My wife & I recently bought new Trek Madone 4 series bikes, both with triple set-ups.
I'm still torn in the triple vs. compact debate, because I like the close gear ratios on the triple, and I can spend most of the day on the 39t middle ring, with almost no FD shifting, and a near-perfect chain line. She likes the wide range of gearing options. On the other hand, the compact is simpler, lighter and just plain looks better.
But now I'm a little concerned about Q-factor, especially with my wife. I have had no issues with pain (now that my fit has been tweaked), but my wife has. When she first started riding, she ha lower back pain & spasms, but a tweak to the fitting & a lift on her cleat one of her cycling shoes (She has a 3/4" discrepancy in one leg, and wears orthtics in her running shoes which are different thicknesses) which got rid of the back pain. After a couple more of weeks of rides, she developed hip bursitis (which she has had before) and had to stop riding. Her fit was checked again, but looked good. She even tried a different size bike, but the one she has fits really good. She is petite, at ~5'3" & 115 lbs. She does have relatively long legs, so has a WSD 52 cm (the 50 cm had her leaning over too much, especially on the drops).

Does a wide Q-factor just affect the knees?
Could the wider Q-factor have contributed to the hip bursitis?
Should I be concerned (I'm 5'7", ~172 lbs) about Q-factor?

Would changing to compacts be of any benefit?

Thanks,

Peter

I suggest finding a bike fitter who is also a physical therapist. IMO, it is too complex an issue to be answered by a simple forum discussion. Q factor affects riders in different ways.

The fitter that we have been using has an advanced degree in exercise physiology, body mechanics etc.
I'm just curious in a general way if Q-factor can adversely affect someone my or her size, ans what body part it affects.

Sounds hot. Pics?

Peter, Triple BBs are around 5-10 mm wider than a double per side. Q factor is also effected by the crankarm shape, ie. straight or curved inwards. I don't notice the difference between my triple and doubles, perhaps if I were looking for it by riding each back-to-back I would. Could the Q factor be a contributing factor to her hip bursitis? Possibly, as could just simply riding a bicycle. I think the best idea is to consult a doctor, preferably a sports physican.

Brad

:facepalm:

Even if you were joking, it's not funny.

I can only speak for my experience with Campy. I have had both a standard double and a triple on my bike. I called Campy twice and spoke to two different people and they both told me that all Campy cranks have the same Q-factor. I guess they angle the cranks inward on triples.

I do not have problems with my triple but am planning on replacing it in the next year with a compact. Weight reduction is great but it isn't the reason that I will be going to a compact. I can put a 12-29 Campy compact on my bike and get the same range that I am getting with a triple. The jumps might be more on the compact from the 29 to the 26 but you don't notice the jumps as much on gears of that size. Where you notice the jumps is at the other end of the cassette and they are one tooth jumps on both the triple and the compact. So, I don't really see a down side to a compact.

The reason that I want a compact is that the gearing works better for me. A 50X29 is the same as a 42X26 and a 50X12 is almost the same as a 53X13 so I have eliminated one chain ring. Then, a 34X29 is the same as a 30X26. So, I haven't lost anything. I will probably go with a 12X27 instead of a 12X29 because I don't need the extra climbing gears.

Campy cranks do not all have the same tread width. Triples are nearly always 8-10mm wider in tread width because you can't add an extra chainring without adding tread width.

FWIW, I've went back and forth from doubles to triples and back to a double (compact) and never had any problems with knee pain or any other physical discomfort. There just is no firm answer as to whether more tread width will be a problem. Some people need more tread width and it's acutally a blessing to have a wider width triple. That's why things like pedal extenders are sold - some people benefit from more tread width.

What I find amaxing is so many people who complain about tread width, but I see a great many riders with their cleats set such that there is a 10mm gap between their shoe and the crankarm. They've added 20mm in tread width with cleat placement. If tread width is thought to be a problem, place the shoes as close as possible to the crankarm.

My bike has a 105 5700 (11-28) & her's has an Ultegra 6600 (12-27).

