Big ring epiphany!
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tsilcyc posted 19 weeks ago.
I like to spin so I'll use whatever ring suits me. I also ride a 12/27 in the back.
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theShiba posted 19 weeks ago.
You may find this tool useful: http://www.sheldonbrown.com/gears/
53x23 is the roughly same as 39x17...
It takes a bit of work.... but imagine...
you are in 53x19. You start climbing and you want to drop down one step. That's 53x21, which is in-between 39x15 and 39x16. So, essentially you would only have to pick up one or two gears in the back to drop one gear. Obviously you are not going to drop the ring up front, and want to match ratios.
548
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314 days
jhudalla posted 19 weeks ago.
What about really hilly courses? I'm running a 53x39 upfront and a 26x11 on the back... even on the 36-26 I'm dying on some of the hillier courses ie: silverman and oceanside. I was (am) considering a 'bailout' gear in the back.
Weary is the path that does not challenge.
28
Member
636 days
zanzabar88 posted 19 weeks ago.
theShiba wrote:
You may find this tool useful: http://www.sheldonbrown.com/gears/
Oh yeah, I used that alot in my bike setup.
Quote:
but imagine...you are in 53x19. You start climbing and you want to drop down one step. That's 53x21, which is in-between 39x15 and 39x16. So, essentially you would only have to pick up one or two gears in the back to drop one gear.
Actually, it's 2-3 gears different...and like I said, now all I have to do is shift once, on the front, to go from 53x21 to 45x21 (which is the same as 39x18) - while you have to shift three times! Haha!
Quote:
Obviously you are not going to drop the ring up front, and want to match ratios.
I don't understand this.
Seriously, the whole purpose here is to let people know this is an option, and it works great for me. If you like spinning at 120rpm that's fine, have fun with that. I like to stay in the 85-95 range.
I wanna start placing in my age group!
28
Member
636 days
zanzabar88 posted 19 weeks ago.
I run a 12-27 on the back, and don't have any problem with hills at 45x27. (I don't think I've ever even used the 27 ring?) In fact, that gear combo is only 1.5mph different than 39x27 at 90rpm, but that could be very significant on steep/long hills. If you're out west in the mountains I suggest keeping the 39.
I wanna start placing in my age group!
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727
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theShiba posted 19 weeks ago.
zanzabar88 wrote:
theShiba wrote:You may find this tool useful: http://www.sheldonbrown.com/gears/
Oh yeah, I used that alot in my bike setup.
Quote:but imagine...you are in 53x19. You start climbing and you want to drop down one step. That's 53x21, which is in-between 39x15 and 39x16. So, essentially you would only have to pick up one or two gears in the back to drop one gear.
Actually, it's 2-3 gears different...and like I said, now all I have to do is shift once, on the front, to go from 53x21 to 45x21 (which is the same as 39x18) - while you have to shift three times! Haha!Quote:Obviously you are not going to drop the ring up front, and want to match ratios.
I don't understand this.Seriously, the whole purpose here is to let people know this is an option, and it works great for me. If you like spinning at 120rpm that's fine, have fun with that. I like to stay in the 85-95 range.
Sorry if my tone was misinterpreted... trying to help here.
What I mean is that if one is shifting from the big ring to the small ring, one probably isn't looking to keep the same gear ratio... one is likely looking for a reduction in gear inches, or vice versa, going small to big.
So, my statement was that with a "standard" setup 53/39 12-whatever 9spd, if one wanted to reduce gear inches by one increment, it would involve dropping from 53 to 39, and picking up two gears on the back. If one wanted to keep relatively the same gear inches, it would require picking up three gears.
All I am saying is I don't see the point of keeping the same gear inches, unless one is trying to set-up for a big hill where one knows that they are going to need to drop to the small ring. In this case, the 10 seconds it takes to make this set-up is probably worth it.
28
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636 days
zanzabar88 posted 19 weeks ago.
theShiba wrote:
Sorry if my tone was misinterpreted... trying to help here.
What I mean is that if one is shifting from the big ring to the small ring, one probably isn't looking to keep the same gear ratio... one is likely looking for a reduction in gear inches, or vice versa, going small to big.
