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What to do when you're in the middle of Synapse frame sizes?

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What to do when you're in the middle of Synapse frame sizes?

Old 07-16-18, 09:26 PM
  #26  
zze86
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Originally Posted by Tony_G View Post
Oddly enough, I am actually worried about the 48 having shorter cranks. I have 170's on my Roam and they are fine for me. I ride up a lot of hills, and I am concerned about shorter cranks providing less leverage on the steep hills. I'll already be dropping the third chain ring that I am accustomed to. I don't know why, but Cannondale does not list crank length in their specs.
I live on the edge of three watersheds, so any which way I go I have to climb eventually so I also understand this concern. While it's true you lose leverage with shorter cranks, this can often be adjusted for through gearing. Since a change in crank length would necessitate a new crank, you could specify a sub-compact up front and/or go to a wider cog. With a 30x36 combo (~24gear inches), you should be able to spin through most anything, although the spinning instead of mashing DOES take getting used to (both physically and mentally).
​​​​
You could go with the 51cm and shorten the stem but a lot of WSD frames specify an already short 60mm stem. ~35mm is the practical limit so you should check the stem length on that as well. Geometry also says raising the stack on the 51cm could also help bring the reach in closer.

Another alternative is to raise the stack height on the 49cm frame, either through keeping the steerer tube longer with more spacers underneath the stem (there are practical limits to this) and or flipping the stem so it points up. Again, the idea is to open up that hip angle.

Your money so your call. Going to shorter cranks necessitated I change my mentality and gearing around but riding is so much more comfortable now. I can actually go and stay in the drops (which I imagine is not all that comfortable for you currently).

edit: one other point. I ride a 17.5 MTBs with 170mm cranks as well. This is considered a medium size bike and conventionally out of my size. It works because, the longer top tube of the MTB geometry keeps my longer torso happy. The short stem keeps the reach within my comfort range. The taller stack height opens up the hip angle more so my legs are happy. I'm in a more upright position than most but it works for me.

Last edited by zze86; 07-16-18 at 09:38 PM.
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Old 07-16-18, 09:45 PM
  #27  
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Buy the other one
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Old 07-16-18, 10:16 PM
  #28  
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If you end up with a Synapse that is too small you will have to supplement your diet with Glutamic acid, Acetylcholine and Serotonin.

There's just no good reason to have small Synapses!
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Old 07-16-18, 10:35 PM
  #29  
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The small one sounds too cramped and it's lot harder to make a small bike bigger than the bigger bike and simply shorten the stem at bit if you feel too stretched out.
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Old 07-16-18, 10:40 PM
  #30  
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At your size in other bikes it probably should be more like a 51 or something bigger so, the Synapse must already be sort of on the big size for it's size if a 48 even seem possible. You are, however, more stretched out on a road bike than on a flat bar upright bike.
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Old 07-17-18, 10:06 AM
  #31  
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Originally Posted by McBTC View Post
The small one sounds too cramped and it's lot harder to make a small bike bigger than the bigger bike and simply shorten the stem at bit if you feel too stretched out.
Really, I've always felt it was easier the other way around. If I'm between sizes I would prefer to size down, can't stand a bike that is too large. Smaller is easier to toss around and you get to show more seat post and run longer stems which looks more pro
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Old 07-17-18, 10:40 AM
  #32  
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Originally Posted by Tony_G View Post
That front hub think is new to me. Also, I had to google KOP. Interesting concept.
Don't buy a bike to get the hub hidden. That is the sign often of a good bike fit, but many good fitting bikes with the proper position and stem for you will not pass this test. Consider: ideally you want your seat and bars the perfect distances from the bottom bracket to best position you for your body's best comfort and efficiency, Say you achieve this exact position on two different bikes. But one bike has a shorter "front end" (the distance from the bottom bracket to the front hub). This means only one of these bikes can pass the hidden front hub test with the stem that gives you your best position. But the ultimate bike for you will have a front center (combined the chainstay length) that best locates the wheels under your weight and therefore handle and corner the best, These criteria are not very closely related to the stem you want for the best fit for your arms and riding position.

