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Dumb chainring question
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 2007-10-18 10:17 PM |
 Tampa Bay |  Subject: Dumb chainring questionI have an Orbea Onix from 2005 which was a demo bike that I bought from the LBS. I am having a lot of problems keeping up with people at speeds above 19 mph sustained on flat surfaces and I was wondering if it's got anything to do with the chainring and cassette that I have. I am a fairly new cyclist but in good shape and was wondering if there was anything unusual about the parts that I have. The chainring says FSA 130mm BCD 53/39 (no, I don't have a granny gear). And the cassette is a Shimano Ultegra 12, 13, 14, 15, 16, 17, 19, 21, 23, 25. Don't know the crank size...assuming it's 170mm...it's whatever came with the bike. Would appreciate any thoughts and links to sites that'll help me make some sense. Thanks! |
| 2007-10-18 10:24 PM in reply to: #1014830 |
Expert  937   Traverse Cityish | Subject: RE: Dumb chainring question That's pretty standard gearing, but the crank arms stand out at me a bit. What is your cadence when you are doing 19+ and what is your height and inseam? If you are 6' tall +/- 3" I'd go to 175MM cranks for sure. People who spin for power and prefer a high cadence or are shorter in height can benefit from shorter cranks. For most folks the 175's just give more leverage resulting in more power transfer with less effort. The cheap fix is to just go do hill repeats.  BTW, great bike! |
| 2007-10-18 10:31 PM in reply to: #1014830 |
Champion 7547  Albuquerque, New Mexico Bronze member | Subject: RE: Dumb chainring question I have problems keeping up with people at 19 mph too! It has nothing to do with the bike. 53/39 and 12-25 is a pretty standard combination. Crank arms are often 172.5 or 175 mm, so 170's are pretty short, but would generally be appropriate for smaller bike frames (and people with smaller legs). If you want to hang with the faster riders, get out there and ride (and ride, and ride)! |
| 2007-10-18 10:37 PM in reply to: #1014830 |
Expert 1023 Ft Gordon, GA | Subject: RE: Dumb chainring question First off, not a dumb question. Secondly, I have to agree with McFuzz's statement. It has nothing to do with your chainring/cassette (or crankarms for that matter). That set up (53/39 with 12-25) is what a lot of pros use and they reach over 30 mph with those gears. Must be something else. Keep riding! Buck |
| 2007-10-18 10:43 PM in reply to: #1014830 |
| Tampa Bay | Subject: RE: Dumb chainring question Thanks for the replies everyone. I am 5'9" and my inseam is 32" (at least). |
| 2007-10-18 11:02 PM in reply to: #1014830 |
Pro 4206 Los Angeles, CA | Subject: RE: Dumb chainring question Like others have said, it's not the chainring. Click on this article on ST about chainrings. On the bottom of the page, there is a chart about max speed of a 53/39 with a 12-25 cog is 30.42 MPH. http://www.slowtwitch.com/mainheadings/techctr/gearing.html |
| 2007-10-19 12:15 AM in reply to: #1014863 |
Expert 1023 Ft Gordon, GA | Subject: RE: Dumb chainring question auto208562 - 2007-10-19 1:02 PM Like others have said, it's not the chainring. Click on this article on ST about chainrings. On the bottom of the page, there is a chart about max speed of a 53/39 with a 12-25 cog is 30.42 MPH. http://www.slowtwitch.com/mainheadings/techctr/gearing.html At 90 RPM. You can go a lot faster than 30.42 mph on a 53/12 if you are sprinting and turning faster than 90 rpm's. |
| 2007-10-19 12:22 AM in reply to: #1014892 |
Pro 4206 Los Angeles, CA | Subject: RE: Dumb chainring question Thanks for the clarification. Karl Hungus - 2007-10-18 10:15 PM auto208562 - 2007-10-19 1:02 PM Like others have said, it's not the chainring. Click on this article on ST about chainrings. On the bottom of the page, there is a chart about max speed of a 53/39 with a 12-25 cog is 30.42 MPH. http://www.slowtwitch.com/mainheadings/techctr/gearing.html At 90 RPM. You can go a lot faster than 30.42 mph on a 53/12 if you are sprinting and turning faster than 90 rpm's. |
| 2007-10-19 2:05 AM in reply to: #1014830 |
Pro 5892 , New Hampshire | Subject: RE: Dumb chainring question Definately not a dumb question at all!!! I don't think it's the gearing that is the issue... Either your cadence is really low, or you just need to train differently. Since you are fit already, I would add interval work. To keep higher speed for a longer time, do 10 min. warmup, 3-4x10min. at 90% of max HR or W with 5min. rest (light spinning at 50% of max.). If you have problems with acceleration, do 3 sets of "spinout sprints". Start with 39x15 (small front and about the middle in the back). Accelerate as much as you can until you nearly spin out (i.e. you start to bounce... probably about 120rpm) then shift up once and continue the sprint, shift a second time and keep going. Do a recovery of 5min. in between each set (se above). This should help you hang on. |
| 2007-10-19 8:48 AM in reply to: #1014830 |
| Tampa Bay | Subject: RE: Dumb chainring question I will try the interval training workout to see if it makes a difference. Also, good article on ST....makes sense now. I also found a nice calculator (I am sure there must be many) http://www.panix.com/~jbarrm/cycal/cycal.30f.html |
| 2007-10-19 9:06 AM in reply to: #1014830 |
Champion 7547 Albuquerque, New Mexico Bronze member | Subject: RE: Dumb chainring question If you're 5'9", the 170 mm crank arms may be shorter than optimal. What size is the frame? Caveat: It can get very expensive very quickly to start swapping out components. |
| 2007-10-19 9:37 AM in reply to: #1014830 |
| Tampa Bay | Subject: RE: Dumb chainring question Actually, I just measured the crank and it's either 172.5 or 175. |
| 2007-10-19 9:38 AM in reply to: #1015198 |
Pro 5892 , New Hampshire | Subject: RE: Dumb chainring question Actually 170mm cranks are not that far off... I doubt that most of us will ever notice the difference between 170 and 172.5mm... I'm 5'8" and using 170mm cranks. Compared to 172.5, it's no difference, but compared to 175mm cranks I find it a bit easier of the hipsmuscles. And yes, I do adjust the seatheight |
| 2007-10-19 10:08 AM in reply to: #1014830 |
Champion 6786 Two seat rocket plane | Subject: RE: Dumb chainring question Cycling specific fitness is a little different from general fitness. You have to get used to the position on the bike, the necessary cadence (lots of folks start out pushing too big of a gear at too slow of a cadence). The good news is that if you are fairly fit to begin with, you'll gain cycling fitness quickly. Your gearing is pretty standard, nothing to change there. Ride lots. |
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