Folding Bikes - Newbie question. Crankset quality

How does one judge the quality of a crankset? I notice that a few folks upgraded the crankset on DTs right after they bought them. 2008 DTs also have upgraded cranks. I wonder what decides the quality of a crankset. I am riding a DT and I don't feel anything about the crankset. By the way, I am 5'5" with 130lbs in case the rider's size matters.

Thanks :)

Like a lot of parts on bicycles, usually quality is dictated by material and weight. When it comes to cranksets, though this will rarely ever factor in with both you and me (I also weigh 130s) the power transfer and stiffness of the crank. Some 200 pounders claim they sometimes feel flex, keep in mind that the bottom bracket type also weighs in.

the DT uses square tapers which are not bad, but the octalinks I and II are said to transfer power better. Again, this is not an issue when it comes to me... because of my weight...

they have quite a number of materials and constructions types on cranksets, gossamer, aluminum, alloy, steel, and I'm sure there maybe titanium there too... (though I don't recall seeing titanium cranks)

I also didn't like the cranks on the DT, but it was because of a loosethread which makes me suspect that the aluminum composition was either too soft, or the assembler overtorqued the pedals...

Just my .0002 cents...

How's Waterloo... are you attending U of W?...

That means that you needn't worry! Save the money, hassle, and effort and ride happily along.

A lot of people make a big deal out of modifying the Downtube. It is fine out of the box, so long as you adjust everything that needs to be adjusted: spokes, BB, hubs. Et viola! You have a bike that is great for commuting. If you plan on racing anyone, you probably want a different bike.

A much more cost-effective way of reducing the bike's weight than replacing the cranks is to buy a $20 saddle that weighs 400gms or less. This will take a pound off the bike. More cost effective still...just remove all the stuff that's on it that you don't need.

OK, so here is the answer to your question: The primary concerns generally are: 1) weight and 2) stiffness. The stock crank is plenty stiff, and the steel chainring will not wear out like alloy chainrings will. It is heavy. But you probably won't be able to perceive the difference between that and a forged aluminum crank after lifting the whole bike up.

Some people worry about square taper versus ISIS or Octalink. This is, for all intents and purposes, bogus. The main advantage of non-square tapers is that they are less likely to strip out if they are improperly installed. There is no difference if the crank is properly installed. I laughed when I read someone comment that they could "feel" a difference in stiffness between a square taper and ISIS crank. In fact, they would have had to perceive a difference to the micron level, as the atoms were slightly compressed together.

Many folks have nice cranks lying around or took advantage of a recent Shimano 105 blowout sale at Nashbar. That $65 for a crank/bb set would also save you about a pound of weight.

Most of the times I changed cranksets it had to do with new (bigger in my case) chainrings not compatible with the currently installed crankset on each bike. After they were removed I realized that the standard crankset on most non-performance bikes are really heavy and cheap-looking.

I am working on finishing 2 papers that I have to read (finishing grad school in 4 weeks) to install a new crankset on my bike :)

14R.

Like a lot of parts on bicycles, usually quality is dictated by material and weight. When it comes to cranksets, though this will rarely ever factor in with both you and me (I also weigh 130s) the power transfer and stiffness of the crank. Some 200 pounders claim they sometimes feel flex, keep in mind that the bottom bracket type also weighs in.

the DT uses square tapers which are not bad, but the octalinks I and II are said to transfer power better. Again, this is not an issue when it comes to me... because of my weight...

they have quite a number of materials and constructions types on cranksets, gossamer, aluminum, alloy, steel, and I'm sure there maybe titanium there too... (though I don't recall seeing titanium cranks)

I also didn't like the cranks on the DT, but it was because of a loosethread which makes me suspect that the aluminum composition was either too soft, or the assembler overtorqued the pedals...

Just my .0002 cents...

How's Waterloo... are you attending U of W?...

Thanks for the explanation. That clarifies quite a bit. It seems DT manufacturer has the-tighter-the-better work motto.

I just moved to Waterloo from Bay area in California. I work for a small company here. It is a nice little city. Originally I anticipate a lot of rainfall. It turns out not so much. Lots of bike riders. Mostly UW students. Bike lanes are scarce comparing to Bay area. So, not surprisingly, most bikes are mountain bikes with suspension riding on sidewalks.

I swapped out the cranksets on my DT VIIIHs to get the gear ratio I wanted (replaced the 48 tooth ring with a 39 tooth) and to replace the stock bottom bracket with a sealed one with better quality bearings. I could have just adjusted the BB's and replaced the chainring.

On my DT Mini I am going to leave the stock crankset on and the BB seemed fine. It is a slighly better crankset and much better bottom bracket than the stock 2006 1/2 and 2007 DT VIIIH crank and BB.

I went to used cranks and misc parts on hand and the cost was low.

That means that you needn't worry! Save the money, hassle, and effort and ride happily along.

Great. I am going to ride it to what it is worth and then upgrade it. I certainly like to make it lighter. The bike is still too heavy to my liking.

Thank you all for quick and detailed responses. :)

KAB:

welcome... you won't get much rain in Wawawoo... you will however, get a load of snow (snowbelt country)...

I went to waterloo for 4 years, and could not believe how much snow it gets (compared to Toronto)... your right about the amount of bicycle trails... almost non existent...

it seems with most people its an issue of gear ratio... I put 50t chain ring on mine... was originally going to up grade the BB and crank itself and still may... but its adequate... and the updgrade at least brand new cost quite a bit...

I'm waiting until I can do a hack job and maybe get a double derrailleur in there...

bang for the buck...

pedals, seatpost and seat... the brake levers are also on the hefty side...

I thought about cutting my seatpost... you can do this depending on how tall you are and it won't cost anything but time...

if you have money...

folding handlebar post (I heard its an anchor, but sure seems SOLID), headset, rims, BB and cranks, tubeless conversion, tires...

you can swap a lot... just depends on your budget...

Many folks have nice cranks lying around or took advantage of a recent Shimano 105 blowout sale at Nashbar. That $65 for a crank/bb set would also save you about a pound of weight.

<$50 about two weeks ago plus a 10% discount and free shipping. They had 105 Octalink bottom brackets on sale too.

you will however, get a load of snow (snowbelt country)...

My wife confirmed that to me. However, since I moved up here last year, the last winter was short, warm and did not have much snow. She has drew a conclusion that I am the one who causes the global warming.



I went to waterloo for 4 years, and could not believe how much snow it gets (compared to Toronto)... your right about the amount of bicycle trails... almost non existent...

The region had a "master plan" cooked up in 2004 to build more bike lanes. So far, I haven't seen much progress. It is kind of ironic that where I have seen fewer cyclists (Bay area) has more bike lanes than where I have seen more (Waterloo).

As of upgrade, oh well, if I have money ..... (dream goes on and on...) :)

I just moved to Waterloo from Bay area in California. I work for a small company here. It is a nice little city. Originally I anticipate a lot of rainfall. It turns out not so much. Lots of bike riders. Mostly UW students. Bike lanes are scarce comparing to Bay area. So, not surprisingly, most bikes are mountain bikes with suspension riding on sidewalks.

Hey, UW B.Math '76. Haven't been back since 77 -- its probably changed a bit :) Used to ride my Motobecane to class and back and there were no bike paths then either :)