Learning about Spindles, Cranks and Chainrings (Oh my!)
 

Well I have learned that the specifications provided with a bike are just enough to drive a person crazy. I have a Fuji '06 Crosstown 1.0 with a SR Suntour NCX-410 28-38-48 that has a four hole 58mm BCD inner chainring. I want to go to a 22t for a 1/4 mi. killer hill on my home commute (yes, I am out of shape but probably is as good of shape as I am going to get on my now 7.5 and soon to be 2 mi. commute).

The 28t ring has a 5mm dish and the few 22t rings I find listed are all flat (uh, as is the 64mm BCD 22t ring I now have, but a cheap lesson as lesson's go). Should I ditch the whole thing? If so, recommendations? It has been a trip learning about the Suntour label, the square Shimano (or Shimano type) spindles, and the odd MTB I assume (left over parts??) 58mm BCD inner ring. Hybrid as specified . . .

TIA

Can you go lower in the rear?

I have a 11 - 32 teeth cog for a low of 23.8 gear inches or 1.8:1 and a top of 118.6 or 8.9:1.

I have been told that anything over 100 for a recreational rider is over kill ( I use the top end very little on my 7 - 10 mi. rides) so dropping down to around 100 GI is fine. The 22t would give me an 18.7 and it "seemed" that the CR would be easiest to change. I haven't shopped for cassettes for numbers to plug in at Sheldon's site. What cassette are you thinking about?

Why don't you just get a whole crankset? 42-34-24 are plentiful. http://www.bizrate.com/bicycle-parts...4-24-crankset/ I found them everywhere when I was looking for a 48-38-28. You will need the specified bottom bracket to accompany it for acceptable chainline and front derailleur adjustability. But I believe the 22 might be a slight overkill with 32 in the rear a hill 1/4 mile long. I go up some hills that are 20% grade in places. I am 64 years old and in pretty good shape, but nothing like some. I have found that dropping down to a super mountain climbing "granny" gear wears me out spinning away and getting nowhere. I try not to use the 34 or 32 rear sprockets on the two different bikes -- or at least hold off for as long as I can -- and I reach the top sooner and less winded. I can't imagine holding up for 1/4 mile with 22 front/32 rear -- I see using that for a sprint up something ridiculous like 20%+ but very short. Not an expert rider, not a winner of races, just offering something to consider FWIW.

Don in Austin

the largest cog you can get is 34 teeth which is not that much of an improvement over your current 32 teeth. Most front derailleurs limit the tooth difference to 20 or 22 teeth so you can't just replace your smallest chainring, you will have to replace the entire set with a 42-32-22 or a 44-32-22 set.

Thanks Don and Bezalel! I had started trying to learn about what I could and couldn't that was part of my 1st question, "What is too big of a jump?" and the reply was that replacing the 28-38-48 with the 22t would be fine. I have a 42-34-24 on my Montaque. It is a replacement when the OEM was damaged in shipping (and it was CHEAP, all rivets made to look like screws) and I have considered trying to swap it to see how it goes.

Don the hill is a 24% grade (I wanted to post my walkrunjog.net route link but the site isn't working on my work computer). I can pull it 95% of the time with the 28 and the other 5% of the time I simply walk it. I sure take your point on and in the end the best solution might be to simply do the exercise I know is good for me. :commute:

Thanks

I run 22/35/48 with an 11-34 9spd, and have NO problem with the XTR 952 RD. I put on bar end shifters to solve a problem shifting my MTB FD with brifters. (That's 26 tooth difference in front). I have an XT FD

You should be able to find a 24t ring that has the 5mm dish, and with the 34t cog, this gives 18.6 gear inches.

If you do not need the lightest, fanciest cassette, you should be able to pick up an 11-34 for $30 or less.

As yo u already know, a 24% grade is VERY! steep. How long is the steep part?

badamsjr, thanks for the insight. JanMM, the main climb is 150' in about 1,500' not including the 60' or so climb after I leave the new Woodrow Wilson Bridge Trail (parallels the I495 on-ramp in the upper right/NE).
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