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Help - gear ratios and indoor trainer(3 posts)

Help - gear ratios and indoor trainerchazman
Mar 30, 2002 6:50 PM
I got an indoor trainer that has progressive resistance (gets exponentially harder with more RPMs, kind of like a wind trainer). It is the 1upUSA trainer. There is no way to adjust resistance. I use my old mountain bike on this.

The problem I am having is that I do not seem to have the right variety in gear ratios. My cassette in the gears I use is 12,14,16,18. This gives the following rations:

3rd Ring = 42: ratios: 3.5, 3, 2.625, 2.333
2nd Ring = 32: ratios: 2.666, 2.286, 2, 1.777

Progrssively this is:
3.5, 3, 2.666, 2.625, 2.333, 2.286, 2, 1.777

Normalized to percent ratio increase this is:
16.7%,12.5%,1.56%,12.5%,2.06%,14.3%,12.5%,0

If I went to a 42/34 combination I would have
2nd Ring = 2.833,2.43,2.125,1.889
Progressively:
3.5, 3, 2.833, 2.625, 2.43, 2.333, 2.125, 1.889
Percent increase:
16.7%,5.89%,7.9%,8.02%,4.16%,9.7%,12.5%,0

It seems to me that the 42/34 combination way better in terms of giving me more regular ratio increases. Any thoughts? With my current setup it is to hard to keep consistent RPMs and get consistent increase in heart rate with increased gear ratios.
Sell it and buy rollers(nm)Lone Gunman
Mar 30, 2002 7:09 PM
re: Help - gear ratios and indoor trainerJekyll
Mar 31, 2002 1:47 PM
Instead of changing your middle chainring why not just get a cheap road cassette 12-23 or 21? This would give you closer ratios while staying in either your big or middle chain ring. A low end Shimano cassette will probably cost less than a middle ring for your crank as well.