OblivionLord

I have a 50/34 double crank with a 9 speed 12-25 cassette on my road bike. I mainly ride on flatland since it's flat in Florida and I use cogs 15-21 the most while on the 50 chainring. I try to maintain a 80-90 cadence and avg a 16-17mph. My issue is that the chain is on the 50 while bending to reach the lower speed cogs just so I can maintain the high cadence. I think this amount of bending is bad for the drivetrain.

My question is....
If I were to get a regular road crank of 53 then I'm thinking cog 15 will be even harder to push than if I were using a 50 chainring on the same 15 tooth cog of the cassette. Therefore if I were to get a 53 then a 10 speed cassette Ultegra 6600 15-25 would probably be the best bet for me since the higher gear cogs are more inline with the 53 chainring.

If I were to stick with a 9 speed and still use my double crank then I'm thinking a cassette Ultegra 6600 14-25 would be the better choice than the 12-25 that I have now.

Any thoughts?

logdrum

The bending you mentioned is technically called cross chaining. Modern drive-trains IMO can take a lot of cross chaining. I do it all the tie and I have not destroyed anything on my compact. I think it is rare to get a 13 small cog and 15 as your smallest cog will almost be impossible. However the 39 inner chainring with your 13 or 14 may be what you are looking for.

You can also raise your cadence past 100. It is a good skill to get to around 18 mph or a 34 X 19.

dstrong 

If you're mainly spending time on the 50 and the 15-21, then that sounds perfect. If you need more gradiation between the 15 and the 21, then maybe a 14-25 is desirable but I'd ride 50/21 all day and not worry about it. Also...if you're working to get strong, then you'll probably start spending more time in the 14-19 range, then the 13-17 range...then you can start considering a standard (53/39) double.

banerjek

Rather than get a standard double, swap out your big ring for a 46T.

You're on flat land and won't be spinning that out, but it will allow you to run in your big ring practically all the time.

OblivionLord

I like the sound of swaping out the 50 for the 46. One issue that happens with my cassette is when I'm at 19 and try to go higher.. since its bending soo much, it doesn't seem to want to stay at the lower gear and tends to switch itself back.

I really do like the sound of the 46t alot. Thanks

botto 

check.

yet you have a compact?

check.

needs. more. spin.



it's called cross chaining, and that's not your only issue.

correct.

correct.



incorrect.

work on your cadence and replace the 34 with a 36, 39, or even a 42.

merlinextraligh

Put an 11-23, or even an 11-21 on the back. 34/23 should be low enough for anything you encounter around here, and the 11-23 will give you tighter spacing. And you'll be able to use the small ring as well (i.e 50/19 is about the same as 34/13)

And a compact works reasonably well in Florida. Put an 11/21 or 11/23 with it and you've got enough gear to cover anything you're going to encounter, with nice tight spacing. And put a 12-27 on it for the annual migration to Six Gap.

OblivionLord

botto
You should ask for more questions about my bike and myself before judging.

I have a 32in inseam and i have 175mm crank length arms. I can increase my cadence tenfold and increase speed slightly if my crank arms were 172.5 or 170mm instead. The double came with my bike which at the time I didn't really know what I was getting since I was very new to this hobby. I'm actually happy with what I own. I would have bought differently had I known then what I know now. I don't plan on selling my bike or buying a new one anytime soon.

merlinextraligh
After looking at the Sheldonbrown gear calculator confirming what your were saying... I think your idea is the best so far. Change out my current cassette for the 11-23 and use my 34 as my main crank while mainly using the middle portion of the cogs which in turn will provide tighter spacing instead of changing out my 50 chainring for a 46.

Although I think for me, the 11-21 will be a better route since there will be no climbing at all involved where I ride and if I ever need to relax a little while I'm riding then the presents of a cog 16 on a 11-21 will provide an even tighter spacing than the 11-23 which jumps from 15 to 17.

Hermes

I have a 32 inch inseam and use 172.5 cranks on my road, TT and Track bikes and 175 on the tandem. I can easily spin 120 rpm at the track and on the tandem with my wife. Your 80 to 90 is okay but could improve dramatically if you work on it.

IMO, MerlinX' gave you the best solution.

banerjek

This sounds like an adjustment problem. If you're lucky, it's just an RD cable that's a little loose.

But I do think the 46T may be the ticket for you -- especially if you spring for the 11-21. Otherwise, you'll find your big ring to be nearly useless.

ahsposo 

You might consider a single speed for rides when the wind is not much of a factor.

c.miller64

When riding around Clermont and Dade City 11/23 just don't cut it (for me).

OblivionLord

I pace myself doing 80-90rpm on the road that I ride on. The ride consist of 40miles in total up to a 2.5 hour duration. 20 minutes of it is a combined total for rests and stretches as well as a snack. If I were to race on a track then I would of course put more effort into it since races are a different story however normal races aren't going to consist of 2 hours consistent riding and if they were then I would be hard pressed to believe anyone can maintain 100-120rpm of 2 hours straight at the amount of wattage I'm putting in on a 175mm crank with a 32in inseam.

