shdemps

I just bought my first road bike on ebay, which I know is not ideal in terms of fit, but i'm pressed for cash and I also wanted something that was cheap enough to replace if it gets stolen once I head back to school.

I ended up purchasing a specialized tricross comp, but the previous owner had switched the crank from the original FSA gossamer double with 38/48 chainrings to a Rocky Mountain (a brand I am not familiar with regarding quality) triple with 28/38/48 chainrings. The previous owner then did not change the front derailleur, so the bike is only capable of shifting the 28/38.

Regardless of the quality of the current crank, I plan on switching it to a double crankset similar to the original, but i'm not sure what I should do chainring wise. I live in a very flat area, and would consider myself a relatively strong rider. I'm looking to buy FSA, since I worked in their North American warehouse for a summer (picked up the cycling bug there...), but should I get close to the original cyclocross oriented 38/48 or go with a more road oriented 39/53 since I plan on using the bike for road riding? I also have no idea what to do in terms of the crank arm length. The frame is 60cm, and I have long legs, should I try and go for 175mm or will 172.5mm be long enough?

As a side note, would anyone know what that used Rocky Mountain crank might be worth?

tc83

My 2 cents: 175 mm crank length for sure at your size. 48 will leave you wanting in terms of top end speed for road riding. A 50/36 or 50/34 compact crank could get you a better range for more varied terrain, and you would survive if you wanted to ride a little bit of cross. A 53/39 would be a commitment to the road, and you would either need to be a strong man in the hills, or it will help you become one.

RollCNY

Sealed Cartridge Square taper bottom bracket, or external bearing? If it is square taper, what length, and did they keep that original or lengthen it? For square taper, I had an FSA Vero and it was cheap and held up fine. If you need a new cartridge BB, usually they are 107 or 110mm spindle length to get chain line right.

I am 6'3" and notice no meaningful difference between 172.5 and 175. I would buy whatever I got the best deal on. Stick to a 50 tooth big ring, as it is close to the 48 original spec and should clear everything. It shouldn't be a MTB FD, but if it is, you might need to replace to work well (curvature of MTB FD usually caps out at 48 and gets hard to set on bigger rings).

shdemps

I finally got the bike in the mail and assembled it, and the bottom bracket is indeed a sealed square taper. I'm assuming it is at least similar to the original MegaExo BB, but I can't tell for sure. I dont yet have the tools to pull the crankset off, but here is a picture of what I can see of the bottom bracket and the current crankset. I'm still unsure of the current crank, it only says "Rocky Mountain" on it and google searches turn up nothing related to a crank of that brand... I'm wondering if it is a MTB crank, which would be extremely strange since the bike arrived with Bontrager race tires, so I doubt the previous owner was doing cross on those. The front derailleur is the original shimano 105, so I think it will fit a 34/50 fine, which is the size I am looking at now.




I currently see two options with what is currently on ebay. There is a vero compact 50/34 (spindle length of 110) for $65 which I can probably just put right on? I'm not sure the spindle length of the bottom bracket, is there any way to measure it? If I put the crankset on a spindle thats a little bit off the recommended length will that be disastrous?

The other option is wait for a higher quality crankset (Maybe a gossamer, or a lightly used carbon team issue) to come on sale and maybe replace the bottom bracket as well, but that would be twice as expensive and I'm not sure if it really worth it.

RT

You can get a Gossamer or Vero at nashbar.com for decent price, with bottom bracket. There are plenty of FSA detractors in here, but for your needs, FSA cranks will be fine. I use them without issue on my commuter/cross bike.

Nashbar even has 6600 series Ultergra cranks with BB for less than $150.

Capecodder

If I were you, I wouls ride it the way it is for a bit. You already said the bike does not fit so why spend the money on this bike? Ride it as is till you can afford the correct size bike.

byrnemm

+1

Ultegra SL crankset is stiff, reasonably light, and extremely well priced. My only complaint is that it turned my bike into a frankenbike (glossy grey crank on matte titanium frame)

shdemps

Thanks for the advice everyone. I think i'm gonna go for the vero today. I'll see if there is a 6600 for less, but I doubt there will be. The current bottom bracket feels almost brand new to my highly untrained legs, and at the least I think it has a few thousand miles left on it.

I currently cannot shift unless i have the gearing just right, the adjuster screws on the FD are either all the way out or all the way in and it can only shift the first 2 cogs (28/38) so I am constantly riding at the top gear. I'm gonna go for a nice 50/34 and take the bike for a tune, so that everything is working. You can tell someone spent a long time trying to get the wrong crankset to work with the 105 FD since the cable running to it is all frayed. Need to replace that.

The bike fits great even though I feared buying it without riding it first was a death sentence in terms of getting a good fit. I'm very pleased overall, just wish the previous owner had left the gossamer crank on it.