My criteria are 1) that the fit I need is achievable (preferably with reasonable, non-custom or super expensive stems and seatpost - I am an unusual fit challenge) and 2) rides like and does what I want.

Ben
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Old 07-17-18, 11:29 AM
  #33  
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Originally Posted by Tony_G View Post
Sorry for the long post. But if my problem were simple, I could easily make a decision without outside input.

I seem to be in the middle between frame size 48 and 51 on a Cannondale Synapse alloy (2018 Cannondale Synapse AL Disc 105 SE). I plan to order the bike today or tomorrow (neither size of that model is in stock at the LBS), I only need to decide the size.

I've already test ridden a 48 and a 51 Synapse. Only to find later out that both bikes were womenss frames! More later on that.

I am 5'5" (165 cm) with 29" inseam, probably slightly shorter than average arms and legs (even for my modest height). A self measurement (may not be accurate) of my arms, from top of shoulder to wrist, is 21.5". My weight is 160. I have the kind of body and metabolism that gains both muscle and fat easily, not the skinny type that that canít get fat or gain much muscle.

My normal rides (not the test ride) are fairly long at a minimum of 50 miles, four or five times per week. 55 and 62 mile rides are common, and I plan to work up to occasional centuries (Iíve only ever done one century, and it was on my trusty Roam hybrid).

The 48 Synapse I test rode had a shorter arm reach that felt welcome compared to the 51. But my legs felt a bit cramped on the 48. I even rode the 48 twice, the second time to see if my elbows would hit my knees when on the drops. They didnít, but it was close, and I would describe the feeling in the drops as cramped (not a literal muscle cramp).

The 51 I rode felt fine on my legs, but I felt a little stretched out on my arms. But, my other bike is a flat bar hybrid that I have put 7,000 miles on in 13 months. Before this test ride, Iíve never rode a road bike. So maybe it is normal to feel stretched when the first time Iím in a road position?

The 51 was an alloy Synapse frame that, after the ride, I noticed the tag said "ladies". The 48 was a carbon frame Synapse 105 with rim brakes (that carbon rode beautifully!), that I almost bought. It was bright yellow, and when I asked, he told me it was a 2017 model.

When I got home I googled the model and year, and was surprised to find no matches for the color. Then I did an image only search and saw that the bright yellow 2017 Synapse 105 rim brake was the womenís model. The only tag on it when I rode it was the bar code and the price.

Now Iím thinking that the test ride results are not really fully representative as they were apparently both womenís frames.

I've Googled for Cannondale size charts, and apparently they don't publish them. Unofficial charts for Cannondale road bikes put me on a 50 cm frame, going by height. I'm not sure why the Synapse line frame sizes don't match the rest of the road bikes, with there being no 50 cm Synapse.

Maybe both sizes would be okay for me, but I dread the thought of making a $1,500 mistake.

Anyone that came up with advice from the above mess is a lot smarter than me. It would be very welcome to hear from anyone that owns a recent year Synapse, especially a 48 or 51 frame, and your experience with the fit to your height. But any advice would be appreciated.
Just another 2 cents here.

My fitter said according to him, it is far easier to fit someone on a bike that is a little to large than to fit someone on a frame that is slightly to small. So, for his money and his fits, it is easier to fit down than fit up.

I would opt for the 51 if it were me but it is really easy to spend other peoples money.

john
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Old 07-17-18, 12:02 PM
  #34  
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Originally Posted by 79pmooney View Post
Don't buy a bike to get the hub hidden. That is the sign often of a good bike fit, but many good fitting bikes with the proper position and stem for you will not pass this test. Consider: ideally you want your seat and bars the perfect distances from the bottom bracket to best position you for your body's best comfort and efficiency, Say you achieve this exact position on two different bikes. But one bike has a shorter "front end" (the distance from the bottom bracket to the front hub). This means only one of these bikes can pass the hidden front hub test with the stem that gives you your best position. But the ultimate bike for you will have a front center (combined the chainstay length) that best locates the wheels under your weight and therefore handle and corner the best, These criteria are not very closely related to the stem you want for the best fit for your arms and riding position.