I don't know the difference in width between these cranks in triple vs. double.
I can't find anything on Shimano's website.

I have two Shimano Triples (Ultegra 6603 & 105 5603) and two Shimano Doubles (also Ultegra & 105).

The Triples have a substantially wider tread than the doubles. My triples are equally wide, I would assume the 5703 is the same Q factor as the Ultegra 6603

You may want to see into uneven crank arm lenghts. Use a longer one for the leg that needs the orthotic.

I have knee pain with a Campy triple. I don't have the pain with a compact double. FWIW, I'm 5'7" tall.

"I can spend most of the day on the 39t middle ring, with almost no FD shifting"

and

"On the other hand, the compact is simpler"

You can only pick one of those, Peter2.

"I like the close gear ratios on the triple"

Is this true, though? I've seen it stated many times on BF.

Look at the Sheldon Brown gear calculator and plug in the numbers. The percentage of the jumps between cogs on the cassette is exactly the same, with either a standard 52x39x30 or a compact 50x34.

The compact acts to, well, compact the range of gearing compared to a triple, by loping off the top and bottom end.

Unfortunately, she may need to perform a regular maintenance regime before and after long rides; anti-inflammatory med before the ride, ice over the affected area afterward 20 minutes on/20 minutes off/repeat, heat before bed, and heat on the off day.

Measure the Q to see if there is a gross disparity between sides. Most of us tend to favor one side of the saddle in any case, but she may be compensating for a mechanical unevenness. I have an older model crank and bottom bracket with a difference between sides that I reduced by chilling the spindle (placed the bike outside in the cold), heating the wide side arm, applying thin lube film to the taper, and quickly mounting the hot arm. You can't do that specifically with yours, it was just sharing. I also have pedals with adjustable Q & tilt (Look CW-7). I'm aware of others who have no problem with uneven cranks, but I'm experiencing a change in comfort from bringing pedal Q to near even from frame center, plus increasing overall Q from narrow widths I preferred 12 years ago. In the past the saddle nose angled off center to keep one thigh from rubbing, now it's straight. BTW, I'm more conscious of sitting centered which may be more important than manipulating Q.

Speaking of saddles, their shape and placement is probably more affecting than Q.

There are a lot of factors that can cause knee pains.
for hip pain, it's usually the saddle being too high.


Things that can cause knee pain
imbalanced leg muscles
q-factor too wide
crank length too long
saddle height too low
low cadence
bad cleat placement
uneven feet soles, correctable by angled cleat wedges.

As far as Q-factor goes, for shimano triple it is about 155mm, and for double it is about 142mm.

have your wife cycle on regular platforms with the running shoes and special inserts. See if that helps.

For me, I only get knee pain if the saddle is too low and the Q-factor is too wide with clipless. On platforms, I can place my feet in closer to the crank, which makes Q-factor, effectively, narrower.

If the same range of gearing is provided with a triple, the cassette can have closer cog spacing than a compact. That should be obvious. For example, if a 53/39/30 triple has the very closest spaced 12-23 cassette (12-13-14-15-16-17-18-19-21-23), a 50/34 compact would need an 11-26 to cover the same range. The 11-26 would be 11-12-13-14-15-17-19-21-23-26. The triple's cassette has seven 1-tooth shifts, compared to four with the compact's cassette, plus the 11-26 has a larger jump at the 23-26. The compact does have a tiny bit of extra top gear, but it's as close as you can get without resorting to a 49T big ring.

If you put a 50/34 in place of a 53/39 with the same cassette, you lose 6% in top gear but gain about 13% at the low end, for an overall increase in range.

DaveSS wrote:

"If the same range of gearing is provided with a triple, the cassette can have closer cog spacing than a compact. That should be obvious."

OK, that's obvious.

It should also be obvious that a compact doesn't have to have the same range as a triple. In fact, the reason for the existence of a compact is that it compacts, at both ends, the range of gears compared to a triple. So comparing a compact and a triple with different cassettes is like mixing apples and oranges.

