36/26 crank which could be swapped with a 44/32/22. The front derailleur would not have to be replaced in this instance.
01-06-07, 09:59 PM
I'm the one who installed a Mountain Tamer on my tandem, and I did not install one on the 520 because it already has 44-34-22. I am a fan of low gearing, especially when travelling with the children and lots of gear.
My tandem already had 48-38-24, which are the lowest possible rings on a 130/74 setup. And changing cranks on a tandem is usually a quite expensive proposition because you need to change all of them, including the special ones with a ring on the left. In the time I used the tandem in its original configuration, it was OK with one daughter, but not for climbing 15% grades with two of them and 100-120 lb of gears.
By comparison, I found that I had no problems climbing 15 % grades with my 520 equipped with 22/32, even when pulling a trailercycle and 6 loaded panniers. On that tour, we only climbed one hill on foot: a 17-18% grade with loose asphalt and a very oblique wet railway crossing at the bottom of the hill.
Would it work on the 520? Here are a few points to consider:
– Inside clearance. I can't check on mine because I don't have the original crankset and bottom bracket, but you need enough space for the extra ring. On the tandem, the original granny if 45 mm to the right of the centre line of the bike, and that's about the minimal distance to get the derailleur working properly. And the ring also needs some space inboard.
It would either work OK as is (I doubt it), or with the 2-mm spacer they sell. Worst case, you will need a newer, longer bottom bracket. 25-30 $, and check what's available.
– Range covered by the derailleur cage. The 105 covers the 48 to 18 range. I think it might cover one extra tooth, but not two. So if you keep your 52, you won't be able to go lower than 22. For that, I would rather look at other options.
– Derailleur and shifter behaviour. The tandem originally came with an Ultegra derailleur and I never was totally satisfied with it, even as a triple and especially as a quad. When it blew apart, I replaced it with a 105 (same as on the 520). Shifts are now perfect throughout the range, but to get it right, I had to fiddle a lot with derailleur height, setting of the cable (I use all the available cable pull from the shifter)... It's the kind of setup you do yourself, unless you have really meticulous bike shop that doesn't mind spending 1-2 hours to adjust it properly... and unless you don't mind paying the bill.
– The shifter. The 520 comes with bar-end shifters (my preferred shifters anyway). It's a blessing for non-traditional setups because you can do whatever you want with your crankset.
– The rear derailleur. With adequate chain length, you will be able to use the large-large combination without breaking anything. On the smallest ring (the tiny 4th one), you will be able to use the 4-5 largest cogs; after that, the chain will be loose. Not a problem in practice.
What would I do if I were buying that bike?
First, If you haven't done so, check the ratios you have on your existing bike, plug them in Sheldon Brown's calculator and decide what gears you need.
Since you are buying it, you might as well negociate your options with the LBS. Better do that before the spring rush.
– My preferred option is indeed the mountain crankset. You could ask to swap the 105 with an LX or XT crankset (LX is same level, so roughly the same price). The swap means a different bottom bracket (105 vs XT anyway). Officially, you need a new mountain derailleur because it works "better". Well, my derailleur doesn't know that and works flawlessly. IOW, don't spend a dime on a new front derailleur!
BTW, 44 looks like a low high gear, but a high of 44/11 is still higher than the high of 52/14 or 50/14 we had 20 years ago!
– If you are fast rider, look for one of the Sugino cransksets (less than 100 $ retail). Instead of 130/74 mm bolt circles, they use 110-74 bolt circles, so the middle rings may be smaller. Suginos typically come with 46-36-26 or 48-38-26. For best climbing ability, change the granny for a 24.
Sugino and Shimano also make a few commuter (or hybrid) cranksets, with 4-arm spider. The granny may go as low as 22.
– My last option – because I'm not a fast guy – would be to keep the 105 crankset, but have the rings replaced by the smallest ones possible. That means 48-38-24.
Finally, if you find you still want a bit lower, you could visit Sheldon Brown's Cassette page (http://sheldonbrown.com/k7.html), dismantle your cassette, buy a loose "34" and replace your large cog by yet a larger one.
02-19-07, 07:50 AM
I just realized that I forgot to say thank you for all the great advice. Anyway, thank you :)