My criteria are 1) that the fit I need is achievable (preferably with reasonable, non-custom or super expensive stems and seatpost - I am an unusual fit challenge) and 2) rides like and does what I want.

Ben
I think what it comes down to is a comfortable bike that is not causing damage to your musculoskeletal system. All the rest is the method, fluff, and buzz words.
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Old 07-17-18, 12:04 PM
  #35  
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Thanks to all who helped. I ordered the 51 cm, and it should be in my grubby paws later this week.
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Old 07-17-18, 10:42 PM
  #36  
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I usually ride a 56cm. When I got my Culprit, they only came in 55 and 58. I didn't like the 58 so I ended up on the 55, with a slightly longer stem. I have 1" pedal extenders due to knee issues (Kneesavers). I'm very happy with the fit. I still have 4 other 56cm bikes in my collection, and they all fit about the same now. Luckily I got the Culprit directly from the builder, not sure if a local shop will mix and match components for fit, but they should.
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Old 07-17-18, 11:00 PM
  #37  
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Originally Posted by Tony_G View Post
Thanks to all who helped. I ordered the 51 cm, and it should be in my grubby paws later this week.
Let us know how it goes!
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Old 07-18-18, 01:29 AM
  #38  
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By the way, keep in mind that if you do change the stem length, it will affect the steering of the bike. A short stem is more "twitchy" and a long stem means that you have to move the handlebars more for a given turn.
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Old 07-18-18, 06:15 PM
  #39  
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Originally Posted by zze86 View Post
Let us know how it goes!
Will do! And they are already forecasting thunderstorms for the weekend. Oh well, it can't rain forever.
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Old 07-18-18, 06:30 PM
  #40  
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Originally Posted by toast3d View Post
By the way, keep in mind that if you do change the stem length, it will affect the steering of the bike. A short stem is more "twitchy" and a long stem means that you have to move the handlebars more for a given turn.
Thanks for that. It was already apparent on the test ride that the Synapse was very twitchy compared to my Roam. The Roam has wide flat bars and a 10 cm longer wheelbase.

I don't plan on buying any new parts for the new Synapse. With the Roam, when I first got it, due to hand and wrist aches I was browsing stem spacers and shorter stems. But after a few months, it became perfectly comfortable with no new parts. Maybe I got used to it, or maybe my core strength improved. I'll do the same with the Synapse, giving myself a few months to settle in before resorting to new parts.
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Old 07-21-18, 08:13 PM
  #41  
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Originally Posted by zze86 View Post
Let us know how it goes!
My Synapse arrived two days ago (Thursday the 19th). I took it for a 34 mile spin on Thursday afternoon, after putting 38 miles on my Roam that morning. Today I put 52 miles on the Synapse (I get the feeling that my Roam might be getting a vacation for a few weeks ) and I would have done a metric century but rain was moving in.

I am really liking it. Only defect so far is that both wheel reflectors came loose, the rear one fell off and got caught in between the spokes and the frame. It snapped the reflector, and chipped the paint on the frame, but no broken or bent spokes. After that, I removed the front reflector. This happened with 3 miles on the bike.

Odd that my $700 Giant has 7,000+ miles on it, including some off road, no trouble with the reflectors but premium brand Cannondale can't properly attach a reflector to wheels.

Anyway, on to the good. The 51 cm frame fits fine. I’m glad I didn’t get the 48. The bike is quick and noticeably faster than my Roam. The bike weighed in at 21.8 pounds with the pedals attached, but no other accessories attached.

