New Chainset 2003 Trek 2300

[Rvzy]

Hi, I'm looking to replace the chainset on this Trek I bought second hand with a compact chainset, it's a bit dated at this point as it's never been replaced and I go up hills a lot, I'm 99% sure this is the year/model of the bike:
http://www.bikepedia.com/QuickBike/Bike ... &Type=bike" onclick="window.open(this.href);return false;

It has 9 speed gears and the BB is Shimano BB-6500 w/ 109.5mm spindle

I've looked in to it a lot but I'm still not really sure I know what I'm doing, I would really appreciate it if someone could tell me what chainsets I can use and what tools I'll need to replace it, I'm a student so I'm looking for a cheaper set.

Thanks in advance!

[eeksll]

a quick google tells me the BB-6500 is a octalink bottom bracket.

So you would need a octalink compatible crank puller/remover and a allen key big enough to remove the crank bolt.

the video here is very useful.
http://www.parktool.com/blog/repair-hel ... hree-piece" onclick="window.open(this.href);return false;

edit: good thing Duck is around.

[zero]

9 speed crank (second hand or new sora) will work perfectly.
10 speed crank will likely work well, but may be harder to perfect the shifting adjustments - there were spacers for that back in the day. It works without them though it may rub.

There is someone on ebay running out (more or less new-old-stock now) 10 speed compact 105 chainsets for a bit over $100, that's probably the best compromise between groupset snobbery and price.

In both cases those are hollowtech II cranks, which really might want the facing of your BB to be checked before installing (one time deal).

Other than that you could find a secondhand octalink crank, but IMO most of such are likely to crack under sustained use due to being old and fatigued. I've cracked 2 dura ace 7700s. I'd also view your rear wheel as something to keep an eye on, if it starts losing true regularly, then its yet another paired spoke bontrager rim crack coming up.

[Duck!]

You will need a new bottom bracket to suit whatever crank you get. The BB-6500 and its attached crank are Octalink Type 1, which - disregarding triple & solid/hollow versions within any groupset - was only ever used for four models, three road & one MTB. No compacts were offered as this design's production run pre-dated the compact concept by several years. Later (still current) Octalink uses the Type 2 longer & thicker spline pattern, which is completely incompatible with Type 1 bits.

To remove the crank all you need is an 8mm Allen key; the crank (assuming it too is 6500 & not 500 105) is a "self-extracting" type, with a cap around the bolt which the bolt pulls against to remove the crank, thus not needing a crank pulling tool. To remove the bottom bracket you'll need a tool with the appropriate spline.

10 speed crank will likely work well, but may be harder to perfect the shifting adjustments - there were spacers for that back in the day. It works without them though it may rub.

There have never been spacers related to the crank for mixing compatibility. 1st-generation 10-sp. (7800/6600/5600) swaps in perfectly. 2nd-gen 10-sp. - 7900/6700/5700/4600 - and 11-sp. has wider chainring spacing, which doesn't work well with older front shifters & derailleurs because they don't have quite the required pull to cover the extra gap. A change to a newer FD with revised leverage will sort that out nicely. Beyond that detail, any 9, 10 or even 11-sp. crank will work.

[Rvzy]

I think I know what BB to get, but I'd rather not mess up,
I was thinking of buying a Shimano 105 5750 set, I assume a 68mm English threaded Ultegra 6800 BB will work just fine?

Thanks for all the help!

[Bentnose]

As zero said in an earlier post, I'd check your back wheel for cracking around the spokes, the Bontrager rims of this vintage are renowned for cracking, I know I had one and had to replace it.

[Duck!]

68mm BB6800 with FC-5750 will be fine. You'll need to give the front shifting a bit of a tweak though. The chainring spacing is a bit wider, which doesn't normally work too well with older shifter/front derailleur pairings. However the 6500 left shifter is also compatible with a triple-ring setup, so with some careful tuning the trim point should be able to be set to suit the more outboard big ring.