|Racing with 13-26 cogs?||MerlinMan|
Jan 12, 2003 3:37 PM
|I live in Michigan where we have slopes instead of hills. Any real disadvantages to racing with a 39/53 and a 13-26 cogset.I wont run out of gear on the flats will I?|
|should be OK||weiwentg|
Jan 12, 2003 4:52 PM
|I'm in MI, too. I have yet to really spin out a 53-12, but I'm not a sprinter. I don't think you'll run out of gears, so don't worry; if you need the 26, go for it. if you think you will need an extra gear, why not the 12-25?|
|Its a 10 cog cassette.||MerlinMan|
Jan 12, 2003 5:09 PM
|I don't need the 26 but this is a 10 record cassette and would like to be able to stay in the big ring more, with a better chain line( less cross chaining ).|
|re: Racing with 13-26 cogs?||tao|
Jan 12, 2003 5:03 PM
|My take, if you have the power to get on top of a 53/13 and overspin it (over 35mph), I doubt you need the 26, a 12-25(ish) is probably better, in fact, I'd even consider an 11.
Consider LA's main TT gear in the Tour was a 54/15, cadence 110, speed 31mph! Even when he reduced his cadence he was still using the 13 and 14.
|Here's a question........||MerlinMan|
Jan 12, 2003 5:22 PM
|With a 53 - 13, what speeds can you reach when sprinting. Of course the other factor is the number of rpm's the typical road sprinter spins during a sprint. Any idea?|
|Here's an answer||Kerry|
Jan 12, 2003 5:36 PM
|Any idea? About something that can be calculated easily and precisely? Maybe we should guess instead! However, if you take front/rear*diameter*0.295 you get speed in mph at 100 rpm. That means 53/13*26.25*0.295 = 31.6 mph. IOW, gear inches times 0.295. At 110 rpm, it's 34.7 mph. At 120 rpm it's 37.9 mph.|
|handy dandy chart||DougSloan|
Jan 12, 2003 8:43 PM
|Here's a question........||tao|
Jan 12, 2003 5:47 PM
|The best Elite Pro sprinters can spin a 54/11 at 120rpm, or about 46mph. Some use a 12, about 130rpm.
Most mortals can sprint at nearly the same cadence though without the gearing and leadout.
53/12 at 115rpm ~40mph, at 125rpm ~43mph
53/13 at 115rpm ~37mph, at 125rpm ~40mph
53/14 at 115rpm ~34mph, at 125rpm ~37mph
53/15 at 115rpm ~32mph ...
you get the idea...
|Get a 12 -- just in case ....||MR_GRUMPY|
Jan 12, 2003 8:13 PM
|What happens when you have a 15 to 20 MPH windy day, where it just happens to be a tail wind with a 5 mile wind-up to the finish.
Back in my 7 speed days, it happened just like that. I spun out in my 13 at 38 mph, and couldn't really sprint to the line. On a day like that, I probably could have used an 11.
If you have multiple wheels, get at least one with a 12.
|re: Racing with 13-26 cogs?||templecat|
Jan 13, 2003 7:53 AM
|Plus the 13/26 gives you an 18t cog.
Cuts the jump from 17-19 (58 & 79.5 gear inches for 39 & 53 respectively). Could be useful!
|Watch out in fast pacelines||DoubleK|
Jan 13, 2003 9:47 AM
|With a 13 you might have to be careful in a fast paceline. Back in the day I had a 13-21 7-speed and on the weekly group hammerfest or races when in a fast paceline going slightly downhill or with a tailwind you had to be careful not to get gapped because if the group is really working well they can push the speed up to the point that if you lose the draft it is very difficult to get back on without a 12. Just something to consider, it might not matter in your area. This was in SoCal.
|I agree -- consider efficiency||DougSloan|
Jan 13, 2003 10:12 AM
|While most of us could sustain the 110 rpms that it takes to keep up in a 35 mph paceline in a 53x13 combo, you might be much more efficient in a 12 cog, which is 100 rpms. I know that I can push 110 rpms and keep up, but I'll get a lot more tired than if I would be running 100 rpms. Drop it down to a 53x11, and you're down to 92 rpms, which is very comfortable.
Take the speed up to 40 mph (really strong tailwinds), and you might get spun out much faster -- 53x11=105 rpms@40 mph; 53x12=115 ; 53x13=124.
I guess you can do it, but efficiency suffers.
|re: Racing with 13-26 cogs?||blanchaa|
Jan 14, 2003 1:13 PM
|I raced last season with a 13-26 and will definetly change this year. Any sprint that is slightly downhill will screw you, even just 1-2 % I lost a sprint in training because of this even though I was stronger. Hopefully I will be on an 11 this year.|| |