After 7,000 miles on flat bars, the reach to the brake levers on the Synapse feels very awkward. But I am already beginning to get comfortable with it. Speaking of comfort, I instantly liked the varied hand positions available with the drop bars.

There were 24 MPH wind gusts today, and I was impressed by how much getting down on the low bars helped in the headwinds.

The stock seat is surprisingly decent. But I like the $80 WTB Pro that I bought for my Roam better, so I swapped them out. That saved 115 grams (steel vs chrome moly rails), and the WTB branded seat nicely matches the WTB rims and tires that came on the Synapse.

Photos attached, assuming that they will upload.

20180719_162913 shows the bike with the stock seat.
20180721_145309 and 20180721_145500 shows the bike with the WTB seat.

I'm not a big fan of the color, but my Roam is essentially the same color so I am used to it. The Roam is Charcoal and the Synapse is Anthracite (and coincidentally, anthracite is a kind of coal). I'm not sure how I feel about the very low contrast branding on the Synapse, "Cannondale" and "Synapse" are all but invisible. Maybe it is meant as a classy understatement, or maybe Cannondale wants to hide away their non carbon frame Synapse models.


Stock seat.


WTB seat.


Bag is 90% empty. Blinker light on front for safety. Oversize water bottle is kept half empty for trail laps 12 to 25 miles, refilled when back at my car.

Last edited by Tony_G; 07-21-18 at 08:15 PM. Reason: photo placement
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Old 07-21-18, 09:58 PM
  #42  
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Looking at how your bike is setup I can see why the bigger one feels more comfortable for your legs. Its definitely in a more upright position, opening up that hip angle. Also looks like the stem is standard length so should be enough room for you to play with the reach.

Glad you are liking it!
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Old 07-21-18, 10:03 PM
  #43  
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IMO its a super sharp bike! It really makes me want to forgo my desire for thru axle and just buy the CaadX SE in same color.

On the saddle, I thought I liked the Fabric. but.... the more I rode it, the worse it was (for me). So now I randomly browse the internet and buy low priced Ritchie Contrail WCS saddles if I find them for a good price. Life sucks when your favorite saddle is discontinued.

btw nice touch on the WTB saddle, I had a super cheap cheesy one and hated it, I have test ridden bikes with better WTB saddles and I liked them, but I have no real miles on them.
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Old 07-21-18, 10:08 PM
  #44  
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Originally Posted by zze86 View Post
Looking at how your bike is setup I can see why the bigger one feels more comfortable for your legs. Its definitely in a more upright position, opening up that hip angle. Also looks like the stem is standard length so should be enough room for you to play with the reach.

Glad you are liking it!
he definitely has lots of wiggle room in the stem department. from flipping it - lowering it - or shorter - or even a 35 degree stem. and stems are relatively inexpensive. buy a used one, and sell the used one for the same price.
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Old 07-21-18, 11:53 PM
  #45  
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I'm surprised at how high those handlebars are. I'll tell you a secret. I wouldn't change it. That's how I like it. Unless you're racing or unless it's causing discomfort, you don't really need to change anything. You should stick with what you're comfortable with, not what other people tell you is the right way.
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Old 07-22-18, 09:12 AM
  #46  
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700x30c tires... sweet.
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Old 07-22-18, 01:24 PM
  #47  
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Normally I say go with the smaller frame. But at 5í6Ē - a 51 should fit you.

Edit: finished reading the thread and see that you did. Good choice.
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Old 07-22-18, 05:34 PM
  #48  
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I use the Cyrille Guimard/Greg LeMond frame size formula. That will get me in the ballpark. You can ride a range of frame sizes. They are....Race, French and Eddie fit. From there you can modify things like stem size as others have suggested. My optimum frame size is 54-55. I have a 32.5" inseam. My Guru is what is called a "square" frame....55 seat tube and 55 reach. It is perfect for me. My Masi is a 58 that I have modified and it fits well. The difference in ride characteristics is sort of like a BMW 3 series and a Boxster. I just wish my bikes had the motor of either.
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