# 56 vs 58 cm 2010 Tramac Pro Sram



## bikeskirun (Sep 1, 2009)

I'm 6' and 155 with a 33.5 inseam and have been riding a 58 Roubaix for a few years. My seat height BB to seat top is 75.5 cm. I guess I have a somewhat longer torso vs leg. My Roubaix has a 120 mm stem and 44 cm wide bars and has always felt too stretched out and wide. I always find myself riding on the tops of the bars rather than the hoods. I'm in the process of replacing with a 110 mm stem and 42 cm bars.

My other bike is a 58 cm Specialized Tricross sport with a 120 mm stem and 42 cm bars. I'm more comfortable on this bike than the Roubaix as it has a shorter top tube.

Now I'm looking to buy a Tarmac Pro with Sram compact. Both a 56 and 58 are available and I've ridden both. At first blush, the 56 felt better since the 58 had a 120 mm stem and 44 cm bar width (felt too stretched out). I'm wondering if the 56 with a ~120 cm stem and 42 cm bars would be better than the 58 cm frame with a ~110 stem and same bars.

I'm planning to do some road races and crits this summer to get super fit for cross season. At times I'd like to slap some clip-on aero bars on for time-trials. Would the larger frame accommodate a better TT position? I do plan to have a comprehensive fit when I buy the bike, but I'd like to know what my trade offs are. Any opinions?

Thanks.


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## steveandbarb1 (Dec 27, 2009)

A good shop should provide you with good fit prior to your purchase, if they don't go somewhere else. I bet a 56 would be more appropriate for you.


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## NealH (May 2, 2004)

Most people can be fit well on two sizes and, I suspect this is the case with you and the 56/58. However, due to the many variables, it would be wise to get a professional fit done. As mentioned above, a good shop will do a good job fitting you. But if you have any doubts, get a professional fit.


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## pdainsworth (Jun 6, 2004)

It seems to me, that the most noticeable difference will be in your saddle to bar drop. The seat height and reach can be made the same, but if you want to be reaching down, in a more aggressive position, then the 56, with its shorter head tube would be a good fit. If, on the other hand, you want a slightly more upright position (which might be nice with the aero bars), the 58 with the slightly shorter stem might be a good fit.


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## mjdwyer23 (Mar 18, 2009)

I'll echo the above posts -- I am 6'1" with a 34" inseam, short torso and long arms. The 56 fits me like a glove. If all else fails, I'e heard great things about the BG fit system.


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## pdainsworth (Jun 6, 2004)

mjdwyer23 said:


> I'll echo the above posts -- I am 6'1" with a 34" inseam, short torso and long arms. The 56 fits me like a glove. If all else fails, I'e heard great things about the BG fit system.


I am 6'1" with a long torso and gorilla like arms. (I'm practically a knuckle-dragger.) The 58 with a 130mm stem does the trick for me. I have a fairly well-developed lunch muscle (ie, gut) and the 56 would have me punching my tummy with my knees when in the drops. Not to mention, I'd have to run a 140 or 150 stem to get comfy.


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## bikeskirun (Sep 1, 2009)

Thanks for all the advice. I think I'll pop for the BG fit as this is my first "really nice" bike.


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## pdainsworth (Jun 6, 2004)

bikeskirun said:


> Thanks for all the advice. I think I'll pop for the BG fit as this is my first "really nice" bike.


Good call. A really god fit can make ALL the difference in the world. Make sure you post some pics and give an update after you get the bike!


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## PJ352 (Dec 5, 2007)

IMO there's consistently solid advice given here. I think the observation made by pdainsworth relating to HT lengths is noteworthy, especially considering the OP is coming from a Roubaix. Depending on his current saddle to bar drop, that might be the tipping point in favor of the 58, but I agree that (at least) a standard fitting and back to back test rides are in order before deciding. With the BG FIT system being the ideal.


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## dave2pvd (Oct 15, 2007)

6'1" here. 32.5 inseam. I ride the 56cm. The 58 is just so freaking long. Plus, unless you have the team geometry frame, the 58 head-tube goes up very high.

I did change the shorty stem that came on mine. Using a 120mm now. I kept the shallow-drop 42 bars. I like them a lot.


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