Crank Replacement Rookie
 

I picked up a low end Cannondale Hybrid (1999 H300) to get back into cycling and to learn a few things about bike mechanics. The bike is great for fitness, but I've started to tear it apart and refit with some inexpensive upgrades, as that is the stuff I love to do. My latest project has been to replace the BB (110-68 square taper-JIS) and upgrade he crank. The original spec listed the crankset as a C.P.I, but once I pulled it I found it to be a 175mm Shimano FC-M290 and it had been the subject of a recall in the late 1990s, so I'm glad I'm doing this upgrade.

The original crank was a 24/34/42 which I plan to replace with a 30/42/52 FSA Vero crankset. Here is where my problem lies. The new FSA crankset slides in too close to the frame. Upon closer inspection I have come to realize the not all crankset BB shafts are created equal. The original Shimano crankset BB shaft extends beyond the innermost chain ring by about 1/8" inch...an "outie", so to speak. The FSA chainring BB shaft is recessed, an "innie", and therefore slides too close to the frame. So I have learned that cranks come as "innies" and "outies".

Can anyone recommend a reasonable triple crank that will fit my "outie" needs. I'd like the largest ring to be in the neighborhood 48-52 teeth. When I look at pictures of cranks, it is really not possible to determine the BB shaft length on the inside. I'm sure there is a more technical description, I'm just not sure what it is.

Thanks to all who have taken the time to read my lengthy post. Any advice will be greatly appreciated.

Bill

You can check Sheldon's site for BB/crank compatibility. https://www.sheldonbrown.com/bbsize.html. If a crankset is not there just look for cranks that fulfill your criteria for length and tooth count and see what BB length they take, until you find one that matches what you have. 2nd option is to buy the crankset with BB and replace what you have.

However I would strongly suggest that you not go to any more than a 48 tooth chainring, as you will "gain" at least one, if not two almost unusable gears. Even with a 48 tooth, a modest 80rpm with the 11 tooth gets you 27mph, and you'll hit 40 or so before you spin it out. I'd recommend the classic 28-38-48.

Measure the BB axle length.
Try a BB with a longer axle.
What are you hoping to gain by the bigger crank?
It is unlikely to play nice with your front derailer.
And one that will is unlikely to play nice with your front shifter.
A 42 biggest on a 26" bike will get an average skill rider to 25+ mph.
Unless you're there, work on riding technique, not ride technology.

A Google on that crank found:
FSA recommend a 110mm spindle length for this crankset

Although everything seems to indicate it's a double crank.

Found the triple, Google says 116 mm spindle. Probably have to go for a 118 mm.

Probably could go for a longer spindle and make sure the cups are in snug. If you insist on a recessed crankset shaft you will probably want to look at track and single speed cranks. I don't know if you can shift well or even use a derailleur well with a recessed crank shaft.

But I want to ride a 52

You find the spindle length that matches the specific crank. There are at least 1/2 dozen different lengths.

Are you seriously spinning out your 42-11 combo on a regular basis?
A 24% increase is relatively huge!

The Sheldon Brown database that cny-bikeman mentioned states the spindle length as 110 or 113 mm for the fc-m290 (and says not to use it because of the recall). Probably that is too short for the FSA vero, so it was too close to the frame. Try measuring the spindle length of the bottom bracket you have now and the chainline you have when you install FSA Vero on it. Chainline is the distance from the middle chainring of the triple crankset to the imaginary plane which goes vertically through the middle of the bike. Alternatively, you can measure the distance to the seat tube and add 1/2 of the seat tube diameter. The chainline should be 47.5 to 50mm for a mountain triple. You are going to have a smaller number, and you can do some simple math and see how much you are missing and how much you need to add to the BB axle length.

You will need a new derailleur and likely a new chain. A short chain will lead to a disaster when shifted to the big/big. Something like FC-M131 crankset, 123mm square taper bottom bracket and FD-M360 front derailleur will do the job. I run this very setup on the old Hardrock. Good workhorse. Or you can get the right bottom bracket for the FSA Vero and something like FD-M360 front derailleur.

Some time ago I had a cheap riveted Sugino Impel triple (48-38-28), that would probably give you an OK chainline with your BB. Not sure if one can find them now.

Some useful links: https://www.sheldonbrown.com/chainline.html Sheldon Brown's Bicycle Glossary Bo - Bz Square Taper Bottom Bracket Interchangeability

Don't know what your bottom bracket is, but when I added a Sugino AT triple to my Raleigh Super Course, I had to shim the fixed cup (drive side) out so the crank bolts wouldn't hit the frame. I used two 1.37" i.d. cassette spacers. See the photos below.

You're looking at a fair bit of effort/cost to make a 52 work on your bike. For little to no practical benefit.
And apart from on the 2-3 highest gears, you won't even feel a difference.
But it's your money, your effort, your bike.
And you're not hurting anyone else.
Go ahead, tickle your fancy.

trailangel is not the OP - text does not show things like sarcasm, irony, etc.

Thanks to all who have responded. I've concluded that a longer BB will not solve my issue with the FSA crank as it will still need to slide fully onto the taper, which will place it too close to the frame. Thanks Slightspeed for the shim recommendation, but that does not seem to be very safe. I've switched to a more practical Shimano 48/38/28 FC-M361 175mm. I also ordered the appropriate BB (68x122.5).

Yes dabac, it is my money and time. I've got the time, as I'm retired, and I enjoy tinkering. Money is always tight, but I plan to re-sell the FSA crank and recoup some of the cost of the new Shimano Crank and BB.

Regarding the oversized crank. I started riding again about two years ago, after a 40 year break. A career, family and life in general just sorta happened in the blink of an eye. Along the way, there was seldom enough time to take those long bike rides that I love so much. Nowadays, I'm having a blast riding the local paved trails here in North Central Florida. I'm blessed with extremely sturdy legs and have stayed pretty fit over the years, and now am ready to whip some youngsters butts. The paved trails are old train beds that have consistent grades, making for long gradual inclines and declines. I usually ride 40-50 miles and have found that I spin out my 42 on all flats and declines. I usually keep it engaged on the inclines, as I have the legs and stamina to do so. With the 42 engaged on an incline, I catch and pass all other riders. What is irritating to me is when I'm passed by kids on the declines and flats. They have not spun out, and are cranking at the same rate I am. I've always been competitive and do not like being passed.

So I continue to work on technique, but I need a bigger crank. The 52 was probably overkill, but I certainly look forward to getting the new 48 installed.

Thanks again to all who took the time to respond.

Bill

Shimming drive side is a common practice when using a modern cartridge BB on a vintage crankset (like the Sugino AT above) that was designed for an asymmetric spindle. Of course, it just moves the crank to the right. If the BB is too short, you just transfer the problem from the drive side to the non-drive side.


Even Sir Sheldon recommends a spacer on the Sugino AT:

https://www.sheldonbrown.com/bbsize.html

I don't understand why the FSA would not work with a longer spindle BB. But the Shimano is a nice choice too.

Was thinking in a certain way based on my experience. Upon further consideration, Innie and outie is not something I've seem enough to suppose there aren't plenty of recessed cranks other than track and single speed. In fact, it looks like you got a recessed mountain style crankset.