Ultimately I think the best thing for me to do is just change out my whole Tiagra 4500 34/50 crank for the Ultegra 6700 39/53 and switch the Tiagra 9spd 12-25 cassette for the Ultegra 6600 9spd 11-21 and mainly ride on the 39t. This will overall be better than riding the 34t along with 11-21.

botto 

irrelevant.

godshammgod

I kind of have to agree. You asked a question about gearing. You provided information about said gearing. What other information was really needed?

Re: your cadence. I don't think you'd be putting out the kindage of wattage you think when you're averaging 16mph on flat land. And it is possible to train yourself to ride at a higher cadence. Do a search and you'll find great suggestions from people who are much smarter than I am.

thirdgenbird

he may have come off as a smarta$$ but it was actually an educated response.

i run cranks that are" too long" for me (180mm) on one bike as well but averaging a 110-120 cadence is still not an issue. 90prm is nothing to be ashamed of, but there is plenty of room for improvement. (regardless of crank length)

fwiw i have been paced at 32+mph (no speedo) on my fixed 42x16 gear bike. thats about 160+rpm

OblivionLord

I know it's late in the game to make mention of this although I really didn't think it was necessary although the main question on this thread has lead us into a tangent about Candace and Athleticism.

I'm not really riding on a road bike. Although I like to consider it to be a road bike, it technically is a hybrid or a very relaxed road bike if you will.

This is my bike...
https://www.giant-bicycles.com/en-US/....1/3875/36255/

My frame is just slightly more relaxed than the Giant Defy series. My Geometry certainly is not comparable to any aggressive frame either. I also don't have drop bars, therefore I really have to fight against the wind. I recently added bolt on Aero Bars and gained an overall of 2.5+ mph to my speed when I am in that position. I do have my bars in a relaxed position because comfort is also a priority to me. Even with the Aero Bars on my particular bike... it's still hard to fight against any amount of wind compared to the higher end TCR series that I test rode or even other brands which I also tested that are in the same type of aggressive positions as the TCR. I chose to go with my bike because of personal reasons which I'm not going to get into simply because it would take a long time to go through.

Another issue I have is that the Catzeye Cadence computer that I use doesn't seem to accurately log 'avg' speed for some odd reason. I can pedal at 19-20mph avg for a whole 15 minutes and the moment I slow down for just a minute or so, the avg reading drops a bit as if the whole 15 minutes wasn't even accounted for. I am using 16mph as a figure for the overall 2 hour duration only because of what the computer readout says. I technically can't be certain of the accuracy of that since I don't have another computer to compare it with. I am going to look into that since it's still under warranty.

Not to say that anyone is better than anyone else, but before throwing out suggestions as to what one should "Work On" or "Improve"... I believe quite a few factors should be present.

ahsposo 

Oh, boy!

banerjek

Presuming that you're remembering to set your trip distance before riding, I have a funny feeling the reason your average speed is low has nothing to do with a faulty computer One way you can be sure is to divide distance by time. Another is to ask someone else how fast they are going. If you go to a group ride, you'll find a significant number of other people riding your pace.

Average speed drops fast. If you ride for 20 miles and get delayed even by 30 seconds, it will show up on your average time. Slight risers in the road, puffs of wind, and the like can quickly knock that number down. But the whole point of average speed is it counts all that.

godshammgod

Regardless of the many other factors you posted, it's still sound advice to work on increasing your cadence. Based on your original post it did seem to be one of the limiters of your current gearing. No matter what change you make it's still a good idea to work on upping your cadence.

Good advice contained here: https://www.bikeforums.net/showthread...ndard-gear-set

OblivionLord

godshammgod
The overall aspect of my bike is going to be different than an aggressive bike. As I made mention before... The TCR series was much easier to pedal overall. Wind is also a great factor especially when you have a drop bar compared to a 'relaxed' Aerobar. Even outside of wind, being more aerodynamic simply plays a large role at higher speeds. When there is no wind drag, while I'm on my Aerobars, I Avg at 20-21mph.

The poster in the forum you linked uses a much different bike than mine which is a CAAD9 which is comparable fitting wise to the TCR that I rode. That is why he felt like he needed a Standard compared to a Compact. Had he ridden my bike for instance, I'm quite sure he wouldn't feel the same way.

Another thing to point out is that although he hasn't purchased a computer to really tell us any actual numbers.... noone can 'accurately' judge his rate of pace since we just don't know for a fact how fast he is pedaling or what his AVG speed is. Furthermore I'm quite sure the results he gives will be much more comparable with anyone that has an aggressive road bike like his instead of comparing results with mine.