General Cycling Discussion - Road Bike size dilemma

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kenyan_boy
07-06-07, 07:54 AM
Hi. Didn't know where to post this but would like your opinions & suggestions.
I got sized at a LBS and was told I need a 58 cm with saddle height of 95 cm. However, a co-woker loaned me his son's Specialized Allez Triple, which I measured to be a size 52. The specs of the sizes are at
http://www.specialized.com/bc/SBCGeometryPopup.jsp?a=b&minisite=10029&spid=21893&language=US
I have a few questions:
1. Does a 58cm mean a size 58 (that is does size mean cm?)
2. When the guy in LBS told me 58cm, does that mean top tube length?
I did a 10 mile ride on Independence Day on the loaner bike and did not feel tired in the shoulders nor was my rear end too sore. Some slight soreness I attribute to not having rode a road bike for so long and to getting adjusted to the seat. I cycled in regular gym shorts for about 45 minutes and this was in an area with many pedestrians, joggers, skaters and other cyclists.
Should I stick with this size 52 bike which I am very comfortable with and will cost me $350 OR should I go with a 58 cm bike from the LBS which was a rental bike for about $690? The sole purpose of this bike will be cycling on weekends for about 20-30 miles.
Thanks in advance for your replies.
Can you rent the 58cm bike to try out for a weekend, doing what you're planning to do? If it's a former rental, see if you can strike a bargin with the owner: you pay what it would normally cost for a weekend of usage, and if you decide to buy it, that that money goes towards the purchase price. I can't see why they wouldn't mind renting it out one last time to a potential buyer.
brianmcg123
07-06-07, 10:17 AM
Hi. Didn't know where to post this but would like your opinions & suggestions.
I got sized at a LBS and was told I need a 58 cm with saddle height of 95 cm. However, a co-woker loaned me his son's Specialized Allez Triple, which I measured to be a size 52. The specs of the sizes are at
http://www.specialized.com/bc/SBCGeometryPopup.jsp?a=b&minisite=10029&spid=21893&language=US
I have a few questions:
1. Does a 58cm mean a size 58 (that is does size mean cm?) Yes
2. When the guy in LBS told me 58cm, does that mean top tube length?No, genearlly bikes are measured by their seat tube length, or the virtual seat tube length as in a compact frame design such as the Allez
I did a 10 mile ride on Independence Day on the loaner bike and did not feel tired in the shoulders nor was my rear end too sore. Some slight soreness I attribute to not having rode a road bike for so long and to getting adjusted to the seat. I cycled in regular gym shorts for about 45 minutes and this was in an area with many pedestrians, joggers, skaters and other cyclists.
Should I stick with this size 52 NO bike which I am very comfortable with and will cost me $350 OR should I go with a 58 cm bike from the LBS which was a rental bike for about $690? The sole purpose of this bike will be cycling on weekends for about 20-30 miles.
Thanks in advance for your replies.
Needing a 95cm saddle height I can not see how you are at all comfortable on a 52cm bike. By that saddle heigth that would put you on some bikes in the 65+ range. I think there has been a mistake somwhere. Maybe the LBS said 75cm which would put you on either a 58 or 60. There would have to be some serious rise on that stem in order to not have a lot of saddle to bar drop.
A 52 cm bike (measured from BB to top of the effective top tube) is a very small bike. Probably the smallest offered. A 58 cm bike is above average size. I suspect you are making an error in measuring the size of the supposed 52 cm bike. If you are measuring from the BB to where the top tube connects to the down tube on a frame with a sloping top tube (almost all frames today), then you are likely undersizing the frame.
A 58 cm bike would be typically used by a person around 5'10" tall. How do you compare to this?
kenyan_boy
07-06-07, 11:22 AM
A 52 cm bike (measured from BB to top of the effective top tube) is a very small bike. Probably the smallest offered. A 58 cm bike is above average size. I suspect you are making an error in measuring the size of the supposed 52 cm bike. If you are measuring from the BB to where the top tube connects to the down tube on a frame with a sloping top tube (almost all frames today), then you are likely undersizing the frame.
A 58 cm bike would be typically used by a person around 5'10" tall. How do you compare to this?
I measured the geometries on the bike and compared them to the Allez chart from the manufacturer. Those measurements matched up numbers to a size 52. My co-worker later found the paperwork and said it was a 52 cm for his son who was about 5' 4" or so.
I am 5' 10" tall. The LBS employee took my in-seam measurement and my height, and used some slide-rule type thingy and wrote down for me a 58cm, 95cm SH. For my wife who is 5' 4", he wrote 52cm, 83 SH.
I am going to go by another bike store when I get a chance and see what bike they measure me to fit. I'm also going to try rent a 58 cm bike, or see if I can ride it in the bike shop's parking lot for a few minutes.
Retro Grouch
07-06-07, 11:45 AM
Should I stick with this size 52 bike which I am very comfortable with and will cost me $350 OR should I go with a 58 cm bike from the LBS which was a rental bike for about $690?
I don't know but there's a world of difference between a 52cm bike and a 58cm bike. I'd think that at least one of those two sizes would have to be way wrong for you.
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