Oh, no worries...I gotcha now.
So answer me this: why does everyone ride such an extreme chain angle, e.g. big ring (53) on the front and 2nd or 3rd lowest (21-25ish) on the rear? Answer: it's because it's a PITA to drop to the small ring and simultaneously upshift two gears on the back, right?
I just like my solution, that's all. YMMV.
I wanna start placing in my age group!
51
Member
316 days
gshuldes posted 19 weeks ago.
If a 45 ring works better for you then it is the way to go ... but I am confused as to why it is a PITA to drop to the small ring and upshift 2-3 on the back. I do this frequently and the shifts are nearly simultaneous. It is all done in 2-3 seconds.
276
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809 days
fastdog5 posted 19 weeks ago.
gshuldes wrote:
If a 45 ring works better for you then it is the way to go ... but I am confused as to why it is a PITA to drop to the small ring and upshift 2-3 on the back. I do this frequently and the shifts are nearly simultaneous. It is all done in 2-3 seconds.
If that. I do this all the time. Is the derailleur a limiting factor? I run Dura Ace; shifts are quick & crisp. A friend I ride with is running Sora; he stays in the big ring a lot. His shifts take forever. Just a thought/observation.
727
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537 days
theShiba posted 19 weeks ago.
It could be an issue of the derailleurs themselves... Sora has a longer throw of the physical derailleur, the guides are longer, so it may take slightly longer to shift. I keep the shifting on my bikes pretty tight, and have pretty crisp shifting. GF has Soras on her bike, and I can still get it shifting pretty nicely. If you have everything adjusted properly, and cables lubed, etc, it should be fast. Sora is definitely NOT smooth, but it's fairly fast.
I wouldn't say it's a PITA to do this shift. It's something that I do fairly frequently, and I don't think about it, because it's pretty quick. Hey... if it doesn't work for you, it doesn't work for you. And, if you can push 45, then more power to ya.
As for the reason behind the cross-chaining, I think it may be driven by duration more than anything. At least for me it is. I would do 53x23 (my biggest cog) if I was just going to get out of the saddle and power over a quick hill. Or if I just needed a break for a minute, and was going to go back up to 53x19 or 53x17 fairly quickly.
I believe that "Swim, Bike, Run" (the book) discusses proper shifting technique and the pros/cons of cross-chaining, and when it is a good/bad idea...
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zanzabar88 posted 19 weeks ago.
Yeah, good point about the Sora shifting. I rode Sora last year, Ultegra/105 this year. Probably why I never got used to doing the multiple shifts. 2-3 seconds sounds about right, but when I'm "in the moment" on a bike course in a race I don't want to pause for that long - or to have to concentrate on gearing - or look down at my gears, etc.
Southern Michigan is about as flat as it gets, so I really have no need for a small front ring.
Do any of you guys ride crits? Wouldn't this setup be infinitely more useful for that type of ride, where quick and frequent shifting is needed?
I'm just confused as to why noone rides this gear combo. Or maybe other crankset combos like 52/42 are more common than I thought?
I wanna start placing in my age group!
[rant] Why do so many people ride on the big ring exclusively? I see it in triathlons constantly, on every hill half of the riders are pushing a 53/21 ratio or some such thing. That's quite an extreme angle for the chain. I'm surprised I don't see more breakdowns. There's an easy solution: shift to a lower front ring!!!
[/rant]
Anyway, I built myself a new bike this year and put on a 53/39 double crank (used to have a triple setup - 53/42/35 or something to that effect). Then I learned why so many people ride that big ring. Shifting from 53 to 39 is like a 36% difference! It sucks trying to find a reasonable gear in the big front ring when you hit the hills. If you shift to the small ring up front, you'll have to upshift like three gears on the rear to make for a reasonable change in resistance.
My ultimate solution: swap out the 39 for a 45 on the front! Beautiful 18% difference, now I can shift front or rear for a very reasonable change in resistance. And for the very tame Michigan hills I can push a 45/27 combo up just about anything. Ahhhh.
I wanna start placing in my age group!