"The compact does have a tiny bit of extra top gear"

Again, apples and oranges. This assumes cassettes are different on the triple and the compact. It's just as easy to assume the cassettes are the same.


"The triple's cassette has seven 1-tooth shifts, compared to four with the compact's cassette"

Which is why I questioned Peter2's claim that a compact is "simpler" than a triple. It's not. The hoary claim that shifting on a double is faster or crisper than on a triple is wrong, because of all the extra shifting required when switching from one chainring to another on a compact.

a triple is simple as long as you don't use indexed shifters.
You wouldn't believe the ease of shifting and trimming a triple on barcons or campy ultra shift levers.

BTW, I've setup one of those crappy truvativ touro GXP triples that everyone hates, so that it shifts buttery smooth, so I'll chalk bad experiences up to mechanics who don't know how to setup a triple.

icyclist...

I made a sincere effort to compare apples to apples - drivetrains with the same range. Having 2% more gear range does not make my comparison "apples and oranges" and it would be no different with a 49/34 chainring setup which is a nearly perfect comparison. You pick the conditions/limitations and I can make another appropriate comparison.

Some people think that dealing with 3 chainrings is more complicated, but it depends on how much of a gear-head the rider is. I used a triple during four seasons of Colorado mountian riding and thought it was great. There is no complication. I never used the small chainring until I got into the mountain climbs. I could ride for 10 miles in the little ring and never shift out of it unless I wanted to. Some people just don't understand that after every chainring shift, you also shift 2-3 cogs to produce the next higher of lower gear. It matters not, if you have two or three chainrings.

That said, I switched to a compact for the last several seasons. I chose to have the 50/11 top gear, but I have less low end with a 34/25 (11 speed). The 34/25 is only like a 30/22, but it gets me through all but the toughest routes. I've chosen to pedal standing a bit more.

I have a triple and want to move to a compact sometime in 2011. I will have a different cassette on the compact than I would on the triple and this will give me approximately the same gear range.

On my triple I have a 53/42/30 with a 13-26 cassette. The compact could have a 50/34 with a 12-29 cassette and have the same range at the top and bottom end or at least really close. The 12-29 is an 11 speed so the jumps between cogs are not too bad. However, I will probably go with a 12-27.

Carbon Unit...

You've made the proper comparison. You won't even notice the 23-26-29 jumps - they're much more tolerable at the low end, when the going gets tough. The top and low end gears will be nearly identical.

Putting it the way you did, we're in basic agreement.

Carbon Unit wrote:

"I have a triple and want to move to a compact sometime in 2011. I will have a different cassette on the compact than I would on the triple and this will give me approximately the same gear range....I will probably go with a 12-27."

So you're giving up a little at the low end, a little less than a 3 inch gear difference, enough that you'll have to work a little harder on the hills. And you'll gain a little at the high end. And you'll lose some gears that you would have with the triple. So why are you making the switch, to save some weight?.

The OP was extolling both the close-set ratio of his gears and the capability of almost never having to shift out of the middle chainring. But those are mutually exclusive concepts. If the cogs are close in number – e.g. 12-23 – then there are no easy gears for climbing in the middle chainring of a triple. And if the cogs aren't that close, then the ratio isn't that tight.

I almost never use the smallest chain ring on my triple. Maybe once a year I might use it. I use the 42 chain ring most of the time but will use the 53 on flats and declines. If I go to a compact, I can just use the 50 chain ring 98% of the time. I will rarely ever need to use the 34, only on really nasty hills. On a Campy 11 speed, the cogs are closer together so it shifts better. It also weighs less but that isn't what is motivating me to go to a compact.


There is probably a part of me that wants something that is new and cool too. My drive train is a mix of 2001, 2003 and 2006 stuff. It all works but a new compact group would be like having a new bike to me.

I only use the granny ring once. And that was on a long climb with my little 3yo daughter in the rear seat. This is with my commuter/touring bike 48/38/28. With my roadbike that has a standard 52/39 I climbed the same hill with ease. Unless you have some steep hills or knee problems, a standard double is all you need.

A standard double is plain bad ass on a road bike. Period.